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Ask the Expert

This page was established by Derek Figurski following inspiration from Prof Michael Goldman, an international guest to our 2003 ASM in Adelaide. The page has steadily built into a resource that I hope will continue to be perused. Chris O'Dea has very kindly accepted the challenge of coordinating the page. Any questions should be e-mailed to (Chris.ODea@health.wa.gov.au) and he will do his level best to come up with an answer for you, or find someone who can do so. The aim of the page is to foster a free sharing of information and experience between members. The success of the page, however, depends on the questions being asked.

  1. Bronchodilator response, can the criteria for a positive response be eased?

  2. Monitoring Patient's lung function after a change of equipment
  3. IOC worksheet for Mannitol provocation for the Beijing Olympics
  4. NHANES III predicted equations and electronic spirometers
  5. Use of the new disposable spacer devices
  6. How do you Managing Oxygen Equipment Inventory?
  7. Canadian Respiratory Therapists and NZ / Aus jobs
  8. An enquiry from Debbie Riley from the institute for Breathing and Sleep at Austin health
  9. Ingrid from the Gold Coast inquired about a pay scale
  10. Daniel Slamka asked the following question:
  11. Bill from Fremantle hospital has been having a few "nosey" patients
  12. Provocation testing requirements for asthma in the lead up to the 2008 Olympics?
  13. Am looking to purchase some of the large volume re-usable/sterilisable spacers.
    Can anyone help with a list of vendors of such spacers?

  14. Selection of the FEF25-75 to report
  15. Withholding times for medication prior to spirometry testing
  16. Systems for the electronic viewing of lung function reports external to the testing laboratory?
  17. Area under the flow-volume curve as a new helpful parameter in spirometry?
  18. Hb and Carboxyhaemoglobin correction in the DLCO test
  19. continous nebulization of a bronchodilator
  20. Our lab is in the process of purchasing a dosimeter. Do you know which companies produce dosimeters? Is there a particular dosimeter you would recommend?
  21. I wondered if anyone had any clinical trial experience using Vitalograph Spirotrac Centralized spirometry system (or other centralised system) and if they had any comments or feedback. We are considering using it for some CF studies.
  22. Is anyone out there using the Sensormedics system for Indirect Calorimetry?
  23. Putting an iv drip and 500 ml NaCl bag in the bodybox during testing, correction for the volume?
  24. What is your opinion about Hb correction in the diffusion test?
  25. Concern about performing diffusion studies on pregnant females?
  26. Experience and methodology about measuring Sniff nasal pressures?
  27. Do you know of any guidelines for choice of spirometer and lab environment specific for testing CF patients with Cepacia?
  28. Urgently need a replacement CO + He Analyser Rack for a Jaeger MasterLab?
  29. How to do Raw measurements so that you can get consistent results every time?
  30. what are other labs using to sterlise their turbines?
  31. Protocols and recommendations for disinfection of re-usable mouthpieces and nose-clips?
  32. Do you know of anyone who is using a KoKO Trek 2 Spirometer on Windows 2000?
  33. Has anyone experience with a motorized Calibration Syringe used as an external calibration device to check the accuracy of any CPX system?
  34. Any good papers looking at resistance of filters and their effect on measurement of lung function?
  35. Does the Respiratory Function Unit really need to have a fully stocked Emergency Trolley
  36. Looking for a validated jet nebulizer
  37. Paper on priming spacers with soapy water
  38. Device for measuring maximum inspiratory and expiratory mouth pressures
  39. Re: sourcing of ultrasonic nebulizers
  40. I am interested to find out what products other Respiratory Units use to clean and disinfect their equipment. I am particularly interested in the vane type flow sensors.
  41. Severity scales based on functional status?
  42. Does anyone do bronchial provocation challenges using such things as wood dust or flour? If so do you have a patient informed consent form that you are happy to share?
  43. Could you please advise a source of ultrasonic nebulisers capable of delivering 15 grams of salt solution as per the Sandra Anderson protocol for hypertonic saline challenge. My understanding is that Omron has just discontinued such a model.
    In addition do you know of any other protocol for hypertonic saline challenges that does not require an ultrasonic nebuliser.
  44. We have been having some difficulties sourcing histamine for challenge testing and getting our hospital pharmacy to make it up. I'm looking into alternatives and would like to know if you've come across any info regarding the Mannitol challenge test
  45. I was wondering if anyone out there is using ulna measurements to estimate height for non-standing patients? [Update]
  46. What is the extent of potential bronchoconstriction induced by performing the forced expiratory meanoeuvre?
  47. Where and how can I get cheap oesophageal balloons or the components for making my own?
  48. How do laboratories monitor their MDI usage?
  49. Where can I get Wright Nebulisers for Histamine / Methacholine Testing?
  50. Where can I get my calibration syringe validated? UPDATED 11-Sep-2008
  51. Can you forward me a list of details of suppliers of skin prick test allergens?
  52. How may puffs of ventolin?
  53. Employment opportunities in Australia and New Zealand for people from the Northern Hemisphere?
  54. Do you know who supplies Koko Spirometers in Australia?
  55. Re: Strengthening Lung Capacity/emphysema
    I refer to the above and would appreciate guidance on tackling emphysema and exercises that could be carried out to strengthen lungs.

Bronchodilator response, can the criteria for a positive response be eased?

A question has been posed by Jane Williams from the Northern Respiratory Group, in Bundoora, VIC

I had a patient recently who had a 440ml/10% improvement in FEV1 and according to the guidelines; this does not meet the criteria for a significant change consistent with asthma. My question is that 440ml is still a huge improvement - could people with larger capacities have a reduction in the criteria from 12% to say 10%?

Thanks :-)


Thanks To David P. Johns (Menzies Research Institute University of Tasmania) and Jeff Pretto (John Hunter Hospital) put their collect knowledge and came up with the following response for Jane:

We would agree that strict application of the ATS/ERS criteria (>= 200ml and >= 12% post-BD improvement in FEV1 and/or FVC) to this one-off result would lead to the conclusion that 'spirometrically' there is a negative or insignificant BD response. Whilst this does appear to be a harsh interpretation given the magnitude of the change in FEV1, this example highlights the problems inherent in using a fixed cutoff value to define a positive or negative response. The reality is that there is always a 'grey zone' and the level of uncertainty in interpretation always increases at close to these threshold values. From the limited data supplied we suggest that the results should more accurately be interpreted along the following lines:

". whilst the post bronchodilator change in FEV1 does not quite achieve significance on this occasion, there is a suggestion of improvement with bronchodilators. This finding needs to be interpreted in light of clinical findings."

The ATS/ERS criteria are based on spirometry and in the context of BD responsiveness should be regarded as a guide and ideally interpreted together with clinical history. The interpretation of the given example would clearly differ if the subject described wheeze on exercise and cough in cold air for example, as opposed to someone without such symptoms.

Furthermore, although FEV1 is the preferred index for quantifying BD response, the ATS/ERS criteria also applies to FVC so it is important to know whether this improved (no data given) - this may be especially significant in people with airflow obstruction where improvement in FVC and/or symptoms can be due to a reduction in the degree of functional hyperinflation, and also if the FVC improves in the 'absence' of an increase in FET.

As you are no doubt aware expressing BD response and its interpretation using spirometry is a somewhat contentious issue and that the widely accepted ATS/ERS criteria is a consensus view taking into account data from healthy populations and people with lung disease, as well as measurement variability (about 180ml). The minimum 200ml absolute change helps exclude measurement variation and the minimum 12% change is the consensus view based on the available literature. We agree that the 440ml improvement in FEV1 observed in your patient is large enough not to be easily explained by instrument error. However, this equated to only a 10% improvement from baseline which is not much greater than the percent change reported in healthy subjects (typically: mean 3%, 95% percentile of 8 - 10%) who do not have evidence of airflow obstruction.

We agree that your patient came temptingly close to meeting the ATS/ERS criteria for a positive response in terms of spirometry. However, we don't think this is justifies altering the criteria. After all, if the percentage change was decreased from 12% to 10% (as you suggested) then we would encounter the same problem when interpreting, say, a 9% improvement in FEV1 - no matter what criteria is set there will always be a grey area. If the criteria were changed then it would have to be evidence-based and currently the evidence suggests that a minimum change of 12% is reasonable.

We would have liked to have seen more information such as age, height, FVC, FEV1/FVC, FET, predicted values, the pre and post flow-volume curves and some clinical details such as why the patient was referred for testing, clinical symptoms and whether the patient was a current or past smoker? Also, we presume that the pre and post-BD trials met acceptability and repeatability criteria.

In a more general sense, the following may be important when interpreting the clinical significance of the BD response:

  • Was there evidence of airflow limitation pre-BD?
  • If there was, did the airflow limitation improve post-BD?
  • Did the patient take BD prior to testing?
  • Why was the patient referred for lung function testing?
  • Did the pre and post-BD trials meet acceptable and repeatable criteria (ATS/ERS)?
  • Which bronchodilator was used, what dose, how was the dose administered, how long after administration was spirometry repeated?
  • Has the patient been tested previously and is there evidence of session to session variability?
We hope these comments are helpful. Perhaps other members can add further comments


Kevin Gain (Royal Perth) and Chris O'Dea (Christchurch) put together a response to Jane's question with regards to the clinical diagnosis

The diagnosis of Asthma compared to COPD is a clinical diagnosis and not a spirometric diagnosis. Clinically the significant reversibility has been used to aid in the diagnosis of asthma when compared to COPD, however, as we know from the "three circles" model there is numerous overlap in the disease states. The extent of reversibility governs the use of medication and does NOT diagnose asthma. The same is true of histamine or methacholine challenge - a negative result means you are very unlikely to have asthma, but a positive merely means you may have asthma. The positive result means you have hyper reactive airways.

In addition the previous school of thought that a significant reversibility would show a response to Inhaled Corticosteroids, however, this is now known not to be true so the reversibility will not aid in the management that way. The lack of a response to a bronchodilator also does not exclude a diagnosis of asthma, and a positive response does not always exclude COPD. The big thing with the reversibility for the diagnosis is whether the airflow limitation is completely reversible in which case COPD can be excluded.

In cases where the bronchodilator response is unclear a bronchial provocation may be useful in shining some light on the case.

posted: 9 June 2009

Monitoring Patient's lung function after a change of equipment

Clint from the Dust Disease's board asked the very valid question about change of equipment.

I'm looking for any laboratories who've upgraded lung function systems / software and who have found significant differences between their old and new system. I believe a number of laboratories have had issues pertaining to changes in mass-flow sensor technology etc and am curious as to how they make use of previously measured trend data when comparing too data measured with new systems.


Thanks to Josh Stanton the creator of ezyQC who provided the following solution to this common problem

The evaluation of trend data from different systems can be assessed by examining the differences in biological control data between the two systems. Assuming we are using stable normal subjects as biological controls, the average values on both systems should theoretically be the same over a small time period, e.g. 6 months either side of the equipment change. They often aren't so we use the difference in mean biological values from the old system compared to the new system to calculate the percent bias between systems. This bias can be added (subtracted) to patient data from the new system to allow a valid comparison.


Thanks to Graham Hall who passed on his experience with this issue:

We transitioned from the older Sensormedics mass flow sensors to the newer ones about 18-24 months ago. At the time we did a range of paired tests in semi-randomised order in both lab staff and in children with CF who had been admitted. We found that the differences between tests were not stable and varied between not difference and up to 500 mL.
Patients with more severe obstruction had larger differences. It was assumed this related to the prolonged period of time at a lower average flow and hence increasing the potential errors. While I agree with Josh's approach it will be important to ensure the differences in patients are similar to that of healthy stable lab staff. It may well be that you can not simply correct the new data by a set amount.

In the end in our lab we had to add information to our lab reports highlighting that equipment had changed and that we could not discount equipment related differences for that visit.

posted: 18 August 2008

IOC worksheet for Mannitol provocation for the Beijing Olympics

Rob Tagliaferri inquired about a Mannitol worksheet.

I have a copy of the recently released guidelines for testing IOC athletes and note that mannitol is now accepted as a test. Do you know if there is any official worksheet for the mannitol test, as we only have the worksheet for EVH test, and searching the IOC web site is a nightmare! ?

Rob.


Thanks to Sandy Anderson who was one of the committee members for her answer to this question.

"All the provocation tests have a report sheet on IOC website. Laboratories have their own work sheets during testing."

A copy of the guidelines can be found on the members tutorial section of the website www.anzsrs.org.au/memberstutorial.php Beta2 adrenoceptor agonists and the Olympic Games in Beijing

(I have tried to find the worksheet myself and have had no such luck- Chris; likewise - KRG)

posted: 7 June 2008

NHANES III predicted equations and electronic spirometers

Ruth Marten from Pharmaxis asked the following:

Do you know if most electronic spirometers used in the labs have the NHANES III predicted's (Hankinson 1999) programmed on them?


After a bit of a search and a ring around the various members and companies most of the new software for electronic spirometers either has the NHANESIII predicted equations or has the ability for them to be entered into the software.

Chris

posted: 10 May 2008

Use of the new disposable spacer devices

Ruth Martens inquired about the new disposable spacers.

I was wondering if anyone has had any experience with Lite-Aire (Thayer) or e-chamber spacers (Bird). Any comments on their use? We are looking to use one of these for a clinical trial.


Thanks to Graham Hall who recently looked at the medication delivery of the spacer devices for the following answer:

We have our study {which can be found in the tutorial section of the web-site http://www.anzsrs.org.au/memberstutorial.php; Laboratory usage habits and delivered salbutamol dose of spacers available in Australia and New Zealand}} which gives deposition information, but I cannot really comment on their use clinically. As the e chamber has only just been released I would doubt that anyone has tested both.

posted: 10 May 2008

How do you Managing Oxygen Equipment Inventory?

We are interested in having a central store for oxygen equipment -humidifiers, blenders, attachments etc. As we have the problem of equipment getting lost and not set up correctly in wards that are unfamiliar with the equipment.

Can anyone please let me know how they store and dispense equipment?

Lyn Joseph

posted: 14 April 2008

Canadian Respiratory Therapists and NZ / Aus jobs

Dear Derek,
I am a Canadian RRT thinking about coming to work in New Zealand next year. I don't have a Bach. degree in Science so is there any chance of me getting a job without this degree?


Thanks to David Robiony-Rogers for this answer

Hi Heidi
I assume as a registered respiratory therapist you have a baccalaureate degree in Respiratory Therapy - am I correct? If so, this degree will be recognised as equivalent to the science degree and provides you the educational level to work in NZ.

What line of work are you looking for? New Zealand does not have respiratory therapy as a profession or roles that fit under the respiratory therapy umbrella - these roles are carried out by our ICU and cardiac ICU nurses. The exception to this is the Starship Children's Hospital in Auckland. This hospital has previously shown interest in hiring people with a respiratory therapist background - especially those with paediatric/children experience. If you are looking to work in pulmonary function we will be looking to see how much experience you have in PFT and whether or not you have a CPFT/RPFT.

Either way, your knowledge of respiratory means that you are a potentially valuable addition to any pulmonary function laboratory in NZ and we will be more than happy to review your CV.

In order to work in NZ you will require either a valid NZ work permit or a NZ residence visa.

If you have any further questions please do not hesitate in contacting me.

Regards
David

posted: 14 April 2008

An enquiry from Debbie Riley from the institute for Breathing and Sleep at Austin health

Does anyone have any paper for the old P.K. Morgan spirometer?

I would be interested in buying said paper. Many thanks in anticipation.

posted: 9 February 2008

Ingrid from the Gold Coast inquired about a pay scale

I was wondering if there is a National award wage scale for Respiratory Scientists/Trainees according to ANZSRS qualification position statement? We are a private lab on the Gold Coast and have been taking a \"stab in the dark\" for years concerning our wages policy for our lab staff.


As far as I am aware there is no national scale and each state is responsible for setting the aware, it would suggest contacting QLD health or your local Public Respiratory lab.
Chris

posted: 9 February 2008

Daniel Slamka asked the following question:

I am currently a student here in the states and will have my RRT certification in one more year. I would really like to practice in the states and around the world. What would I have to do to practice in Australia & New Zealand?

Thank you and look forward to your response


Daniel the required qualifications vary depending on what you want to do and where you want to work. Most jobs for Respiratory Scientists in Australia and New Zealand require as a minimum a B. Science with a major in physiology. The jobs section on this site provide a useful guide to the sorts of positions available and the required qualifications/experience.

Hope this helps
Cheers,
Chris

posted: 9 February 2008

Bill from Fremantle hospital has been having a few "nosey" patients

I'm looking for a supplier of nose clips of the type that incorporate a spring and rubber pads (for the more challenging nostril) rather that the plastic/foam variety.
Regards,
Bill Smith

posted: 9 February 2008

Derek, Have you been advised of provocation testing requirements for asthma in the lead up to the 2008 Olympics?

I am starting to get a couple of questions about what test to do - but can't find any guidelines apart from the 2004 ones you have on our website.

Pharmaxsis have advised me that they hope the IOC will approve Aridol at their next meeting in January, & the WADA website (wada-ama.org) has information regards their recommendations for provocation testing which includes mannitol.

Just wondering if you have heard of anything else.

Thanks for your help

Glenn Thomas
Senior Pulmonary Scientist
Ashford Lung Function Unit


Thanks to Sandy Anderson who was able to provide the following response:

The official information will be posted at the IOC website first week of February, meanwhile 2006 information stands plus mannitol will be included. My abstract at APSR meeting in December has some further information.

Thanks again to Sandy, and I look forward to finding out more at APSR.

Am looking to purchase some of the large volume re-usable/sterilisable spacers.
Can anyone help with a list of vendors of such spacers?

Many thanks

Tom Parks


Thanks to Graham Hall who was able to provide the following answer:

The new TGA guidelines have prompted a review of spacer practices from many units. In conjunction with Sunalene Devadason from the Aerosol Research laboratory I have conducted a survey of spacer use in Australia and New Zealand and we are also looking at delivered dose of a range of spacers. This information will be presented at the ANZSRS conference in Melbourne.
Spacers can be single use or processed according to local preference and/or conditions with either fulfilling TGA guidelines. The processing of single use items is obviously not appropriate.

I have listed below the spacers available in Australia and NZ that I am aware of (in no particular order), but would note it may not be a complete list. Some of these companies make both single and mutli-use spacers

Volumatic via GSK
Breath-a-tech via Visiomed
Space Chamber via Medical Developments International
LiteAire via Niche Medical
AeroChamber and RespiChamber via Ecomed

Thanks to Graham for this answer and I look forward to seeing the results of this research.

Dear Derek,

The ATS recommendations for selection of the FEF25-75 to report is the value taken from the curve which has the highest sum of FEV1 and FVC. In case of two curves having the same sum, does the choice revert to the curve with the largest FVC?

Clare Perry
Royal Prince Alfred Hospital


Thank you to Mike Brown who stepped up to the plate to try and deliver an answer:

An interesting question, to which I don't have a definitive answer, unfortunately - I haven't been able to find anything in any of the standard literature referring to this (as I'm sure neither could Clare, hence the Ask Derek!).

My own approach is to take the curve with the highest PEF, this being indicative of greatest initial effort. This, of course, assuming that the test meets the ATS/ERS criteria for acceptability and repeatability, so the maximum difference between the 2 best FEV1s & FVCs will be only 0.15 litres anyway.

I will also occasionally take as best curve one which has a slightly lower sum of FEV1 & FVC but significantly higher PEF than another, as I'm happier to accept a curve where the evidence is that effort has been closer to maximal. Generally I'd only do this if the difference between the sums was no greater than 0.1 litres, but the difference betwen the PEFs was greater than 10%. Not strictly by the book, I admit, however the whole utility of the forced expiratory flow-volume curve is based on the assumption of maximal effort & I'll willingly bend (slightly) what is, after all, a fairly arbitrary rule, to ensure my results are from an effort approximating that ideal.

posted: 13-March-2007

Dear Derek,

Can you please advise on the withholding times for medication prior to spirometry testing? I have been reading conflicting information on this subject.

Kelly Hill
Monash Medical Centre


The withholding of medications for spirometry testing has recently be standardised by the ATS/ERS guidelines for the standardisation of spirometry issued in 2005. Unless reversibility testing is being undertaken then the guidelines do not state withholding of medication.
If the clinician is looking for evidence of reversibility of airflow limitation then the following withholding times should be met:

Short acting beta agonists (salbutamol) or the short acting anti cholinergic (ipratropium bromide) >4hrs

Long acting Beta Agonists (salmeterol or eformeterol) >12hrs

Oral therapy with aminophylline- >12hrs

No smoking for 1hr or more and refrained from during testing.

It would also be advisable to withhold Tiotropium bromide for >12hrs

posted: 7-March-2007

Dear Derek,

Please Help! I am trying to find out if there are any labs who are currently (and successfully) running any systems for the electronic viewing of lung function reports external to the testing laboratory (ie. within the hospital wards etc.). We are investigating the potential of providing physicians with access to lung function reports in much the same way as pathology or medical imaging tests can be accessed. If anybody knows of, or has experience with a commercially available system we would be most appreciative of any advice that you may have. We are currently using Sensormedics Vmax equipment for lung function testing. Any help would be much appreciated.

Chris Brown
Respiratory & Sleep Unit. The Townsville Hospital


Thanks to Stephen West from Westmead who kindly took up the challenge to answer this question

The results of tests performed in the Respiratory Function Laboratory at Westmead Hospital are entered into a commercial software package so that the results can be displayed on any computer within the Area Health Service.
Data entry into Millennium is relatively quick and straightforward as the entire respiratory function test results file from the testing equipment (SensorMedics) is simply copied and dumped into Millennium.

posted: 22-November-2006

Dear Derek

Do U think that calculating the area under the flow-volume curve can be a new helpful parameter in spirometry? Can it be a general index of overall lung function?(something like Ejection Fraction in cardiology?)

Regards,
Dr Mahmood Nekooee
Melbourne


The Editor has asked me to comment on Dr Mahmood Nekooee interesting question regarding whether or not the area bounded by the maximal expiratory flow-volume curve can be used to provide new and useful physiological information.

Like Dr Nekooee, I would be very interested to hear the opinions of others. I don't claim to know the answer but offer the following comments to facilitate discussion:

  1. Simple overview: Although the flow-volume curve represents the summation of many complex biological signals, it is remarkably reproducible. This suggests that the shape of the curve contains a lot of information about the dynamics of the respiratory system, which, in turn reflect lung health.

    I tell my students that the first thing to look at when interpreting a flow-volume curve (or loop) is its shape which defines the flow-volume relationship and can be interpreted at a glance. In healthy adult lungs the shape approximates a straight-sided triangle with the PEF dimensionally equal to approximately twice the FVC (i.e. PEF is about 8 L/sec when the FVC is 4 L). However, an outward convexity in the descending limb is not uncommonly seen in younger adults (and post double-lung and heart-lung transplant recipients) and may indicate that, to some extent, their airways have greater capacity to resist the compressive forces developed during the forced expiration. [This is similar to the bell-shaped expiratory curve seen in marine mammals whose airways resist collapse due to the presence of cartilage throughout the tracheobronchial tree.] In the presence of airflow limitation, however, the descending limb usually shows concavity and maximal flows are reduced. If these flows are only reduced towards the end of the blow (i.e. near RV), the curve is often said to have a 'tail'. This is suggestive of 'early' peripheral airways disease e.g. in people who smoke. Truncation of the curve can occur in the presence of a 'rigid' obstruction to the large intra- or extra-thoracic airway. In restrictive lung diseases the descending limb is often convex, with expiratory flows often increased in relation to lung volume, and dimensionally PEF is often a much higher than twice FVC. Unfortunately, I am not aware of any existing simple and validated method for objectively quantifying shape and would be interested to learn if there is - perhaps an area parameter could help (see below).

    I find it useful to keep in mind that the expiratory manoeuvre is initiated at full lung inflation, when the airways are at their stiffest and have attained their greatest dimensions. As expiration proceeds the airways become less stiff and 'shrink', particularly the smallest ones which lose parenchymal support as the alveoli empty. In a healthy young lung the expiration is usually complete once the maximal force developed by the respiratory muscles can no longer deform the chest wall i.e. many airways are still patent at RV and more volume could be 'exhaled' if expiration was assisted by compressing the chest wall. However, in the elderly and people with obstructive lung disease excessive narrowing and closure of the airways, blockage of the lumen with secretions, and breathlessness usually limit expiration. External compression of the chest does not usually result in more air being expired in this group.

  2. The area under the flow-volume curve has the units, litres2/second, and I suspect is mainly determined by:
    1. The capacity to change the cross-section and vertical height of the lung (ie FVC - essentially determined by lung 'size', the capacity of the inspiratory and expiratory muscles to deform the chest wall, and airway narrowing and closure).
    2. The maximum flow achieved (i.e. PEF - occurs near TLC and is largely determined by muscular force applied).
    3. Shape of the curve's descending limb (i.e. maximal flows at given lung volumes below about 75% TLC are mainly determined by the lungs elastic recoil (not muscular force) and resistance of the airways. During this phase elastic recoil falls and resistance increases as the lung empties. Expiring with greater force does not result in an increase in flow because any 'excessive' energy is dissipated due to flow-limiting mechanisms causing airway narrowing in proportion to the pressure applied).
  3. As mentioned, the shape of the expiratory curve in health approximates a straight-sided triangle with a height equal to the PEF and width equal to FVC, where both are close to the subject's predicted. If we assume that the PEF is reached instantaneously, then the area under the curve approximates (FVC x PEF)/2 litres2/second, and can be predicted for a given healthy individual from (pred FVC x pred PEF)/2.
  4. If we arbitrarily use a lower limit of normal of 80% for FVC and 80% for PEF, then for a straight-sided expiratory curve the area under the curve would remain within normal limits down to 64% of the area obtained if the FVC and PEF were 100% predicted. This suggests to me that the area bounded by the whole expiratory flow-volume curve, is likely to be less sensitive for detecting subtle changes to ventilatory capacity than currently used parameters and subjective shape analysis.

    It is not unusual to obtain a normal FVC and PEF despite the descending limb of the flow-volume curve showing a degree of concavity. I would interpret this as evidence of excessive airway narrowing or closure consistent with airflow limitation. If the estimated lower limit for area is 64% ((4) above) then this abnormal result might be missed if area alone was used. Furthermore, a tail to the curve as seen in some people with 'trivial' or mild obstruction can dramatically alter the shape of the flow-volume curve, but I can visualise curves where the area under the tail (this area is very small) would not significantly impact on the total area parameter as it may well remain 'normal'. In this instance, it may be useful to divide the area parameter into volume segments and express the segment near RV as a function of the total area?

    Similarly, a relatively large decrease in FVC alone would need to occur before the area parameter would signal a restrictive abnormality, particularly if the curve shape was convex.

  5. A few thoughts:
    1. The whole curve area parameter may be more useful for monitoring changes in an individual over time?
    2. Perhaps connecting a straight line between PEF and RV and expressing the area between it and the patient's actual curve (standardised for e.g. FVC), may offer a more sensitive area index as this would get rid of a big chunk of the area not directly related to any concavity?
    3. I also wonder whether analysing the area under the curve as a series of volume (or time) segments rather than a single area could be of value, as the area(s) closer to RV would be expected to be lower than 'normal' in the presence of any concavity - although this may suffer the same problems we encounter when trying to interpret flows near RV i.e. very wide normal range. As for (b) above this is shape analysis really, but may provide a useful approach to quantifying shape.

I conclude that the area under the whole would be insensitive to subtle changes in airway function and less useful than provided by conventional spirometric parameters and curve-shape analysis. However, as discussed, partial areas may be useful as a way of advancing curve-shape analysis.

I look forward to learning your views.

Yours faithfully,

David P. Johns
University of Tasmania
Email: david.johns@utas.edu.au

posted: 7-October-2006


Mike Brown also put forward his thoughts on the area under the curve:

As usual, David has provided a very thorough analysis! I had reason to consider this question earlier this year, & basically came to the conclusion that the area under the curve (AUC) can be affected by too many variables, particularly PEF, FVC, and degree of concavity/convexity, each of which may be subject to change effectively independent of the others, to be useful on its own. David's suggestion about using a line between PEF & RV might be useful, although ultimately you'd end up with a new parameter, not strictly AUC as such.

David's thought regarding analysis of the curve in terms of volume or time segments harks back to the transit time analysis of the spirogram that was in vogue for a short while in the late 70s/early 80s. That really didn't come to anything, largely I think due to ultimately not providing any more useful information above what we already get from the standard FV parameters.

posted: 12-November-2006

Our lab has been discussing Hb and Carboxyhaemoglobin correction in the DLCO test and we were wondering how many labs actually corrected for this and also where they got their Hb values from - do they use the most recent pathology results or do they collect and analyse a sample on the day of respiratory function testing?

Thanks, Cathy Dyroff


Cathy,

ATS/ERS guidelines give a recommendation that Hb and COHb corrections should be made.

In our lab we currently use a hemocue to measure the Hb at the time of the testing unless a pathology result is available for that day. This can be entered into our software, the current recommendation suggest the correction of the predicted value and not the actual value, and the report should contain the corrected and uncorrected results.

COHb measurements are made routinely in our laboratory for all current smokers and once again this is entered into our software, although the guidelines once again give the correction factor. This correction does not need to be done for a COHb<2% as the current predicted value ranges incorporate this as this is a normal environmental exposure range.

Hope this helps.
Cheers,
Chris

Christopher O'Dea CRFS

posted: 7 July 2007

Dear Derek,
Its been a practice for some pediatric pulmonologist in my institution in which in certain asthma and bacterial bronchopneumonia pedia patient they would order a continous nebulization of a bronchodilator (Ventolin) some would take up to 12 hours straight. consuming about 50 to 60 nebules of the said bronchodilator. My question is why do they order this kind of management to pedia patient? isnt it dangerous for the patient with the side effect of the drug, and with the principle of lock and key, they keep on giving the bronchodilator and yet the receptor sites still have the effect of the drug, I think its just a waste of the drug. are there any research or study that would support the kind of aggresive management that they are doing or that would conflict the practice of ordering continous aerosol drug therapy (bronchodilator) so that I can suggest it to them.

Richard Chock.


Answer courtesy of Dr Andrew Wilson, a paediatric respiratory & sleep consultant.

While there is good evidence that pMDI and spacer are the preferred method of drug delivery in children with mild to moderate asthma, nebulised therapy has a continuing role in severe asthma. In children with severe asthma nebulisation may need to be continuous. The safety and efficacy of continuous nebulised beta agonist has been studied in children (Craig et al 1996, Katz et al 1994). Side effects are more likely when intravenous salbutamol is used, especially if continuously infused (Habashy et al 2003). Common side effects will include tachycardia and tremor, these side effects are predictable and are thought to be an indication of effective drug delivery! More serious side effects such as hypokalemia (reduced serum potassium concentration) and cardiac arrhythmias are thought to be much more likely with intravenous than inhaled therapy.

Craig VL. Bigos D. Brilli RJ. Efficacy and safety of continuous albuterol nebulization in children with severe status asthmaticus. [Journal Article] Pediatric Emergency Care. 12(1):1-5, 1996 Feb.

Katz RW. Kelly HW. Crowley MR. Grad R. McWilliams BC. Murphy SJ. Safety of continuous nebulized albuterol for bronchospasm in infants and children.[erratum appears in Pediatrics 1994 Feb;93(2):A28]. [Journal Article] Pediatrics. 92(5):666-9, 1993 Nov.

Habashy D. Lam LT. Browne GJ. The administration of beta2-agonists for paediatric asthma and its adverse reaction in Australian and New Zealand emergency departments: a cross-sectional survey. [Journal Article] European Journal of Emergency Medicine. 10(3):219-24, 2003 Sep.

Our lab is in the process of purchasing a dosimeter. Do you know which companies produce dosimeters? Is there a particular dosimeter you would recommend?

Thanks
Kelly


A. Thanks to Andrew Coates who pointed me in the direction of David Johns for an opinion.

I don't consider myself an 'expert' in the field of dosimeters but we have done some work in the area, partly as part of our involvement in the second phase of the European Community Respiratory Health Survey (prevalence study). All centres participating in this study use the Mefar MB3 dosimeter with pre-calibrated nebulisers. This dosimeter (and the pre-calibrated nebulisers) is manufactured by Markos-Mefar (Boveezzo, Italy) and is available in Australia from Mayo Healthcare (tel:1300 360 226 - ask for Emma Jordan (Product Manager)). We now have substantial experience with the Mefar MB3 and are quite happy with it.

As you would expect, the output of the nebuliser (and hence measured PD20) will depend on the driving pressure, so it is important that quality control measures are in place to ensure that it is close to 180 kPa (suposed manufacturers setting) and remains unchanged year to year. This is important because we found that driving pressure varied between Mefar dosimeters used around the world in the ECRHS (Ward RJ et al, Eur Resp J, 1999, 430-434.)

Hope this helps.

Regards

David P. Johns

I wondered if anyone had any clinical trial experience using Vitalograph Spirotrac Centralized spirometry system (or other centralised system) and if they had any comments or feedback. We are considering using it for some CF studies.

Thanks
Ruth Martens


A. Thanks to Gary Nolan for his response to Ruth's question.

I must qualify what follows with the fact that I have not had any experience with this spirometer per se.

However, we have used an earlier version of Spirotrac and I suspect this is a system where testing is done locally and the local Access or SQL style database has a backend that reports to some central (drug company) database. In the clinical trials setting this can be very useful as quality data is (as always!) paramount and if this system has been set up for trials I would hope it transfered more than just the numerical data but also the raw curves. This would allow one central appropriately trained and qualified co-ordinator to oversee quality criteria.

The only other comment I would make is that where ever the spirometry is actually performed it would be useful to have a graphical feedback for both the operator and the subject. Also the Fleich type pneumotach used in the Spirotracs is reliable once calibrated although it is a "cold" pneumotach and as such is at risk of drifting if condensation of exhaled breath clogs any of the small capillaries. This is usually only a problem if repeated testing on many patients is performed in a short space of time.

I would be interested to hear any other feedback or indeed have a little more details from Ruth on the way the system has been put together.

Hope this helps

regards

Gary

Gary Nolan CRFS, M(app)Sc
Principal Hospital Scientist
Adjunct Senior Lecturer (CSU)
Respiratory Investigation Unit
Gosford & Wyong Hospitals
Northern Sydney and Central Coast Health
NSW 2250
Tel: +61 (0) 2 4320 3254
Fax: +61 (0) 2 4320 2042
Mob: 043 004 8700

Hi Derek,

Is anyone out there using the Sensormedics system for Indirect Calorimetry, if there is I would like to get in touch.
Thanks,
Barbara

Email: P2

Hello Derek,

We had a discussion in the lab about putting an iv drip and 500 ml NaCl bag in the bodybox during testing. Do you know how to correct for the volume and how much does it influence the results?

Thanks, Carolina

Email: car.guido@optusnet.com.au

Hello Derek,

What is your opinion about Hb correction in the diffusion test?

Thanks, Carolina

Email: car.guido@optusnet.com.au

Hi Derek,

I am concerned about performing diffusion studies on pregnant females. Do other labs have a standing policy on this? Is there any basis for concern?

Regards, Roger Darby
Email: rogerd@bhs.org.au

We have recently started measuring Sniff nasal pressures (SNIP) in a group of patients from our motor neurone clinic. The literature re the method seems to be confusing. Some authors talk about a sniff with the contralateral nostril blocked and others with the contralateral nostril patent. Can others using the technique share their experience and methodology? Currently we are using both techniques and will compare the results, though this has probably been done. If so can anyone supply the reference.

Many thanks for any feedback
Robin Schoeffel CRFS
Email: rschoeff@doh.health.nsw.gov.au

posted 29th March 2005

Dear Derek,

We (Resp Function Lab at Royal Children's in Brisbane) are considering changing our spirometer for CF patients with Cepacia (+MRSA etc). Do you know of any guidelines for choice of spirometer and lab environment specific for testing CF patients with Cepacia?

Many thanks

Barry Dean
Email: Barry_Dean@health.qld.gov.au

Pulmonary Function Laboratory at Lung Services in Launceston needs urgently a replacement CO + He Analyser Rack for a Jaeger MasterLab system.

If any laboratory has a spare or unused Analyser rack available can you contact
Nicky Harvey on 03 6331 0580 or mobile 0419 631 302.

We don't routinely do Raw (only TGV & TLC) but we are participating in a study that requires Raw. We've been perfecting the technique on fellow staff, but, at times, still get variable results.

Does anyone have any tips on how to do Raw measurements so that you can get consistent results every time?

Thanks.

Rob_Tagliaferri
Email: robert.tagliaferri@fcconventions.com.au

Hi Derek.

We have a Oxycon Pro Cardiopulmonary exercise sytem in our lab and are finding that our turbines have a short life span.In the past we have sterlized them with 70% alcohol, as suggested in the Jaeger manual (with and without using an ultrasonic bath).

I was wondering if you could help me find out what other labs are using to sterlise their turbines. I feel that our method of sterilization may be affecting the life span.Many thanks for you assistance.

Regards,

Kelly Hill
Email: kelly.hill@southernhealth.org.au

Hi Derek,

My current protocol for disinfection of re-usable mouthpieces and nose-clips is under review. I use Chlorhexidine/70% ethanol at present. What are other labs using/what are the recommendations?

Thanks,
Patrick
Email: nlfs@bigpond.net.au

Derek,

do you know of anyone who is using a KoKO Trek 2 Spirometer on Windows 2000 and has successfully been able to calibrate the unit. My installation recognises the spirometer on the comm port but not during the calibration process.

Cheers
Trevor Bonney

Canberra Hospital
tel: 02 62076445
Email: trevor.bonney@act.gov.au

Has anyone experience with a motorized Calibration Syringe used as an external calibration device to check the accuracy of any CPX system ?

I would very much like to hear the likes and dislikes.

Han beurskens
Pulmonary Function Technologist
Mxima Medisch Centrum loc. Eindhoven
Eindhoven
The Netherlands
Email: longfunctie.ehv@mmc.nl

Derek,

Just wondering if you know of any good papers looking at resistance of filters and their effect on measurement of lung function?

Thanks,
Rosemary
Email: Rosemary_stephens@hotmail.com


I direct you to the journal article by David Johns

Johns, D.P, Ingram, C, Booth, H, Williams, T.J & Walters, E.H 1995, 'Effect of a micro - aerosol filter on the measurement of lung function', Chest, vol.107, pp.1045 - 8.

The article evaluated the Pall filter and concluded there were statistically significant decreases in only FEV1 and PEF. However, this difference was reported to not be clinically significant.

These observations are further supported by Fuso, et al 1995.

Fuso, L, Accardo, G, Ferrante, E, Della Corte, A & Pistelli, R, 1995 'Effects of a filter at the mouth on pulmonary function tests', European Respiratory Journal, vol.8, pp.314 - 317.

This paper evaluated the Spirobac filter and concluded statistically significant differences were evident in FEV1, FVC, Raw, & sGaw. The majority of the difference was explained by intraindividual variability. Again, the results showed there were no clinically significant differences when using filters.

Hi Derek,

There has been recent discussion in our hospital from the Resuscitation Committee re: does the Respiratory Function Unit really need to have a fully stocked Emergency Trolley.

As we do Cardio-Respiratory Stress Testing, it is my understanding that a fully stocked resus trolley be at the site of testing.

Are there quidelines that state such requirement?

Cheers,
Tom Parks
Senior Respiratory Scientist
Royal Hobart Hospital
tom.parks@dhhs.tas.gov.au
(please copy any direct answers to Derek at derek.figurski@fcconventions.com.au )


Dear Tom,

Good question! I always assumed the need was there. Looking at the recent ATS statement-
2003. ATS/ACCP Statement on cardiopulmonary exercise testing. Am J Respir Crit Care Med 167(2):211-77.
Under section 4.3.1 "Foreseeable risk of cardiopulmonary exercise testing", the authors state that "the risk of complications is related to the underlying disease, and it appears that the rate of death for patients, during exercise testing is 2 to 5 per 100,000 clinical exercise tests." So the risk is small, but ever present. The go on to say in section 4.3.3 page 227, that "resuscitation equipment should always be available in the exercise laboratory." It doesn't specifically state a fully-stocked emergency trolley.

Also the ERS have a say on this. See-
1997. Clinical exercise testing with reference to lung diseases: indications, standardization and interpretation strategies. ERS Task Force on Standardization of Clinical Exercise Testing. European Respiratory Society. Eur Respir J 10(11):2662-89. On page 2677 they state:-
"Full CPR equipment should be available in the CPET Laboratory"

Fortunately I am collocated with a sleep lab who have a full crash cart, so I don't need to look after it myself. I hope this helps.

Cheers

Andrew Coates MAppSc CRFS
Senior Respiratory Scientist, Advanced Clinician
Lung Function Laboratory
Dept Respiratory and Sleep Medicine
Mater Children's Hospitals
South Brisbane QLD 4101
tel 07 38408146
fax 07 38408366
Email: Andrew.Coates@mater.org.au


Tom

A source for this information I have for Australia is 'Clinical exercise stress testing -- Safety and performance guidelines' by The Cardiac Society of Australia and New Zealand.

Available online at http://www.mja.com.au/public/issues/mar4/freedman/freedman.html

Dr Bruce Graham
Postgraduate Respiratory Science Coordinator
Lecturer in Human Anatomy and Physiology
School of Biomedical Sciences
Charles Sturt University
Locked Bag 588
WAGGA WAGGA NSW 2678
Ph (02) 6933 2674
Fax (02) 6933 2587
Email bgraham@csu.edu.au

Hi Derek,

I am looking, as many with me I understand, for a validated jet nebulizer with a MMAD between 1 and 4m and calibrated to give an output as estimated by weight loss of 0.13 ml/min-1. Up till now I used the DeVILBISS 646, but this one is no longer available in Europe. What kind of nebulizer is commonly used in Australia?

Thank you to Sunalene Devadason for providing a response.

The Sidestream nebuliser has a median particle diameter of ~3 m, depending on the compressor flow used. I'm not sure what the exact weight output is, but it could be altered by adjusting the flow rate. The Sidestream used with it's standard angled mouthpiece has an open vent system which enhances the driving gas flow using passive entrainment, increasing output and decreasing the particle size. If the output is too high, the open vent can be blocked off with generic T-piece, decreasing the output but increasing particle size slightly. If anyone else has any further information email "Ask Derek".

Refer also to the poster presented at the 2003 meeting by Chris Nathan "Bronchial Provocation - are we meeting the standard?" (K.G)


Ed van Riet of Technipro advises:

We distribute DeVilbiss jet nebulisers ( for use in, say, PDS KoKo DigiDoser &/ or Dosimeter devices). 2 types are available.. a 'straightforward DeVilbiss & "characterised" version.

Enquiries to EdvanRiet@technipro.com.au

Hi Derek!

We are looking for the paper on priming spacers with soapy water. We are looking for the evidence behind it. Can anybody help? We are also looking for the paper that provides evidence to support priming spacers with puffer actuations following autoclaving, when there is lack of time to wash in soapy water and leave to air dry.

Please send any information you may have to:
Jill Petherick jill@asthmsa.org.au
tel: 8238 9300
Asthma Foundation of SA

Thanks for your help,

Jill


Further information about spacers.
Based on current infection control guidelines - spacer devices are ONLY to be used for a single patient and require washing and steam sterilisation or pasteurisation between uses.
www.health.gov.au/internet/wcms/publishing.nsf/Content/icg-guidelines-index.htm-copy6/$FILE/part3b.pdf section 17.6

1 Pierart F, Wildhaber JH, Vrancken I, Devadason SG, Le Souef PN. Washing plastic spacers in household detergent reduces electrostatic charge and greatly improves delivery. European Respiratory Journal Mar 1999; 13(3):673-8

2 MacGregor KJ & Wuber J-A. Factors affecting the electrostatic charge of spacer devices. Drug Delivery to the Lungs X 2-3 December 1999; Abstract of Presentations 69-72

Glenn Thomas
Ashford Lung Function unit

Hi Derek,

I am seeking advice regarding the choice of a device for measuring maximum inspiratory and expiratory mouth pressures for use in the Dee Why laboratory. The Morgan instrument is no longer available and I would appreciate advice as to alternatives people have had experience with, and would recommend, that are currently available in Australia. Please contact me at pridler@bigpond.net.au (with a copy to Derek at derek.figurski@fcconventions.com.au , KG)

Thanks for your help,

Prue


Hi Prue,

We use a Dobbie pressure gauge (+/- 200 cmH20).
it was purchased from Beacon Engineering, tel: (03) 9561-7322. hope this helps.

regards, Van LeBlanc


Prue

We use the MIPS & MEPS option on the SensorMedics VMax unit, but I wouldn't rush out to buy one on this basis. The test doesn't allow control of the shutter closure time and often it is difficult to exhibit an obvious plateau before the shutter opens. I have asked quite a while back if we can access the software to change the algorithm but have not received a reply from Mayo Health or SensorMedics USA.

It may be possible to get a simple electronic pressure transducer with USB connectivity to your computer from somewhere like Dick Smith's. You would have to attach it to a mouthpiece filter somehow and also obtain some simple software for recording the pressure tracing. However, this should be a far cheaper option than most commercial PFT units.

Bruce Graham
Postgraduate Respiratory Science Coordinator
Lecturer in Human Anatomy and Physiology
School of Biomedical Sciences
Charles Sturt University
Locked Bag 588
WAGGA WAGGA NSW 2678
Ph (02) 6933 2674
Fax (02) 6933 2587
Email bgraham@csu.edu.au


RE: Respiratory pressure measurement (Q19)

We use a Micromedical hand-held respiratory pressure meter that measures inspiratory, expiratory and SNIP. It can also be linked to a PC via software, but this costs as much as the meter

Nigel Wong North Shields, UK
mailto: nigel.wong@northumbria-healthcare.nhs.uk

Re: sourcing of ultrasonic nebulizers.

I, too, am looking for an ultrasonic nebulizer for saline challenges. Unfortunately DeVilbiss no longer make these either. They do have parts and are still able to repair/service old machines but there are no longer new machines available. Would anyone know where I could get a second hand one?

Merylese Mercieca
Nepean Hospital RFL
merciem@wahs.nsw.gov.au

Hi Derek,

I am interested to find out what products other Respiratory Units use to clean and disinfect their equipment. I am particularly interested in the vane type flow sensors (Jaeger oxycon delta or similar types). We have had a problem with the flow sensors having a short lifespan because of the vane shifting on its axis after cleaning and therefore producing erroneous measurements.

I would also be interested in discovering if anyone else has this problem.

Annette Dent

The Prince Charles Hospital, Brisbane


Hi Annette,

At RGH we clean the vane flow sensors with "Pryroneg" powder (left in the solution for a minimum of 20 minutes). Then the sensors are washed with sterile water and air dried. Previously we cleaned the sensors in alcohol, but noticed that this shortened the lifespan. We contacted Jaeger in Germany about this and was told verbally that the alcohol will cause the vane to shift resulting in variable volumes at low flows. This current cleaning process was sufficient in meeting the hospital's infection control guidelines.

Presently, we are reviewing our infection control procedures with the hospital's infection control department and if you have any comments please forwarded them on.

Derek Figurski

Hi Derek,

Just wondering if you or any of the readership are aware of severity scales based on functional status for spirometry. I am also interested in severity scales for lung volumes in terms of severity of restriction and hyperinflation.

From the literature search I have done, evidence for severity scales based on functional status is scant.

I am interested in whether other institutions grade severity and if so, based on what parameters? Do other institutions only grade for particular disease groups or use the same scale across all subjects tested. Do institutions put in a qualifier, as suggested by the ATS 1991 paper, that severity is based on parameters of lung function and are not necessarily representative of functional state.

Looking forward to lots of feedback,

Brigitte Borg
The Alfred, Melbourne.


Dear Brigitte,

When assessing the severity of lung function abnormalities I base interpretation on the data in Table 13 from the ATS document, 'Lung Function Testing: Selection of Reference Values and Interpretative Strategies (Am Rev Respir Dis 1991; 144: 1202-1218). There are alternatives for grading obstructive disease such as those contained within the various COPD guidelines from the ATS, ERS and TSANZ.

There is a grading scheme for RV in MILLER William F. Laboratory Evaluation of Pulmonary Function 1987 JB Lippincott Co. (Table 5-4).

When assessing disease severity physiologic (i.e. lung function)assessments may differ greatly from clinical assessments. Examples are patients with asthma and severe airway hyperresponsiveness but minimal symptoms and patients with moderate to severe COPD who may or may not be dyspneic or exercise intolerant.

Steve

Stephen West CRFS, M App Sci
Senior Hospital Scientist
Clinical Measurement Department
Westmead Hospital
Westmead 2145
AUSTRALIA
Tel: 02 9845 6044
Fax: 02 9843 8320

Does anyone do bronchial provocation challenges using such things as wood dust or flour? If so do you have a patient informed consent form that you are happy to share?

Andrew Thornton
Royal Adelaide Hospital
tel: (08) 8222-5436
email: athornto@mail.rah.sa.gov.au


From David Schembri in response to Andrew Thornton's question regarding wood dust and flour challenge tests.

Hello Andrew,

FMC undertook such challenges many years ago but ceased back in the 80's or early 90's. Mostly due to the time and resources required to safely conduct the challenges. Our protocol involved 3 full days (12 hours) of monitoring. One day for each of reference, placebo (which was often difficult)and test. A physician was required to be immediately available and was present for at least most of the test day. Of course patients would immediately recognise when there was a difference, such as the clinician being present. We also experienced difficulties in controlling some exposures eg TDI. Given that our pollution chamber has been dismantled we will refer any such testing to the RAH!!

Re consent forms. I can't recall that we used them back then. If we were to perform a challenge test we wouldn't proceed without a signed consent form of some sort today.

I do know of a clinician who performs non respiratory challenges and I'll chase what is used in that setting.

Best wishes

David

Could you please advise a source of ultrasonic nebulisers capable of delivering 15 grams of salt solution as per the Sandra Anderson protocol for hypertonic saline challenge. My understanding is that Omron has just discontinued such a model.

In addition do you know of any other protocol for hypertonic saline challenges that does not require an ultrasonic nebuliser.

Sterk, et al (1993) state that ultrasonic nebulisers are recommended for generation of non - isotonic aerosols, because they produce aerosols which are more dense than conventional jet nebulisers. Anderson & Brannon (2003) suggest the De Vilbiss 99 and 2000 (Somerset, PA USA), Timeter Compumed and MistO2gen EN Series (Lancaster PA USA). These nebulisers have large - volume canisters (400ml capacity) that can be detached easily for weighing, and are the ones recommended. The protocol demands delivery of large volume of saline with Anderson, et al (1994) recommending a constant starting fluid of 200 - 250ml. Small - volume ultrasonic nebulisers are not recommended for the use for these challenges. It is important to choose a nebuliser that has a reproducible output of at least 1.2ml min - 1 (for adults) with the breathing circuit attached as stated by Sterk et al (1993). Generally the preferences is 1.5ml min-1 as stated by Anderson & Brannon (2003). Anderson & Brannon (2003) further suggest not to use routinely medicine cups to hold solution, because of the loss of nebuliser output leading to false negative tests. The only recommendation for the medicine cup if there is question of hygiene.
When doing saline challenges you must also keep in mind the corrosive nature of the solutions and ensure that any exhaust from the nebuliser or mouthpiece is vented away form any equipment - particularly any air intakes for the nebuliser itself.

References:
Sterk PJ, Fabbri LM, Quanjer PhH, Cockcoft, DW, O'Byrne, PM, Anserson SD, Juniper EF, Malo, J- L (1993). Airway responsiveness: Standardized challenges testing with pharmacological, physical and sensitzing stimuli in adults. Eur Resp J 6:(Suppl 16) 53 - 83.

Anderson, SD, & Brannon, JD (2003) Methods for indirect challenge tests including, eucapnic voluntary hyperpnea and hypertonic aerosols. Clinical Reviews in Allergy and immunology, 24: 27 - 54.

Anderson SD, Smith CM, Rodwell LT, du Toit JI, Riedler J, & Robertson CF. 1994. Hypertonic saline challenge in an epidemiological survey of asthmas in children. Am J Respir Crit Care Med. 150, 1632 - 1639.

Suppliers for DeVilbiss Nebulisers

Sunrise Medical Pty Ltd,
7/15 Carrington Road, Castle Hill NSW, 2154.
The contact is Ian McKenzie at 02 9899 3144.

We have been having some difficulties sourcing histamine for challenge testing and getting our hospital pharmacy to make it up. I'm looking into alternatives and would like to know if you've come across any info regarding the Mannitol challenge test

Thankyou to John Brannon for an update on Mannitol.

We are currently doing a multi-centre trial (12 centres in Melbourne, Canberra, Sydney, Brisbane) in an effort to get the mannitol registered for use in Australia then perhaps Europe. The study is aimed to finish mid-2004 then upon analysis and submission of this data with the TGA, it can take 9mths until Pharmaxis, the company developing the mannitol can be permitted to produced and sell the test known as Aridol.

In the meantime this person may be able to set up the hypertonic saline. Indirect tests as per my article have advantages when you need to identify or exclude asthma. Methacholine is still available but is now quite expensive and I think this is supplied by a company called MetaPharm, I do not know about histamine and don't know of many these days that use it.

A good introduction on Mannitol is the article published in the RT International, Fall 2003. As far as updates for mannitol there are plenty of papers that have been published in 2003 in regard to mannitol as a bronchial provocation test that were not included in that article as it was written in early 2003. Go to Pubmed and type in "asthma" and "mannitol" and you should get them all.

Suggested introductory references:
Anderson, S & Brannon, J.D (2003). Methods for "Indirect" Challenge Tests Including Exercise, Eucapnic Voluntary Hyperpnea and Hypertonic Aerosols. Clinical Reviews in Allergy and Immunology. V24, pp 27 - 54.

ERS Task Force (2003). Indirect Airway Challenges. European Respiratory Journal, 21, pp 1050 - 1068.

Kevin Gain has provided on some insight on supply and costing regarding histamine.

We have just been informed that from now on histamine prepared for challenge testing will cost us $50 per vial - no matter what the concentration. We have two options either pay for the prepared dilutions as previously supplied or buy the highest strength and dilute to prepare our own dilutions. Bearing in mind the need for sterile dilution etc this is less than desirable. This was inevitable and puts methacholine in a more economic light. In Wellington I had used Methacholine from MetaPharm and it was a very practical way of doing things if expensive.

Further suggestions on regular and cost effective supply of histamine and methacholine can be forward to "Ask Derek"

--------------------------------

I also received an update from Graham Hall to Rob Tagliaferri's response to the ulna length question from last month's column.:

An addition to Rob's contribution on ulna length and FEV1, is the recently published work of L Gauld et al in the American Journal of Respiratory and Critical Care Medicine (Am J Respir Crit Care Med Vol 168. pp 804-809, 2003). Leanne collected spirometry and various bone length data on approx 2500 Melb. school aged children. Well worth a look.

Derek

I was wondering if anyone out there is using ulna measurements to estimate height for non-standing patients? Do you know the equation that is used for this calculation? I am aware of an equation that calculates for FEV1 but not height.

Thank you to Robert Tagliaferri from WA for responding to this question.

I have investigated ulna and forearm length equations and presented a poster at Cairns in 2002. The equations we looked at were developed for children by Miller & Koreska (Height measurement of patients with neuromuscular disease and contractures. Dev Med Child Neurol 1992; 34:55-60). The equations are as follows:

SH=3.497 x FL + 9.595
SH=6.332 x UL + 1.157
SH: standing height; FL: forearm length; UL ulna length. All units are cm.

Our findings were that the equations, however, are not appropriate for adults without correcting for the decrease in standing height that occurs with age. I can't go into too much detail as we are looking to have this data published in the near future. Also, we need to do more work to come up with appropriate regression equations for adults. However, the Miller & Koreska equations are useful for children.

I am a physiotherapist currently doing a study on the effect of exercise on spirometry readings. What I'm trying to find out is what degree can the spirometry test itself cause bronchospasm and how long does it take to relieve. How can I get to know whether changes in the readings are do to the test itself or because of exercise.

Background to the study:
Basically we are doing this small study to find out the effect of exercise in mild to moderate asthmatics by assessing the change in values of the FEV1. We are doing the spirometer before a 6 minute walking test and then 5, 10, and 15mins after. What we would like to know is whether the test itself - that is the spirometer can cause bronchoconstriction to the extent that it effects the values therefore the results are not 100% due to exercise.

Thankyou to Bruce Graham for a suggested answer to this question.

Firstly, (start with the last question) to distinguish whether the test itself is triggering bronchospasm, test the patient's spirometry several times prior to challenge (exercise) so that any decrement (trend) may become apparent (and thus indicating an effect of the test itself). However, there is potential for an interaction effect such that neither stimulus alone causes supra-threshold bronchoconstriction but exercise followed by spirometry may do so. It would then be difficult to cite the cause. It may be that the trigger is airway cooling and/or drying but conceivably if occurring in response to a couple of peak efforts it might also simply be mechanical irritation (say by impact of mucus droplets on the airway wall?) in the same way as a cough may be triggered by performing spirometry.

Secondly, if a bronchodilator is used once bronchospasm has been determined then the time to relief will be as for a "standard" bronchodilator response (onset 1-3 minutes but up to 20 mins for max response though usually considerably more quickly!?). However, the time for "spontaneous" (unassisted) relief (back to 95% of baseline?) will depend on the degree of bronchoconstriction achieved, the prior history of medication, the pattern of breathing (deep inspirations promote bronchodilatation) and of course individual variation. Someone who has seen more spirometry induced coughing and subsequent bronchoconstriction may have a better idea as to the time but I would have thought well under the hour (though they may still be hypersensitive to a further bout during this period).

If there is anyone else in the membership can provide further information, can this be forward to the Ask Derek Webpage.

I'm on the search for a cheaper alternative of the oesophageal balloons currently used (Ackrad Labs via Incision) for both the Respiratory & Sleep Labs. I'm particularly interested in locating those people who manufacture their own balloons (something I did many, many years ago). Locating suppliers of the components of the balloon system (the catheter & the balloons).

Thankyou to Peter Catcheside for supplying useful information on manufacturing your own oesophageal balloons

The best that we have so far managed is to use Jaeger balloons (from Viasys were ~$230 per pack of 5) which we have dismantled and rebuilt onto our own customised catheters. Several years ago I tried to source the balloons by themselves but had no success (there used to be a Canadian distributer but I gather it disappeared). I would still really like to do this because the materials *should* cost only a small fraction of assembled balloon catheters.

We use suture silk, wound around the balloon end to tie the balloon onto our catheter, then roll the rubber sleeve that the Jaeger balloons come with over the suture silk. This makes it a bit smoother and looks more professional. We use polyethylene tubing (2.08 mm OD which comes as a 30 m roll from Microtube Extrusions Pty Ltd, North Rocks Sydney (02) 9630 7899) as the catheter which allows us to pass it through and 0-ring seal at a luer port on a mask (which we couldn't easily do with Jaeger catheters). We've also done very similar to build 2-balloon catheters (one tied to the tip and one chopped at both ends then tied on at both ends mid-catheter) using a swan-ganz catheter which has 2 reasonably sized channels inside.

Hope this helps a bit. Hopefully someone has a good alternative source of balloons?

Any further suggestions can be sent to the Ask Derek Webpage.

It has recently been drawn to my attention that the new propellants in MDAs preclude checking whether they are empty by dropping them into a bowl of water to see if they float. See this month's Trade Topics page for some comments from GSK.
This raises the question as to how we can conveniently keep track of how many doses are left. Clearly the approaches include regular weighing of the cannisters and manually counting the doses administered. I am interested to know how other labs using MDIs for reversibility testing monitor their MDI usage.

Please send any responses to Derek for publication next month.

Where can I get Wright Nebulisers for Histamine / Methacholine Testing?

In preparing our poster for the meeting we found a source in Vancouver, Canada. It may be of interest to note that we located this source through the Purchasing Department of the University of British Colombia's web-site.

The source is:

Roxon-Universal Medical Ltd
New Westminster
British Colombia
Canada
Contact: Ruth VanOosten, Office Manager
e-mail: roxon@uniserve.com

At the time this information was obtained they had 2 in stock at Can$165 plus shipping and handling.

Kevin Gain
RPH, Perth

Where can I get my calibration syringe validated?

Umesh Kotwal of the NSW Standards Laboratory, has provided the following information re syringe validation.

The NSW Standards Laboratory is able to provide a service which validates your calibration syringe and they will provide a certificate for the syringe accuracy.

They are able to tailor the process to individual requirements eg validate total volume only, or validate linearity of volume over a range. Obviously the cost depends on the amount of work involved and prospective users of the service should contact the laboratory directly to determine the cost involved. Turnaround time remains approximately 10 working days.

The Laboratory can be contacted at:

NSW Office of Fair Trading Standards Laboratory
C/- CSIRO Bradfield Road West Lindfield NSW 2070
Ph: 02-8467 4402
e-mail: umesh.kotwal@oft.commerce.nsw.gov.au

updated 11th September 2008

"Can you forward me a list of details of suppliers of skin prick test allergens?"
Linda Ruedinger

The skin prick allergens in general use are supplied by Hollister-Stier. The Australian agent for this company is:

Richard Thomson Pty Ltd
Unit D1, 46 - 62 Maddox Street
Alexandria NSW
Postal Address: PO Box 386, Alexandria NSW 1435
Telephone 02 9319 2644 Toll Free 1800 269 534
Email: rtsyd@richardthomson.com.au

In New Zealand the allergen extracts are available from Ebos Group Limited. Auckland Contact Details are:

243-249 Bush Road
Albany
Private Bag 302161 North Harbour Postal Centre
Telephone (09) 4153267.

Christchurch contact details are:

324 Cashel Street
PO Box 411.
Christchurch

Some people mentioned Bayer, but it has been some time since members have ordered from them. (The last time I tried to get allergens from Bayer, while in NZ, I drew a blank. KG)

Bayer Australia Ltd
875 Pacific Highway
Pymble NSW 2073

I hope this helps with the New Zealand group. I've talked to our supply department and they are under the assumption that Richard Thomson is the only reliable skin prick allergen supplier in Australia.

One member mentioned the USA address for Hollister - Stier which may need to be put on the web-site as a reference.

Hollister-Stier
Laboratories LLC
U.S. License No.1272
Spokane, WA 99207 USA

How may puffs of ventolin?
I believe that the ANZSRS has looked into how many puffs of ventolin should be given to determine before/after bronchodilator effect. There is quite a range from 2 to 12 puffs via spacer that I've heard of. Does the ANZSRS have recommendations on this?

At present the ANZSRS and TSANZ do not have any recommendations. I direct you to the online abstract titled:

The Assessment and Interpretation of Reversibility of Airflow Limitation Using Bronchodilators: Current Practice in laboratories in Australia and New Zealand. (2001). Authors: B. Borg, E.A Slide, & D.P Johns www.anzsrs.org.au/asm2001/asm2001borg2.pdf

I would like to thank Brigitte Borg and David Johns for their comments on this topic.

Dear Derek,

Thank you for asking me to comment on the dose of bronchodilator to administer when assessing reversibility.

I am pleased that the subject of BD reversibility is still being discussed, as there is still no uniform approach to this fundamental assessment. Your letter is timely as I will be presenting an update of our research in this area at the next Victorian Branch meeting. You may also be interested to learn that we have just submitted a manuscript to the MJA (Brigitte Borg, David W. Reid, E. Hayden Walters, David P. Johns. Bronchodilator Reversibility Testing: Laboratory Practices in Australia and New Zealand).

The following comments only relate to adults, as I have no experience of the paediatric population.

Firstly, there are no universal guidelines for assessing BD response. The guidelines that are available recommend a variety of modes of administration, doses, waiting times and criteria for a significant response. The literature suggests that for asthma, two doses (puffs) of 100ug of salbutamol, (administered with or without a spacer) and waiting 5-6 minutes before retesting should be adequate to record a significant response (ATS criteria). However, one would need to wait 20 minutes to record the maximal response.

It is less clear when assessing patients with COPD.

When combination drugs are given (eg salbutamol and ipratropium bromide) one has to wait for about 30 minutes to measure a response. Give a single agent (salbutamol) and wait 20 minutes to see maximal response.

The TSANZ COPDx guidelines published in March 2003 give little practical guidance, as their recommendations for mode, dose and waiting time are very broad. This is also true for the British Thoracic Society COPD guidelines.

A review of RCT looking at mode of delivery, found that in the adult asthma and COPD groups, MDI's with or without spacers were as effective as other modes of delivery such as nebulisers and DPI devices.

Perhaps an ANZSRS committee could be formed to further review the literature and develop a practical set of guideline for assessing BD response and criteria for significant response. This would reduce the wide range of practices currently used in Australia and New Zealand. After all, the assessment of bronchodilator response is a very important routine test performed on the majority of patients attending a lung function laboratory. Such guidelines would also need to include how long patients would need to withhold their short and long-acting b2-agonists prior to assessing reversibility.

References

  1. British Thoracic Society. Guidelines for the Management of COPD. Thorax 1997;52 (Suppl 5):Si28.
  2. British Thoracic Society and Association of Respiratory Technicians and Physiologists. Guidelines for the Measurement of Respiratory Function. Respiratory Medicine 1994;88:165-194.
  3. Morris AH, Kanner RE, Crapo RO, Gardner RM. Clinical pulmonary function testing: a manual of uniform laboratory procedures. 2nd Ed. Salt Lake City (UT): Intermountain Thoracic Society; 1984.
  4. Thoracic Society of Australia and New Zealand and The Australian Lung Foundation. The COPDX Plan: Australian and New Zealand Guidelines for the management of Chronic Obstructive Pulmonary Disease 2003. MJA 2003;178 (Suppl):S1-S39.
  5. American Association of Respiratory Care Clinical Practice Guideline Spirometry, 1996 update. Respir Care 1996;41(7):629-636.
  6. Dorinksy PM, Reisner C, Ferguson GT et al. The combination of ipratropium and albuterol optimizes pulmonary function reversibility testing in patients with COPD. Chest 1999;115(4):966-971.
  7. Levin DC, Little KS, Laughlin KR et al. Addition of anticholinergic solution prolongs bronchodilator effect of b agonist in patients with chronic obstructive pulmonary disease. Am J Med 1996;100: 40S-48S.
  8. Riding WD, Dinda P, Chatterjee SS. The bronchodilator and cardiac effects of five pressure-packed aerosols in asthma. Brit J Dis Chest 1970;64:37-45.
  9. Kamburoff PL, Prime FJ. Oral and inhaled salbutamol as a bronchodilator. Brit J Dis Chest 1970;64:46-54.
  10. Seberova E and Andersson A. Oxis (formeterol given by Turbuhaler) showed as rapid an onset of action as salbutamol given by a pMDI. Respir Med 2000;94:607-611.
  11. Blom MW, Sommers DeK. Comparative Pharmacology of salmeterol and formeterol and their interaction with salbutamol in healthy volunteers. Clin Drug Invest 1997; 14(5):400-404.
  12. Brockelbank D, Ram F, Wright J et al. Comparison of the effectiveness of inhaler devices in asthma and chronic obstructive airways disease: a systematic review of the literature. Health Technol Assess. 2001;5(26):1-149.

Brigitte Borg
Senior Respiratory Scientist and Oxygen Therapy Coordinator
Department of Respiratory Medicine
The Alfred
PO Box 315

Employment opportunities in Australia and New Zealand for people from the Northern Hemisphere?

Thank you to the ongoing enquiries regarding work as Respiratory Therapist in Australia. The responses have been encouraging and I hope the following helps answer your questions and guides you in your future endeavor in obtaining employment.

Essentially, there are no Respiratory Therapist positions in Australia. 'Respiratory Therapists' work is spread over a number of different disciplines including physiotherapists, nurses with intensive care training, and respiratory scientists. The ANZSRS is a professional society dealing with the latter group and we, generally, work in diagnostic and research Respiratory and Exercise Laboratories. Although there are no single formal qualifications required to obtain work in Respiratory Laboratories in either Australia or New Zealand, most laboratories require people employed in this area to have attained a relevant tertiary qualification (such as a health science/science degree).

However, there are a number of expatriate Americans and Canadians with Respiratory Therapy backgrounds who have successfully obtained work in Australia and New Zealand. Knowledge and experience in respiratory function testing is a particular advantage to obtain work in this field. If you are considering working in Australia and/or New Zealand, I would suggest you contact the Respiratory Medicine departments of the larger hospitals in the states that interest you. Alternatively, there are ANZSRS Board Members in each state, who can be contacted via e-mail to help with your enquiries www.anzsrs.org.au/currentboard.html .

In recent times there have been many job opportunities in Sleep Laboratories in Australia & New Zealand, and as I understand it, Respiratory Therapists sometimes work in this field. If you have experience working in a Sleep Laboratory I would expect that it should not be difficult to find work in this area. Again, contact the major hospitals in each state, or alternatively contact the Australasian Sleep Technologists Association at http://www.sleeptechnologists.com

If you wish to submit an expression of interest for employment in Australia, you should contact the Web-site Co-ordinator directly.

Dear Derek,

Do you know who supplies Koko Spirometers in Australia?

Answer:

Technipro Marketing Pty Ltd
13 Bourke Strret, Nth Parramatta, NSW 2151
P.O Box 6390, Parramatta Business Centre NSW 2150
Ph: 02 980 9311, Fax: 02 9890 7488

Mat van Heerden from Technipro advises:
"The range includes KoKo PFT, KoKo DigiDoser and KoKo Trek spirometers. In addition to these we carry the full range of Barrier Filters and a standard 3 Litre and a MultiFlow 3 Litre, calibration syringe, from PDS."

{As an aside, the name KoKo derives from the legendary figure KoKopelli, a humpbacked flute player who traveled from village to village through the South West USA spreading fertility in the hunt and in the field. His abundance was also bestowed upon village women, barren wives welcoming him and unmarried maidens fleeing in terror. There are several theories as to the origin of the hump back. Some view the hump as being a sack of babies for distribution while others believe it represents the results of tuberculosis. K.G.}

Dear Derek,

Re: Strengthening Lung Capacity/emphysema
I refer to the above and would appreciate guidance on tackling emphysema and exercises that could be carried out to strengthen lungs.

Answer:
The information that you are looking for regarding improving muscle strength and optimising therapeutic management suggests that you may benefit from enrolling in a Pulmonary Rehabilitation Program. These programs are available at major hospitals and in the community in all states of Australia. You need to discuss this your doctor and ask for a referral,

What is Pulmonary Rehabilitation?
Pulmonary Rehabilitation (PR) is a multi-modality system that includes patient education, exercise training and psychosocial support delivered by an interdisciplinary team of therapists. PR is designed for people with moderate to severe emphysema. The benefit's of PR for a person with respiratory disease is to provide a supportive environment, with close liaison with healthcare professionals.

For Further Information contact

The Australian Lung Foundation Web site: www.lungnet.org.au
Telephone: 1800 654 301
National Office Address: Level 3, 454 Upper Edward Street
Spring Hill, Queensland, 4000

This organisation can provide you with comprehensive information on PR and can direct you to healthcare providers offering PR programs.

The Buteyko approach to breathing problems may also offer you some help. I suggest you visit sites such as www.buteyko.com.au for further information. An internet search on "Buteyko" will produce a great many sites in Australia alone.

There are many COPD support groups operating in Australia which could also help you. I suggest you contact your Doctor or local Hospital for information as to groups that are active in your area.

Thank you for your enquiry and I hope there is something in this answer to assist you.

Derek Figurski

 

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