Cardiopulmonary exercise testing in our practice

When we invested in new gear for the lung function lab last year I was very keen to obtain the appropriate equipment to allow us to do cardiopulmonary exercise testing. Having trained in labs where this test was performed frequently I felt that we were not quite providing a comprehensive respiratory function laboratory facility unless we had this capacity.

In conversation with a local anaesthetist recently I was made aware that there are only four facilities in Melbourne that offer medicare-funded cardiopulmonary exercise testing. There are none in regional Victoria, apart from us. Makes me wonder at what point I should reign in my enthusiasm for developing our practice!

The point of our conversation, however, was that there is a growing interest in the anaesthetic literature surrounding the role of cardiopulmonary exercise testing (CPX) in pre-anaesthetic evaluation. Cardiopulmonary exercise testing has previously been demonstrated to be useful in predicting risk of perioperative complications or death following surgery to resect lung cancers. There is a growing body of evidence - not all of it yet consistent - to suggest that measurements of peak oxygen consumption (VO2 max) or anaerobic threshold may also be relevant when it comes to predicting likelihood of complications following bowel resections. The two parameters require a CPX for their calculation.

I will blog more about this in future. At present, indications for CPX as per The American Thoracic Society/American College of Chest Physicians Statement on Cardiopulmonary Exercise Testing (2003) include:

1. Evaluation of exercise tolerance, where the diagnosis is known, in order to objectively evaluate functional capacity, disability or response to treatment.
2. Evaluation of undiagnosed exercise intolerance where cardiac and respiratory aetiologies may coexist, the symptoms are disproportionate to the results of resting investigations or the investigations are non diagnostic.
3. Evaluation of patients with cardiovascular diseases.
4. Evaluation of patients with respiratory diseases/symptoms.
5. Pre-operative evaluation.
6. Exercise evaluation and prescription for pulmonary rehabilitation.
7. Evaluation of impairment/disability.
8. Evaluation for lung, heart and heart-lung transplantation.
   

Some of these are pretty general. Items 1 and 2 cover most of our CPX patients. For some patients who are young but have a considerable burden of respiratory disease, CPX provides a wholistic baseline measure of fitness against which we can refer back to monitor how well a general program of management is working. In patients with cardiac and respiratory disease it can help tease out which is the exercise limiting problem. And finally, in some patients who are simply unfit ('deconditioned') the the CPX can simply confirm that 'diagnosis', which otherwise is usually based on clinical impression.

Andrew

Type 2 diabetes and OSA

Last Wednesday the 16th of September I was invited to do a presentation for the South East SA Diabetes Educators Seminar in Mount Gambier. The topic was `Obstructive Sleep Apnea and Type 2 Diabetes’ which proved to be a very interesting area to explore.

I thought it would be useful to share some interesting (and perhaps surprising) facts about these two conditions from the International Diabetes Federation (IDF) Taskforce on Epidemiology and Prevention Consensus Statement on Sleep Apnoea and Type 2 Diabetes.

It has been estimated that between 5-7 % of the population have OSA, but it is largely undiagnosed. Those diagnosed with Type 2 DM is also expected to rise significantly into the future.

“Research shows that it is likely in people with type 2 diabetes that more than 50% suffer from some form of sleep disorder such as sleep apnea,”
“At the same time, up to 40% of people diagnosed with sleep apnea have diabetes and they have significantly greater risk of developing diabetes compared to those that don’t suffer from the sleep disorder.”
Professor Paul Zimmet AO MD PhD FRACP FRCP FDECo Chair of the IDF working group Director Emeritus and Director of International Research, Baker DI Heart and Diabetes Institute, Melbourne Australia

OSA has been found to be associated with insulin resistance independent of obesity (Punjabi, et al ASRCCM, 2002)

Those with OSA and Type 2 DM are at increased risk of developing other conditions such as high blood pressure, heart disease, and obesity just to name a few.

More research needs to be done to determine the exact physiological pathways which link these conditions and the effects of treatment. However, the most important message for health professionals is to be aware of this, and screen those with one condition for the other.

Lisa

Singing, Quality of Life and Pulmonary Function

A blog Andrew posted a few weeks ago about COPD rehab and showed a gentleman singing beautifully while on oxygen reminded me of some research I had heard of a few years ago while working in Health Promotion. The study investigated the benefits of singing for respiratory health.

A study like this was conducted in Brazil at the Internal Medicine Department, Medical School of Ribeirão Preto, University of São Paulo.

This study aimed to investigate the effects of weekly singing classes on pulmonary function parameters and quality of life (QoL) of COPD patients. Forty-three patients were randomized to weekly classes of singing practice, or handcraft work. They performed spirometry and completed maximal respiratory pressure measurements, evaluations of dyspnea, and the Saint George's Respiratory Questionnaire, before and after 24 training classes. A functional evaluation, immediately after 10 minutes of singing practice, was also performed at the end of the study. Fifteen subjects completed the study in each group. In comparison to controls the singing group exhibited transitory elevations on the dyspnea Borg scale (p = 0.02), and inspiratory capacity (p = 0.01), and decreases of expiratory reserve volume (p = 0.03), just after a short session of singing. There was a significant difference on changes of maximal expiratory pressures in the comparison between groups at the end of training. While the control group showed deterioration of maximal expiratory pressure, the singing group exhibited a small improvement (p = 0.05). Both groups showed significant improvements of QoL in within group comparisons.

The researchers concluded that singing classes are a well tolerated activity for selected subjects with COPD. Regular practice of singing may improve Quality of Life, and preserve the maximal expiratory pressure of these patients.

Jessica

Quality control in Spirometry

The recent Respiratory Update Seminar at WDHS has inspired me to write a bit about the quality of lung function testing. We were fortunate to be given the opportunity to present at the seminar and give a practical demonstration of one of the simplest measures of lung capacity spirometry.

It is essential we strive to provide quality test results enabling the physician to confidently base decisions upon.

Reference values, which produce predicated equations must be appropriate; the machine must be reliable, results accurate & precise with documented quality control. The lab must adhere to good practices & standards including frequent biological controls & have well trained technicians, there is nothing better than experience and busier labs produce better quality results.

As the tests are effort dependant a good rapport must be struck between the patient and the scientist to achieve maximal manoeuvres.

Test results must meet American Thoracic Society acceptability and reproducibility criteria. A reproducible effort is defined as being without excessive variability and an acceptable effort is defined as being free from error or artifacts.

The machine must be calibrated at least daily. This is the process in which a signal from a spirometer is adjusted to produce a known output using a calibrated 3L syringe.

Quality Control is a formal program to document & maintain instrument and laboratory staff personnel and includes testing performed to determine the accuracy and/or precision of the device using a known standard or signal. Documented Quality Control performed on a regular basis is an important part of good laboratory practise plus corrective & preventative maintenance. Other important components are infection control, accurate record keeping, personnel training and professional development.

The daily QC enables us to quickly determine the onset of a problem within one day
Evidence shows labs with poor quality controls generally produce results which are lower which may result in a misdiagnosis of diseased lungs.

Vanessa

The ubiquitious fungus

Evaluating a patient with difficult asthma this morning, my registrar asked me about ABPA. Aspergillus-related lung disease is poorly understood by doctors in training, and a little bit complicated. Allergic broncho-pulmonary aspergillosis is by-far the commonest manifestation of aspergillus disese which I encounter.

Aspergillus occurs in the lungs in the following ways:

1. Commensal in people with intact immunity and chronic lung disease

2. Aspergilloma in people with cavitating lung disease (old TB, emphysema); no treatment is usually required (the risks of surgery outweighing the benefit).

3. Chronic pulmonary aspergillosis; in people with chronic lung disease and mildly impaired immunity - for example on glucocorticoids. There is some invasion of lung parenchyma, and antifungal therapy may be required.

4. Allergic bronchopulmonary aspergillosis. IgE mediated sensitivity to the fungal spores, usually presents as difficult - to - control asthma. Any one or all of the following clincial features may occur; migratory lung infiltrates, peripheral blood eosinophilia, proximal bronchiectasis. Diagnosis depends on demonstrating the immunological response to aspergillus - not on demonstrating aspergillus in the airway. IgE is elevated about 1000, RAST or skin-prick sensitivity to aspergillus is evident. Treatment is targetted at the immune response (with glucocorticoids) and at antigen reduction. In regard to the latter, the only good evidence is for the benefit of itraconazole for up to 4 months at a dose of 200mg bd. Itraconazole is not on the PBS in Australia for this indication. Success of treatment is measured by clincal response and pulmonary physiology, and perhaps also by monitoring total IgE. A trial underway at the Alfred Hospital in Melbourne is evaluating the efficacy of the anti-IgE monoclonal antibody Omalizumab in treatment of ABPA.

5. Invasive aspergillosis occurs in patients with severely compromised immunity - for example bone marrow transplant recipients. Aggressive treatment with antifungals is required.

Glad to have clarified all that.

Andrew

Pulmonary rehab

In the last decade pulmonary rehabilitation has become a mainstay of management of COPD. Improvements in quality of life and exercise tolerance are generally the goals of pulmonary rehab programs, which should run for at least 8 weeks at a time. In our small country communities, pulmonary rehabilitation programs have resulted in apparently significant reductions in utilisation of hospital resources over winter.

These programs generally include supervised exercise and education. I have not, much as I love to sing, been involved with choral pulmonary rehab.

A friend recently brought to my attention this video clip - a moving rendition of the Coldplay song 'Fix You'. The song is sung by an aged gent with a rich baritone - and an oxygen concentrator at his side - backed up by the 'Young at heart' choir. I found it moving, and inspirational.

Andrew

Clean that nose!

So many of our patients with asthma and bronchiectasis have chronic nasal infection. Without control of the nasal disease - particularly when the problem is infective sinusitis - the lower airway problems never settle.

Sometimes we are a bit micky-mouse about this. 'Try this steroid spray'. 'Sprinkle a bit of FESS up there'.

This is probably how it should be done.



Andrew