Borderline pulmonary hypertension in Scleroderma

The lost table from my previous post on this topic, showing difference in 6 minute walk test distance covered in a group of 29 patients with systemic sclerosis but no heart or lung disease, who develop pulmonary hypertension on exertion, divided into two halves - above and below median pulmonary artery pressure. From recent paper in AJRCCM.



Figure 1. Six-minute-walk distance (mean ± SD) in patients with mean pulmonary arterial pressure values above (white) and below (black) the median as measured at rest (P < 0.005), at 25W (P < 0.005), at 50W (P < 0.0005), and at maximal exercise (not significant). *P < 0.005; **P < 0.0005.

Andrew

OSA and traffic accidents

Many studies have demonstrated that patients with OSA have a higher rate of road accidents.

A study earlier this year OSA as a cause of road traffic accidents took 163 patients with OSA (AHI>10) who were diagnosed by a PSG. Of these participants 18.4% drove for a living. Patients were asked to self report about any accidents they have had or near misses in the last three 3 years.

From this information participants were then divided into two groups, accidents and near misses and those who had had none. Both groups were compared by age, BMI, ESS, daytime PaO2 and PaCO2, functional outcome of sleep questionnaire (FOSQ) and PSG data.

The researchers demonstrated patients who have had road traffic accidents and near misses had more severe OSA, higher AHI's, excessive daytime sleepiness and lower quality of life.

It is estimated that over 50% of Australian truck drivers have mild OSA or worse. Access economics has estimated that the cost of sleep disorders in the Australian community is over $7 billion and much of this can be attributed to OSA.

In Victoria alone it is estimated fatigue results in more than 70 deaths and 500 serious injuries per year. Again it is estimated that a significant percentage of this fatigue is due to sleep disorders.

Being awake for more than 17 hours then driving has the same effect on someone as a blood alcohol level of being .05. Extend that to 24 hours without sleep and there is a similar effect on driving performance as having a blood alcohol concentration of .10. At this level there is a seven time greater risk of having an accident.

The TAC has an interesting case study on various advertising campaigns they have used to educate the community about the consequences of fatigue on our roads.

Jessica

Spirometry

Bronchial provocation testing was our topic for last month and this month lets talk about spirometry
Spirometry is a measure of airflow and lung volumes during a forced expiratory manoeuvre from full inspiration. The measurements made during spirometry are sometimes referred to as ‘dynamic lung volumes’. Although the simplest of all respiratory function tests correct interpretation requires that it be performed correctly

Spirogram
A diagrammatic representation of lung volumes and capacities based on a simple spirogram which we see every day. Relationships between the subdivisions and relative sizes as compared with TLC are shown. Resting expiratory level is used as a starting point for FRC determinations because it remains more stable than other identifiable points during repeated measurements

Volume-Time Curve
Spirometry measures airflow obstruction, airflow reactivity, lung restriction and normal lung function and these can be graphed in a volume-time or flow-volume format.
The volume-time curve produces FVC & FEV1. We can then calculate the ratio of these to obtain FEV1/FVC or FER. Accurate measurement of FEV1 requires an acceptable spirometer, preferably one that allows inspection of the volume-time curve and back-extrapolation. Additionally we can measure mid expiratory flow which gives an indication of small airway function & PEF which tells us how much force the patient is able (or willing) to generate

Mathematically these can be converted on some equipment to flow-volume curves and many conditions have typical curves. A flow-volume curve usually records flow in liters per second and the volume is recorded in liters, BTPS

Flow-Volume Loop
Expiratory and inspiratory flow-volume curves constitute a flow-volume loop and most modern spirometers can produce flow-volume loops. Visual pattern recognition from repeatable maximal flow volume loops, if available will help decide whether the measurement was performed correctly, as well as confirming the presence of abnormality

Of all the pulmonary function tests performed, spirometry remains the most widely used test. Although the simplest pulmonary function test, special emphasis must be placed on the performance of each test and the technician must have a sound understanding of the criteria for judging the acceptability and repeatability of test data based on the most recent guidelines published by the American Thoracic Society/European Respiratory Society (ATS/ERS) Task Force on Standardization of Lung Function Testing

Vanessa

Mild pulmonary hypertension in scleroderma

Scleroderma / systemic sclerosis is a rare connective-tissue disease. In this condition, hardening of ‘elastic’ tissue throughout the body results in a range of end-organ problems. Scleroderma affects the skin, gastro-intestinal tract, lungs, kidneys. It affects the blood vessels.

Blood vessel problems in the fingers and toes cause ‘Raynaud’s phenomenon’. Problems in the kidneys can cause dramatic renal failure. Problems in the lungs cause a condition called ‘pulmonary hypertension’.

In the last 15 years there has been a progressive increase in the number of medical treatments available for treatment of pulmonary hypertension. With this has come an increased amount of research into what had previously been something of an ‘orphan’ condition. Treatment (with prostacyclin analogues; with endothelin receptor antagonists (Bosentan); with the phosphodiesteraseE5 inhibitor Sildenafil, sometimes known as Viagra™) remains expensive and tightly controlled. Often treatment is not accessed until people have severe, or end stage, pulmonary hypertension. I have a handful of patients with scleroderma, and looked after many such patients when working in London. In London the bar for access to treatment for pulmonary hypertension seemed significantly lower than it is in Australia.

So I read, with much interest, a recent report from Austria/Germany/California about the impact of even high-normal pulmonary artery pressures (PAP) on the exercise tolerance of people with scleroderma. Twenty-nine patients with systemic sclerosis but no evidence of lung or heart disease participated in this trial. They all had normal resting pulmonary artery pressures on echocardiogram, but demonstrated an increase in systolic pulmonary artery pressure with exercise ( to over 40mmHg) or a deceased exercise capacity (peak VO2 <75% predicted). They all proceeded to have a more accurate measure of pulmonary artery pressure obtained via catheterization of the right side of the heart ( an invasive procedure, something like an angiogram). A cardiopulmonary exercise test was performed while the right heart catheter was in place to measure changes in PAP with exercise. Subsequently – right heart catheter now removed, but within 48 hours - they went on to perform a 6 minute walk test (6MWT). This test is as simple as it sounds. The supervisors of the 6MWT were not aware of the right-heart-catheter results.

The median resting PAP of the group was 17mmHg. A resting PAP greater than that level was associated with a reduced distance walked on 6MWT, reduced peak V02 and reduced maximal work rate. An early increase in PAP at low work levels showed essentially the same correlations, but PAP at peak exercise did not show an association with distance walked on 6MWT or peak V02 and maximal work rate.

These results are very interesting, and could be quite important. They suggest that people with scleroderma who have high-normal pulmonary artery pressures, and particularly those who show an early rise in PAP during exercise, have a lowered exercise capacity. The possibility that these people may have a worse prognosis needs to be considered and investigated. (There is evidence that patients with scleroderma, pulmonary fibrosis (which is often associated with scleroderma) and a resting PAP > 17mmHg have decreased survival when compared with patients whose PAP was <17mmhg (5- year survival 16.7% vs 62.2%)). Ultimately it may well turn out to be important to treat such patients with even high-normal PAP early with the available medications.

The wheels of evidence-based medicine turn slowly for ‘orphan’ conditions such as pulmonary hypertension. Translation of this sort of research, fascinating though I may find it, into meaningful therapeutic changes will take many years.

I have had no end of trouble with hyperlinks and pics on this post - will post table from the paper seperately.

If the mask fits, wear it!

Today I traveled to Portland, where the weather was very pleasant to visit the PDH sleep centre. During the morning we spent some time refreshing or for some newer staff members learning how to fit a cpap mask.

I was one of the ‘refreshers’ and thought I was quite experienced when it came to fitting masks but there were a few useful pieces of information that challenged my way of thinking.

Different people, places and companies all have their own ideas, routines or procedures when fitting cpap masks but the main two points are find a mask the minimizes leak and maximizes patient comfort.

I veered toward being a nasal mask advocate, always letting the patient try a full face as a comparison but was of the belief that nasal if they fitted well, the patient was able to tolerate it and there were no leaks it was a good choice. My reasoning being full faces having more surface area seemed to provide more opportunities to leak.

Nasal pillows were on my last resort list, although on many occasions I have seen them be very effective in managing OSA. If a patient arrived armed with some research and wanted to try them of course I would oblige but other than that I did not always offer patients the choice to try these on. My reasoning this time was nasal pillows can be very fiddly, difficult to fit and less tolerant of higher pressures.

The advice given today was always allow the patient to try on the three different sorts of masks. Unless they try them on we cannot make a judgment as to what fits them, what the patient finds the most comfortable and ultimately it is the patient who chooses the mask.

For the record I had on a nasal mask for a while today at 10cmH20. It was more comfortable than I remember and I think it is important to periodically wear different mask to give an insight into what the patients are experiencing. Kath tried on nasal pillows at 20cmH20. The mask tolerated this pressure and so did Kath! Raelene fitted her first mask on Gerri and also experienced cpap for the first time.

Pictured above are the three different types of masks mentioned. Our trainer today suggested we try to use cpap for a week to gain an even greater understanding of what our patient’s experience. Maybe I will blog about this at a later date.


Jessica

Spirometry Course

As the newest recruit to our Lung Function Testing Lab, I attended the Spirometry Course held at the Alfred Hospital in Melbourne on the 5th and 6th of November. This I enjoyed.

The Course was very well presented. The presenters were interesting and had a wealth of experience. They interspersed the Theory sessions with great hands-on Prac sessions to keep us all awake, and some quite complicated information was clearly presented with time to absorb it.

Thorough information was presented on how to achieve the proper standards of Quality Assurance, incorporating equipment and personnel, so that all tests done can be reliable, and provide an accurate clinical picture of each patient’s lung function. I realized at this point just how well our Lab measures up in this area.

I returned with an enthusiasm to 1) learn more in the areas of the documentation and analysis of Quality Control data, 2) look at research done on FEV6 ( the Forced Expiratory Volume at 6 seconds) which might be introduced as a measure of patient performance, and 3) to perfect my instructions to patients performing the test.

This was a thoroughly thought-provoking, challenging and enjoyable experience. Thank you to the presenters.

Heather.

Non-adherence to treatment regimes in difficult asthma

The accompanying picture of a Seretide ™ combined corticosteroid/ long- acting beta-agonist inhaler device hopefully evens the score a little in the war of the combination puffers on this blog (see comment on the post about use of eformoterol/budesonide in COPD) Each of Seretide ™ and Symbicort™ are excellent medications in airways disease (can I say it often enough?)– particularly asthma…… if our patients take them!

Which brings me to the topic of this post: non-adherence with prescribed medications in difficult asthma. A recent study from Northern Ireland, published in the American Journal of Respiratory and Critical Care Medicine (The Blue Journal) at the start of November, looked at this issue in a population of asthmatics referred to a tertiary – hospital ‘difficult asthma’ program. These were patients with persistent asthma symptoms in spite of regular combination inhaler use (one of the two above), with some on maintenance oral prednisolone. Around forty percent were referrals from other respiratory specialists to the hospital program.

I see many patients with ‘difficult asthma’, although they make up only about 5% of the adult asthmatic population. In general the first question I ask myself is always ‘does this person really have asthma?’ Frequently they do not, and the failure of asthma therapy reflects an initial misdiagnosis. The second question is ‘Is this person really using their medications?’ This recent study is the first that looks rigorously at adherence to prescribed medications amongst adults with ‘difficult asthma’.

The findings were startling. Although everyone claimed to use all of their medication as prescribed when asked at the commencement of the study, of 182 consecutive patients seen in the service 78% used less than their prescribed amount of combination inhaler medication, with at least 35% using less than half of what they were prescribed. Twenty-one percent used more of their combination inhaler (preventer) than had been prescribed, leaving 1% of patients using medication as prescribed!

The study then looked further at patients prescribed maintenance oral prednisolone, and found that 45% were non-adherent with that medication.

There were three variables that were associated with poor adherence to treatment. These were female gender (nearly 2/3 of the group on the whole was female. 42% of them were in the least-adherent group, where only 23% of the men were); low quality of life; and frequent hospitalizations in the previous year.

How was data collected? In Northern Ireland all medications that a patient is taking are prescribed by one GP only. Review of the number of prescriptions issued by that GP, compared against the dose of medication which the person is supposed to be using, allowed a reasonable measure of compliance to be obtained in this study. In the case of oral prednisolone dosing, regular use of prednisolone should lead to suppression of adrenal cortisol secretion. Blood test measures of prednisolone and cortisol levels were used in that patient group to evaluate compliance.

The findings of this study require reflection. Doctors of patients with ‘difficult asthma’ will be considering a range of alternative treatment approaches, including use of maintenance prednisolone orally, use of theophylline or montelukast (Singulair ™) or else a more expensive biological therapy (for example, Xolair™(omalizumab), with others on the horizon). It’s important that we don’t proceed to the more complicated, dangerous or expensive medications without clarifying whether the standard medications are, in fact, being used.

The authors of this study state that they believe ‘the key message off this study – that non-adherence is a significant issue in an unselected population with difficult-to-control asthma and significant asthma-related morbidity….is valid and needs to be proactively identified and addressed’. I agree. I suspect, however, that a systemic change in the way we distribute medication and monitor compliance may be required to effectively achieve this.

Andrew