Tuesday, December 29, 2009

How safe is Spirometry?


A recent publication by CG Araujo and LC Vianna in the Primary Care Respiratory Journal (2009); 18(3): p185-188 is headed: How often does spirometry testing induce cardiac arrhythmias?

This is something every Respiratory Scientist might want to know! How likely is it for spirometry to induce cardiovascular complications in our patients?

This study was carried out in Rio de Janeiro, Brazil, and used as its subjects 735 persons (548 men), who were referred to their centre for clinical diagnosis and/or exercise testing. They were aged from 10 to 98 years (mean age 54 years SD +/- 15). Each subject was submitted to a conventional medical examination and spirometry testing prior to a maximal cardiopulmonary exercise test (CPET). A continuous digital electrocardiogram (ECG) was recorded during spirometry and CPET, and later reviewed by the same physician who supervised the procedures.

The results: 64% of subjects did have cardiac arrhythmias during one or both procedures (33% during spirometry) and the arrhythmias occurred more often in those with pre-existing disease. In 59 % of the 64% of subjects, the arrhythmias caused were supraventricular (half of them one or more isolated beats), and only 5% presented with more complex arrhythmias including frequent premature ventricular beats or non-sustained ventricular tachycardia. No episodes of ventricular tachycardia occurred during spirometry.

The researchers conclude that spirometry is a safe procedure in terms of its induction of cardiac arrhythmias. Any spirometry-induced arrhythmias tended to be both simple and clinically irrelevant and were always short-lasting even in patients with mild or moderate obstructive pulmonary disease. Interestingly the researchers found that the large majority of the arrhythmias occurred during the “take a full breath” phase of the flow-volume loop manoeuvre.

The limitations of the study as described by the authors is that they selected a convenient sample of primarily Caucasian and upper socioeconomic strata subjects, a substantial number of whom had long-term chronic diseases, which might have affected the frequency and type of cardiac arrhythmias. The strengths of the study were that the study comprised a large number of consecutively enrolled subjects who were evaluated by a single physician who supervised all procedures.

The researchers also suggested that if easily available, it might be informative (particularly with men with a history of palpitations) to add ECG recording during spirometry, because in 70% of the 21% of patients who had reported a history of palpitations at the medical interview, spirometry and/or CPET induced a cardiac arrhythmia.

So, spirometry is a safe procedure (Phew!) with some interesting effects on the heart which could be further investigated.

Heather

1 comment:

  1. Thanks Heather. Great summary of the article. Worth remembering that there are some contraindications to spirometry - I think a list of these is found here; http://www.betterbreathing.com.au/?id=lungfunctiontesting

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