JAMA 9 Feb 2011 Vol 305
585 Last week we learned that elevation of cardiac troponins happens in up to 30% of percutaneous coronary procedures, but seems to have little prognostic importance. This week a study looks at enzyme elevations in coronary artery bypass surgery and comes to a less reassuring conclusion. The main end-point is 30-day mortality and this shows a strong correlation with increasing levels of creatine kinase. Surprisingly, perhaps, the correlation with levels of troponin-1 is much weaker.
http://jama.ama-assn.org/content/305/6/585.abstract
BMJ 12 Feb 2011 Vol 342
371 A couple of weeks ago, the NEJM published a remarkable opinion piece suggesting that out-of-hospital cardiopulmonary resuscitation using chest compression lacks any evidence base and is in need of a randomised controlled trial. One respondent on doc2doc suggested that this was a bit like the suggestion in a Christmas issue of the BMJ for an RCT of jumping from a plane with or without a parachute. Not so: we know the results of that from the invariable observation of splats on the ground versus intact people under billowy silk umbrellas, whereas since CPR was devised 40 years ago, nobody has dared leave any pulseless patient without it. Maybe one in ten really has a pulse or will get one back anyway, and the rest will die, as they do following CPR. This study is consistent with the hypothesis of a useless procedure - it shows that if you improve the quality of CPR by real-time feedback, you do not improve patient outcomes.
http://www.bmj.com/content/342/bmj.d512.full
372 A mercury sphygmomanometer fitted with a large adult cuff was often the default method of measuring office blood pressure. After several years of backing this up with ambulatory BP monitoring before starting people on lifelong treatment, it has now moved towards encouraging home BP measurement, though the quality of most electronic sphygmomanometers on sale to the public (see British Hypertension Society website) is variable. These issues are very well summarised in the editorial on p.343 (provocatively subtitled "Must be done carefully, or not at all"), in response to this groundbreaking Canadian study of conventional versus automated BP measurement in primary care patients with systolic hypertension. The new "gold standard" - if there is such a thing - for BP measurement in primary care may be the use of BpTRU device in a room uninhabited by scary health professionals of any kind. The device automatically takes the BP at preset intervals and calculates the average of five readings. These are usually significantly lower than doctor measurements and correlate well with home measurements. It could be suggested that for most practices, the barrier will be finding a quiet room rather than buying a BpTRU machine.
http://www.bmj.com/content/342/bmj.d286.full
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