A total of 12,653 patients were assigned to continuous chest compressions (the intervention group) and 11,058 to interrupted chest compressions (the control group). The primary outcome—the rate of survival to hospital discharge—was 9.0% in the intervention group and 9.7% in the control group, a nonsignificant difference. Similarly, the rate of survival with favorable neurologic function did not differ significantly, at 7.0% and 7.7%, respectively, the investigators said.1
However, it is also possible that three important limitations of this trial unduly influenced the results.
First, the per-protocol analysis, which used an automated algorithm to assess adherence to the compression assignments, could not classify many patients as having received either continuous or interrupted chest compressions. Second, the quality of postresuscitation care, which certainly influences outcomes, was not monitored. And third, actual oxygenation levels were not measured, nor were minutes of ventilation delivered. Thus, “we do not know whether there were important differences in oxygenation or ventilation between the two treatment strategies,” he said.
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RCT findings vs observational data
It is not yet clear why this large randomized trial1 showed no benefit from continuous chest compressions when previous observational research showed the opposite. One possibility is that many of the previous studies assessed not just chest compressions but an entire bundle of care related to CPR, so the benefits they reported may not be attributable to chest compressions alone.
In addition, in this study the mean chest-compression fraction – the proportion of each minute during which compressions are given, an important marker of interruptions in chest compressions – was already high in the control group (0.77) and not much different from that in the intervention group (0.83). Both of these are much higher than the target recommended by both American and European guidelines, which is only 0.60.
And of course a third reason may be that the interruptions for ventilation during CPR aren’t all that critical, and may be less detrimental to survival, than is currently believed.
Dr Rudolph W. Koster is in the department of cardiology at Amsterdam Academic Medical Center. He reported having no relevant financial disclosures. Dr Koster made these remarks in an editorial accompanying Dr Nichol’s report (Koster RW. Continuous or interrupted chest compressions for cardiac arrest [published online ahead of print November 9, 2015]. N Engl J Med).
Answers elusive in quest for better chlamydia treatment
BY BRUCE JANCIN
EXPERT ANALYSIS FROM ICAAC 2015
SAN DIEGO – The hottest topic today in the treatment of sexually transmitted diseases caused by Chlamydia trachomatis is the unresolved question of whether azithromycin is still as effective as doxycycline, the other current guideline-recommended, first-line therapy, Dr Kimberly Workowski said at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
“This is important, because doxycycline is administered twice a day for 7 days, and azithromycin is given as a single pill suitable for directly observed therapy,” noted Dr Workowski, professor of medicine at Emory University in Atlanta and lead author of the 2015 Centers for Disease Control and Prevention STD treatment guidelines.1
Several recent retrospective case series have suggested azithromycin is less effective, with the biggest efficacy gap being seen in rectal C. trachomatis infections. These nonrandomized studies were further supported by an Australian meta-analysis of six randomized, controlled trials comparing the two antibiotics for the treatment of genital chlamydia. The investigators found roughly 3% greater efficacy for doxycycline, compared with azithromycin, for urogenital chlamydia, and a 7% advantage for doxycycline in treating symptomatic urethral infection in men.
However, the investigators were quick to add the caveat that “the quality of the evidence varies considerably.”2
There’s a pressing need for better data. Dr Workowski and her colleagues on the STD guidelines panel are eagerly awaiting the results of a well-structured randomized trial led by Dr William M. Geisler, professor of medicine at the University of Alabama, Birmingham. The investigators randomized more than 300 chlamydia-infected male and female inmates in youth correctional facilities to guideline-recommended azithromycin at 1 g orally in a single dose or oral doxycycline at 100 mg twice daily for 7 days. The results, which are anticipated soon, should influence clinical practice, Dr Workowski said.