CPR often does not meet or adhere to standard guidelines

New research indicates that CPR performed outside the hospital and in the hospital often does not meet or adhere to standard guidelines, according to 2 studies in the January 19 issue of JAMA.

The importance of CPR (cardiopulmonary resuscitation) for survival of cardiac arrest patients has been demonstrated, according to background information in the article. There are indications that the quality of CPR performance influences the outcome. When tested on mannequins, CPR quality performed by lay rescuers and health care professionals tends to deteriorate significantly within a few months after training, but little is known about the quality of actual clinical performance of CPR on patients.

CPR guidelines recommend target values for chest compressions, ventilations, and CPR-free intervals allowed for rhythm analysis and defibrillation. There is little information on adherence to these guidelines during advanced cardiac life support during out-of-hospital cardiac arrest.

In the first study, Lars Wik, M.D., Ph.D., of Ulleval University Hospital, Oslo, Norway and colleagues examined the performance of paramedics and nurse anesthetists during out-of-hospital advanced cardiac life support (ACLS) by continuously monitoring all chest compressions and ventilations during resuscitation episodes using online defibrillators. The study included 176 adult patients with out-of-hospital cardiac arrest treated by paramedics and nurse anesthetists in Stockholm, Sweden, London, and Akershus, Norway, between March 2002 and October 2003. The defibrillators were modified to measure chest compressions and ventilations, in addition to standard event and electrocardiographic recordings.

The primary outcome measure was adherence to international guidelines for CPR. Target values for compression rate were 100 to 120/min; for depth, 38 to 52 mm; and for ventilation rate, 2 ventilations for every 15 compressions before intubation and 10/min to 12/min after intubation.

The researchers found that chest compressions were not given 48 percent of the time without spontaneous circulation; this percentage was 38 percent when subtracting the time necessary for electrocardiographic analysis and defibrillation. Combining these data with an average compression rate of 121/min when compressions were given resulted in an average compression rate of 64/min. Average compression depth was 34 mm, 28 percent of the compressions had a depth of 38 mm to 51 mm, and the compression part of the duty cycle was 42 percent. An average of 11 ventilations were given per minute. Sixty-one patients (35 percent) had return of spontaneous circulation, and 5 of 6 patients discharged alive from the hospital had normal neurological outcomes.

“Whether some of these deficiencies can be improved by specific focus during training needs attention. Through better understanding of the mistakes made in a real-life cardiac arrest situation, training courses might be designed to focus on these aspects. Another approach would be to develop online tools that prompt the rescuer to improved performance. Audiotapes giving instructions on chest compression rate have been reported to improve the compression rate during cardiac arrest in patients,” the authors write.

“If our study represents how CPR is delivered during resuscitation from out-of-hospital cardiac arrest in other communities, there is a great opportunity to improve CPR quality and, hopefully, patient survival by focusing on delivery of chest compressions of correct depth and rate, with minimal ‘hands-off’ periods,” the researchers conclude.