Annie, Annie, Are You OK? Does Anyone Know CPR?
Abstract & Commentary
Synopsis: This single-center, prospective, observational study of resuscitation for in-hospital cardiac arrest reveals that the performance of cardiopulmonary resuscitation is inconsistent with current guidelines.
Source: Abella BS, et al. JAMA. 2005;292(3);305-310.
The study objective was to assess compliance of cardiopulmonary resuscitation (CPR) for in-hospital arrest with national and international guidelines by measuring several surrogate parameters of CPR quality (compression rate, compression depth, ventilation rate, no-flow time). Inpatients older than 18 years of age experiencing cardiorespiratory arrest at the study hospital were eligible. Those having arrest in the emergency department or operating room and those not resuscitated with the study monitor/defibrillator were excluded. The study monitor/defibrillator was modified by Laerdel Medical Corporation to record presence or absence of pulse, rate and depth of chest compressions and rate and volume of ventilations. This device has been tested and validated previously.
Compression rate, compression depth, ventilation rate and no-flow time (time without compressions and thus without blood flow to vital organs) were recorded for the first 5 minutes of CPR. American Heart Association guidelines were used to define expected values (compression rate 100/minute, compression depth 1.5-2.0 inches, ventilation rate 12-16/minute, no-flow time 10 seconds/minute of CPR). A no-flow fraction (NFF, fraction of cardiac arrest time without compressions) was then calculated (expected value 17%). CPR quality parameters were compared for patients who died vs those who had return of spontaneous circulation (ROSC). Standard statistical methods were employed.
Over 16 months, 67 patients were enrolled. Mean age was 62 years. Two-thirds of patients were men and nearly the same number were black. Half (52%) of the cardiac arrests occurred in an intensive care unit. The initial rhythm was identified as pulseless electrical activity in 60%, pulseless ventricular fibrillation/tachycardia in 15%, and asystole in 10%. Forty percent of patients had ROSC and 10% survived to hospital discharge. Mean compression rate was < 90/minute 28% of the time and compression depth was < 1.5 inches 37% of the time. Mean ventilation rate was > 20/minute 61% of the time. In regards to ventilation volume, Abella and associates report "[this] did not appear to deviate greatly from physiological ranges." Mean NFF was 24%. No significant associations were seen between these parameters and ROSC.
Comment by Saadia R. Akhtar, MD, MSC
Standardized, internationally accepted adult CPR certification courses and guidelines exist.1 Nearly every health care professional is required to complete such a course and to maintain CPR certification. Despite this, compliance with guidelines appears to be poor. This report from Abella et al is the latest to demonstrate that compression rate and depth and ventilation rate during real-world in-hospital CPR deviate considerably from recommendations: the ultimate and most important impact of this is prolonged no-flow time. In addition to this report, a recent European observational study of quality of CPR during out-of-hospital arrest (published in the same issue of JAMA) found inadequate chest compressions nearly half of the time.2 Neither of these studies was designed to measure the effect of CPR quality on outcomes. There are no randomized controlled human trials of impact of CPR provision according to guidelines on the outcomes of cardiac arrest. However, it is clear from animal and other observational human studies that providing adequate and continuous compressions and limiting no-flow time significantly improves survival and neurological outcomes.3 In addition, hyperventilation may worsen survival.4
As health care professionals in intensive care medicine, we focus much time and attention on maximizing outcomes by employing sophisticated therapies, technologies and artificial life-support mechanisms for all patients, including those post-cardiorespiratory arrests. This study is an important reminder that without initial effective resuscitation, other interventions may be futile; the quality of CPR we are providing currently must be improved. On a personal and local scale, I recommend sharing these findings, re-training frequently and monitoring resuscitation events at our own institutions for compliance with guidelines: I believe that if we start by focusing on one thing, the essence of continuous and adequate compressions, we can make an impact. On a larger scale, future studies must eval uate what optimal CPR is, how it impacts outcomes and how to best teach and implement it.
1. Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. The American Heart Association in collaboration with the International Liaison Committee on Resuscitation. Circulation. 2000;102 (Suppl):I1-I403.
2. Lars W, et al. JAMA. 2005;292(3):299-305.
3. Gallagher EJ, et al. JAMA. 1995:274(24):1922-1925.
4. Aufderheide TP, et al. Crit Care Med. 2004;32:345-351.
Saadia R. Akhtar, MD, MSc, Pulmonary and Critical Care Medicine Yale University School of Medicine, is Associate Editor for Critical Care Alert.