Research on CPR: reordering priorities.
The "ABCs" of CPR, i.e., airway, breathing, and circulation, represent the sequence of interventions currently advised and taught to providers of both basic life support (BLS) and advanced life support (ALS) by the American Heart Association. Nevertheless, in the settings of suspected or confirmed ventricular fibrillation, the ABCs may be deferred such that external electrical countershock(s) take(s) precedence. However, efforts to restore circulation by chest compression (or alternative mechanical means) remain the lowest of the three priorities for both BLS and ALS as presently prescribed. This ordering of priorities is based largely on the consensus rather than objective experimental or clinical evidence of improved outcomes. During the last 5 yrs, both clinical and experimental studies demonstrated that the A and B of these ABCs, and specifically positive-pressure ventilation, may not be essential during the initial 6 to 12 mins of CPR under conditions of sudden dysrhythmic cardiac arrest and in the absence of asphyxia. Recent studies further suggested that either or both precordial compression and spontaneous gasping may of itself generate sufficient alveolar ventilation during the initial 6 mins of CPR. Defibrillation now emerges as the highest priority. Automated defibrillators have a pivotal role. The need for objective controlled research, including experience with devices in clinical settings and technical improvements of operation, are essential.