Ventilation—Cardiac Compression Rates and Ratios in Cardiopulmonary Resuscitation

Abstract

Ventilation-compression frequencies and ratios during cardiopulmonary resuscitation in dogs with ventricular fibrillation and ventilation frequencies in apneic healthy human subjects were studied. Lung inflations interposed between sternal compressions gave better ventilation and about equal carotid blood flows as compared to simultaneous inflations. A ventilation-compression ratio of 3/15 (using air) maintained normal oxygenation and ventilation whereas 6/iO did not. In apneic adults with 2 inflations (tidal volume 1,000 ml.) every 15 sec, oxygenation and ventilation were adequate with FIO2 - 50; but borderline with exhaled air. One inflation every 5 sec. with exhaled air gave normal values. In dogs carotid flows during external cardiac compression were about 10 to 25% of control. Seventy-two compression/min. gave better carotid flows than 60 compressions/roin., while 120 compressions/min. gave significantly greater flows than 72 compressions/min. The recommendations of a ventilation-compression ratio of 2/15 for 1 operator and 1/15 interposed for 2 operators (compressions at 1 sec. intervals without interruption) is sound.