Cardiac output during cardiopulmonary resuscitation (CPR) was measured by a modified indicator-dilution technique in 20 anesthetized dogs (6-12 kg) during repeated 1- to 2-min episodes of electrically induced ventricular fibrillation and CPR, produced by a mechanical chest compressor and ventilator. With compression rates from 20 to 140/min and compression durations (duty cycles) from 10 to 90% of cycle time, cardiac output (CO) was predicted by the equation:


where CR is compression rate, DC is duty cycle, SVmax (19 ml) is the effective capacity of the pumping chamber, and kl (0.00207 min) and k2 (0.00707 min) are ejection and filling constants. This expression predicts maximal CO for DC = 0.40 and CR = 126/min as well as 90-100% of maximal CO for 0.3 < DC < 0.5 and 70 < CR < 150/min. Such mathematical analysis may prove useful in the optimization of CPR.


This is the author accepted manuscript of Fitzgerald K.R., Babbs C.F., Frissora H.A., Davis R.W., Silver D.I., Cardiac output during cardiopulmonary resuscitation at various compression rates and durations, Am. J. Physiol. Heart 241, H442-H448, 1981. Copyright American Physiological Society, the version of record is available at http://ajpheart.physiology.org/content/241/3/H442.short.


cardiac arrest; cardiac arrhythmias; fibrillation, sudden cardiac death

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