Tom P. Aufderheide,
MD; Gardar Sigurdsson, MD;
Ronald G. Pirrallo, MD, MHSA; Demetris
Yannopoulos, MD; Scott McKnite,
BA; Chris von Briesen, BA,
From the Department of Emergency Medicine,
Medical College of Wisconsin, Milwaukee (T.P.A., R.G.P., C.J.C.); Advanced
Circulatory Systems, Inc, Eden Prairie, Minn (C.v.B., C.W.S., T.A.P., K.G.L.); and the Cardiac Arrhythmia
Center, Departments of Internal Medicine and Emergency Medicine, Hennepin
County Medical Center, University of Minnesota, Minneapolis (G.S., D.Y., S.M.).
Correspondence to Keith G. Lurie, MD, Box 508, UMHC, 420 Delaware Street SE,
Minneapolis, MN 55455. E-mail lurie002@tc.umn.edu
Received October 22, 2003; revision
received December 30, 2003; accepted February 2, 2004.
Background— A clinical observational study revealed that rescuers
consistently hyperventilated patients during out-of-hospital cardiopulmonary
resuscitation (CPR). The objective of this study was to quantify the
degree of excessive ventilation in humans and determine if
comparable excessive ventilation rates during CPR in animals
significantly decrease coronary perfusion pressure and survival.
Methods and Results— In humans, ventilation rate and duration during
CPR was electronically recorded by professional rescuers. In 13
consecutive adults (average age, 63±5.8 years) receiving CPR (7
men), average ventilation rate was 30±3.2 per minute (range, 15 to
49). Average duration per breath was 1.0±0.07 per second. No patient
survived. Hemodynamics were
studied in 9 pigs in cardiac arrest ventilated in random order with
12, 20, or 30 breaths per minute. Survival rates were then studied
in 3 groups of 7 pigs in cardiac arrest that were ventilated at 12
breaths per minute (100% O2), 30 breaths per minute (100%
O2), or 30 breaths per minute (5% CO2/95% O2).
In animals treated with 12, 20, and 30 breaths per minute, the mean
intrathoracic pressure (mm Hg/min) and coronary
perfusion pressure (mm Hg) were 7.1±0.7, 11.6±0.7, 17.5±1.0 (P<0.0001),
and 23.4±1.0, 19.5±1.8, and 16.9±1.8 (P=0.03), respectively.
Survival rates were 6/7, 1/7, and 1/7 with 12, 30, and 30+ CO2
breaths per minute, respectively (P=0.006).
Conclusions— Professional rescuers were observed to excessively
ventilate patients during out-of-hospital CPR. Subsequent animal studies
demonstrated that similar excessive ventilation rates resulted in
significantly increased intrathoracic pressure and
markedly decreased coronary perfusion pressures and survival rates.
Key Words:
cardiopulmonary resuscitation • death, sudden • heart arrest • ventilation •
hypotension