Am. J. Respir. Crit. Care Med., Vol 150, No. 3, Sep 1994, 861-864.
Spontaneous gasping during cardiopulmonary resuscitation without mechanical ventilation
M Noc, MH Weil, S Sun, W Tang and J Bisera
Institute of Critical Care Medicine, University of Health Sciences, Chicago Medical School, Illinois.
Spontaneous gasping is frequently observed during cardiac arrest,
especially when mechanical ventilation is withheld during precordial
compression. We related spontaneous gasping to pulmonary gas exchange and
cardiac resuscitability in a rodent model of cardiac arrest. Ventricular
fibrillation was electrically induced in 15 Sprague-Dawley rats. After 4
min untreated ventricular fibrillation, precordial compression was
initiated. Coronary perfusion pressure was maintained between 25 and 30 mm
Hg. Oxygen was supplied at the tracheal tube port coincident with start of
precordial compression in 10 animals. Five additional control animals were
identically treated except they were mechanically ventilated coincident
with start of precordial compression. After 6 min precordial compression,
defibrillation was attempted and five of 10 nonventilated animals, and all
control animals, were resuscitated by direct current countershock. In the
successfully resuscitated, nonventilated animals, the frequency of
spontaneous gasping during precordial compression progressively increased
to an average of 19 gasps/min but it was < 6 gasps/min in
nonresuscitated animals. More frequent gasping was associated with
correspondingly greater arterial PO2 (110 versus 51 mm Hg, p < 0.01) and
lesser PCO2 (55 versus 91 mm Hg, p < 0.01). In control animals, no
spontaneous gasping was observed during precordial compression. Arterial
PO2 and PCO2 of mechanically ventilated animals was more like that of
spontaneously gasping rats. According, the frequency of spontaneous gasping
in absence of mechanical ventilation is predictive of cardiac resuscitation
success and associated with improved arterial oxygenation and CO2 removal.
