Continued breathing followed by gasping or apnea in a swine model of ventricular fibrillation cardiac arrest.
BACKGROUND
Continued breathing following ventricular fibrillation has here-to-fore not been described.


METHODS
We analyzed the spontaneous ventilatory activity during the first several minutes of ventricular fibrillation (VF) in our isoflurane anesthesized swine model of out-of-hospital cardiac arrest. The frequency and type of ventilatory activity was monitored by pneumotachometer and main stream infrared capnometer and analyzed in 61 swine during the first 3 to 6 minutes of untreated VF.


RESULTS
During the first minute of VF, the air flow pattern in all 61 swine was similar to those recorded during regular spontaneous breathing during anesthesia and was clearly different from the patterns of gasping. The average rate of continued breathing during the first minute of untreated VF was 10 breaths per minute. During the second minute of untreated VF, spontaneous breathing activity either stopped or became typical of gasping. During minutes 2 to 5 of untreated VF, most animals exhibited very slow spontaneous ventilatory activity with a pattern typical of gasping; and the pattern of gasping was crescendo-decrescendo, as has been previously reported. In the absence of therapy, all ventilatory activity stopped 6 minutes after VF cardiac arrest.


CONCLUSIONS
In our swine model of VF cardiac arrest, we documented that normal breathing continued for the first minute following cardiac arrest.
Zuercher
Mathias
M
University of Arizona Sarver Heart Center, Tucson, AZ, USA.
Ewy
Gordon A
GA
Hilwig
Ronald W
RW
Sanders
Arthur B
AB
Otto
Charles W
CW
Berg
Robert A
RA
Kern
Karl B
KB
D000818:Animals; D001049:Apnea; D001944:Breath Tests; D004195:Disease Models, Animal; D006801:Humans; D007320:Inspiratory Capacity; D058687:Out-of-Hospital Cardiac Arrest / Q000175:diagnosis / Q000503:physiopathology*; D012119:Respiration; D013552:Swine; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000503:physiopathology*