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Stroke volumes and end-tidal carbon dioxide generated by precordial compression during ventricular fibrillation
Andrej Pernat1, Max Harry Weil, Shijie Sun
1Institute of Critical Care Medicine, Palm Springs, CA, USA.
Objective:
The objective of this study was to measure stroke volumes produced by precordial compression during cardiopulmonary resuscitation and to quantitate relationships of stroke volume to measurements of end-tidal carbon dioxide.
Design:
A prospective, observational animal study.
Setting:
Medical research laboratory in a university-affiliated research and educational foundation.
Subjects:
Domestic pigs.
Interventions:
Eighteen anesthetized male, domestic pigs weighing between 40 and 45 kg were investigated. Ventricular fibrillation was electrically induced and continued for intervals ranging from 4 to 10 mins. Precordial compression was maintained at 80 per minute together with mechanical ventilation after endotracheal intubation.
Measurements And Main Results:
Stroke volumes were measured with the aid of transesophageal echocardiographic imaging. End-tidal carbon dioxide was quantitated with conventional capnography. Baseline values of thermodilution cardiac output were highly correlated with echocardiographic measurements (r =.92). The stroke volume index produced by precordial compression averaged 0.45 mL/kg or approximately 37% of the average prearrest value of 1.22 mL/kg. The end-tidal carbon dioxide was highly predictive of stroke volume index (r =.88, p <.001) with a mean bias of 0.003 mL/kg.
Conclusions:
We confirmed that precordial compression produces approximately one third of prearrest stroke volumes during cardiopulmonary resuscitation and demonstrated that end-tidal carbon dioxide was quantitatively predictive of stroke volume index estimated by transesophageal echocardiographic imaging.