Microvascular blood flow during cardiopulmonary resuscitation is predictive of outcome

SummaryThere is growing evidence that microcirculatory blood flow is the ultimate determinant of the outcome in circulatory shock states. We therefore examined changes in the microcirculation accompanying the most severe form of circulatory failure, namely cardiac arrest and the effects of subsequent cardiopulmonary resuscitation. Ventricular fibrillation was electrically induced in nine pigs and untreated for 5 min prior to beginning closed chest cardiac compression and attempting electrical defibrillation. Orthogonal polarization spectral imaging was utilized for visualization of the sublingual microcirculation at baseline, 0.5, 1, 3 and 5 min after onset of ventricular fibrillation and at 1 and 5 min after start of chest compression. Images were also obtained 1 and 5 min after restoration of spontaneous circulation. Microvascular flow was graded from 0 (no flow) to 3 (normal flow). Aortic and right atrial pressures were measured and coronary perfusion pressure was computed continuously. Microcirculatory blood flow decreased to less than one-fourth within 0.5 min after inducing ventricular fibrillation. Precordial compression partially restored microvascular flow in each animal. In animals that were successfully resuscitated, microvascular flow was significantly greater after 1 and 5 min of chest compression than in animals with failed resuscitation attempts. Microvascular blood flow was highly correlated with coronary perfusion pressure (r = 0.82, p < 0.01). Microvascular blood flow in the sublingual mucosa is therefore closely related to coronary perfusion pressure during cardiopulmonary resuscitation and both are predictive of outcome.