The correlation between carotid blood flow and the parameters derived by pulse oximetry plethysmographic waveform during cardiopulmonary resuscitation in a porcine model / 中华急诊医学杂志

ABSTRACT

Objective:To explore the correlation between carotid blood flow and the parameters derived by pulse oximetry Plethysmographic waveform in cardiopulmonary resuscitation, so as to provide a new index for carotid blood flow monitoring in cardiopulmonary resuscitation.Methods:Seven male domestic pigs were utilized for cardiac arrest model through ventricular fibrillation induced by electrical stimulation. Eight minutes after cardiac arrest, artificial chest compression was given for 4 min, and epinephrine 20 μg/kg was injected intravenously at 2 min after chest compression. The compression frequency, compression depth, right carotid blood flow, pulse oximetry plethysmographic waveform, aortic pressure, right atrium pressure and end tidal carbon dioxide partial pressure were continuously monitored and recorded. From 30 s to 4 min after chest compression, the values of the mean right carotid blood flow, the area under curve (AUC) of pulse oximetry plethysmographic waveform, the mean perfusion index, the mean coronary perfusion pressure and the average end-tidal carbon dioxide partial pressure during 6 s before time point were calculated every 30 s. The correlations between right carotid blood flow and the AUC of pulse oximetry plethysmographic waveform and perfusion index were analyzed respectively.Results:Ventricular fibrillation was induced successfully in seven animals. There were no significant differences in the mean chest compression frequency and depth per min during 4 min of chest compression. Right carotid blood flow at 30 s after chest compression was (92.7±32.7) mL/min, and decreased to (48.5±23.5) mL/min at 1 min after chest compression ( P<0.05). There was no significant difference in blood flow before and after epinephrine injection ( P>0.05). The AUC of the blood oxygen plethysmographic waveform and perfusion index showed synchronous change trends with right carotid blood flow. Both coronary perfusion pressure and end-tidal carbon dioxide partial pressure showed different change trends with right carotid blood flow. There was a positive correlation between the right carotid blood flow and the AUC of blood oxygen plethysmographic waveform ( r=0.66, P<0.01), and also a positive correlation between right carotid blood flow and perfusion index ( r=0.57, P<0.01). Conclusions:Carotid blood flow is positively correlated with the AUC of blood oxygen plethysmographic waveform and perfusion index in a porcine model of cardiopulmonary resuscitation. Real-time monitoring of the two parameters derived by pulse oximetry plethysmographic waveform can reflect the changes of carotid blood flow to a certain extent.