Evaluation of acute cardiovascular effects of propofol on hemodynamic function in pigs

Background: Although propofol is a common hypnotic in laboratory pigs, its acute effects on cardiovascular function have not been investigated in this species. Therefore, the short-term cardiovascular effects of intravenous propofol bolus injection were observed using vascular ultrasonography and pulse contour–derived cardiac output (PiCCO) thermodilution monitoring. Materials and methods: In this prospective, experimental study, anesthesia was induced and maintained intravenously with propofol in six pigs. During anesthesia, three defined bolus injections of propofol were given intravenously. Vascular and hemodynamic variables were recorded by capnometry, pulse oximetry, and ultrasonography of the right common carotid artery before injection and for 10 minutes after each propofol bolus injection. Additionally, body temperature, blood pressure and central venous pressure, cardiac output, contractility, volumetric variables for preload and afterload, and extravascular lung water were recorded by PiCCO. Results: Propofol bolus injections caused a significant decrease in vessel diameter after 15 seconds at the right common carotid artery after each bolus injection. Simultaneously, peak systolic and end-diastolic blood flow velocities and heart rate significantly increased, while mean arterial blood pressure and systemic vascular resistance index significantly decreased. After these acute initial changes, vascular diameter reincreased towards baseline data and peak systolic blood-flow velocity significantly decreased, while mean arterial pressure and systemic vascular resistance index significantly increased until 10 minutes after bolus injection. Conclusion: Bolus injections of propofol produced biphasic vascular and hemodynamic changes in pigs. However, these alterations were only associated with minor changes in cardiac output and did not lead to significant changes in volumetric flow, indicating well-preserved cardiovascular function, particularly of the baroreceptor reflex within the first 10 minutes after propofol bolus injection.