Comparison the Effect of Changing from the Supine to Lateral Position and Vice Versa on Plethysmographic Variability Index and Hemodynamic Values Assessed by Ultrasonic Cardiac Output Monitors in Patients Who Undergo Thoracotomy

Background: The change in patients positions has a bold effect on the ventilation and hemodynamic parameters during surgery. In this study, we evaluated the changes in hemodynamic and ventilator values resulting from conversions in the position of patients under the thoracotomy from supine to lateral position and vice versa, to determine the most favourable position with the best hemodynamic stability and ventilation conditions. Methods: In this pre and that post interventional clinical trial, 50 patients scheduled for thoracotomy were included. Following general anesthesia induction and 5 minutes later, hemodynamic data before thoracotomy and after the surgical intervention was measured, the patient was placed in the supine position and all hemodynamic data were recorded. Then, the position of the patient was slightly changed to the lateral recumbent position. Then, at the end of the surgery, the position was changed to supine. Results: Regarding the change in study indices (including HR, SBP, DBP, MAP, SVV, CO, and PVI), changes in supine to lateral status led to only a decrease in systolic blood pressure, diastolic blood pressure, and mean blood pressure and other indicators did not show a statistically significant change. Similarly, the change in the above indices by changing the lateral to the supine state was only an increase in systolic blood pressure, diastolic blood pressure, mean blood pressure, and other data remained unchanged. Conclusion: Changing the position of patients during surgical thoracotomy from supine to lateral position or vice versa is associated only with significant changes in patient s blood pressure and has no significant effect on other ventilatory and cardiovascular parameters.