Prediction of hemodynamic fluctuations after induction of general anesthesia using propofol in non-cardiac surgery: A retrospective cohort study

Background: Although propofol is a common anesthetic agent for the induction of general anesthesia, hemodynamic fluctuations are occasionally prominent during induction/intubation. The aims of this study were to determine the influential factors on enhanced hemodynamic fluctuation and to establish a prediction formula to quickly determine the dose of propofol to protect against hemodynamic fluctuations. Methods: This retrospective cohort study patients (n = 2097) were 18 years or older. They underwent general anesthesia induction using propofol and orotracheal intubation for non-cardiac surgery at Kyushu University Hospital during April 2015 to March 2016. Preoperative patient clinical information was collected from anesthesia preoperative evaluation records. Intraoperative data were obtained from computerized anesthesia records. If patients' post-induction mean arterial blood pressure (MAP) decreased or increased 30% or more from their pre-induction MAP, they were determined to have enhanced hemodynamic fluctuations. Unconditional logistic regression was used to assess the adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Structural equation modeling (SEM) was conducted to simultaneously examine the direct and indirect effect (path coefficient = r) of potential variables. Results: In the SEM analysis, age was significantly associated with enhanced hemodynamic fluctuations (adjusted odds ratio = 1.008, 95% CI = 1.001-1.015, P = 0.03). Age (path coefficient (r) = - 0.0113, 95% CI = - 0.0126-0.010, P < 0.001), American Society of Anesthesiologists physical status (ASA-PS) (r = - 0.0788, 95% CI = - 0.1431-0.0145, P = 0.02), sex (r = 0.057, 95% CI = 0.0149-0.9906, P = 0.01), and fentanyl dose (r = 0.1087, 95% CI = 0.0707-0.1467, P < 0.001) influenced the dose of propofol in induction. The prediction formula of "Propofol dose (mg) = [2.374 - 0.0113 × age (year) - 0.0788 (if ASA-PS 3 or 4) + 0.057 (if female) + 0.1087 × fentanyl dose (μg/kg)] × body weight (kg)" was derived. Conclusions: Age was associated with hemodynamic fluctuations in induction. Although the prediction formula is considered to be acceptable, future studies validating whether it can decrease patients' risk of enhanced hemodynamic fluctuations in clinical situations are necessary.