Risk Factors for Postinduction Hypotension among Elderly Patients Undergoing Elective Non-Cardiac Surgery under General Anesthesia

Objective: We aimed to determine risk factors for hypotension occurring after induction among elderly patients (aged 65 years and older). We hypothesized that the dosage of intravenous anesthesia drugs as well as the type of inhalation agent have an effect on hypotension during post-induction periods. We aimed to test this hypothesis to determine risk factors for hypotension after induction among elderly patients who underwent non-cardiac surgery.Material and Methods: This retrospective cohort study analyzed data from 580 patients between December 2017 and July 2018 at a tertiary university hospital in the south of Thailand. Hypotension is defined as a more than 30.0% decrease in mean arterial pressure from baseline after induction and within 20 minutes of the use of a vasopressor agent to treat hypotension. The intraoperative parameters were blood pressure and heart rate immediately after arrival at the operating room, immediately after intubation, and 5, 10, 15, and 20 minutes after intubation.Results: The median age was 72.5 (68, 78) years. The association of post-induction hypotension was raised with a diuretic drug as preoperative medication (p-value=0.025), and the degree of hypertension immediately after arrival at the operating room (p-value<0.001). Increasing fentanyl dosage during induction was associated with hypotension (p-value<0.010). There was no statistically significant difference in the increase of the propofol dosage.Conclusion: The degree of hypertension immediately after arrival at the operating room coupled with higher fentanyl dosage were significant risk factors for postinduction hypotension in elderly patients.