Fentanyl Effect on Blood Pressure in Elderly Patients After Induction of General Anesthesia

Overview

Hypotension is frequently encountered after induction of general anesthesia. It can be pronounced in elderly patients and can require administration of vasopressor agents including ephedrine and phenylephrine. Intraoperative hypotension, especially prolonged episodes, can contribute to an increase in morbidity and mortality in the postoperative period as suggested by some former studies. The investigators hypothesize that fentanyl can contribute to the decrease in blood pressure (BP) that is seen after induction of general anesthesia in older patients. This hypotension may be due to fentanyl blocking effect on the sympathetic nervous system. This study will be the first one to examine the effect of fentanyl administration on blood pressure in elderly patients with induction of general anesthesia prior to the start of surgery. If the study shows that fentanyl contributes to hypotension during this period, it may lead to a change in practice and better patient outcomes and mortality rates.

This is a prospective double-blinded randomized controlled trial (RCT) where patients will be assigned randomly by the investigational pharmacist. Patients will be assigned to one of three groups: (1) A control group that receives 0.9 mcg/kg sodium chloride (NaCL), (2) a fentanyl group that receives 1 mcg/kg fentanyl, or (3) a fentanyl group that receives 2 mcg/kg fentanyl. The definition of intraoperative hypotension in this study is defined as a mean blood pressure (MAP) less than 25% compared to the baseline value (i.e., the participants' first blood pressure reading after entering the operating room). All study drug agents will be dispensed by the pharmacy in five milliliter syringes labeled as "study medication". The volume of any of the three study medication will be adjusted by the pharmacist to reflect an equal volume.