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

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.

Fentanyl is a synthetic opioid analgesic that will be used as the experimental intervention in this trial

Inclusion Criteria: Age: 60 years and older Patients coming from home (including those who will be admitted post-operatively) Surgeries with general anesthesia alone or if combined with peripheral nerve blocks Patients must be seen at the Russo operating room at Loyola Medical Center (Maywood, IL) Exclusion Criteria: Age less than 60 Patient refusal Inpatient or emergency cases Patients having combined general anesthesia and epidural anesthesia Patients with a pre-induction mean arterial blood pressure (MAP) less than 50 or greater than 150 Patients who will receive rapid sequence induction with succinylcholine Patients scheduled for cardiovascular surgery Patients scheduled for inhalational induction Patients with weight greater than 125 kg Patients with a history of chronic opioid use

Bijker JB, van Klei WA, Vergouwe Y, Eleveld DJ, van Wolfswinkel L, Moons KG, Kalkman CJ. Intraoperative hypotension and 1-year mortality after noncardiac surgery. Anesthesiology. 2009 Dec;111(6):1217-26. doi: 10.1097/ALN.0b013e3181c14930.

Bijker JB, van Klei WA, Kappen TH, van Wolfswinkel L, Moons KG, Kalkman CJ. Incidence of intraoperative hypotension as a function of the chosen definition: literature definitions applied to a retrospective cohort using automated data collection. Anesthesiology. 2007 Aug;107(2):213-20. doi: 10.1097/01.anes.0000270724.40897.8e.

Billard V, Moulla F, Bourgain JL, Megnigbeto A, Stanski DR. Hemodynamic response to induction and intubation. Propofol/fentanyl interaction. Anesthesiology. 1994 Dec;81(6):1384-93. doi: 10.1097/00000542-199412000-00013.

Reich DL, Hossain S, Krol M, Baez B, Patel P, Bernstein A, Bodian CA. Predictors of hypotension after induction of general anesthesia. Anesth Analg. 2005 Sep;101(3):622-628. doi: 10.1213/01.ANE.0000175214.38450.91.

Monk TG, Saini V, Weldon BC, Sigl JC. Anesthetic management and one-year mortality after noncardiac surgery. Anesth Analg. 2005 Jan;100(1):4-10. doi: 10.1213/01.ANE.0000147519.82841.5E.