Platelet Function as Affected by Total Intravenous and Inhalational Anesthesia

Abstract

Propofol is a frequent choice of hypnotic anesthetic for TIVA due to its role as a vasodilator [1]. The advantages for ESS of a lower patient blood pressure, however, may be negated by reports that propofol has an adverse effect on blood coagulation [1][2][3][4][5][6]. The choice of anesthesia regimen is further complicated by research indicating inhalational anesthetics also inhibit platelet aggregation [5,6].The purpose of this study was to investigate the potential differences in effects of two anesthesia regimens by measuring blood loss and platelet function. It was our hypothesis that, for the purposes of ESS, TIVA with propofol/remifentanyl would result in reduced blood loss than inhalational anesthesia with sevoflurane/remifentanyl. MethodsThis study was registered with the National Institutes of Health and can be found at http://clinicaltrials.gov/ct2/show/NCT01214057. After obtaining approval from the Committee for the Protection of Human Subjects, 23 patients aged 18-80, American Society of Anesthesia (ASA) grade I or II, scheduled to undergo endoscopic sinus surgery (ESS) for chronic rhinosinusitis were screened, consented and enrolled. Exclusion criteria included known coagulopathy or use of any drug that could affect thrombocyte function (e.g., aspirin, clopidogrel). Anesthetic ProtocolPatients were randomly assigned using a blocked randomization method to receive either propofol/remifentanil (PR, n=12) or sevoflurane/remifentanil (SR, n=11) general anesthesia. Both patients and surgeons were blinded to the type of anesthetic used. Patients were premedicated in the holding area with dexamethasone and midazolam. The patients were monitored by American Society of Anesthesia (ASA) standards with ECG, non-invasive blood pressure, pulse oximetry and temperature probe. Their blood pressure was recorded every 2 minutes for the first 10 minutes, then every 5 minutes.In order to reduce the visual bias of a propofol infusion, anesthesia was induced in both SR and PR groups with lidocaine 0.5 mg/kg, propofol infusion at 250 mcg/kg/min and total volume infused was adjusted for an induction dose of 2-3 mg/kg before bolus of muscle relaxant, rocuronium 0.5 mg/kg. Remifentanil infusion was started at a rate of 0.4 mcg/kg/min one to two minutes before the propofol infu- AbstractBackground: Few studies have attempted to demonstrate a benefit of a total intraveneous anesthesia (TIVA) as the sole technique to optimize and reduce bleeding. Also few reports have linked the use of propofol to platelet dysfunction, and while Thromboelastography (TEG ® ) has been used previously, its complement platelet mapping (PM™) has not. The aim of the study was to exclude different causes for blood loss during surgery, including drug effects on platelet function. Methods:After IRB approval, we studied 23 patients scheduled to undergo endoscopic sinus surgery. Using a double-blind experimental method, we randomly assigned patients to receive either TIVA with propofol/remifentanil (PR) or inhalational anesthesia with sevoflurane/remi...