effect of intraoperative use of esmolol and nicardipine on splanchnic perfusion in functional endoscopic sinus surgery

ABSTRACT

There are many techniques for reduction of mean arterial blood pressure [MAP] and heart rate [HR] during anesthesia. We designed this prospective, randomized, double-blinded study to test the effect of this technique for maintaining hemodynamic stability during general anesthesia and their influences on splanchnic perfusion. Sixty healthy consenting patients undergoing functional endoscopic sinus surgery [FESS] were randomly assigned to 1 of 3 treatment groups Group I [control n = 20] received normal saline 5 mL and 1 mL, followed by a saline infusion at a rate of 0.005 mL kg[-1] min[1]; Group 2 [n = 20] received esmolol 50 mg and saline 1.mL, followed by an esmolol infusion 5 micro g kg[-1] min[-1]; and Group 3 [n = 20] received esmolol 50 mg and nicardipine 1 mg, followed by an esmolol infusion 5 micro g kg[-1] min[-1]. The study drugs were administered after the induction of anesthesia with fentanyl 1.5 micro g/kg, and propofol 2 mg/kg IV. Tracheal intubation was facilitated with vecuronium 0.12 mg/kg IV. Anesthesia was initially maintained with sevoflurane 2% end-tidal and N[2]O 50% In oxygen in all 3 groups. After induction of anesthesia a gastric tonometer [TRIP] NGS Catheter and a radial catheter were inserted. Baseline values of gastric intramucosal pH [pHi] were determined before induction of hypotension. The [pHi] values were calculated every 30 min until hypotension was discontinued .The CO2 -gap [i.e., the difference between arterial and gastric Pco2] was registered. Arterial blood lactate levels also were measured. During surgery, the mean arterial blood pressure [MAP] was maintained within +/- 15% of the baseline value by varying the study drug infusion rate and the inspired concentration of sevoflurane. In addition to MAP and heart-rate values, were recorded throughout the perioperative period. Recovery times and postoperative side effects were assessed. None of the [pHi] values calculated was less than 7.35 in the three studied groups. Arterial blood lactate levels did not increase in any of the patients. Compared with the control group, adjunctive use of esmolol and nicardipine attenuated the increase in heart rate [in Group 2] and MAP [in Group 3]. after tracheal intubation. Furthermore, the use of an esmolol infusion as an adjunct to sevoflurane to control the acute autonomic responses during the maintenance period significantly decreased emergence times [4 +/- 2 versus 7 +/- 4 min], decreased the need for postoperative opioid analgesics [35% versus 60%], and reduced the time before discharge [209 +/- 89 versus 269 +/- 100 min]. We conclude that the adjunctive use of esmolol alone or in combination with nicardipine during the induction of anesthesia reduced the hemodynamic response to tracheal intubation. It did not compromise splanchnic tissue oxygen balance in healthy patients nor increased blood lactate. Furthermore, use of an esmolol infusion as an adjuvant to sevoflurane- N[2] O anesthesia for controlling the acute hemodynamic responses during the maintenance period improved the recovery profile after functional endoscopic sinus surgery