Cerebral oxygen saturation monitoring during hypotensive anesthesia in shoulder arthroscopy: A comparative study between dexmedetomidine and esmolol

Abstract

BackgroundBeach chair position (BCP) is used in arthroscopic shoulder operations for its advantages. The BCP together with deliberate hypotension used to decrease intraoperative blood loss during arthroscopic shoulder procedures, this may have risk to cause postoperative neurological insults. Dexmedetomidine and esmolol are used to induce deliberate hypotension. Near-infrared spectroscopy (NIRS) provides a non-invasive technique of continuous monitoring of regional cerebral tissue oxygen saturation (rScO2). In this study we evaluate the prevalence of rScO2 during hypotensive anesthesia induced by intra-operative infusion of either dexmedetomidine or esmolol in patients undergoing elective arthroscopic shoulder surgery in the BCP.Patients and methodsFifty patients scheduled for elective arthroscopic shoulder surgery under general anesthesia with hypotensive technique in BCP, randomly assigned into two equal groups, dexmedetomidine group (D Group) and esmolol group (E Group) according to the drug used for deliberate hypotension. MAP, HR, BIS and rScO2 were recorded before induction of anesthesia T0, post-induction of anesthesia T1 as baseline, 5 min after BCP T2, 5 min after starting the studied drug T3, 30 min T4, 60 min T5, 90 min T6, 5 min after stopping the studied drug T7, 5 min after return to supine T8 and after extubation T9.ResultsIn D group there was significant decrease in Lt.rsco2 and Rt.rsco2, at T2 to T7 compared to T1. In E group there was significant decrease in Lt.rsco2 and Rt.rsco2 at T2, to T7 compared to T1. In D group two patients had CDEs compared to five patients in E group.ConclusionIn patients undergoing shoulder arthroscopic surgery under general anesthesia, the BCP significantly decreases rScO2, with further slight decrease of rScO2 with dexmedetomidine and esmolol induced hypotension with no affection of postoperative cognitive function with both drugs. Dexmedetomidine and esmolol are safe drugs with better safety of dexmedetomidine over esmolol.