UNASSIGNED: There is limited literature wherein the hypotensive drugs have been compared to know the cerebral effects by monitoring regional cerebral oxygen saturation (rScO2). This study aimed to compare the effects of dexmedetomidine and nitroglycerin on rScO2 during controlled hypotensive anaesthesia using near-infrared spectroscopy (NIRS). The primary objective was to evaluate the non-inferiority of dexmedetomidine versus nitroglycerin in the occurrence of cerebral desaturation events (CDEs) during hypotensive anaesthesia.
UNASSIGNED: Adult patients scheduled to undergo head and neck surgery under general anaesthesia randomised to receive either dexmedetomidine or nitroglycerin infusion for controlled hypotensive anaesthesia. Cerebral oximetry was monitored with NIRS, and data regarding CDEs, bilateral rScO2, and peri-operative haemodynamics were collected. Continuous data were analysed using unpaired Student\'s t-tests except for intra-group analyses, which were analysed using paired t-tests. Categorical data were analysed using the Chi-square test. For comparison of time to CDEs, Kaplan-Meier survival analysis with log-rank test was performed.
UNASSIGNED: Of the 82 patients in both groups, CDEs were observed in 15 patients each. A decrease from baseline by 20% was observed in three patients: one in Group N and two in Group D. Statistically, there was an equal risk of getting CDEs in the groups. The time to CDE was comparable (P > 0.05). The difference in heart rate was statistically significant (P < 0.001).
UNASSIGNED: Dexmedetomidine is non-inferior to nitroglycerin in terms of the occurrence of cerebral desaturation events when used for controlled hypotensive anaesthesia in head and neck surgeries.

BACKGROUND: Devastating transient and permanent postoperative neurocognitive complications in previously healthy, low-risk patients have been observed after elective shoulder arthroscopy in the beach chair position (BCP). Continuous monitoring of cerebral oxygen saturation has been recommended to identify cerebral desaturation events (CDEs) and improve patient safety. However, the relatively high cost and limited availability of monitoring may not be cost-effective. More cost-effective and available measures, including the use of thigh-high compression stockings (CS), have been investigated. However, efficacy data of CS usage is limited, especially for obese patients, who have been shown to be at increased risk for CDEs. The purpose of this was study was to determine if the intraoperative addition of thigh-high compression stockings decreases the incidence, frequency, and magnitude of CDEs in obese patients undergoing shoulder arthroscopy in the BCP.
METHODS: Thirty-three patients in the treatment group wore both thigh-high compression stockings (CS) and sequential compression devices (SCDs), and the remaining 33 patients in the control group wore SCDs alone. Cerebral oximetry was monitored during surgery using near-infrared spectroscopy.
RESULTS: The incidence of CDEs was equal between groups, with 9 patients (27%) in each experiencing desaturation events. The median number of CDEs per patient was 3 for the control group and 1 for patients wearing CS (P = .29). There was no difference between groups in terms of median time from induction of anesthesia to onset of CDE (P = .79), median time from upright positioning to onset of CDE (P = .60), mean CDE duration per patient (P = .22), and median cumulative CDE duration (P = .19). The median maximal desaturation from baseline was also not different between groups: 27.6% in the control group and 24.3% in the treatment group (P = .35).
CONCLUSIONS: The combination of thigh-high CS and SCDs did not decrease the incidence, frequency, or magnitude of CDEs in patients undergoing shoulder arthroscopy in the BCP. Twenty-seven percent of patients undergoing shoulder arthroscopy in the BCP demonstrated CDEs with or without the use of CS. Therefore, further research is required to identify cost-effective, minimally invasive, and universally available methods of decreasing the incidence of CDEs during this common surgical procedure.

OBJECTIVE: The beach chair position (BCP) during shoulder arthroscopy is a known risk factor for cerebral ischemia. We retrospectively investigated whether maintaining the arterial blood pressure (ABP) prevented the decrease in the regional cerebral tissue oxygen saturation (rSO2).
METHODS: We analyzed 20 consecutive patients who underwent elective shoulder surgery in the BCP under general anesthesia. The bilateral rSO2 was monitored continuously throughout the procedure with the help of near-infrared spectroscopy (INVOS 5100 Cerebral Oximeter, Somanetics Corporation, Troy, MI, USA). Anesthesiologists maintained patient blood pressure while they were in the BCP, which was measured using an ABP transducer placed at the level of the external auditory meatus. We compared rSO2 measured in the supine position and in the BCP.
RESULTS: Measurement of cortex level mean ABP (mABP) values in the BCP were >50 mmHg and over 60% higher than those noted for the supine position in most patients. Although all bilateral rSO2 values in the BCP were significantly lower than those in the supine position, the reductions was <20%. Further, 35% (7 of 20) patients that were part of the study experienced cerebral desaturation events at any given point during the procedure. None of the patients experienced clinical postoperative neurological complications.
CONCLUSIONS: Although cortex level mABP in the BCP was >50 mmHg, a decrease was recorded in the rSO2 values. This rSO2 decrease was proportional to the reduction in the cortex level mABP induced by a postural change to the BCP. Therefore, despite appropriate blood pressure management, shoulder surgery in the BCP might involve certain risks for patients with cerebrovascular diseases.

BACKGROUND: Cerebral oximetry (rSO2) has emerged as an important tool for monitoring of cerebral perfusion during surgery. High rates of cerebral desaturation events (CDEs) have been reported during surgery in the beach chair position. However, correlations have not been made with blood pressure measured at the cerebral level. The purpose of this study was to examine the correlations between brachial noninvasive blood pressure (NIBP) and estimated temporal mean arterial pressure (eTMAP) during CDEs in the beach chair position.
METHODS: Fifty-seven patients underwent elective shoulder surgery in the beach chair position. Values for eTMAP, NIBP, and rSO2 were recorded supine (0°) after induction and when a CDE occurred in the 70° beach chair position. Twenty-six patients experienced 45 CDEs, defined as a 20% drop in rSO2 from baseline.
RESULTS: Median reduction in NIBP, eTMAP, and rSO2 from baseline to the CDE were 48.2%, 75.5%, and 33.3%, respectively. At baseline, there was a significant weak negative correlation between rSO2 and NIBP (rs = -0.300; P = .045) and no significant association between rSO2 and eTMAP (rs = -0.202; P = .183). During CDEs, there were no significant correlations between rSO2 and NIBP (rs = -0.240; P = .112) or between rSO2 and eTMAP (rs = -0.190; P = .212). No significant correlation between the decrease in rSO2 and NIBP (rs = 0.064; P = .675) or between rSO2 and eTMAP (rs = 0.121; P = .430) from baseline to CDE was found.
CONCLUSIONS: NIBP and eTMAP are unreliable methods for identifying a CDE in the beach chair position. Cerebral oximetry provides additional information to the values obtained from NIBP and eTMAP, and all should be considered independently and collectively.