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

Comparison of the effects of dexmedetomidine and nitroglycerin on cerebral oxygen saturation using near-infrared spectroscopy in patients undergoing controlled hypotensive anaesthesia: A randomised controlled non-inferiority trial

Background and Aims

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.

Methods

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.

Results

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).

Conclusion

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.

Effect of combined use of cerebral oximetry and electroencephalogram monitoring on the incidence of perioperative neurocognitive disorders in adult cardiac and non-cardiac surgery: A systematic review of randomized and non-randomized trials

Background: There is insufficient evidence to recommend using either intraoperative cerebral oximetry or (processed) electroencephalogram (EEG) alone for preventing perioperative neurocognitive disorders (PNDs). Objective: To evaluate the effectiveness of combined use of cerebral oximetry and electroencephalogram-guided anesthesia on the incidence of PNDs in adult patients undergoing cardiac and non-cardiac interventions. Methods: A PICOS - based systematic review of English articles using Pubmed and Embase (from inception to August 2022) was performed. There were no exclusion criteria regarding the type of the study. Abstract proceedings and new study protocols or ongoing studies were not included. Review articles were analyzed in search of eligible references. All possible terms that were illustrative of PNDs were used. Results: Among the 63 full manuscripts that were analyzed in detail, 15 met the inclusion criteria. We found 2 retrospective, 8 prospective observational and 5 randomized controlled trials of which 1 did not evaluate the use of neuromonitoring in the randomization process. The definition and the methods used to diagnose PNDs were very heterogeneous. Only 8 studies used an algorithm to avoid/treat cerebral oxygen desaturation and/or to treat EEG abnormalities. Overall, there was a tendency towards less PNDs in studies where such an algorithm was used. Conclusions: Our results suggest that integrating information obtained from cerebral oximetry and an EEG monitor may reduce the incidence of PNDs whenever an adapted algorithm is used to improve brain function.

The Effects of Dexmedetomidine on Perioperative Neurocognitive Outcomes After Noncardiac Surgery: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Objective

The purpose of this review is to examine the effect of dexmedetomidine on delayed neurocognitive recovery (dNCR; cognitive dysfunction ≥1 week postoperative) after major noncardiac surgery.

Background

Dexmedetomidine (DEX) effectively reduces delirium in the intensive care unit and reportedly attenuates cognitive decline following major noncardiac surgery. Ascertaining the true effect on postoperative cognition is difficult because studies are limited by suboptimal selection of cognitive assessment tools, timing of testing, and criteria for defining significant cognitive decline.

Methods

Prospective randomized trials comparing perioperative DEX to placebo for major noncardiac surgery assessing cognitive function ≥1 week postoperative were included. Pediatric, nonhuman, and non-English trials, and those where executive function was not assessed were excluded. Data were abstracted by 3 reviewers independently and in parallel according to PRISMA guidelines. The a priori binary primary outcome is dNCR defined as cognitive function declining by the minimal clinically important difference or accepted alternate measure (eg, Reliable Change Index ≥1.96). Bias was assessed with the Cochrane Collaboration tool. Data were pooled using a random effects model.

Results

Among 287 citations identified, 26 (9%) met criteria for full-text retrieval. Eleven randomized trials (1233 participants) were included for qualitative analysis, and 7 trials (616 participants) were included for meta-analysis of dNCR. Dexmedetomidine did not reduce the incidence of dNCR significantly (OR 0.57, 95% CI 0.30-1.10, P = 0.09) compared with placebo. There was no difference in the incidence of delirium (OR 0.94, 95% CI 0.55-1.63, P = 0.83) and a higher incidence of hemodynamic instability (OR 2.11, 95% CI 1.22-3.65, P = 0.008).

Conclusions

Dexmedetomidine does not reduce dNCR 1 week after major noncardiac surgery. This meta-analysis does not yet support the use of perioperative DEX to improve short term cognitive outcomes at this time; trials underway may yet change this conclusion while larger trials are needed to refine the point estimate of effect and examine long-term cognitive outcomes.

Improving the safety of shoulder arthroscopy in the beach chair position: a prospective randomized trial investigating the effect of compression stockings on cerebral desaturation events in obese patients

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).

CONCLUSION

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.

Cerebral Desaturation Events During Shoulder Arthroscopy in the Beach Chair Position

The beach chair position (BCP) is commonly used position in upper extremity surgery. Although there are many advantages to surgery in this position, there are also potential drawbacks and described complications including devastating neurologic outcomes. The etiology of these complications is postulated to be due to the gravitational effects of the seated position leading to cerebral hypoperfusion. We review the current literature on intraoperative cerebral monitoring and neurocognitive complications with shoulder surgery performed in the BCP. A previous systematic review estimated the incidence of neurocognitive complications after surgery in the BCP to be 0.004%. However, the true incidence is unknown and is likely much more common. Reports of neurologic complications have revealed a need for heightened vigilance, alternative anesthesia techniques, and improved monitoring. Methods for monitoring have included near-infrared spectroscopy, a measurement of cerebral oximetry shown to reliably detect cerebral hypoperfusion. In this literature review, we sought to update the incidence of intraoperative cerebral desaturation events (CDEs) to investigate the relationship of CDEs to neurocognitive complications and to review recent reported cases of neurocognitive complications. Existing literature suggest that accurate intraoperative monitoring of cerebral perfusion may improve patient safety.

Comparison of the Effects of Dexmedetomidine and Remifentanil on Cognition State After Cataract Surgery

BACKGROUND

Dexmedetomidine is a potent and highly specific α2-adrenoreceptor agonist that induces sedative and analgesic effects over a short-term period. As a result of these benefits, dexmedetomidine may be a better alternative than other available drugs for keeping the patient's cognition state in an acceptable condition after outpatient ophthalmic surgeries.

OBJECTIVES

This randomized study was conducted to compare the sedative effects of dexmedetomidine and remifentanil on the cognitive state of patients who have undergone cataract surgery.

PATIENTS AND METHODS

A total of 100 patients who were candidates for cataract surgery under local anesthesia received either dexmedetomidine (50 patients; D group) or remifentanil (50 patients; R group) in a double-blind, randomized study. The baseline cardiovascular status and mini mental state examination (MMSE) score for each patient were recorded. As a loading dose, dexmedetomidine (0.5 µg/kg) and remifentanil (0.1 µg/kg) were infused at 10 minutes and 5 minutes before topical anesthesia, respectively. Subsequently, the maintenance dose was administered at 0.2 µg/kg/hour and 0.05 µg/kg/minutes in the D and R groups, respectively. The surgical procedure was begun when the bispectral index (BIS) reached 70 - 80. MMSE test was done at a postanesthetic care unit (PACU) 120 minutes after the discontinuation of the drug.

RESULTS

There was no statistically significant difference between the MMSE scores of the two groups before surgery (P = 0.6), but the MMSE test conducted at the PACU revealed significantly better cognitive outcomes in the D group than in the R group in patients younger and older than 65 years (P = 0.03 and P = 0.0001, respectively).

CONCLUSIONS

This study revealed that dexmedetomidine may be a suitable agent for sedation in cataract surgery because it results in a more favorable postoperative cognitive status than remifentanil. Likewise, dexmedetomidine had no significant adverse effects on cardiovascular or respiratory systems.