The efficacy and safety of an adapted opioid-free anesthesia regimen versus conventional general anesthesia in gynecological surgery for low-resource settings: a randomized pilot study

Combination of a propofol emulsion with alpha-2 adrenergic receptor agonists used for multimodal analgesia or sedation in intensive care units: a physicochemical stability study

OBJECTIVES

To assess the physicochemical stability of the combination of a propofol emulsion with an alpha-2 (α2) adrenergic receptor agonist (α2A; clonidine or dexmedetomidine) under conditions mimicking routine practice in an intensive care unit or in multimodal analgesia procedures.

METHODS

We developed and validated three stability-indicating methods based on high-performance liquid chromatography with ultraviolet (HPLC-UV) detection. Eight different conditions per combination were evaluated in triplicate, with variations in the simulated, bodyweight-adjusted dose level and the drugs' flow rate. The drugs were mixed in clinically relevant concentrations and proportions and then stored unprotected from light, in clear glass vials at room temperature for 96 hours. At each sampling point, we assessed the chemical stability (the HPLC-UV drug level, pH, and osmolality) and physical compatibility (visual aspect, zeta potential (ZP), mean droplet diameter (MDD, Z-average) and polydispersity index (PDI)). We validated our stability findings in positive and negative control experiments.

RESULTS

Over the 96-hour test, the concentrations of propofol, clonidine and dexmedetomidine did not fall below 90% of the initial value, and the pH and osmolality were stable. The visual aspect of the mixed propofol emulsions did not change. The MDD remained below 500 nm (range 165-195 nm). The PDI was always below 0.4; 78.7% of the measurements were below 0.1 and 21.3% were between 0.1 and 0.4. The ZP measurements (-31.3 to -42.9 mV) suggested that the emulsion was stable. The MDD and PDI increased slightly at 96 hours under some conditions, which might indicate early destabilisation of the emulsion. Given that the MDD remained below 500 nm, these emulsions are compatible with intravenous administration.

CONCLUSIONS

Our results demonstrate the chemical and physical compatibility of propofol-α2 agonist mixtures at concentrations and in proportions representative of standard protocols when stored unprotected from light at room temperature for 96 hours.

A nomogram to predict postoperative nausea and vomiting in the ward following laparoscopic bariatric surgery

BACKGROUND

Postoperative nausea and vomiting (PONV) is a common and distressing complication of laparoscopic bariatric surgery (LBS). However, there is a lack of effective integrated prediction models for preventing and treating PONV in patients after LBS.

METHODS

Based on a randomized controlled trial conducted between November 1, 2021, and May 13, 2022, we included 334 participants who underwent LBS according to the inclusion criteria. The database was divided randomly into training and validation cohorts in a ratio of 7:3. Least absolute shrinkage and selection operator plus multivariable logistic regression were used to identify independent predictors and construct a nomogram. The performance of the nomogram was assessed and validated by the area under the receiver operating characteristic curve (AUC), the concordance index (C-index), calibration plots, and a decision curve analysis (DCA). We also explored specific risk factors for PONV in patients with diabetes.

RESULTS

The subjects were divided randomly into training (n = 234) and validation (n = 100) cohorts. Age, history of diabetes, type of surgery, and sugammadex use were incorporated to construct a nomogram prediction model. In the training cohort, the AUC and the optimism-corrected C-index were 0.850 [95% confidence interval (CI) 0.801-0.899] and 0.848, while in the validation cohort they were 0.847 (95% CI 0.768-0.925) and 0.844, respectively. The calibration plots showed good agreement between the predicted and actual observations. The DCA results demonstrated that the nomogram was clinically useful. The type of surgery, sugammadex use, and insulin level at 120 min were predictors of PONV in patients with diabetes with an AUC of 0.802 (95% CI 0.705-0.898).

CONCLUSIONS

We developed and validated a prediction model for PONV in patients after LBS. A risk factor analysis of PONV in patients with diabetes provides clinicians with a more precise prophylactic protocol.

The Performance of Opioid-Free Anesthesia for Bariatric Surgery in Clinical Practice

PURPOSE

Opioid-free anesthesia (OFA) is an alternative to conventional opioid-based anesthesia (OBA) in patients undergoing bariatric surgery. Several small studies and a meta-analysis have suggested advantages of OFA for bariatric surgery, but current evidence is still contradictory, and a universally accepted concept has not yet been established. The purpose of this study was to determine whether patients undergoing bariatric surgery experience less postoperative pain and better postoperative recovery when anesthetized with an OFA regimen than with an OBA regimen.

MATERIALS AND METHODS

This prospective observational cohort study, conducted between October 2020 and July 2021, compared patients receiving OFA with patients receiving OBA. Patients were visited 24 and 48 h after the surgical procedure and asked about their postoperative pain using the visual analogue scale (VAS). Additionally, the quality of recovery-40 questionnaire (QoR-40) and the postoperative opioid requirements were recorded.

RESULTS

Ninety-nine patients were included and analyzed in this study (OFA: N = 50; OBA: N = 49). The OFA cohort exhibited less postoperative pain than the OBA cohort within 24 h (VAS median [interquartile range (IQR)]: 2.2 [1-4.4] vs. 4.1 [2-6.5]; P ≤ 0.001) and 48 h (VAS median [IQR]: 1.9 [0.4-4.1] vs. 3.1 [1.4-5.8]; P ≤ 0.001) postoperatively. Additionally, the OFA cohort had higher QoR-40 scores and required less opioid therapy postoperatively.

CONCLUSION

Based on our results the use of OFA for bariatric surgery results in less pain, reduced opioid requirements, and improved postoperative recovery-adding additional evidence regarding the use of OFA in everyday clinical practice.