Application of remimazolam-0.6% sevoflurane anesthesia for flash visual evoked potential monitoring during pituitary adenoma resection: a non-inferiority randomized controlled trial

BACKGROUND

Flash visual evoked potential (FVEP) is a critical method for monitoring intraoperative visual function during neurosurgery. A new benzodiazepine drug called remimazolam has recently been used for general anesthesia. However, the impact of remimazolam on FVEP remains unclear. Therefore, we aimed to investigate how remimazolam, in comparison to propofol, when combined with 0.6% sevoflurane anesthesia, affects the FVEP waveform during pituitary adenoma resection.

METHODS

Overall, 36 patients undergoing pituitary adenoma resection under general anesthesia were randomly assigned to either the remimazolam group (Group R) or the propofol group (Group P) in a prospective, randomized, controlled, non-inferiority trial. For anesthesia induction, a bolus of 0.2 mg/kg remimazolam or 2 mg/kg propofol was intravenously infused for approximately one minute. The anesthesia was maintained by continuous infusion of either remimazolam (0.7-1.0 mg/kg/h) or propofol (4-6 mg/kg/h), in combination with 0.6% sevoflurane, aimed at sustaining the bispectral index (BIS) within the range of 40-60. The primary outcome was the N75-P100 amplitude of FVEP recorded at approximately 20 min after intubation (T0). 10% of the amplitude at T0 in group P was defined as the non-inferiority margin (δ). Confidence interval testing was used to evaluate the non-inferiority hypothesis. The secondary outcomes covered the P100 latency of FVEP, electroretinogram (ERG) b wave amplitude, demographic characteristics, hemodynamics, and occurrence of adverse events.

RESULTS

The BIS index during anesthesia was comparable between the groups at the same measured time points (P > 0.05). The N75-P100 amplitude at T0 in group R was 7.64 ± 1.36 µV, while it was 6.96 ± 0.95 µV in group P (P = 0.09), with a mean difference of 0.68 µV (95% CI, -0.11 µV to 1.48 µV). The δ was set at 0.7 and the lower limit of the 95% CI exceeded the -δ. Both remimazolam and propofol had little effect on ERG b-wave amplitudes. At the designated time points, FVEP amplitude and P100 latency displayed no appreciable variation between the two groups (P > 0.05). Furthermore, there were no significant differences in the incidence of adverse events related to anesthesia, needle electrodes, or surgery between the two groups (P > 0.05).

CONCLUSION

Our findings suggest that remimazolam-0.6% sevoflurane is non-inferior to propofol-0.6% sevoflurane for general anesthesia, based on the FVEP N75-P100 amplitude. The electrophysiological data obtained in both groups indicate that reproducible and stable FVEP and ERG waveforms can be acquired at set time points. Therefore, for reliable FVEP monitoring, remimazolam-0.6% sevoflurane appears to be a safe and effective protocol in general anesthesia.

TRIALS REGISTRATION

This study was registered on chictr.org.cn (ChiCTR2200056803, 17/02/2022).

[Study on the causes, prevention and treatment of complications after transsphenoidal pituitary tumor resection under neuroendoscope]

Objective: To analyze the causes of complications after endoscopic transsphenoidal pituitary adenoma resection and summarize the corresponding prevention and treatment measures. Methods: The pathological data of 120 patients with pituitary adenoma in hospital were analyzed retrospectively. All patients were treated surgically, five kinds of common complications were collected, the risk factors of complications were statistically analyzed, the causes of postoperative complications were determined, and then the specific prevention and treatment strategies were summarized. Results: Long operation time (P<0.05), hypopituitarism before operation (P<0.01) and large tumor (P<0.01) were the main inducing factors of CSF rhinorrhea after operation; long operation time (OR=1.394, P<0.01), lumbar cistern puncture (OR=1.531, P<0.01) and CSF rhinorrhea after operation (OR=3.861, P<0.01) were the independent risk factors of infection; Age, large tumor and preoperative hypophysis are the main factors of postoperative hypophysis; Postoperative hypophysis and intraoperative cerebrospinal fluid rhinorrhea are the main factors of postoperative diabetes insipidus; Postoperative hypophysis and giant adenoma are the main factors of postoperative hyponatremia. Conclusion: Endoscopic transnasal transsphenoidal resection of pituitary adenoma is the most minimally invasive method at present. There are still risk factors for postoperative complications. Targeted prevention of risk factors for complications and corresponding interventions can effectively reduce the incidence of postoperative complications of pituitary adenoma.