Comparison of remimazolam and sevoflurane on arterial oxygenation during one-lung ventilation in thoracoscopic surgery: a randomized controlled trial.

Abstract

Background: One-lung ventilation (OLV) during thoracoscopic surgery can impair oxygenation due to increased intrapulmonary shunts. Remimazolam has gained attention for its hemodynamic stability and rapid recovery profile; however, its effects on arterial oxygenation during OLV remain unclear. This study aimed to compare the effects of remimazolam and sevoflurane on arterial oxygenation during OLV.

Methods: In this prospective, randomized controlled trial, 58 adult patients undergoing thoracoscopic surgery were assigned to receive either sevoflurane or remimazolam for anesthesia maintenance. Arterial blood gas analysis and hemodynamic parameters were measured at four time points: 10 min after lateral positioning during two-lung ventilation (TLV10) and 15, 30, and 60 min after initiating OLV (OLV15, OLV30, and OLV60). The primary outcome was arterial partial pressure of oxygen (PaO₂) at OLV30. Secondary outcomes included time-dependent changes in PaO₂, hemodynamic variables, and serum lactate levels.

Results: No significant difference in PaO₂ at OLV30 was observed between groups (108.9 ± 37.9 vs. 107.0 ± 37.8 mmHg; 95% CI: -21.8-18.0; P = 0.815). In within-group analysis, PaO₂ at OLV60 increased significantly from TLV10 in the remimazolam group (95% CI: 0.3-36.8; P = 0.044), while no such improvement was observed in the sevoflurane group. Serum lactate levels exhibited a significant time-by-group interaction with a greater reduction in the remimazolam group (P = 0.021).

Conclusions: Remimazolam provided arterial oxygenation and hemodynamic stability comparable to sevoflurane during OLV. The greater reduction in serum lactate levels with remimazolam suggests its potential metabolic or immunomodulatory advantages that warrant further investigation.