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Randomized Controlled Trial Comparative Study
The effects of laryngeal mask versus endotracheal tube on atelectasis after general anesthesia induction assessed by lung ultrasound: A randomized controlled trial.
When suitable for the surgery, using an LMA instead of ETT may reduce postoperative atelectasis by allowing faster airway placement and requiring less muscle relaxation.
pearl- Bin Liu, Yaxin Wang, Ling Li, Wei Xiong, Yifan Feng, Yan Liu, and Xu Jin.
- Department of Anesthesiology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100070, China.
- J Clin Anesth. 2024 Nov 1; 98: 111564111564.
Study ObjectiveThis study aims to evaluate the impact of Supreme™ laryngeal masks versus endotracheal tubes on atelectasis during general anesthesia using lung ultrasound (LUS), and provide evidence for respiratory management.DesignA single-center, double-blind, randomized controlled trial was conducted.SettingThe study was conducted in both the operating room and the post-anesthesia care unit, with follow-up assessments performed in the ward.PatientsEnrollment included 180 cases undergoing non-laparoscopic surgeries in gynecology, urology, and orthopedic limb surgeries.InterventionsPatients were randomly assigned 1:1 to the endotracheal intubation or laryngeal mask group.MeasurementsLUS scores were recorded across 12 lung regions at baseline, 15 min after airway establishment, at the end of surgery, and 30 min following airway removal. Outcome measures encompassed the oxygenation index, dynamic lung compliance, incidence of postoperative pulmonary complications, throat pain, and other postoperative complications assessed at 24 and 48 h postoperatively. The primary outcome focused on the LUS score in all 12 lung regions at 15 min after airway establishment.Main ResultsIntention-to-treat analysis of 177 subjects revealed endotracheal intubation led to significantly higher LUS scores at 15 min {P < 0.001, mean difference 4.15 ± 0.60, 95% CI [2.97, 5.33]}, end of surgery (P < 0.001, mean difference 3.37 ± 0.68, 95% CI [2.02, 4.72]), and 30 min post-removal (P < 0.001, mean difference 2.63 ± 0.48, 95% CI [1.68, 3.58]). No major complications occurred in the two groups.ConclusionsCompared to endotracheal intubation, laryngeal masks effectively reduce atelectasis formation and progression in gynecological, urological non-laparoscopic, and orthopedic limb surgeries. However, caution is warranted when generalizing these findings to surgeries with a higher risk of laryngeal mask leakage or obese patients. Additionally, the efficacy of laryngeal masks in reducing postoperative atelectasis remains uncertain when comprehensive monitoring of muscle relaxation and reversal therapy is employed.Copyright © 2024. Published by Elsevier Inc.
Notes
This study from Liu et al. investigated whether using laryngeal mask airways (LMAs) might reduce atelectasis formation compared to endotracheal tubes (ETTs) during general anaesthesia (sufentanil/propofol/rocuronium → propofol/remifentanil TIVA; VCV: TV 6-8 mL/kg, PEEP 5 cmH2O, I:E 1:1.5, RR 12-20 & FiO2 40%.).
In their single-centre, double-blind randomised controlled trial of 180 patients undergoing non-laparoscopic surgery, they used lung ultrasound scoring to assess atelectasis at various timepoints.
The results were interesting: the LMA group showed significantly lower lung ultrasound scores at all timepoints, better oxygenation, and fewer postoperative pulmonary complications. The authors attribute this to several factors, including faster airway insertion (41 vs 95 seconds of apnoea), reduced airway irritation, and lower requirements for anaesthetic depth and muscle relaxation.
While these findings are limited to relatively healthy patients having shorter procedures, they suggest that when appropriate, using an LMA rather than ETT may help reduce atelectasis formation. However, as the authors acknowledge, these results may not apply to longer procedures, laparoscopic surgery, or higher-risk patients, and the risk-benefit balance of an unprotected airway versus an ETT must always be considered.
Daniel Jolley
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