Journal Article

Gastric insufflation with and without an inserted gastric tube in second-generation laryngeal mask airways: A randomized controlled cross-over trial

Schmutz, Axel, Schelker, Grischa, Schumann, Stefan, Hell, Johannes

2024

Overview

Second-generation laryngeal mask airways are equipped with an additional lumen for a gastric tube, with the intention to reduce the risk of aspiration by draining gastric content. However, the effect of an inserted gastric tube through the gastric channel on gastric insufflation, a substantial part of the pathomechanism of aspiration, during positive-pressure ventilation is not clear. We hypothesized, that an inserted gastric tube increases the risk of gastric insufflation. Single center, prospective, randomized-controlled cross-over trial. Tertiary academic hospital in Germany. 152 patients, ASA I-III, scheduled for general anesthesia with a laryngeal mask airway. Gastric insufflation was investigated during an incremental pressure trial up to a maximum airway pressure of 30 cmH2O and during oropharyngeal leak pressure measurement with and without an inserted gastric tube while one of two laryngeal mask airways with different cuff designs (inflatable or thermoelastic) was used. Gastric insufflation was detected with real-time ultrasound. Frequency of gastric insufflation was higher with than without inserted gastric tube during the incremental pressure trial (10.9 % (16/147) vs. 2.7 % (4/147), p = 0.009) and during oropharyngeal leak pressure measurement (16.3 % (24/147) vs. 5.4 % (8/147), p = 0.004). Risk of gastric insufflation didn't differ between the two cuff-types (p = 0.100). Flow over the open gastric channel was associated with gastric insufflation during positive-pressure ventilation (p = 0.003) and during oropharyngeal leak pressure measurement (p = 0.049). Incidence of postoperative nausea and vomiting was higher in patients in which gastric insufflation was detected, compared to others (17.1 % (6/35) vs. 5.4 % (6/112), p = 0.037). Placement of a gastric tube through the gastric channel of a second-generation laryngeal mask airway, independent of the cuff-type, increases the risk of gastric insufflation. Flow over the gastric channel indicate a higher risk of gastric insufflation and gastric insufflation may increase the risk of postoperative nausea and vomiting. [Display omitted] •Risk of gastric insufflation in 2nd generation LMAs increases with a gastric tube.•Cuff-type of 2nd generation LMA does not influence the risk of gastric insufflation.•Flow over the gastric channel is a sign of an increased risk of gastric insufflation.•Patients with gastric insufflation experienced PONV more often at the PACU.

• Publisher: Elsevier Inc,Elsevier Limited
• Subject: Adult / Aged / Airway management / Anesthesia / Anesthesia, General - methods / Cross-Over Studies / Female / Gas flow / Gastric insufflation / Gastric tube / General anesthesia / Humans / Insufflation - adverse effects / Insufflation - instrumentation / Insufflation - methods / Intubation, Gastrointestinal - adverse effects / Intubation, Gastrointestinal - instrumentation / Intubation, Gastrointestinal - methods / Laryngeal Masks - adverse effects / Male / Middle Aged / Pain Medicine / Patients / Positive-Pressure Respiration - adverse effects / Positive-Pressure Respiration - instrumentation / Positive-Pressure Respiration - methods / Prospective Studies / Real-time ultrasound / Second generation laryngeal mask / Stomach / Surgery / Ultrasonic imaging / Ventilators