Clinical Evaluation of the i-gel® Plus Supraglottic Airway in Japanese Patients: A Prospective Observational Study

Background The i-gel® Plus, a new supraglottic airway, has a high oropharyngeal leak pressure of 32 ± 7 cmH ₂ O in the European population. Because the i-gel® series was developed according to the laryngeal anatomy in Western countries, its performance in other regions, such as East Asia, is unknown. Therefore, we aimed to evaluate the clinical performance of i-gel® Plus in Japanese patients. Methods This prospective observational study, conducted from March to June 2024 at a university hospital in Japan, recruited a total of 64 adult patients, 16 each of nonelderly (18–69 years) male, nonelderly female, elderly (≥ 70 years) male, and elderly female patients. Patients with a suspected high risk of aspiration or a predicted difficult airway were excluded. We recorded the oropharyngeal leak pressure (primary outcome), first-attempt success rate, insertion time, and fiberoptic views of the i-gel® Plus. Continuous variables were evaluated for normality using the Shapiro–Wilk test and Q-Q plot. The groups were stratified by age and sex for exploratory analysis. Results Three patients (a 70-year-old male for failed ventilation and two for missing data) were dropped from 67 patients, and 64 (16 each of different age-sex groups) were finally analyzed. The oropharyngeal leak pressure was 23.7 ± 6.9 (mean ± standard deviation) cmH ₂ O, which was normally distributed with the Shapiro–Wilk normality test (P = 0.593) and Q-Q plot. The first-attempt success rate was 92% (including one failed ventilation case), the insertion time (median [Q1, Q3]) was 23.0 (17.0, 31.8) s, and the visible vocal cords were observed in 80% of the cases. Exploratory analysis showed lower oropharyngeal leak pressure (P = 0.027) and fewer visible vocal cords (P = 0.001) in male patients than in female patients. The other outcomes were comparable between nonelderly and elderly patients as well as between male and female patients. Conclusions The i-gel® Plus showed a high first-attempt success rate of 92%; however, its oropharyngeal leak pressure was lower than expected at 23.7 ± 6.9 cmH ₂ O in Japanese patients. Trial registration: The study protocol was registered at the Japan Registry of Clinical Trials (jRCT1042230158; registered on February 27, 2024).