The evaluation of endotracheal tube cuff pressure in pediatric patients by subjective inflation techniques: a prospective observational study.

Background: Cuffed endotracheal tubes (ETTs) are commonly used in pediatric patients, with the gold standard for measuring cuff pressure being a cuff pressure manometer. However, this equipment is not always available in every operating room. Subjective inflation techniques, such as the minimal occluding volume (MOV) technique and the stethoscope-guided (Steth) technique, offer convenient and safe alternatives to standard methods but do not provide quantitative measurements. This study aimed to evaluate ETT cuff pressures and volumes of air inflated using the two subjective techniques (MOV and Steth) in pediatric patients.

Methods: This prospective observational study was conducted at the Department of Anesthesiology, Faculty of Medicine, Khon Kaen University, Thailand. We included healthy pediatric patients aged 2 to 7 years undergoing elective surgeries under general anesthesia with a cuffed ETT. The primary objective of this study was to compare the mean ETT cuff pressures and volumes of air inflated using the two subjective inflation techniques (MOV and Steth method). The secondary objectives include identifying factors associated with inappropriate inflation and evaluating post-intubation complications.

Results: Sixty-four pediatric patients were analyzed. The overall mean ETT cuff pressure was 26.52 ± 8.68 cmH₂O. The target was achieved in 46.88% of patients, with overinflation in 32.81% and underinflation in 20.31%. The mean ETT cuff pressure in the MOV group was 27.77 ± 8.89 cmH₂O and in the Steth group was 25.33 ± 8.34 cmH₂O, with a non-significant mean difference of 2.44 cmH₂O (95% CI [-1.89, 6.77], p = 0.264). The mean volume of air inflated in the MOV group was 0.78 ± 0.25 ml, and in the Steth group was 0.68 ± 0.22 ml, with a non-significant mean difference of 0.10 ml (95% CI [-0.01, 0.22], p = 0.084). Younger age, lower weight, and shorter height were significantly associated with an increased risk of overinflation. An ETT size with an internal diameter (ID) of 5 mm was significantly associated with an increased risk of underinflation. No post-intubation complications were reported.

Conclusions: Subjective inflation techniques (MOV or Steth) achieve target ETT cuff pressures in less than 50%, and carry the risks of both overinflation and underinflation, even without post-intubation complications.

Trial registration: TCTR20211016001 (registered with the Thai Clinical Trials Registry on October 16, 2021).