Background  The effect of subglottic suction with tapered-cuff endotracheal tube is the key to the prevention of ventilator-associated pneumonia, and the volume of subglottic secretion drainage is an important index for the effect of suction. Low drainage volume may indicate incomplete subglottic suction or subglottic secretion leaking into the trachea, but the influencing factors are various. At present, there are few studies on elderly patients with this disease.

  Objective  To investigate the influencing factors for low volume of subglottic secretion drainage in elderly patients using tapered-cuff endotracheal tube, and provide evidence for standard use of tapered-cuff endotracheal tube.

  Methods  The patients, aged > 65 years, who used the tapered-cuff endotracheal tube in our hospital from January 2018 to December 2019 were included, and the volume of subglottic secretion drainage was recorded. The patients were divided into low drainage group and normal drainage group based on median drainage volume, and related indices were compared between the two groups.

  Results  A total of 63 elderly patients were enrolled, with 59 male patients and 4 female patients aged from 65-103 (84.87 ± 9.76) years. The duration of use of tapered-cuff endotracheal tube was 21-132 (74.33 ± 34.59) days; suction was performed 441 times in total, and the volume of subglottic secretion drainage was 0-8 (3.69 ± 1.43) mL, with a median of 4 ml. Univariate analysis showed that low volume of subglottic secretion drainage was significantly associated with secretion viscosity, supine position, primary disease and sex (P < 0.05), while multivariate analysis showed that gel-like secretion, a primary disease of pulmonary infection, and male sex were independent influencing factors for low volume of subglottic secretion drainage (odds ratio > 1, P < 0.05).

  Conclusion  For the elderly patients using tapered-cuff endotracheal tube, low drainage volume is associated with a primary disease of pulmonary infection, male sex, and gel-like subglottic secretion, which needs to be completely removed by subglottic irrigation.