Factors associated with lack of tracheal sealing by a cuff inflated to more than 30 cmH2O during mechanical ventilation: A cross-sectional study

Objectives: The cuff pressures > 30 cmH2O may create a seal in the trachea. The objective of this study was to identify risk factors associated with lack of tracheal sealing by an endotracheal cuff inflated to > 30 cmH2O in patients undergoing mechanical ventilation.

Methods: This prospective cross-sectional study was conducted from 2019 to 2020 in the cardiothoracic intensive care unit and respiratory medical care unit of a Hospital in Nantong, China. Patients aged >16 years undergoing cardiothoracic surgery with mechanical ventilation using endotracheal intubation were included. Patient characteristics and ventilator parameters were analyzed. Cuff pressure was maintained with the minimum leak technique (MLT) and measured with a cuff pressure gauge. Cuff pressure was measured for 30 seconds when ventilation was accompanied by no leak, simultaneously detected by the ventilator or auscultation with a stethoscope.

Results: Of 352 patients undergoing mechanical ventilation, 51 patients (14.5%) had a cuff pressure of >30 cmH2O. Multivariable analysis showed that cuff manufacturer (Guangzhou Weili) and nasal endotracheal intubation significantly increased the risk of an unsealed trachea. Peak inspiratory pressure, cuff diameter and male sex had a strong inverse association with an unsealed trachea.

Conclusions: These findings suggest that an endotracheal cuff pressure of 20 to 30 cmH2O is adequate for most patients, but lack of a tracheal seal still occurs in a small number of people. An unsealed trachea is most likely because cuff and tracheal diameters do not match.