[Study on mechanical ventilation pressure under continuous cuff pressure monitoring in critical patients]

To explore the effective pressure range under continuous cuff pressure monitoring in critical patients with mechanical ventilation, so as to achieve the goal of ensuring ventilation quality and reducing mucosal injury without increasing the incidence of endotracheal catheter displacement and aspiration.

Ninety critically ill patients with non-pulmonary diseases admitted to the department of intensive care unit (ICU) of Airport Hospital of Tianjin Medical University from June 2017 to June 2019 were enrolled, and divided into three groups according to the random number table, with 30 patients in each group. For all patients in the three groups , the head of the bed was raised by 30 degree angleand the balloon was measured continuously. Cuff pressure in the three groups were maintained at 20, 25 and 30 cmH₂O (1 cmH₂O = 0.098 kPa) respectively. The patient's air leakage, oxygen saturation, tracheal tube displacement of each group were recorded every hour when the patients were calm. Fiberbronchoscope was used to aspirate sputum during extubation to check for mucosal damage. Chest X-ray examination was used to evaluate pulmonary infection and sputum bacteria culture examination was conducted at the same time.

There was no significant difference in gender, age and critical condition among the three groups. The number of patients with airway mucosal injury in the 30 cmH₂O group was significantly higher than that in the 20 cmH₂O group (cases: 8 vs. 4, P < 0.05). There was no significant difference in airway mucosal injury between Group 20 cmH₂O and Group 25, Group 25 cmH₂O and Group 30 cmH₂O. When the balloon pressure was 20, 25, and 30 cmH₂O, there was no significant difference in air bag leakage (cases: 14, 10, 12), trachea catheter displacement (cases: 18, 11, 16), ventilator-associated pneumonia (cases: 3, 4, 3), all P > 0.05, and there was no significant difference in mechanical ventilation time and the hospitalization time [mechanical ventilation time (hours): 77.07±65.34, 80.80±70.20, 77.60±65.23; the length of ICU stay (days): 5.70±3.74, 5.30±4.57, 6.23±3.51, all P > 0.05].

The cuff pressure of 20 cmH₂O will not increase the mechanical ventilation time and hospitalization time of patients, while 20 cmH₂O is much safer in airway mucosal injury.