Abstract:Objective To discuss the influences of pre-inflation manometry on endotracheal tube cuff so as to provide reference for the standardization of manometry technique. Methods A clinical and in vitro study was performed. In-vitro study, there were routine manometry group and pre-inflation manometry group, respectively tested for the initial value of pressure cuff at 25 cm H2 O and 30 cm H2 O, which were repeated for 50 times with a total of 200 times to observe the changes of cuff pressure loss value. In clinical study, 50 patients with artificial airway for mechanical ventilation in the Department of Critical Medicine from June to August 2020 were selected, and target values of pressure cuff of 25 cm H2 O (low pressure) and 30 cm H2 O(high pressure) were set and measured respectively by routine manometry and pre-inflation manometry in each patient (total 200 times in 50 cases) to observe the influence of different pre-inflation values on cuff pressure. Results In-vitro study, the cuff pressure loss values were (8.54 ± 0.89) cm H2 O by routine manometry and (0.11 ± 0.28) cm H2 O by pre-inflation manometry at 25 cm H2 O and were（10.18±0.56）cm H2 O by routine manometry and（0.06±0.24）cm H2 O by pre-inflation manometry at 30 cm H2 O,and there were statistical differences in them( P ＜0.01). In clinical study, there were significant differences in cuff pressure at the same target values by different manometry ( P ＜0.01).When the target value of pre-inflation was 30 cm H2O, the measured cuff pressure values were (27.52±0.76) cm H2O and (29.32±0.62) cm H2O at the initial value of 25 cm H2O and 30 cm H2O respectively, both of which were above the safety pressure value of 25 cm H2O. Conclusions The routine manometry can lead to the significant decrease of cuff pressure .The pre-inflation manometry can reduce the cuff pressure drop. It is safer to set the pre-inflation target value to 30 cm H2 O in clinical pressur