Comparison of positive and negative pressure extubation after mechanical ventilation in intensive care unit patients

Abstract

To investigate the effect of positive and negative pressure extubation on mechanical ventilation patients in the intensive care unit (ICU). A prospective randomized controlled study was performed, 105 ICU patients who successfully passed the spontaneous breathing test (SBT) after mechanical ventilation of Nanjing Jiangbei Hospital Affiliated to Nantong University from January 2019 to March 2021 were enrolled. According to random number table method, they were randomly divided into positive pressure extubation group (53 cases) and negative pressure extubation group (52 cases). During extubation, all patients were placed in semi-decubitus position (raising the head of bed at an angle range from 30 degree angle- 45 degree angle), the secretions from mouth, nose, throat and trachea were removed. In the negative pressure extubation group, the sputum suction tube was inserted into the tracheal tube and passed over the distal opening to carry out continuous negative pressure suction in the tracheal tube after disconnecting the ventilator. Meanwhile, after the tracheal tube balloon was evacuated, the sputum suction tube was pulled out together with the tracheal tube. In the positive pressure extubation group, the patients were guided to inspiratory forcibly under the original SBT mode. When the patients reached the inspiratory peak, the ballon was evacuated and the tracheal tube was removed. After extubation, all patients were given nasal catheter oxygen inhalation (oxygen flow 5 L/min). Arterial blood gas analysis indexes [pH value, arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2)] were recorded 5 minutes and 1 hour after extubation in both groups. Vital signs (including tachypnea, tachycardia, elevated blood pressure and decreased oxygen saturation) and complications (including severe cough, airway hyperresponsiveness and pneumonia) were observed 30 minutes after extubation in both groups. Five minutes after extubation, blood gas analysis showed that the PaO2 of positive pressure extubation group was significantly higher than that of negative pressure extubation group [mmHg (1 mmHg ≈ 0.133 kPa): 123.4±30.2 vs. 111.0±21.1, P < 0.05], the pH value and PaCO2 in positive pressure extubation group were slightly lower than that of negative pressure extubation group [pH value: 7.411±0.042 vs. 7.419±0.040, PaCO2 (mmHg): 39.7±4.7 vs. 40.5±5.6], but the differences were not statistically significant (both P > 0.05). One hour after extubation, the pH value, PaO2 and PaCO2 in positive pressure extubation group were slightly lower than those in negative pressure extubation group, but the differences were not statistically significant. Within 30 minutes after extubation, the incedences of tachypnea, tachycardia, elevated blood pressure and oxygen desaturationin in positive pressure extubation group were significantly lower than those in negative pressure extubation group [tachypnea: 9.4% (5/53) vs. 28.8% (15/52), tachycardia: 15.1% (8/53) vs. 32.7% (17/52), elevated blood pressure: 11.3% (6/53) vs. 30.8% (16/52), oxygen desaturation: 7.5% (4/53) vs. 34.6% (18/52), all P < 0.05], the incidence of severe cough in positive pressure extubation group was significantly lower than that in negative pressure extubation group [9.4% (5/53) vs. 30.8% (16/52), P < 0.05], but there was no significant difference in the incidence of complications of airway hyperresponsiveness between the two groups [1.9% (1/53) vs. 5.8% (3/52), P > 0.05]. No pneumonia occurred in both groups within 48 hours after extubation. The positive pressure extubation method can ensure full oxygenation of patients undergoing mechanical ventilation in ICU, avoid hypoxia, and reduce the occurrence of hypoxia and severe cough, which is more conducive to the stability of vital signs.