Effect of body position and head of bed angle on intra-abdominal and endotracheal tube cuff pressure in mechanically ventilated patients

Changing position is one of the typical nursing care in intensive care units. This study aimed to investigate the effect of body positioning on intra-abdominal pressure and endotracheal tube cuff pressure and their relationship with each other in patients undergoing mechanical ventilation

This was a before-after clinical trial study performed on 70 patients over eight months. Eligible patients were placed in one of the positions of bed angle (flat, 30, and 45 degrees) and body position sideways toward an opposite direction to the mechanical ventilator. The intra-abdominal pressure and the endotracheal tube cuff pressure were measured with each change in body position and head of the bed. Data were analyzed at a significance level of 0.05.

Mean intra-abdominal pressure was different in positions (P<0.001). The mean intra-abdominal pressure at the flat angle was (7.4±0.49) CmH2O at the lowest and 45 degrees was (11.98±0.45) CmH2O at the highest. The mean intra-abdominal pressure in the supine position was significantly lower than in other positions (P<0.001). The endotracheal cuff pressure was significantly higher in lying down on the opposite side of the ventilator than in other positions (P<0.001). There is no significant relationship between intra-abdominal pressure and endotracheal tube cuff pressure (P=0.15).

The results showed that at the flat angle and opposite direction to the mechanical ventilator, the tube cuff pressure was maximal and at an angle of 45° and the position of the opposite side of the mechanical ventilator, the intra-abdominal pressure was the highest. Although there was no significant relationship between intra-abdominal pressure and endotracheal tube cuff pressure, when lying on the opposite side of the mechanical ventilator, intra-abdominal pressure and endotracheal tube cuff pressure were abnormally high. Therefore, it is recommended to avoid the patient in this situation.