Effect of body position changes on endotracheal tube cuff pressure in ventilated patients

Introduction

In order to avoid either microaspiration (<20 cmH₂O) or tracheal injury (>30 cmH₂O), the target for endotracheal tube (ETT) cuff pressure (CP) is between 20 and 30 cmH₂O. Our objective was to assess the effect of patient positioning changes on CP in adult patients.

Methods

A sample of 12 orally intubated and sedated patients was selected. Patients received neuromuscular blockade and were positioned in a neutral start position (backrest, head of bed elevation (HoB) 30°, head in neutral position) and CP set at 25 cmH₂O. Subsequently 16 different position changes were performed: anteflexion head, hyperextension head, left and right lateral flexion of head, left and right rotation of the head, semirecumbent position (HoB 45°), recumbent position (HoB 10°), horizontal position, trendelenburg (-10°), left and right lateral positioning over 30°, 45° and 90°. Once the patient was correctly positioned, CP was recorded during an end-expiratory ventilatory hold. CP observed was compared with CP at start position (25 cmH₂O). Also the number of values outside the target range (20 to 30 cmH₂O) was reported as considered clinically relevant.

Results

A total of 192 measurements were performed (12 subjects×16 positions). Results are shown in Table 1 (CP reported as median, IQR). In every position a significant deviation in CP was observed. In total, 40.6% of values exceeded the upper limit of 30 cmH₂O. No values beneath the lower target limit of 20 cmH₂O were observed. In each position the upper target limit was exceeded at least once.

Table 1 Endotracheal tube cuff pressure values following patient position changes

Conclusion

Simple changes in patient positioning may result in potentially harmful CP (>30 cmH₂O). These observations call for strict CP monitoring.