Tracheal wall pressures in the clinical setting: comparing Portex Soft Seal and Lotrach cuffs

Introduction

The tracheal wall pressure (TWP) exerted by a tracheal tube cuff should normally be kept between 20 and 30 cmH₂O. This protects against mucosal injury whilst allowing ventilation without an audible air leak [1]. The Portex Soft Seal high-volume low-pressure (HVLP) cuff has a working intracuff pressure of 30 cmH₂O, providing a safe TWP of the same value because there is no tension in the cuff wall material. There are, however, folds within the cuff wall that allow passage of subglottic fluid to the tracheobronchial tree below, increasing the risk of ventilator-associated pneumonia [2]. The Lotrach endotracheal tube was designed to prevent this leakage at an equivalent TWP to that of correctly inflated HVLP cuffs [3]. Each Lotrach cuff is individually calibrated to transmit only 30 cmH₂O to the tracheal wall, yet because of the lack of folds in the cuff wall it has been shown to prevent of aspiration of subglottic contents [4]. Although extensively tested in benchtop models and pig tracheas, we wished to demonstrate that the Lotrach cuff had an identical sealing pressure, and therefore TWP, as the HVLP cuff in normal clinical practice.

Methods

One hundred and two ventilated patients were intubated with either the Lotrach (n = 54) or the Portex Soft Seal (n = 48) tubes. Both the Lotrach and Portex Soft Seal cuffs were inflated to their working pressures. Whilst undertaking staged recruitment manoeuvres (up to 40 cmH₂O), the positive end-expiratory pressure at which laryngeal air leak occurred was noted.

Results

The seal pressures (TWP) are presented in Table 1.

Table 1 Seal pressures for the Lotrach and Portex Soft Seal cuffs

Conclusion

Both the Portex Soft Seal and Lotrach cuffs exert an equal and safe TWP when inflated to their recommended working pressures.