Effect of applying positive pressure with or without endotracheal suctioning during extubation: a laboratory study

Background: During invasive mechanical ventilation, secretions accumulate in the subglottic space; consequently, there is a risk of aspiration of these secretions into the airway during cuff deflation and extubation. To minimize this risk, 2 extubation methods are used. The first consists of introducing a suction catheter into the endotracheal tube (ETT) and the trachea. After initiating suctioning, the cuff is deflated and the ETT is removed together with the suction catheter. The second technique involves applying positive pressure to the ETT using a resuscitation bag. Once the manual breath is delivered, the ETT cuff is deflated and the ETT is removed without suction. The aim of this laboratory study is to determine the existence and magnitude of differences in leak volume during cuff deflation and extubation using various combinations of positive pressure with or without endotracheal suctioning.

Methods: An ETT connected to a ventilator was placed in a model trachea. Colored water was instilled in the space above the cuff. To measure the leak volume, a collection chamber was attached to the distal end of the model. Nine procedures were defined, based on the delivery of different positive pressure levels with or without endotracheal suctioning during extubation. The volume of leakage, in milliliters, was the unit of analysis. Procedures yielding values lower than 1 mL were assessed by the Friedman test, and a P value of less than .05 was considered significant. Post hoc comparisons were performed with a Wilcoxon test, followed by a Bonferroni correction.

Results: The application of CPAP 15, pressure support ventilation (PSV)15/10, and PSV 20/5 produced 0.4, 0.2, and 0.1 mL of leak volume, respectively. Statistically significant differences were found between CPAP 15 and PSV 15/10 (P = .003) and between CPAP 15 and PSV 20/5 (P = .01), but not between PSV 15/10 and PSV 20/5 (P = .30). The addition of suctioning increased leak volume, with statistically significant differences between CPAP 15 and CPAP 15 + endotracheal suctioning (P = .001) and between PSV 15/10 and PSV 15/10 + endotracheal suctioning (P = .001).

Conclusions: Endotracheal suctioning during cuff deflation and extubation produced greater leakage. Application of CPAP 15, PSV 15/10, and PSV 20/5 resulted in the lowest leak values, with the best results being obtained with the use of PSV 15/10 and PSV 20/5.