In Vivo Evaluation of a New Endotracheal Tube Cuff Controller Promoting Tracheal Secretion Clearance: Preliminary Results

Abstract

Background: Patients undergoing invasive mechanical ventilation accumulate secretions into the trachea, both below and above the endotracheal tube (ETT) cuff. Therefore, suctioning is required to prevent complications due to secretion retention, but such a procedure is not without risks. TrachFlush is a new cuff controller synchronized with the mechanical ventilator that generates an artificial cough maneuver by briefly deflating and re-inflating the ETT cuff within the inspiratory time.

Methods: 7 patients admitted to our general intensive care unit were enrolled in the study and connected to TrachFlush (expected sample size 72 patients). A sigh (total inspiratory pressure 35 cm H₂O, inspiratory time about 2 seconds, once per minute) was introduced if not present. The ETT cuff pressure was set to 25 cm H₂O. We performed 3 artificial cough maneuvers during 3 consecutive sighs. The primary aim of the present study was to estimate the artificial cough flow generated around the ETT cuff, computed as the leaked volume divided by the cuff deflation time (average 1.18 s), see Figure 1. In 4 patients mouth aspiration was performed at the start and end of the study while in 5 patients endotracheal suctioning was performed at the end of the study. The study was approved by local IRB. Data are reported as mean ± standard deviation.

Results: Table 1 reports the baseline data and the main results. All patients underwent 3 artificial cough maneuvers. All the artificial cough maneuvers in all patients produced an artificial cough flow ranging from 6.2 to 37.4 L/min. The mean flow was 21 ± 9 L/min. The average of the maximum flow reached in each patient was 28 ± 7 L/min. The maximum flow was recorded predominantly during the third cough maneuver. At the end of the study, in all the 4 patients in which mouth secretions were evaluated, we could detect secretions while endotracheal secretions were present in 4/5 of the patients. In one patient undergoing pressure support ventilation, the artificial cough maneuver stimulated the patient’s cough. No complications were recorded during the study.

Conclusions: The tested ETT cuff controller was able to produce a significant artificial cough flow around the cuff promoting the transport of tracheal secretions, either sub-glottal or sub-cuff, into the mouth.

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