Effect of an Automatic Triggering and Cycling System on Comfort and Patient-Ventilator Synchrony during Pressure Support Ventilation

Abstract

Background: The digital Auto-Trak™ system is a technology capable of automatically adjusting the triggering and cycling mechanisms during pressure support ventilation (PSV). Objective: To compare Auto-Trak with conventional settings in terms of patient-ventilator synchrony and discomfort. Methods: Twelve healthy volunteers underwent PSV via the mouth by breathing through an endotracheal tube. In the conventional setting, a pressure support of 8 cm H₂O with flow cycling (25% peak inspiratory flow) and a sensitivity of 1 cm H₂O was adjusted. In Auto-Trak the triggering and cycling were automatically set. Discomfort, effort of breathing, and the asynchrony index (AI) were assessed. In a complementary bench study, the inspiratory and expiratory time delays were quantified for both settings in three mechanical models: ‘normal', obstructive (COPD), and restrictive (ARDS), using the ASL 5000 simulator. Results: In the volunteer study the AI and the discomfort scores did not differ statistically between the two settings. In the bench investigation the use of Auto-Trak was associated with a greater triggering delay in the COPD model and earlier expiratory cycling in the ARDS model but with no asynchronic events. Conclusions: Use of the Auto-Trak system during PSV showed similar results in comparison to the conventional adjustments with respect to patient-ventilator synchrony and discomfort in simulated conditions of invasive mechanical ventilation.

Influences of Duration of Inspiratory Effort, Respiratory Mechanics, and Ventilator Type on Asynchrony With Pressure Support and Proportional Assist Ventilation

“…In a previous study conducted by our research group, Auto-Trak and manual adjustments of the cyclingoff criteria showed similar results with respect to patientventilator synchrony and patient comfort. 23 In the present study, the use of Auto-Trak in a single-limb circuit ventilator showed similar results to conventional settings concerning cycling asynchrony.…”

“…The Auto-Trak system consists of a technology capable of automatically adjusting, breath by breath, the triggering and cycling mechanisms. 23 Table 2 shows the configuration of the rise time and the inspiratory trigger sensitivity, which was set to the minimum value on all ventilators to prevent the occurrence of auto-triggering. 15…”

Patient-ventilator asynchrony

“…Patient-ventilator asynchrony can be defi ned as a mismatch between the patient, regarding time, fl ow, volume, or pressure demands of the patient respiratory system, and the ventilator, which supplies such demands, during MV. (3) Asynchrony events can range from subtle changes, the detection of which demands strong suspicion and refi ned monitoring, to an evident "struggle" between the patient and the ventilator.…”

What is the role of noninvasive ventilation in cystic fibrosis?

“…In clinical practice, this may have an important influence on the numbers of asynchronous events and/or patient comfort [24].…”