Role of Automatic Tube Compensation as Spontaneous Breathing Trial in Critically Ill Patients: A Systematic Review and Meta-Analysis

Objectives: The role of automatic tube compensation (ATC) compared to other spontaneous breathing trials (SBTs) in critically ill receiving mechanical ventilation remains uncertain. The aim of this meta-analysis was to determine the role of ATC in critically ill patients compared to alternative SBT techniques. Methods: We searched PubMed, Cochrane Library, and Embase to capture all potential randomized controlled trials (RCTs) investigating the comparative efficacy of ATC related to other SBT techniques including pressure support (PS), T-piece, continuous positive airway pressure (CPAP) from their inception to February 2020. Primary outcomes were successful extubation rate. Duration of weaning, intensive care unit (ICU) stay, hospital stay, and hospital mortality was regarded as secondary outcomes. We used a risk ratio with accompanying 95% confidence interval (CI) to express estimates. Reviewer Manager (RevMan) 5.1.0 was used to complete all statistical analyses. Results: We included 13 studies enrolling 1117 patients in the final analysis. Pooled results indicated no significant difference when ATC plus CPAP (ATC/CAPA) compared to PS (6 RCTs; 572 patients; risk ratio [RR], 1.15; 95% confidence interval [CI], 1.00 to 1.31), ATC versus T-piece (2 RCTs; 157 patients; RR, 1.14; 95% CI, 0.93 to 1.40), ATC plus PS (ATC/PS) versus PS alone (1 RCTs; 100 patients; RR, 1.15; 95% CI, 0.98 to 1.35), ATC/CPAP versus CPAP alone (3 RCTs; 247 patients; RR, 1.12; 95% CI, 0.97 to 1.29) in terms of successful extubation. Additionally, ATC was also not superior to PS, T-piece, or CPAP in improving the rate of reintubation, the duration of weaning, ICU stay, hospital stay, and hospital mortality. Conclusions: Compared to alternative SBT techniques including PSV and T-piece, ATC may have comparable predictive power of successful extubation in critically ill patients. However, a definite conclusion on this topic can not be drawn due to limited data. Therefore, further studies were required to establish our findings due to limited number of eligible studies and small accumulated sample size.

Low-pressure support vs automatic tube compensation during spontaneous breathing trial for weaning

Background During spontaneous breathing trial, low-pressure support is thought to compensate for endotracheal tube resistance, but it actually should provide overassistance. Automatic tube compensation is an option available in the ventilator to compensate for flow-resistance of endotracheal tube. Its effects on patient effort have been poorly investigated. We aimed to compare the effects of low-pressure support and automatic tube compensation during spontaneous breathing trial on breathing power and lung ventilation distribution. Results We performed a randomized crossover study in 20 patients ready to wean. Each patient received both methods for 30 min separated by baseline ventilation: pressure support 0 cmH2O and automatic tube compensation 100% in one period and pressure support 7 cmH2O without automatic tube compensation in the other period, a 4 cmH2O positive end-expiratory pressure being applied in each. Same ventilator brand (Evita XL, Draeger, Germany) was used. Breathing power was assessed from Campbell diagram with esophageal pressure, airway pressure, flow and volume recorded by a data logger. Lung ventilation distribution was assessed by using electrical impedance tomography (Pulmovista, Draeger, Germany). During the last 2 min of low-pressure support and automatic compensation period breathing power and lung ventilation distribution were measured on each breath. Breathing power generated by the patient’s respiratory muscles was 7.2 (4.4–9.6) and 9.7 (5.7–21.9) J/min in low-pressure support and automatic tube compensation periods, respectively (P = 0.011). Lung ventilation distribution was not different between the two methods. Conclusions We found that ATC was associated with higher breathing power than low PS during SBT without altering the distribution of lung ventilation.

Special Ventilation Functions

‘Special Ventilation Functions’ examines those hard-to-classify features such as standby; sigh; temporary oxygen enrichment or 100% O2; apnoea backup or apnoea ventilation; and tube resistance compensation, also known as tube compensation or automatic tube compensation. It describes each function in depth, including indications for use and details on typical implementations, providing examples from popular ventilators.