Proportional modes versus pressure support ventilation: a systematic review and meta-analysis

Abstract

BackgroundProportional modes (proportional assist ventilation, PAV, and neurally adjusted ventilatory assist, NAVA) could improve patient–ventilator interaction and consequently may be efficient as a weaning mode. The purpose of this systematic review is to examine whether proportional modes improved patient–ventilator interaction and whether they had an impact on the weaning success and length of mechanical ventilation, in comparison with PSV. MethodsWe searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from inception through May 13, 2018. We included both parallel-group and crossover randomized studies that examined the efficacy of proportional modes in comparison with PSV in mechanically ventilated adults. The primary outcomes were (1) asynchrony index (AI), (2) weaning failure, and (3) duration of mechanical ventilation.ResultsWe included 15 studies (four evaluated PAV, ten evaluated NAVA, and one evaluated both modes). Although the use of proportional modes was not associated with a reduction in AI (WMD − 1.43; 95% CI − 3.11 to 0.25; p = 0.096; PAV—one study, and NAVA—seven studies), the use of proportional modes was associated with a reduction in patients with AI > 10% (RR 0.15; 95% CI 0.04–0.58; p = 0.006; PAV—two studies, and NAVA—five studies), compared with PSV. There was a significant heterogeneity among studies for AI, especially with NAVA. Compared with PSV, use of proportional modes was associated with a reduction in weaning failure (RR 0.44; 95% CI 0.26–0.75; p = 0.003; PAV—three studies) and duration of mechanical ventilation (WMD − 1.78 days; 95% CI − 3.24 to − 0.32; p = 0.017; PAV—three studies, and NAVA—two studies). Reduced duration of mechanical ventilation was found with PAV but not with NAVA.ConclusionThe use of proportional modes was associated with a reduction in the incidence with AI > 10%, weaning failure and duration of mechanical ventilation, compared with PSV. However, reduced weaning failure and duration of mechanical ventilation were found with only PAV. Due to a significant heterogeneity among studies and an insufficient number of studies, further investigation seems warranted to better understand the impact of proportional modes.Clinical trial registration PROSPERO registration number, CRD42017059791. Registered 20 March 2017Electronic supplementary materialThe online version of this article (10.1186/s13613-018-0470-y) contains supplementary material, which is available to authorized users.

Proportional assist ventilation versus pressure support ventilation for weaning from mechanical ventilation in adults: a meta-analysis and trial sequential analysis

“…However, Kataoka et al did not compare the mortality rate between proportional mode and PSV. While Kataoka et al [38] compared proportional mode with PSV, we focused on the comparison between PAV and PSV. Three more studies were included in our meta-analysis.…”

Proportional modes of ventilation: technology to assist physiology

“…As such, patients with a high respiratory drive can also be under-assisted, with a risk of diaphragm load-induced injury and patient self-inflicted lung injury [ 15 , 16 ]. Additionally, perfect patient-ventilator synchrony is frequently not achieved in PSV [ 19 , 40 , 41 ]. The risk of late cycling (i.e., mechanical insufflation finishing after the end of inspiratory effort; also known as prolonged insufflation or prolonged cycling) is high during PSV, as insufflation cycles-off to exhalation once the flow has reached a set percentage of the peak inspiratory flow: the higher the assist, the longer the time to reach the cycling-off criterion and the longer the mechanical inspiratory time, thereby increasing the mismatch with the patient’s neural inspiratory time [ 42 , 43 ] (Fig.…”

“…Proportional modes improve patient-ventilator synchrony, neuromuscular coupling and gas exchange, and restore breathing variability [ 19 , 41 , 50 – 53 ]. This improved patient-ventilator interaction is a potential mechanism by which NAVA and PAV+ might provide lung and diaphragm-protective ventilation.…”

“…Moreover, safe targets for respiratory effort may vary among patients, depending on the severity of lung injury and diaphragm function [ 15 – 17 ]. The uncertainty regarding titration of inspiratory support with NAVA and PAV+ might be one of the reasons why there is still limited data showing improved clinical outcomes when using proportional modes as compared to conventional modes [ 18 , 19 ], but clinical benefits of NAVA compared to PSV were recently demonstrated in difficult-to-wean patients [ 20 , 21 ]. At the same time, despite having very complex physiological consequences, PSV maintains an appearance of simplicity and is the most frequently used partially supported mode of ventilation [ 22 ].…”

How to ventilate obstructive and asthmatic patients

“…PAV protects against high tidal volume and subsequent dynamic hyperinflation [93]. The use of PAV is associated with a shorter weaning time compared with pressure support ventilation [94].…”