Secondary Logo

Journal Logo

Institutional members access full text with Ovid®

Effect of Neurally Adjusted Ventilatory Assist on Patient-Ventilator Interaction in Mechanically Ventilated Adults: A Systematic Review and Meta-Analysis

Pettenuzzo, Tommaso MD1; Aoyama, Hiroko MD, MScCH1; Englesakis, Marina MLIS2; Tomlinson, George PhD3,4; Fan, Eddy MD, PhD1,3,4

doi: 10.1097/CCM.0000000000003719
Online Review Article

Objectives: Patient-ventilator asynchrony is common among critically ill patients undergoing mechanical ventilation and has been associated with adverse outcomes. Neurally adjusted ventilatory assist is a ventilatory mode that may lead to improved patient-ventilator synchrony. We conducted a systematic review to determine the impact of neurally adjusted ventilatory assist on patient-ventilator asynchrony, other physiologic variables, and clinical outcomes in adult patients undergoing invasive mechanical ventilation in comparison with conventional pneumatically triggered ventilatory modes.

Data Sources: We searched Medline, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central, CINAHL, Scopus, Web of Science, conference abstracts, and until July 2018.

Study Selection: Two authors independently screened titles and abstracts for randomized and nonrandomized controlled trials (including crossover design) comparing the occurrence of patient-ventilator asynchrony between neurally adjusted ventilatory assist and pressure support ventilation during mechanical ventilation in critically ill adults. The asynchrony index and severe asynchrony (i.e., asynchrony index > 10%) were the primary outcomes.

Data Extraction: Two authors independently extracted study characteristics and outcomes and assessed risk of bias of included studies.

Data Synthesis: Of 11,139 unique citations, 26 studies (522 patients) met the inclusion criteria. Sixteen trials were included in the meta-analysis using random effects models through the generic inverse variance method. In several different clinical scenarios, the use of neurally adjusted ventilatory assist was associated with significantly reduced asynchrony index (mean difference, –8.12; 95% CI, –11.61 to –4.63; very low quality of evidence) and severe asynchrony (odds ratio, 0.42; 95% CI, 0.23–0.76; moderate quality of evidence) as compared with pressure support ventilation. Furthermore, other measurements of asynchrony were consistently improved during neurally adjusted ventilatory assist.

Conclusions: Neurally adjusted ventilatory assist improves patient-ventilator synchrony; however, its effects on clinical outcomes remain uncertain. Randomized controlled trials are needed to determine whether the physiologic efficiency of neurally adjusted ventilatory assist affects patient-important outcomes in critically ill adults.

1Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada.

2Health Sciences Library, Toronto General Hospital, Toronto, ON, Canada.

3Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, ON, Canada.

4Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, ON, Canada.

Drs. Pettenuzzo and Fan conceived the study. Drs. Pettenuzzo, Aoyama, Englesakis, and Fan performed the systematic review. Drs. Pettenuzzo and Tomlinson performed the analysis on the result of the literature search, and Drs. Pettenuzzo, Aoyama, Tomlinson, and Fan provided input on the interpretation. Dr. Pettenuzzo wrote the initial draft of the article, and Drs. Aoyama and Fan revised the article, which was approved by all authors.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (

The authors have disclosed that they do not have any potential conflicts of interest.

For information regarding this article, E-mail:

Copyright © 2019 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.