Which NPPV mode, CPAP or PSV, is the best solution for the management of acute hypoxemic respiratory failure: A systematic review and network meta-analysis protocol v1
Authors: Sakuraya,MD, MPH Masaaki , Okano,MD Hiromu , Masuyama, MD, PhD Tomoyuki , Kimata,MD, MPH Shunsuke , Hokari, MD, PhD Satoshi 
Published: April 2021

Background: For mild to moderate ARDS, noninvasive positive pressure ventilation (NPPV) is an option for respiratory support in patients without multiple organ failure. Whether the differences among the modes of NPPV have an impact on outcomes has not been fully investigated.Compared with pressure support ventilation (PSV), continuous positive airway pressure (CPAP) may improve clinical outcomes by avoiding excessive tidal volume. Search: We searched for eligible trials using the following databases: 1) The Cochrane Central Register of Controlled Trials; 2) MEDLINE via PubMed; 3) EMBASE; 4) Ichushi, a database of Japanese papers. The language and country in which the studies were conducted will be restricted to English and Japanese. Types of studies to be included We accept published, randomized controlled trials. The languages and countries in which the studies were conducted were restricted to English and Japanese. Randomized crossover trials, cluster-randomized trials, and quasi-experimental trials were excluded. Participants/population Inclusion: We will include patients aged 18 years or older who have acute respiratory failure, defined by the new onset (<7 days) of clinical signs (e.g., tachypnea, increased work of breathing), radiologic signs (unilateral or bilateral chest X-ray opacities), and hypoxemia. Hypoxemia was defined as a P/F ratio below 300 cm H2O, SaO2/SpO2< 94% in room air, PaO2 < 60 mmHg in room air, or <80 mmHg with O2. We will consider studies including patients treated in the intensive care unit, intermediate care unit, and emergency department. Intervention(s), exposure(s) All interventions considered in this review are noninvasive ventilation, which provides positive pressure ventilation that can be delivered with different modalities; any type of interface and ventilators can be used. The NPPV mode will be divided into two ventilation modes: CPAP and PSV, or bi-level positive airway pressure (BiPAP). Given the potential differences in reported patient outcomes, we compared these modes with two different interventions. Duration of ventilation, management during the NPPV interval, and weaning methods are not limited. Comparator(s)/control Conventional oxygen therapy: Low-flow nasal cannula, face mask, and Venturi mask (flow rate is not limited). High-flow nasal cannula: The flow rate and fraction of inspired oxygen (FiO2) are not limited. Invasive mechanical ventilation: Via endotracheal intubation, with or without a lung protective strategy. Main outcome(s) 1)Mortality (death in the intensive care unit [ICU], hospital, at the end of the study period, and within 100 days). 2)Intubation during ICU stay (NPPV will not be included in intubation). * Measures of effect The number of each outcome and total participants in each group were used to calculate the relative risk (risk ratio). Additional outcome(s) None * Measures of effect None Data extraction Network meta-analysis will be performed using a frequentist-based approach with multivariate random-effects meta-analysis. The inconsistency of the network model is estimated using inconsistency factors and their uncertainties. In addition, ranking plots (rankograms) were constructed using the probability that a given treatment had the highest event rate for each outcome. The surface under the cumulative ranking curve (SUCRA), which is a simple transformation of the mean rank, was used to set the hierarchy of treatments. We will perform a meta-analysis using the GRADE Working Group Approach for network meta-analysis