Prehospital PEEP for Acute Respiratory Distress: Protocol for a Scoping Review

Positive end-expiratory pressure (PEEP) can improve oxygenation and reduce the work of breathing in patients with acute respiratory distress. In the prehospital setting, systems providing continuous positive airway pressure (CPAP), bi-level positive airway pressure (BiPAP) and adjustable pressure-limiting (APL) valves are used inconsistently, and the evidence base is heterogeneous across their use in patients with chronic obstructive pulmonary disease, asthma, pneumonia and cardiogenic pulmonary oedema.

This scoping review aims to map the existing evidence on prehospital use of PEEP-based ventilation in adults with acute respiratory distress, including reported clinical outcomes and safety.

This scoping review will be conducted in accordance with the JBI methodology for scoping reviews and reported in line with the PRISMA extension for Scoping Reviews (PRISMA-ScR). We will systematically search MEDLINE, Embase, CINAHL, Cochrane CENTRAL and the Cochrane Database of Systematic Reviews (CDSR) with support from a research librarian. Empirical studies of adults (≥ 18 years) receiving PEEP-based ventilation in the prehospital setting will be eligible, including randomised controlled trials, observational studies, case series and well-described case reports. Two independent reviewers will screen, extract and map the data on study characteristics, interventions, comparators and outcomes, with disagreements resolved by a third reviewer. Methodological quality will be appraised at study level using the Jadad Scale for randomised trials and the Newcastle-Ottawa Scale for cohort and case-control studies.

We expect to identify a limited but clinically relevant body of evidence reporting effects on oxygenation, dyspnoea severity, escalation to advanced airway management, adverse events and feasibility. The findings will be synthesised narratively and presented in descriptive and tabular form. We specifically anticipate sparse evidence for the prehospital use of APL systems.

This scoping review will provide a comprehensive mapping of prehospital PEEP use in adults with acute respiratory distress, summarising its clinical effects, safety signals and feasibility, and identifying gaps to inform future studies.