Inline Positive End-Expiratory Pressure Valves: The Essential Component of Individualized Split Ventilator Circuits

BACKGROUND: As resources are overwhelmed with the coronavirus disease 2019 pandemic, multiple approaches to produce individualized split-ventilator designs have emerged. These designs attempt to address the significant limitations and safety concerns of coventilation practices by allowing practitioners to adjust pressure settings for individual patients connected with specialized circuits to a single ventilator. The critical component in virtually all individualized circuit designs is the adjustable inline positive end-expiratory pressure valve. METHODS: We reviewed the literature on the mechanics of inline positive end-expiratory pressure valve function, the implications and considerations for advanced application of inline positive end-expiratory pressure valves in individualized circuits, available methods of adapting commercial positive end-expiratory pressure valves in the resource-restricted setting, and major caveats of the use of inline positive end-expiratory pressure valves. RESULTS AND CONCLUSIONS: The function of adjustable inline positive end-expiratory pressure valves in advanced individualized ventilator circuits has not been described. Adjustable inline positive end-expiratory pressure valves are critical to individualized circuit reliability and patient safety when attempting to extend ventilator capacity in the setting of extreme ventilator shortages. Adjustable inline positive end-expiratory pressure valves provide a means to reduce delivered peak inspiratory pressure to an individual patient circuit, a method to increase positive end-expiratory pressure for an individual patient circuit, and act as an one-way valve to ensure unidirectional gas flow through the divided circuit. Adjustable inline positive end-expiratory pressure valves can be adapted from commercial valves or printed de novo when commercial options are unavailable. Noncommercial sourcing of ventilator components should only be considered in the setting of extreme ventilator shortages under the supervision of a knowledgeable anesthesiologist or intensivist.