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.

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Background Ventilator sharing is one option to emergently increase ventilator capacity during a crisis but has been criticized for its inability to adjust for individual patient needs. Newer ventilator sharing designs use valves and restrictors to control pressures for each patient. A key component of these designs is an inline Positive End Expiratory Pressure (PEEP) Valve but these are not readily available. Creating an inline PEEP valve by converting a standard bag-valve-mask PEEP valve is possible with the addition of a 3D printer collar. Methods This was a feasibility study assessing the performance and safety of a method for converting a standard PEEP valve into an inline PEEP valve. A collar was designed and printed that covers the exhaust ports of the valve and returns exhaled gases to the ventilator. Results The collar piece was simple to print and easily assembled with the standard PEEP valve. In bench testing it successfully created differential pressures in 2 simulated expiratory limbs without leaking to the atmosphere at pressures greater than 60 cm of H2O. Conclusion Our novel inline PEEP valve design shows promise as an option for building a safer ventilator sharing system.