Titration of Parameters in Shared Ventilation with a Portable Ventilator

Background Dual-patient single ventilator protocols may be required in times of crisis. These are protocols to ventilate two patients with a single conventional ventilator. This study demonstrates a means to titrate peak inspiratory pressure (PIP), positive end-expiratory pressure (PEEP), and fraction of inspired oxygen (FiO₂) for test lungs ventilated via a dual-patient single ventilator circuit.

Methods: This prospective observational study was conducted using a ventilator connected to two test lungs. Changes in PIP, PEEP, and FiO₂ were made to the experimental lung, while no changes were made to the control lung. Measurements were obtained using NICO2 Respiratory Profile Monitor simultaneously measuring each test lung. PIP was titrated using 3D-printed resistors added to the inspiratory circuit. PEEP was titrated using LTV 900 expiratory circuit tubing with an attached manual PEEP valve. FiO₂ was titrated by using a 3D-printed T-splitter added to the ventilator tubing.

Results: PIP, PEEP, and FiO₂ were reliably and incrementally titratable in the experimental lung with some notable but manageable pressure and FiO₂ changes documented in the control lung during these titrations. Similar results were measured in lungs of identical and different compliances.

Conclusions: Individual pressures and fraction of inspired oxygen can be reliably adjusted when utilizing a dual-patient single ventilator circuit with simple, low-cost modifications to the circuit. This innovation could potentially be lifesaving in a resource-limited or crisis setting. Understanding the interactions of these circuits is imperative towards making their use safer.