A Novel System of 'Split Ventilation' using electronically controlled valves can be used to deliver modified lung protective ventilation in a porcine model of acute respiratory distress syndrome

Introduction: During surges in demand for ventilator capacity, demand may outstrip supply Split ventilation has been suggested as a temporising measure for individual hospitals to cope with such surges in demand Optimising split ventilation may be important in the ongoing pandemic of SARS-CoV-2 and the associated high prevalence of acute respiratory distress syndrome We developed a low cost electronically controlled system for delivering split ventilation, provisionally termed the Combiventilate system Objectives: 1) To demonstrate that an electronically controlled split ventilation system could be used to delivery independent volumecontrolled ventilation to two test lungs under conditions of varying resistance, compliance and leak 2) To demonstrate that in a porcine model of acute respiratory distress syndrome, the Combiventilate system could deliver independent modified lung protective ventilation 3) To show that in a porcine model of ARDS, markers of ventilator induced lung injury were similar in Cobiventilate ventilated animals and single ventilated animals 4) To demonstrate that with minimal training, critical care staff could independently operate the Combiventilate system in simulated clinical scenarios Methods: We performed benchtop testing of the Combiventilate system using linear test lungs to ensure it's ability to provide differential ventilation and accommodate for changes in respiratory mechanics We established a porcine model of acute respiratory distress syndrome by administering intrabronchial hydrochloric acid We compared ventilation using the Combiventialte system to traditional individual ventilation in both injured and uninjured animals (n = 30) Groups were;individually ventilated uninjured (n = 5), individually ventilated injured (n = 5), Combiventilate managed uninjured (n = 10) and Combiventilate managed injured (n = 10) We compared between group differences in the ability to deliver lung protective ventilation and meet gas exchange targets over a period of 6 hours of mechanical ventilation We also compared immunological and histological markers of ventilator induced lung injury between groups We performed benchtop simulations of clinical scenarios to verify that, with minimal training, clinical staff could set up and operate the Combiventilate system under conditions simulating common clinical scenarios Results: The Combiventilate system was able to deliver individualised volume-controlled ventilation in benchtop testing with linear test lungs In a porcine model of ARDS, the Combiventilate system was able to facilitate similar adherence to modified lung protective ventilation as compared to individual traditional ventilation Immunological and histological markers of ventilator induced lung injury were similar in the Combiventilate managed groups compared to the traditionally ventilated groups In benchtop simulations, clinical staff were able to set up and operate the Combiventilate system with minimal training Conclusion: Performance of the Combiventilate system in benchtop testing and in a large animal model of ARDS supports the ability to deliver modified lung protective ventilation Similar degrees of ventilator induced lung injury as observed in the Combiventilate group as compared to the individually ventilated group These data are promising and support further efforts to develop and investigate this system for use in humans as a temporising measure when surge demand exceeds capacity for indivualised ventilation