A Simulated Single Ventilator / Dual Patient Ventilation Strategy for Acute Respiratory Distress Syndrome During the COVID-19 Pandemic

Jose A. Solis-Lemus; Edward Costar; Denis Doorly; Eric C. Kerrigan; Caroline H. Kennedy; Frances Tait; Steven A Niederer; Peter E. Vincent; Steven E. Williams

Specifically, we designed two models. The first was a simple Standard Splitter configuration that involved connecting two T-junctions to the ventilator, as proposed previously. 7 This configuration is shown in Figure 1 . The second was a Modified Splitter configuration, which had two elements added to each branch of the splitter: specifically, on the inspiration arms we added variable resistors (RV1 and RV2) to control pressure/flow/volume to each patient, and on the expiration arms we added diodes to prevent back flow through each of the channels, and stop the expiration arms acting as a short circuit between inspiration arms during inspiration. This configuration is shown in Figure 2 . The model outputs the pressure set by the ventilator (VM) and the pressure (VL1 and VL2), flow (IL1 and IL2) and volume (QL1 and QL2) delivered to each patient. The ventilator pressure set by VM is defined as a square wave. The maximum value is set to the peak inspiration pressure (PIP). The minimum value is set to positive end expiratory pressure (PEEP). The cycle rate is defined by respiratory rate (RR) measured in breaths per minute. The ratio of time spent at the maximum and minimum values is defined by the inspiration to expiration ratio (I:E ratio).