Carbon monoxide (CO) delivery system used in animal models and Phase 1 clinical trials. Carbon monoxide (CO) delivery system used in animal models and Phase 1 clinical trials. A: Front view. B: Schematic including ventilator, CO delivery system with injector module, and CO gas cylinder. C: Volumetric mixing data using the CO delivery system, a mechanical ventilator, and test lung. Flow-matching results in instantaneous flow of CO gas proportional to the inspiratory flow (Vent Flow) to deliver and maintain a precise and constant CO concentration. From Reference 95, with permission. Dean R Hess Respir Care 2017;62:1333-1342 (c) 2012 by Daedalus Enterprises, Inc.