Fig. 1. The explosion in the Datex-Ohmeda Aestiva™ Model 5 gas circuit and ventilator unit resulted in: 1) the splitting of the top of the unit from its base; 2) the expulsion of the APL valve from the unit; 3) blow out of the front flow sensor module of the unit; 4) fracture and destruction of the plastic expiratory valve disc. In addition, the scavenger tubing was blown off the back of the unit.