Simplicity, Quality and Reliability The OES Orion Anaesthesia Ventilator is a pneumatically driven, time cycled ventilator for use with adults and paediatrics by changing the bellows assembly. The Orion ventilator has adjustable inspiratory time, expiratory time and flow rate giving a wide range of settings. For patient safety, the pressure relief is adjustable. The Orion Ventilator is designed to require minimum servicing and can be serviced without special service tools.