System and method of monitoring composition of a flow of breathable gas using a detector and emitter positioned on the same side of the flow of breathable gas
A gas measurement module (16) for use with an airway adapter (22) is configured such that both an emitter (48) and a detector (52, 54) are disposed on the same side of a sampling chamber (46) formed within the airway adapter. Optical elements (56) that guide electromagnetic radiation from the emitter back and forth across the sampling chamber to the detector include at least one toric element. The at least one toric element compensates for a tilted folding mirror positioned on a side of the sampling chamber opposite from the emitter and the detector.