摘要: Continuous monitoring of inspiratory oxygen can be accomplished by placing an electrochemical cell into the limb anaesthesia circuit, or analyzing gas sampled from Y-piece. Polarographic cells in two sites and a side-stream paramagnetic analyzer were compared clinical experiment. The times to low alarm comparable when measured method. Breath-by-breath end-tidal concentrations offered patient information rather than mere levels. inspiratory-expiratory difference seems more sensitive indicator hypoventilation carbon dioxide. Awareness alveolar (end-tidal) level shorten alert and, invariably, increases safety.