END-TIDAL OXYGRAPHY AND SAFE DURATION OF APNEA IN YOUNG-ADULTS AND ELDERLY PATIENTS

Using an end-tidal fractional oxygen concentration of 0.9 as an end po int for pre-oxygenation, we have compared the time taken to achieve th is end point and the safe duration of apnoea after induction of anaest hesia following pre-oxygenation in elderly patients and young adults. The times taken to reach the end point of pre-oxygenation and for the oxygen saturation to decrease to 92% during a period of apnoea were fo und not to be significantly different between the two age groups. It i s concluded that in spite of the physiological changes that occur with age, end-tidal oxygen concentration monitoring is as useful in the el derly population as in young adults as an end point for pre-oxygenatio n.