COMPARISON OF NONINVASIVE RESPIRATORY AND ARTERIAL BLOOD-GAS ANALYSIS - A RECOVERY ROOM STUDY ON ACUTE RESPIRATORY DEPRESSION

The effect on invasive and non-invasive oxygen, carbon dioxide and haemoglobin saturation measures of two repeated doses of alfentanil 0.5-mu-g/kg were tested in 16 patients scheduled for elective cataract surgery under periocular anaesthesia. Alfentanil caused an acute respiratory depression, which was demonstrated as increased levels of arterial and end-tidal carbon dioxide and concomitant decrease in arterial and end-tidal oxygen levels as well as decreased arterial blood saturation and pulse oximeter readings. There was a good correlation between the non-invasive respiratory parameters and blood gas levels, as well as between pulse oxymetry numbers and oxygen saturation of arterial blood. Therefore, hypoventilation and concurrent hypoxaemia can be predicted by monitoring end-tidal CO2.