[Frequency of hypoxic episodes during general anesthesia in children]

We measured the frequency and extent of arterial hypoxemia during pediatric general anesthesia under routine clinical conditions. The subjects were 91 children (13 newborns, 27 infants, 37 children under 6 years, 14 children under 14 years) with normal heart and lungs scheduled for extrathoracic surgery. Mask anesthesia (spontaneous/assisted ventilation) was performed in 30 cases, endotracheal anesthesia (controlled ventilation) in 61 cases. Arterial oxygen saturation (SaO2) was determined by pulse oximetry at entry into the operating room and recorded continuously from induction of anesthesia to emergence. Hypoxic episodes (minimum duration: 30 s) were classified as slight (SaO2 less than or equal to 95%), minor (SaO2 less than or equal to 90%) and major (SaO2 less than or equal to 85%). The data were analyzed with the Fisher's test. 52% of all children experienced at least one hypoxic episode. Frequency and extent of hypoxic episodes decreased as age and weight of the children increased. Major hypoxic episodes occurred in 54% of the newborns, 26% of the infants, 8% of the children under 6 and 7% of the children under 14. A body weight of 10 kg appeared to constitute a threshold: in children below this weight arterial oxygen desaturation occurred significantly more frequently (p less than 0.001), and the incidence of major episodes was significantly higher (p less than 0.005). Major episodes were almost evenly distributed between induction and awakening from anesthesia, only one episode occurred during maintenance. Desaturation was more likely to occur in intubated children than in those with a mask (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)