The effect of premedication on oxygen saturation during the post-premedication period in 20 Chinese children undergoing elective surgery.

Peri-operative continuous pulse oximetric data were studied in healthy Chinese children randomly allocated to receive either pethidine 1 mg kg-1 and atropine 0.02 mg kg-1 intramuscularly 90 min prior to surgery (n = 10), or midazolam 0.5 mg kg-1 and atropine 0.02 mg kg-1 orally, 120 min before surgery (n = 10). Data were collected during the night before surgery, after premedication and for 8 h post-operatively. The pulse oximeter (Nellcor N-200E) output was retrospectively evaluated using Satmaster, a computer programme which permits storage, retrieval, signal evaluation and compilation of oximetric data. There was no significant difference in the frequency, duration, or magnitude ofdesaturation episodes recorded during the post-premedication period compared to the desaturation episodes which occurred in the same child during normal sleep, on the night before surgery. Furthermore, there was no significant difference in the desaturation data between the two premedicant regimens. No child recorded a genuine desaturation less than 80% for longer than 15 s at any time during the study. Neither regimen significantly depressed saturation in otherwise healthy children presenting for minor surgical procedures.