Analgesia and ventilatory response to CO2 following epidural sufentanil in children

The authors studied the effects of epidural sufentanil (0.75 microgram.kg-1) after urologic surgery in 15 children ranging in age from 4 to 12 yr, and in weight from 14 to 47 kg. The onset and duration of analgesia were 3.0 +/- 0.3 and 198 +/- 19 min, respectively (mean +/- SEM). Side effects included pruritus (3/15), nausea and vomiting (5/15), drowsiness (10/15), and urinary retention (1/11). No apnea was observed. Periosteal analgesia and ventilation were studied in eight of the children (mean age 8.6 +/- 0.8 yr). There was significant periosteal analgesia of the tibia (30, 60, 90, and 120 min after injection) and of the radius (60, 90, and 120 min after injection). Resting respiratory rate and tidal volume did not change during the study. Resting minute-ventilation decreased from 6.3 +/- 0.5 l.min-1 preoperatively to 5.6 +/- 0.6 l.min-1 (P less than 0.05) postoperatively, before epidural sufentanil injection; it did not decrease further after epidural sufentanil. Similarly, end-tidal CO2 tension increased significantly from 37.2 +/- 0.7 mmHg preoperatively to 39.9 +/- 1.2 mmHg (P less than 0.05) postoperatively, before epidural sufentanil; epidural sufentanil did not cause a further significant increase in end-tidal CO2 tension. The slope of the CO2 ventilatory response curve decreased significantly from 1.68 +/- 0.12 l.min-1. mmHg-1 preoperatively to 1.10 +/- 0.13 l.min-1.mmHg-1 (P less than 0.01) postoperatively. There were further significant decreases to 0.68 +/- 0.10 and 0.89 +/- 0.16 l.min-1.mmHg-1 30 and 60 min after epidural sufentanil.