Assessing the safety of pediatric laparoscopic surgery.
We studied deviations from normal physiology in piglets (n = 10; average weight 5.75 kg) during carbon dioxide (CO2) pneumoperitoneum. Cardiopulmonary data were gathered during varying intraabdominal pressures (IAP = 8, 12, 15, 20 mm Hg), each sustained for 10 mins. Each animal was its own preinsufflation and exsufflation control. A rapid, significant rise in arterial CO2 pressure from preinsufflation (46.5 +/- 6.7 mm Hg) to insufflation at 20 mm Hg (72.9 +/- 15 mm Hg; p < 0.05) initiated further cardiac adjustments. Responses included a sustained increase in cardiac index (presufflation = 3.1 +/- 1.4; 20 mm Hg IAP = 3.6 +/- 1.2), increased heart rate (preinsufflation = 121 +/- 21; 20 mm Hg IAP = 150 +/- 28; p < 0.05), and left ventricular stroke work (20 mm IAP = 22.7 +/- 8.9; exsufflation 20 min = 15.3 +/- 9.4 g.m/m2; p < 0.05). There was a significant arterial-end CO2 tidal difference throughout insufflation, as great as 15 mm Hg (p < 0.05), suggesting increasing ventilation dead space. Core temperature decreased significantly from preinsufflation (35.3 +/- 1.3 degrees C) to 20 mm Hg IAP (33.6 +/- 1.5 degrees C, p < 0.05). We suggest the following guidelines based on the above data: (a) preoperative examination screening for cardiopulmonary abnormalities; (b) fluid replacement to normal hydration only; (c) cuffed endotracheal tubes for effective ventilation; (d) careful adjustment of minute ventilation to achieve normocapnia; (e) CO2 warming; (f) maximal insufflation pressure of 12 mm Hg; (g) postoperative care emphasizing respiratory and thermoregulation status.