The physiological effect of CO2 pneumoperitoneum in pediatric laparoscopy

The physiological effect of CO2 pneumoperitoneum during laparoscopy is a great concern of the anesthesiologists. Its effect in pediatric laparoscopy has not been previously reported. The purpose of this study was to examine the physiological alteration of pediatric patients during CO2 pneumoperitoneum.

One hundred and twenty six children aged from 11 mon to 13 yr undergoing laparoscopic inguinal exploration were divided into three groups based on age orientation: group I comprising 40 children with age from 11 mon to 2 yr; group II 46 children with age between 2 to 5 yr; and group III 40 children aged from 5 to 13 yr. All patients received endotracheal anesthesia with halothane-N2O in 50% O2 and atracurium for muscle relaxation. Respiration was controlled by an Ohmeda 7000 ventilator with constant minute ventilation to maintain baseline end-tidal CO2 tension (PETCO2) between 32-33 mmHg. After anesthesia, CO2 was insufflated into the peritoneal cavity via the opened hernia sac. The intraabdominal pressure exerted by CO2 was 10 mmHg and the duration of pneumoperitoneum and laparoscopy was 15 min. We recorded airway pressure, PETCO2, body temperature, blood pressure, heart rate, heart rhythm, and oxygen saturation simultaneously at 1 min interval before, during, and after laparoscopy.

The airway pressure and PETCO2 showed significant increases during laparoscopy (15-18% and 18-20% respectively) in all cases, but the percentage of increases were not significantly different among groups. However, the PETCO2 change in terms of time lag were different between groups: (1) the time lag from CO2 insufflation to the emergence of PETCO2 change (latent period) was respectively 0.7 +/- 0.1 (mean +/- SD) min in group I, 0.9 +/- 0.2 min in group II and 1.5 +/- 0.2 min in group III (p < 0.05); (2) the PETCO2 change from baseline to a plateau (ascending period) was respectively 4.2 +/- 0.6 min in group I, 6.3 +/- 1.0 min in group II and 9.1 +/- 1.1 min in group III (p < 0.05); (3) the PETCO2 decline from plateau to baseline after CO2 deflation (descending period) was respectively 6.2 +/- 0.5 min in group I, 8.3 +/- 0.8 min in group II and 12.0 +/- 1.3 min in group III (p < 0.05). The body temperature and hemodynamics including blood pressure, heart rate, heart rhythm, oxygen saturation were not significantly changed during laparoscopy in all groups.

The changes of PETCO2 during laparoscopy did not influence the hemodynamic stability in our study. The younger children give a faster reaction time of PETCO2 change after CO2 insufflation than do the older children which may be related to the variation of physiological exhibition at different state of development.