everal factors are responsible for hypercarbia during laparoscopic procedures. This study was undertaken because we observed a sudden increase in Paco₂ in children with portal hypertension (PHT), which was unusual in healthy children undergoing laparoscopic procedures. Fifty-seven children underwent laparoscopic procedures under general anesthesia and were mechanically ventilated. Arterial blood samples were obtained 5 min after intubation (T₀), 15 min and 30 min after CO₂ pneumoperitoneum (T₁₅ and T₃₀), 5 min after desufflation (T_end), and 10 min after extubation (T_ext) for blood gas analysis. The changes in Paco₂, pH, and ETco₂ were statistically significant during the study periods in both groups (P < 0.05). The percentage of Paco₂ increase between T₀and T₁₅ was 11.5% and 20.1%, respectively, in the control group and the PHT group (P < 0.05). This increase reached 36.8% at T₃₀ in the PHT group, whereas the control group had a 17.2% increase (P < 0.05). ETco₂ presented similar changes. The variability in base excess, bicarbonate, Pao₂, arterial oxygen saturation, and Spo₂ was not significant in either group (P > 0.05). The Paco₂increased remarkably in children with PHT undergoing laparoscopy, with no difference in intrahepatic or extrahepatic origin. Limiting the duration of CO₂pneumoperitoneum and intraabdominal pressure and adjusting ventilatory variables to accommodate hypercarbia are of the utmost importance for such cases.

The advantages of diagnostic laparoscopy in portal hypertensive (PHT) patients include visual examination of the liver, regional collateralization, and obtaining liver biopsy specimens directly from the nodular structures. However, laparoscopic investigation, which is performed with the use of CO₂ insufflation into the peritoneal cavity, is not without potential complications. In 1993, we recognized that the Paco₂ levels of PHT patients were remarkably higher than those of systemically healthy children, for instance, patients with undescended testis. Changes in arterial CO₂ (Paco₂) and the hemodynamic state that occurs during laparoscopic procedures have been extensively studied in adult patients(1,2). Several factors have been considered as responsible for the hypercarbia encountered during diagnostic or interventional laparoscopic procedures. These factors include absorption of CO₂ by the peritoneum, alterations in cardiac output and respiratory mechanics and function caused by increased intraabdominal pressure, and cephalad displacement of the diaphragm, resulting in decreases in lung volume and functional residual capacity (1–7). The aim of this study was to verify the differences arising from changes in blood gases in two groups of children undergoing laparoscopic procedures: 1) PHT patients and 2) children who were otherwise in reasonably good health (the control group).