Physiological Changes in Transperitoneal Versus Retroperitoneal Laparoscopy in Children: A Prospective Analysis

Abstract

The choice of minimally invasive surgical approaches in pediatric urology is largely influenced by surgeon preference and experience. Little is known about the differences in physiological variables that might objectively influence the choice of surgical approach. We compared the cerebral and systemic hemodynamic effects of transperitoneal vs retroperitoneal CO(2) insufflation in children. After receiving ethical review board approval and written parental consent 36 pediatric patients undergoing transperitoneal (18) or retroperitoneal (18) laparoscopic surgery were enrolled in this study. A standardized anesthetic technique of isoflurane 1 MAC and remifentanil 0.2 mcg/kg per minute was used. Measured parameters included end tidal CO(2), middle cerebral artery blood flow velocity, heart rate and noninvasive mean arterial blood pressure. Transcranial Doppler ultrasound was used to measure middle cerebral artery blood flow velocity. Data were collected before, during and after CO(2) insufflation to 12 mm Hg pneumoperitoneum at regular intervals, including every minute for 10 minutes and every 2 minutes thereafter. Within group analysis was done using repeated measures ANOVA. Nonlinear regression analysis was used to determine the best fit and the relationship of each variable with time with p <0.05 considered significant. Patient age and weight were comparable in the 2 groups. Transperitoneal CO(2) insufflation resulted in a rapid parallel increase in middle cerebral artery blood flow velocity, mean arterial pressure and end tidal CO(2) during the first 8 minutes of pneumoperitoneum (p <0.05). Despite a continued increase in end tidal CO(2) thereafter middle cerebral artery blood flow velocity and mean arterial pressure attained a plateau within the first 8 minutes (p <0.05). In contrast, middle cerebral artery blood flow velocity and end tidal CO(2) increased progressively throughout the retroperitoneal CO(2) insufflation period (p <0.01). Cerebral blood flow velocity and end tidal CO(2) seem to increase progressively and gradually during retroperitoneal laparoscopy, in contrast to the more rapid increase and plateau effect during transperitoneal laparoscopy. Presumably the smaller absorptive surface in the retroperitoneal space explains this physiological difference.