2 Physiology of PediatricGenitourinary Laparoscopy

The expanding scope of paediatric genitourinary laparoscopy has meant that increasingly complex procedures are being carried out in ever younger patient populations. Surgeons and anaesthetists alike have thereby been confronted with and gained awareness of a mounting repertoire of physiological consequences related to both intra and retroperitoneal gaseous insufflation. The physiological responses encountered clinically are mainly due to the mechanical and biochemical effects of carbon dioxide (CO2) insufflation. CO2 is absorbed across the thin peritoneal membrane of paediatric patients resulting in hypercarbia and acidosis and leads to an increased CO2 load presented to the lungs. Mechanically, the increased intraabdominal pressure decreases lung compliance and worsens ventilation perfusion mismatch, ultimately leading to hypoxia. Cardiovascularly, the paediatric patient is prone to developing increases in systemic and pulmonary vascular resistance resulting in significant decreases in cardiac output. These cardiopulmonary effects are pressure dependent and have an occurrence that is inversely proportional to patient age and weight, warranting use of the lowest insufflation pressures possible, especially when dealing with very young and/or acutely ill patients. Abdominal insufflation also leads to acute elevations in intracranial pressure, a caveat with specific relevance to genitourinary laparoscopy as myelodysplastic patients constitute a significant patient subgroup who stand to benefit from laparoscopic procedures under specific precautionary measures. Other physiological consequences include effects on renal function, thermoregulation, surgical stress and metabolism. Despite this long list of untoward physiological effects the overwhelming majority of genitourinary From: Current Clinical Urology: Pediatric Robotic Urology Edited by: J. S. Palmer, DOI 10.1007/978-1-60327-422-7_2 C © Humana Press, a part of Springer Science+Business Media, LLC 2009