Near Infrared Spectroscopy in Patients Undergoing Robotic Assisted Laparoscopic Surgery in the Trendelenburg Position

Some robotic endoscopic surgeries require a steep Trendelenburg position and a carbon dioxide pneumoperitoneum. This minimally invasive approach has the advantages of less postoperative pain, shorter hospital stay and faster recovery. After prolonged operative time in a Trendelenburg position rare but significant complications are a cerebral oedema or a well leg compartment syndrome. Well leg compartment syndrome results from inadequate perfusion in the lower limbs and the perfusion pressure is decreased proportionally to the lower extremity elevation. The condition can lead to release of intracellular proteins and myoglobinuria, hyperpotassaemia and metabolic acidosis followed by cell necrosis. The risk for tissue damage increases after 4 hours in a Trendelenburg position. If not promptly diagnosed and treated, a compartment syndrome has devastating complications like permanent dysfunction, limb loss, renal failure or even death. There are no specific guidelines for diagnosis and for the timing of surgical decompression. Fasciotomy is a clinical decision. There is no universal agreement at which compartment pressure irreversible muscle damage occurs. The only objective diagnostic tool available is currently to measure the intramuscular pressure, however this is invasive, painful and may yield unreliable results. An intracompartment pressure of 0- 10mm Hg is the normal range. Near Infrared Spectroscopy (NIRS) monitors are validated and approved to measure cerebral and somatic tissue oxygenation below the sensors and may help detecting promptly a compartment syndrome. Therefore, the investigators designed the present study to detect a change in the tissue oxygenation in the lower legs during robotic assisted, laparoscopic surgery in the Trendelenburg position.