Cerebral Oximetry as a Guide Monitor in Extreme Trendelenburg P Position and Elevated Intrathoracic Pressure for Prolonged Robotic Assisted Radical Prostatectomy Cerebral Oximetry as a Guide Monitor in Extreme Trendelenburg P Position and Elevated Intrathoracic Pressure for Prolonged Robotic Assisted Radical Prostatectomy R. F. Ghaly MD, S. Saatee, MD, N. N. Knezevic, MD, PhD, A. Khorasani, MD, K. D. Candido, MD Department of Anesthesiology, Advocate Illinois Masonic Medical Center, Chicago, IL USA Abstract Case Description Introduction Discussion 1. Edmonds HL Jr, et al. Semin Cardiothorac Vasc Anesth 2004;8: Kalmar AF, et al. Br J Anaesth. 2010;104 : Park EY, et al. Acta Anaesthesiol Scand. 2009;53: A 69-year-old man presented for a robotic radical prostatectomy. This procedure which requires prolonged extreme Trendelenburg position can compromise venous return and promote brain swelling. We used brain oxygenation monitor to record regional oxygen saturation (rSO 2 ) in both hemispheres under scalp probe. Intrathoracic pressure rose from 22 cmH 2 O in a supine to 45 cmH 2 O in Trendelenburg position. rSO 2 was decreased only 4% on average during 5-hour surgery (average of 64% on the right and 74% on the left). The use of guided therapy fluid restriction, vasopressors and intravenous anesthetics (remifentanyl 0.5 mcg/kg/min and propofol 50 mcg/kg/min) can prevent brain swelling during extreme Trendelenburg position and elevated intrathoracic pressure. The use of Robotic Assisted Radical Prostatectomy (RARP) improves the outcomes and reduces the complications compared with open radical prostatectomy. Extreme Trendelenberg (40°) position for several hours which facilitates this surgery plus CO 2 pneumoperitoneum potentially can cause significant cardiovascular and neurophysiologic changes including intracranial hypertension and reduction of cerebral tissue oxygen saturation (SctO 2 ). Noninvasive cerebral oximtery is a technique utilizing Near-Infrared Spectroscopy (NIRS) light ( nm) and can be used to assess the continuous and non invasive monitoring of the regional cerebral tissue oxygen saturation. Desaturation of more than 10 scale below baseline or an absolute value of less than 50 are associated with decreased SSEP amplitude and is the threshold for intervention. 1 A 69-year-old man, ASA class III with the past medical history of poorly controlled hypertension treated by Ramipril 10 mg/daily and Prostate CA (Gleason Score 7) presented for RARP. The patient was premedicated with Midazolam 3 mg IV. Upon arrival in the OR, standard monitoring was applied. Bilateral frontal lobe brain O 2 saturation sensors were placed and the rSO 2 values recorded, continuously. Anesthesia was induced using propofol 2mg/kg, fentanyl 3mcg/kg, succinylcholine 1mg/kg and the trachea intubated. Arterial line was placed for beat to beat monitoring of BP and the transducer was zeroed at external acoustic meatus as a reflection of the base of the brain pressure. Anesthesia was maintained with sevoflurane 0.5 MAC and propofol, remifentanyl infusion (50 mcg/kg/min and 0.5 mcg/kg/min respectively). The patient was slowly placed in steep Trendelenburg position and the intraperitoneal pressure was adjusted as needed by the surgeon. He was awakened in the operating room, transferred to the PACU without any neurologic impairment and discharged after 3 days with a satisfactory condition. Previous reports indicated that intracranial pressure and extracranial vascular pressure increases during acute head down tilt and may cause cerebral edema. 1 Kalmar demonstrated that in the first 5 min after Trendelenburg positioning, CPP increases by 11 mmHg and then decreases modestly. After resuming to supine position, CPP decreases by 12 mmHg that recovered to its baseline within 3 minutes. 2 Park showed that in a population of 32 patients going for daVinci RARP, rSO 2 increased slightly, which suggests that the procedure did not induce cerebral ischemia and was well tolerated by the majority of the patients. 3 Using TIVA technique, fluid restriction and vasopressors when needed, will help to restore the rSO 2 as an indirect measure of cerebral edema and ICP toward their baseline. Steep Trendelenburg positioning during RARP have a potential to disrupt the normal, tightly controlled balance between brain oxygen supply and demand. Such disruption if not prevented and managed can result in brain ischemia, presented from transient subtle cognitive decline to more serious permanent functional impairments. Cerebral oximtery provides noninvasive means of continually monitoring brain oxygen imbalance and guiding interventions aimed at its correction especially in patient that are at increased risk for position related decline in rSO 2 such as patients with carotid stenosis, previous TIA or stroke. Conclusions References