Changes in cerebral oxygen saturation following prone positioning for orthopaedic surgery under general anaesthesia: A prospective observational study

BACKGROUND: Prone positioning is often necessary in orthopaedic surgery. The prone position, however, may result in impaired cerebral venous drainage with a subsequent reduction in cerebral perfusion. As a consequence, cerebral hypoxia may occur with the potential for neurological impairment. OBJECTIVE: We assessed the changes in cerebral oxygen saturation with near-infrared spectroscopy using two different monitors after positioning the patient from supine to prone. DESIGN: Prospective observational study. SETTING: Primary Care University Hospital, from May 2010 to February 2011. PARTICIPANTS: Forty patients undergoing general anaesthetic procedures, of which 35 completed the investigation. Similar measurements were done in 35 volunteers, who were studied while awake. INTERVENTIONS: Near-infrared spectroscopy was measured throughout anaesthesia using INVOS (a trend monitor using two infrared wavelengths) for one hemisphere and FORE-SIGHT (a monitor using four wavelengths of laser light to calculate absolute oxygen saturation) for the other hemisphere in an alternate randomisation pattern. OUTCOME MEASUREMENTS: The primary outcome was a change in cerebral oxygen saturation of more than 5% during prone positioning. A comparison with the changes obtained in awake volunteers following similar positioning was also made. RESULTS: Cerebral oxygen saturation increased during prone positioning with INVOS 0.032% per minute (P 
Source: European Journal of Anaesthesiology - Category: Anesthesiology Tags: Monitoring Source Type: research