Abstract
Degenerative joint diseases affect the elderly population, and advanced orthopaedic surgery offers novel solutions. The semi-sitting position is used during shoulder replacement surgery. There have been reports of transient and permanent neurological damage following surgery. We aimed to determine cerebral desaturation events (CDEs) during shoulder replacement surgery under general anaesthesia. This prospective, observational study was conducted at the Hospital of Traumatology and Orthopaedics. A cohort of 24 patients received combined plexus brachialis block and endotracheal anaesthesia. Their cerebral regional oxygen saturation index (rSO2) and mean arterial blood pressure (MAP) were recorded and compared in predefined intervals: before induction, post-induction, after getting in a sitting position, after cementing, and after extubation. Hypotension was defined as the occurrence of any of the following: either a > 30% decline in MAP from the baseline or a MAP < 65 mmHg. CDEs were defined as a 20% reduction in frontal lobe oxygenation. Calculations were made using SPSS software (Version 14.0.2, SPSS Inc.). There was a significant correlation between MAP and rSO2 after positioning, between MAP after intubation and rSO2., and between MAP before intubation and rSO2 at the end of surgery. One in three patients who experienced hypotension also experienced a CDE. rSO2 fluctuations correlated with MAP.