P1246CEREBRAL TISSUE REGIONAL OXYGEN SATURATION AND BLOOD PRESSURE IN HEMODIALYSIS PATIENTS

Abstract

Abstract Background and Aims Patients undergoing hemodialysis (HD) often develop cerebral disease complications. Cerebral tissue regional oxygen saturation (rSO2) through near-infrared spectroscopy (NIRS) is a non-invasive method for cerebral tissue oxygenation monitoring. The aim of the study was to investigate the relationship between rSO2 and hemodialysis in stable HD patients. Additionally, we wanted to investigate how blood pressure during HD is associated with rSO2. Method This is a single centre cross-sectional study in clinically stable HD patients. Cerebral rSO2 was monitored at the forehead 10min before, during and 10min after HD, using an INVOS 5100C device (Medtronic, United Kingdom). Results Thirty-nine stable HD patients (23 men and 16 women; mean age, 62.4 ± 14.6 years were recruited. Dialysis vintage was 65.7 ± 72.1 months, 9 patients had diabetes mellitus, 12 had vascular disease while 14 were smokers. The baseline rSO2 levels (49.6±9.1 %) were significantly lower in HD patients compared with historic results on healthy subjects. We found no difference in rSO2 results in patients with diabetes mellitus, vascular disease or smoking. Although we found a decrease (figure) in rSO2 when patients start dialysis (10min before vs 10min after starting dialysis 49.6±9.1 vs 48.1±9.9 %, p=0.021) rSO2 value returned to baseline after dialysis (10min before vs 10min after dialysis 49.6±9.1 vs 49.9±5.9 %, p=ns. Systolic blood pressure scientifically dropped during the first hour of dialysis (146.7 ± 21.1 vs 137.3 ± 24.6, p=0.03) and systolic blood pressure drop correlated with rSO2. Three patients developed hypotensive episodes requiring iv fluids but these hypotensive episodes had no correlation with rSO2 variations. Conclusion Cerebral rSO2 decreases while patients are on dialysis but return to baseline after dialysis. Blood pressure variations correlate with rSO2 levels but rSO2 do not forecast hypotensive episodes on dialysis.