Abstract
Background and Aims
A significant deterioration of cognitive function in hemodialysis patients is observed in elderly and non-elderly patients. One of possible explantation is significant changes in the circulatory system caused by regular lower cerebral regional saturation of oxygen (rSO2) during dialysis. We aimed to identify the factors affecting the cerebral rSO2 in HD patients during session.
Method
27 patients out of 80 hemodialysed in center patients were recruited for the study (exclusion criteria: significant vision defect, fistula in the dominant hand, previous stroke, other neurological diseases impaired cognitive functions). The mean age of the patients was 51 ±18 y, BMI 25.5±5, dialysis vintage was 2.3 y; 6 with DM and 22 with HT. During the study, each patient completed battery of cognitive function tests (MOCA, Beck's Scale) including computer based assessment validated for elderly (Cognifit), arterial stiffness surrogates (PWV, Aix75 using IEM Mobil-O-Graph) and the saturation (rSO2) of frontal lobes were measured (INVOS 5100c system). Patient regular passive or active (reading, crosswords solving, electronic games) behaviour during sessions was noticed.
Results
Factors showed correlations with rSO2 are displayed in table. Lack of correlations between rSO2 and HD vintage, diabetes or BMI was observed. Patients mentally active during dialysis showed significant (p<0.05) higher rSO2 (60 vs 53% left, 58 vs 49% right), Cognifit score (368 vs 233) and PWV (6,3 vs 9,3 m/s) when compared to passive patient behavior (sleeping, watching TV).
Conclusion
Significant differences in cerebral oxygenation in hemodialysis patients correlated with cognitive functions. In HD patients, cerebral rSO2 was affected by multiple factors, including non modifiable factors: arterial stiffness, age and modifiable factors – active mental activity during session and smoking. Furthermore, this is the first report describing lower levels of rSO2 in HD patients with significant central arterial stiffness (Figure).
Changes in cerebral oxygenation and cognitive functions during controlled hypotension
