Low Cerebral Oxygenation Is Associated with Cognitive Impairment in Chronic Hemodialysis Patients

Abstract

Background/Aims: High rates of cognitive impairment (CI) are an alarming problem in patients undergoing chronic hemodialysis (HD). Its pathophysiology remains unclear and there are indications that brain ischemia might be one of the key causes. Cerebral tissue oxygenation, as measured by near-infrared spectroscopy, is known to be decreased in HD patients. However, it is unknown whether CI is associated or not associated with lower cerebral oxygenation in these patients. The primary aim of our study was to probe this possible association. Our secondary aim was to assess other factors possibly related to cerebral ischemia and CI. Methods: Thirty-nine patients treated by chronic HD were included in this cross-sectional study. All measurements were performed before the initiation of an HD session. The Montreal Cognitive Assessment (MoCA) was administered according to published recommendations. Regional saturation of oxygen (rSO2) of the left frontal lobe was measured using the INVOS 5100C device. Basic medical history and laboratory data were recorded, and handgrip strength was analyzed. We used the unpaired t test to compare the rSO2 and other variables between cognitively normal patients (MoCA score ≥26) and those who displayed CI (MoCA score <26). Multiple linear regression analysis was used to adjust for principal confounders. Results: Cognitively impaired patients had lower brain rSO2 values compared to cognitively normal patients (48 ± 9 vs. 57 ± 10%, p = 0.01). Among other variables, higher red cell distribution width (15.8 ± 1.9 vs. 13.8 ± 1.6%, p = 0.01) and lower hand grip strength (49.2 ± 23.3 vs. 99.3 ± 31.4 lbs, p < 0.001) also displayed a significant association with CI. The relation between rSO2 and MoCA score was significant after adjustment for age and gender (p = 0.007). Conclusion: Decreased brain oxygenation is associated with weaker cognitive performance in patients undergoing chronic HD. Further understanding the causes of cerebral ischemia in HD patients could lead to the prevention of cognitive decline in this population.

Sensitivity and reliability of cerebral oxygenation responses to postural changes measured with near-infrared spectroscopy

“…Adequate cerebral oxygenation is essential for physical and cognitive functioning (Agbangla et al 2017 ; Lotte et al 2018 ; Vasta et al 2018 ; Kovarova et al 2018 ). Cerebral oxygenation depends on blood pressure and cerebral perfusion (Krakow et al 2000 ), which are challenged by postural changes, such as standing up from supine or sitting position (Kim et al 2011 ).…”

Sleep apnea syndrome caused lowering of cerebral oxygenation in a hemodialysis patient: a case report and literature review

“…The measurement of cerebral rSO 2 by NIRS has recently been performed in various clinical settings, including cardiovascular surgery, pediatrics, and dialysis [3][4][5][6][7][8][16][17][18]. We therefore, reviewed the literature for reports of cerebral rSO 2 values in dialysis patients (Table 1).…”

“…In particular, cerebral rSO 2 was measured in patients in various clinical settings, including hemodialysis (HD) patients [3][4][5][6][7][8]. It would be considered important to maintain cerebral rSO 2 levels because that low cerebral rSO 2 has been associated with cognitive impairment in patients with chronic kidney disease (CKD) [5,8] and poor neurologic outcomes in post-cardiac arrest patients [7]. We aimed to examine the associations between changes in cerebral rSO 2 and those in systemic oxygenation using the measurement of peripheral arterial oxygen saturation (SpO 2 %) in a patient undergoing HD with SAS.…”

Intra‐ and interdialytic cerebral hypoxia: A culprit of cognitive decline going unpunished?

“…However, this baseline value has repeatedly been found to be significantly lower than in matching non-HD controls, 2,4 and we described its association with the severity of cognitive impairment. 5 This shows that the brain is subject not only to acute ischaemia associated with the HD procedure, but also to chronic lack of oxygen, and that cognitive function mirrors the decrease in cerebral tissue oxygenation. The finding is consistent both with the fact that cognitive impairment in this population is mainly of vascular aetiology, and with the typical radiological findings.…”

“…After this initial drop, the rSO 2 value returns to its starting (baseline) value by the end of HD procedure. However, this baseline value has repeatedly been found to be significantly lower than in matching non‐HD controls, and we described its association with the severity of cognitive impairment …”