Cerebral Perfusion in Hemodialysis Patients: A Feasibility Study.

BACKGROUND: Patients on hemodialysis (HD) are known to exhibit low values of regional cerebral oxygenation (rSO2) and impaired cognitive functioning. The etiology of both is currently unknown. OBJECTIVE: To determine the feasibility of serially monitoring rSO2 in patients initiating HD. In addition, we sought to investigate how rSO2 is related to hemodynamic and dialysis parameters. DESIGN: Prospective observational study. SETTING: Single-center tertiary academic teaching hospital in Ontario, Canada. PARTICIPANTS: Six patients initiating HD were enrolled in the study. METHODS: Feasibility was defined as successful study enrollment (>1 patient/month), successful consent rate (>70%), high data capture rates (>90%), and assessment tolerability. Regional cerebral oxygenation monitoring was performed 1 time/wk for the first year of dialysis. A neuropsychological battery was performed 3 times during the study: before dialysis initiation, 3 months, and 1 year after dialysis initiation. The neuropsychological battery included a traditional screening tool: the Repeatable Battery for the Assessment of Neuropsychological Status, and a robot-based assessment: Kinarm. RESULTS: Our overall consent rate was 33%, and our enrollment rate was 0.4 patients/mo. In total 243 rSO2 sessions were recorded, with a data capture rate of 91.4% (222/243) across the 6 patients. Throughout the study, no adverse interactions were reported. Correlations between rSO2 with hemodynamic and dialysis parameters showed individual patient variability. However, at the individual level, all patients demonstrated positive correlations between mean arterial pressure and rSO2. Patients who had more than 3 liters of fluid showed significant negative correlations with rSO2. Less cognitive impairment was detected after initiating dialysis. LIMITATION: This small cohort limits conclusions that can be made between rSO2 and hemodynamic and dialysis parameters. CONCLUSIONS: Prospectively monitoring rSO2 in patients was unfeasible in a single dialysis unit, due to low consent and enrollment rates. However, rSO2 monitoring may provide unique insights into the effects of HD on cerebral oxygenation that should be further investigated. TRIAL REGISTRATION: Due to the feasibility nature of this study, no trial registration was performed.

CONTEXTE: Les patients sous hémodialyse (HD) sont connus pour présenter de faibles valeurs de saturation cérébrale régionale (rSO2) et des fonctions cognitives altérées. L'étiologie de ces deux affections est actuellement inconnue. OBJECTIFS: Vérifier la faisabilité d'un suivi en série de la rSO2 chez des patients ayant amorcé des traitements d'HD. Nous souhaitions également étudier la façon dont la rSO2 est liée aux paramètres hémodynamiques et de dialyse. TYPE D'ÉTUDE: Étude observationnelle prospective. CADRE: Un centre hospitalier universitaire de soins tertiaires situé en Ontario, au Canada. SUJETS: L'étude porte sur six patients ayant amorcé des traitements d'HD. MÉTHODOLOGIE: La faisabilité a été définie par un recrutement efficace à l'étude (plus d'un patient/mois), un taux de consentement élevé (au-delà de 70 %), des taux de saisie de données élevés (au-delà de 90 %) et la tolérance de l'évaluation. La rSO2 a été mesurée une fois par semaine pendant la première année de dialyse. Une batterie neuropsychologique a été réalisée trois fois au cours de l'étude: avant l'initiation de la dialyse, puis trois mois et un an après l'initiation de la dialyse. La batterie de tests neuropsychologiques comprenait un outil de dépistage traditionnel: le Repeatable Battery for the Assessment of Neuropsychological Status, et une évaluation robotisée: Kinarm. RÉSULTATS: Le pourcentage global de consentement était de 33 % et le taux de recrutement était de 0,4 patient/mois. En tout, 243 mesures de la rSO2 ont été enregistrées, avec un taux de saisie des données de 91,4 % (222/243), chez les 6 patients inclus à l'étude. Aucune interaction indésirable n'a été signalée en cours d'étude. Les corrélations entre la rSO2 et les paramètres hémodynamiques et de dialyse étaient variables d'un patient à l'autre. Tous les patients ont cependant montré une corrélation positive entre la pression artérielle moyenne et la rSO2 d'un point de vue individuel. Des corrélations négatives significatives avec la rSO2 ont été observées chez les patients ayant plus de trois litres de liquides. Moins de troubles cognitifs ont été détectés après l'amorce de la dialyse. LIMITES: La faible taille de la cohorte limite les conclusions pouvant être tirées sur les liens entre la rSO2 et les paramètres hémodynamiques et de dialyse. CONCLUSION: Le suivi prospectif de la rSO2 chez les patients s'est avéré irréalisable dans cette unité de dialyse en raison des faibles taux de consentement et de recrutement. Le suivi de la rSO2 pourrait cependant fournir une perspective unique sur les effets de l'HD sur la saturation cérébrale, laquelle devrait être examinée plus attentivement.

Robotic technology quantifies novel perceptual-motor impairments in patients with chronic kidney disease.

BACKGROUND: Neurocognitive impairment is commonly reported in patients with chronic kidney disease (CKD). The precise nature of this impairment is unclear, due to the lack of objective and quantitative assessment tools used. The feasibility of using robotic technology to precisely quantify neurocognitive impairment in patients with CKD is unknown. METHODS: Patients with stage 4 and 5 CKD with no previous history of stroke or neurodegenerative disease were eligible for study enrollment. Feasibility was defined as successful study enrollment, high data capture rates (> 90%), and assessment tolerability. Our assessment included a traditional assessment: The Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and a robot-based assessment: Kinarm. RESULTS: Our enrollment rate was 1.6 patients/month. All patients completed the RBANS portion of the assessment, with a 97.8% (range 92-100%) completion rate on Kinarm. Missing data on Kinarm were mainly due to time constraints. Data from 49 CKD patients were analyzed. Kinarm defined more individuals as impaired, compared to RBANS, particularly in the domains of perceptual-motor function (17-49% impairment), complex attention (22-49% impairment), and executive function (29-37.5% impairment). Demographic features (sex and education) predicted performance on some, but not all neurocognitive tasks. CONCLUSIONS: It is feasible to quantify neurocognitive impairments in patients with CKD using robotic technology. Kinarm characterized more patients with CKD as impaired, and importantly identified novel perceptual-motor impairments in these patients, when compared to traditional assessments.