Acute Effect of Moderate-Intensity Interval Intradialytic Exercise on Cerebral Oxygenation in Hemodialysis Patients: A Randomized Crossover Trial.

Abstract

Patients undergoing hemodialysis experience a decrease in regional cerebral oxygenation (rSO₂) during hemodialysis. This randomized crossover trial investigated acute changes in the rSO₂ by intradialytic exercise. This study revealed that acute intradialytic exercise increased the rSO₂ and offset the decrease in rSO₂ during hemodialysis. Cognitive dysfunction in hemodialysis patients is associated with a decrease in regional cerebral oxygenation (rSO₂). Intradialytic exercise improves cognitive function; nonetheless, the acute effect of intradialytic exercise on cerebral circulation remains unknown. This study aimed to evaluate the acute effect of intradialytic exercise on rSO₂ during hemodialysis. This single-center, open-label, randomized crossover trial included 20 hemodialysis patients. Patients received the control condition as usual care and the intradialytic exercise condition in random order. The intradialytic exercise condition involved the performance of anaerobic threshold–intensity interval exercise for 35 minutes. Cerebral oxygenation (rSO₂, oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin) in the prefrontal cortex was measured using near-infrared spectroscopy during hemodialysis. Cardiovascular responses, including the heart rate, cardiac index, mean arterial pressure, and blood gas, were also assessed. The two conditions were compared using two-way repeated-measures analysis of variance. The analysis included 16 patients, four of whom were excluded because of artifacts in the cerebral oxygenation data. The rSO₂ (<i>P</i> < 0.001), oxygenated hemoglobin (<i>P</i> < 0.001), and total hemoglobin (<i>P</i> = 0.004) showed significant interactions and were increased at end of exercise (rSO₂, 1.3%; 95% confidence interval [CI], 0.5 to 2.1; oxygenated hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.02; total hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.03) and 15 minutes after exercise (rSO₂, 1.1%; 95% CI, 0.2 to 2.0; oxygenated hemoglobin, 0.01 mM; 95% CI, 0.00 to 0.03; total hemoglobin, 0.02 mM; 95% CI, 0.00 to 0.03) in the intradialytic exercise condition compared with the control condition. The rSO₂ at the end of hemodialysis in the control condition was significantly decreased compared with that during predialysis (−1.5%; 95% CI, −2.7 to −0.3), but not in the intradialytic exercise condition (−1.2%; 95% CI, −2.8 to 0.5). Intradialytic exercise significantly increased rSO₂ during and after exercise and improved rSO₂ to the same extent as predialysis. University Hospital Medical Information Network Center Clinical Trials Registry. Registry name: Effect of Intradialytic Aerobic Exercise to Changes in Regional Oxygen Saturation during Hemodialysis. Registration: UMIN000048885.