Immediate effects of hemodialysis on upper extremity and cognitive function.

Background: Subjects undergoing hemodialysis often describe feeling "weak" and "fatigued" after dialysis. This has not previously been quantified. We sought to evaluate upper extremity and cognitive function before and after hemodialysis to see if differences existed and how long recovery takes.

Methods: Subjects undergoing hemodialysis in an inpatient hospital dialysis unit were recruited. Subjects underwent assessment of upper extremity strength (grip (GS) and pinch (PS)), dexterity (pegboard assembly (PA)), finger sensation (monofilaments), and cognitive function (mini-mental status exam (MMS)) immediately pre- and post-dialysis, 3 h post-dialysis, and the following morning. Both the dialysis (index) and non-dialysis extremities were evaluated. Results were also stratified for fistulas vs. central venous catheters. Patients were dialyzed at the same flow rate and duration.

Results: 21 subjects were evaluated, 13 (62%), male, mean age 56 ± 17 years, 15 (71%) diabetic, 15 (71%) fistulas, 6 (29%) central venous catheters. Overall, there were no significant changes in GS, PS, PA, immediately or 3 h after dialysis. MMS was non-significantly reduced 3 h after dialysis (22.8 ± 10.3 vs 27.0 ± 3.5, p = 0.06). PA was significantly improved the following morning (6.4 ± 4.8 assembled units vs 7.5 ± 5.1, p = 0.049). Patients dialyzing through catheters had reduced grip strength 3 h after dialysis compared to fistulas (-4.6 ± 2.7 N from baseline vs 1.4 ± 4.3 N from baseline, p = 0.018) that was resolved by the next day.

Conclusions: Hemodialysis in hospitalized inpatients does not cause acute objective deficits in upper extremity or cognitive function, with a significant improvement in hand dexterity the day after dialysis.