Experimental Therapies in Renal Replacement: The Effect of Two Different Potassium Acetate‐free Biofiltration Protocols on Striated Muscle Fibers

Abstract

Dramatic removal of potassium during hemodialysis sessions can induce changes in the electrical properties of nerve cells or muscle fibers, which may underlie neuromuscular symptoms referred by end-stage renal disease patients. The primary aim of our study was to investigate the effects of acetate-free biofiltration (AFB) on the amplitude of compound motor action potential (cMAP) obtained after stimulation of the ulnar nerve at the wrist. The secondary aim was to compare the effect of two different potassium removal modalities on cMAP amplitude and to analyze the effects on muscular force by specific dynamometric tests. Twenty-eight patients received dialysis for 4 h, 3 times per week, first with standard AFB with constant potassium (AFB) and then with AFB with a variable concentration of potassium in the dialysis bath (AFB(K)). The amplitude of cMAP was determined after ulnar nerve stimulation at the wrist at different time intervals: at the start of dialysis; at 15, 45, 90, and 120 min after beginning the session; and at the end of treatment. At the same time intervals, muscle force generation was determined using a dynamometer. Finally, we measured plasma electrolytes, intraerythrocytic potassium, and the electrical membrane potential at rest (REMP) of the erythrocytic membrane. The main finding of this study was a significant reduction of cMAP amplitude in the first 45 min after AFB, which paralleled the reduction in serum potassium levels. Moreover, there was a reduction of muscular strength determined with dynamometric measurements. Potassium removal induced by the two different modalities of AFB may significantly affect myocardial and fibromuscular cells by modulating the electrochemical balance of cell membranes. The transient alteration of the electrical properties on voluntary striated muscle fibers may contribute to the brief reduction in muscular strength we detected in patients who underwent AFB. AFB(K) can minimize the negative effects of standard AFB treatment on neuromuscular excitability, most likely through a more gentle variation of potassium levels during dialysis.

Acquisition of optical coherence tomography angiography metrics during hemodialysis procedures: A pilot study

“…Weight loss and systolic/diastolic blood pressure (SBP/DBP) were measured for each patient every hour. Exclusion criteria were dialysis vintage <6 months, recent history of hospitalization for cardiovascular diseases and severe cognitive or physical impairment ( 12 , 13 ). Each patient underwent dilated fundus ophthalmoscopy and ocular exclusion criteria included any other retinal diseases (including retinal vascular diseases, vitreoretinal diseases, or macular dystrophies), any previous eye surgical intervention or laser photocoagulation in the study eye, ocular media opacity, poor quality images with significant artifact, inaccurate or incorrect segmentation at the level of the superficial capillary plexus (SCP) and deep capillary plexus (DCP).…”

Mechanisms of muscle function

“…The dialysis bath has also been examined as a possible factor affecting neuromuscular function in HD patients. Coppolino et al (Coppolino et al, 2007) examined the hypothesis that plasma potassium reduction due to standard acetate-free biofiltration negatively affects neuromuscular function. Therefore they studied the effect of 2 techniques of acetate-free biofiltration (AFB) on the motor action potential (cMAP) and force production of HD patients before, during and at the end of HD treatment (6 time points).…”