Sodium profiling in elderly haemodialysis patients

Abstract

Intradialytic vascular instability continues to be one of the most frequent complications in elderly haemodialysis patients. Signs of impending hypotension such as sweating, apprehension, tachycardia, nausea, or vomiting may be infrequent in the geriatric population. The onset of hypotension in the elderly may be sudden and profound and may lead to serious consequences such as myocardial infarction, stroke, or aspiration if not treated promptly. Prevention of vascular instability is extremely important in the elderly. Avoiding rapid ultrafiltration sedatives, or antihypertensive medications and food intake may be beneficial. Optimal dialysate composition (dialysate sodium, bicarbonate, and calcium concentration) is important. Dialysate sodium profiling may be useful in the elderly to reduce intradialytic hypotension. Step sodium profiles result in better plasma volume refilling in early dialysis, while linear dialysate sodium profiles have greater plasma volume in late dialysis, suggesting that dialysate sodium profiles may need to be individualized for optimal response. Sodium profiling could also result in sodium retention, and long-term studies are needed in the elderly before their widespread use is recommended. Use of newer modalities such as continuous monitoring of plasma volume with Crit Line, and determination and monitoring of body-fluid compartments with bioimpedance may further improve vascular stability in the elderly.

A Critical Review of Sodium Profiling for Hemodialysis

“…With regard to the possibility of profiling causing sodium accumulation, it is worth noting that there was no follow‐up of predialysis and/or postdialysis sodium levels or of clinical signs of sodium accumulation in six of the studies (12, 20–22, 24,33). Clinical or laboratory signs of sodium accumulation were found in eight studies (9,13,19,23,25,27,29,31) but not in the other eight cases (4,14,18,26,28,30,32,34). In one of these investigations (4), a decreasing sodium profile reduced serum sodium levels to normal or even hyponatremic values and led to a decrease in thirst and interdialytic weight gain.…”

“…In addition to this, dialysis fluid sodium concentrations can be selected not only to prevent intracellular water uptake but also to support water transport into the extracellular space, that is, to support plasma refilling (9–14). However, the effect of sodium profiling on preserving EC volume is small compared to the volume depletion caused by ultrafiltration (11,15).…”

“…The effect of linear (9,23,25,31), stepwise (2,23,25,31), and exponential (23,25) profile forms have also been examined in some studies. Postdialysis hypotension (23) and early intradialytic hypotension (11) were best attenuated by decreasing, stepped profiles; linear profiles sometimes reduced muscle cramps (25) and late intradialytic hypotension (11).…”

“…Patients of various ages have been studied: sodium profiling reduced dialysis‐related symptoms in two children, but was associated with an increase in predialysis blood pressure and interdialytic weight gain (19); profiling was found to be mostly advantageous in young adults (25) and in geriatric patients (9).…”

Optimization of dialysate sodium in sodium profiling haemodialysis

“…A number of authors believe that the sodium profiling haemodialysis causes ‘interdialytic’ discomforts more frequently than the conventional haemodialysis in spite of its success in preventing intradialytic hypotensive episodes. In the review of previous studies, clinical or laboratory signs of sodium accumulation were found in eight studies, 2,3,7 , 8,34 , 39,40 ,41 but not in the other eight cases 4,37 , 42–47 . In one exceptional study in which the sodium was profiled from 137 to 128 mmol/L, the decreases of serum sodium levels, thirst, and interdialytic weight gain were observed 43 .…”