A patient with end-stage renal disease on dialysis presents with hypotension and sepsis. He is also hyperkalemic. How do you fluid resuscitate him? Prior teaching was to never give potassium-containing solutions to a hyperkalemic patient. However, acidosis will further shift potassium extracellularly, and normal saline has a pH of 5.6, significantly lower than the physiologic pH of 7.4. Lactated Ringers and Plasma-lyte have higher pH (see table below), and while they do contain some potassium, the concentration of potassium in these solutions is approximately phyisiologic (4 and 5 mEq, respectively), so will actually serve to lower the serum potassium level. This makes sense physiologically, but is there data to support this?

Solution pH Na+ (mEq) Cl- (mEq) K+ (mEq)
NaCl 0.9% 5.6 154 154 0
LR 6.5 130 156 4
Plasma-lyte A 7.4 140 98 5

 

This Emcrit post does a nice review of the available data, but the short answer is that multiple randomized controlled trials comparing intraoperative and perioperative NS vs Plasma-lyte  in patients undergoing renal transplant demonstrated that patients receiving NS had a significantly higher incidence of hyperkalemia (64%) compared to patients who received Plasma-lyte (21%). Patients who received Plasma-lyte also required less emergent hemodialysis post-operatively.

While these studies can’t necessarily be generalized to treating acutely hyperkalemic patients, the evidence certainly seems to favor the administration of a more physiologically balanced fluid such as LR or Plasmalyte over normal saline, especially if a patient is already acidotic.

 

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