sodium bicarb leads to lower serum K compared to other fluids

The optimal fluid management for a patient who is hypovolemic and also hyperkalemic is an important question for clinical care. Although some evidence from renal transplant suggested that balanced crystalloid may be less prone than normal saline to increase serum potassium levels, in the SMART and SALT-ED trials, there was no obvious difference in potassium levels between normal saline and balanced crystalloid despite the tendency of normal saline to induce acidosis when compared with results of balanced crystalloids. This is despite the fact that both lactated Ringer’s solution and Plasmalyte contain potassium. On the basis of the SMART and SALT-ED trials, there is little reason to anticipate a difference in serum potassium levels between normal saline and balanced crystalloids.

Long-standing debates about the role of IV sodium bicarbonate have emphasized the risks of intracellular acidosis even in the face of an induced alkalemia. In any case, by inducing a relative (or absolute) alkalemia, sodium bicarbonate solutions will, on average, decrease serum potassium levels. Randomized controlled trials of sodium bicarbonate for the prevention of contrast material-induced nephropathy or acute kidney injury complicating cardiac surgery have not shown evidence of benefit. However, the moderate-sized BICAR-ICU trial (N = 389) suggested that administration of hypertonic sodium bicarbonate (4.2%; roughly 1 US ampoule of sodium bicarbonate diluted in approximately 150 mL of sterile water) in patients in the ICU with acute kidney injury and acidemia (pH ≤7.20, PaCO2 ≤45 mm Hg, and serum bicarbonate concentration ≤20 mEq/L [20 mmol/L]) led to lower rates of renal replacement therapy. Other outcomes were positive but exploratory. As anticipated, serum potassium levels were lower in the sodium bicarbonate group than in the control group within the BICAR-ICU trial.1234

Footnotes

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  2. Jaber S, Paugam C, Futier E, et al; BICAR-ICU Study Group. Sodium bicarbonate therapy for patients with severe metabolic acidaemia in the intensive care unit (BICAR-ICU): a multicentre, open-label, randomised controlled, phase 3 trial. Lancet. 2018;392(10141):31-40. PubMed ↩

  3. O’Malley CMN, Frumento RJ, Hardy MA, et al. A randomized, double-blind comparison of lactated Ringer’s solution and 0.9% NaCl during renal transplantation. Anesth Analg. 2005;100(5):1518-1524. PubMed ↩

  4. Self WH, Semler MW, Wanderer JP, et al; SALT-ED Investigators. Balanced crystalloids versus saline in noncritically ill adults. N Engl J Med. 2018;378(9):819-828. PubMed ↩