Hyperkalaemia: isotonic bicarbonate infusions offered no real benefit in lowering potassium.

Clinical bottom line (level 3b)

  1. Isotonic bicarbonate infusions over one hour did not have a clinically significant effect in potentiating the potassium-lowering effect of insulin in patients with end-stage renal disease on maintenance haemodialysis.
Allon and Shanklin: American Journal of Kidney Disease 1996; 28 (4): 508-514
Expires February 2004

The study

Case-control study with objective outcomes, not adjusted for confounding factors, not validated in an independent set of patients.
Setting: outpatient dialysis unit, university hospital, USA

8 patients (aged mean 50 years, 88% male) nondiabetic chronic haemodialysis patients receiving 3-4 hours of dialysis three times a week, for at least three months

Excluded if
  • angina
  • myocardial infarction within 6 months
  • excessive (>3/min) or complex ventricular premature beats
  • using beta-blockers


    • Control Group: (n = 8, 8 analysed): isotonic saline, given as experimental group
    Experimental Group: (n = 8, 8 analysed): Isotonic bicarbonate in 10% dextrose at 90 mmol/l and IV insulin (5 mU/kg/min) for 60 minutes; total volume administered 600 mL. Given with or without albuterol.

    100% followed for 60 minutes

    The evidence

    Outcome Control Group
    (SD)    		 Experimental Group
    (SD)    		 Mean Difference
    (95% CI)
    change in potassium (mol/l) without albuterol -0.85
    (0.06)     		-0.81
    (0.15)     		-0.04
    (-0.16 to 0.08)
    change in potassium with albuterol -0.53
    (0.15)     		-0.71
    (0.16)     		0.18
    (0.01 to 0.34)

  • No change in pH or arterial bicarbonate was found on any regimen.

    • Comments

    1. Non-ideal study design (non-randomised, unblinded and very small).
    2. Patients were neither very hyperkalaemia (eg. potassium of around 4.2) nor acidaemic (pH at baseline 7.39).
    3. Isotonic bicarbonate infusions were used because of previous studies showing lack of effect of bolus hypertonic bicarbonate.

    Citation

    1. Allon M, and Shanklin N: Effect of bicarbonate administration on plasma potassium in dialysis patients: interactions with insulin and albuterol. American Journal of Kidney Disease 1996; 28 (4): 508-514
    Contributor: Warren Lee, Chris Ball and Clare Wotton, February 2000
    Reviewer:

    Clinical Question.
    Patient chronic haemodialysis
    Intervention or Exposure isotonic bicarbonate
    Comparison placebo
    Outcome fall in potassium