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Three Part Question

In [adults (>16 years) presenting to the emergency department with hyperkalaemia] is [intravenous insulin] effective at [lowering serum K+ levels]?

Clinical Scenario

A 50- year old woman is referred to the Emergency Department by her GP with a serum potassium level of 6.4 mmol/L. A repeat blood test confirms hyperkalaemia, with a serum potassium of 6.8 mmol/L. After giving a cardiac membrane stabiliser you order an IV infusion of insulin and glucose, but wonder how effective this will be in lowering her serum potassium.

Search Strategy

Cochrane Library for Systematic Reviews: May 2011
MEDLINE using OVID interface: 2003 to June week 2 2011
EMBASE: 2003 to 2011 week 24. Reviewed week 26.
Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus: 1947 to June 26th 2011
COCHRANE: hyperkalaemia, hyperkalemia, hyperkal*, hyperpotass*, potassium and hyperpotassaemia

MEDLINE: [exp Potassium/ OR exp Hyperkalemia/ OR hyperkalaemia.mp/ OR high potassium.mp/ OR hyperkal$.mp/ OR hyperpotass$.mp] AND [insulin.mp/ or exp Insulin/] Limit to (english language and humans and yr="2003 -Current")

EMBASE: [exp Potassium/ OR exp Hyperkalemia/ OR hyperkalaemia.mp/ OR high potassium.mp/ OR hyperkal$.mp/ OR hyperpotass$.mp] AND [insulin.mp/ or exp Insulin/] Limit to (human and english language and adult <18 to 64 years> and yr="2003 -Current")

CINAHL: [Hyperkalaemia/ OR Hyperkalemia/ OR Potassium /OR High Potassium/ OR Hyperkal*/ OR Hyperpotass*] AND [Insulin] Limit to (human and english language)

Search Outcome

COCHRANE:51 papers found, one of which was relevant.
MEDLINE: 317 papers found, none of which were considered relevant.
EMBASE: 568 papers found, one of which was relevant.
CINAHL: 182 papers found, 2 of which were relevant.
After removing duplicates a total of 3 relevant papers were found.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Mahoney BA, Smith WA, Lo D, Tsoi K, Tonelli M, Clase C 2005 Canada.	2 RCTs and 2 randomised prospective cross-over trials.	Systematic review. 1a	Serum potassium concentration.	Insulin with glucose effective at lowering serum K+ by 15 minutes in studies which assessed this time point, and by 30 minutes in all studies.	Detailed results of these studies not shown.
Mushtaq MA, Masood M 2006 Pakistan	15 patients with ARF or CRF with a serum potassium > 6 mmol/L. Group B (5 patients) received glucose 25 grams diluted in 100ml of water over 15 minutes and 10 units of insulin as a bolus.	Prospective interventional cohort. 2b	Serum potassium concentration (mmol/L)	0 minutes : 6.5 ± 0.3. 30 minutes: 5.9 ± 0.2. 60 minutes: 5.7 ± 0.2. 180 minutes: 5.9 ± 0.2. 360 minutes: 6.0 ± 0.2.	No sample size estimates performed and sample size was very small. Only patients with renal failure included.
Allon M, Copkney C. 1990 USA	12 HD patients with a serum K+ >5.0mmol/L. Insulin 10U bolus followed by glucose 50ml of a 50% solution IV over 5mins.	Randomised prospective cross-over design. 1b.	Reduction in serum K+ concentration (mmol/L)	15 mins: approx. 0.45 (P<0.001 Vs baseline.) 30 mins: approx. 0.58 45 mins: approx. 0.62 60 mins: 0.65± 0.09.	Approximations as results read from diagram and not supplied in text. No sample size estimates performed. Small sample size. Only HD patients included.

Comment(s)

There is some high level evidence supporting the use of IV insulin and dextrose in the management of hyperkalaemia. From these studies it can be seen that insulin effectively reduces serum K+ levels within 15 minutes and reaches maximum effect at 60 minutes. However, it is important to note that these studies only consider the use of insulin in patients with renal failure and the sample sizes used are small.

Clinical Bottom Line

Insulin with glucose is an effective treatment in the emergency management of hyperkalaemia.

References

1. Mahoney BA, Smith WA, Lo D, Tsoi K, Tonelli M, Clase C Emergency interventions for hyperkalaemia Cochrane Database of Systematic Reviews 2005, Issue 2
2. Mushtaq MA, Masood M Treatment of hyperkalemia with salbutamol and insulin. Pakistan Journal of Scientific and Industrial Research 2006; 22 (2): 176 - 179
3. Allon M, Copkney C. Albuterol and insulin for treatment of hyperkalemia in hemodialysis patients. Kidney International, 1990; Vol. 38, pp. 869 - 872.