Nephrol Dial Transplant (2004) 19: 1333-1334
Nephrol Dial Transplant Vol. 19 No. 5 © ERA-EDTA 2004; all rights reserved
Letter
Using calcium salts for hyperkalaemia
Sir,I enjoyed the recent article on ‘Controversial issues in the treatment of hyperkalaemia’ [1]. The terms of reference were clearly limited to shifting potassium into cells and the role of cation exchange resins. Keeping to this brief avoided any discussion of the role of calcium salts in the immediate management of hyperkalaemia with ECG changes. This was, perhaps, an opportunity missed, not least because this is where real controversy lies. The intravenous administration of calcium salts under these circumstances is common in the UK, in keeping with clinical teaching and a number of available guidelines (e.g. http://www.clinicalschool.swan.ac.uk/wics/itugl/hik.htm and West Mercia Guidelines Partnership: Medical Guidelines, 2003) which advise using intermittent injections of 10 ml of 10% calcium gluconate and/or calcium chloride. This advice has also been promulgated and considered in Emergency Medicine literature [2], yet it is based on the evidence of anecdote, extrapolation and experience rather than any randomized prospective trial. The extrapolations which carry most weight are from cardiac surgery, where directly applied calcium salts help restore sinus rhythm intraoperatively, and the indubitable correction of the hyperkalaemic ECG abnormalities that many of us have observed first hand using calcium salts under these circumstances. Unfortunately, the ECG improvement and inferred membrane stabilization do not often persist, hence the advice to repeat doses as necessary. Tempting as it is to jump logically from an improved ECG appearance to a reduced chance of an adverse outcome, there is no hard evidence to show that such a manoeuvre does actually diminish the incidence of life-threatening dysrhythmia. One of the main supports for the advice may be guilty of succumbing to this temptation [3]: in a case series of five instances of treating severe hyperkalaemia with intravascular calcium, ECG improvement was seen every time. Unfortunately, the outcomes were: immediate death (case 3), death within an hour (case 2), death within a few days (case 4), death after a couple of months (case 5) and only in one case did long-term survival ensue (case 1). Given such outcomes, particularly in the absence of randomization, it is only a speculation that the calcium was actually helpful. It can properly be argued that ‘If calcium does no harm but may save a life in a minority of cases then surely its use is worthwhile?’ This might be so, but then we can go on to ask whether a calcium-containing infusion, giving steadier calcium levels, would yield better outcomes. One of the largest studies, again non-randomized and essentially observational, would suggest so [4]. The successful management of 46 cases of battlefield acute renal failure in Korea by the US army employed a continuous infusion containing calcium gluconate, sodium bicarbonate, dextrose and insulin.
At the end, I do not know the answer regarding the place of calcium salts in the acute management of hyperkalaemia with ECG changes, but would certainly value the opinion of the authors.
Conflict of interest statement. None declared.
Department of Nephrology University Hospital of North Staffordshire NHS Trust Stoke-on-Trent UK Email: D.detakats{at}uhns.nhs.uk
References
- Kamel KS, Wei C. Controversial issues in the treatment of hyperkalaemia. Nephrol Dial Transplant 2003; 18: 2215–2218
[Free Full Text] - Ahee P, Crowe AV. The management of hyperkalaemia in the emergency department. J Accid Emerg Med 2000; 17: 188–191
[Abstract/Free Full Text] - Chamberlain MJ. Emergency treatment of hyperkalaemia. Lancet 1964; I; 464–467
- Meroney WH, Herndon RF. The management of acute renal insufficiency. J Am Med Assoc 1954; 155: 877–883
[Abstract/Free Full Text]
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