Interventions for non-oliguric hyperkalaemia in preterm neonates

Vemgal P, Ohlsson A

Published Online:

January 21, 2009

Elevated levels of potassium (an important salt for normal body functions) are common in infants born very preterm or with birth weight less than 1500 g. High potassium levels in the blood may lead to irregular or rapid heart rate that may result in bleedings in the brain and/or sudden death. The objective of this review was to determine the effectiveness and safety of interventions for this serious condition. Two studies enrolling 52 infants that assessed the use of a combination of insulin and sugar to reduce the blood levels of potassium were identified. This combination reduced the duration of high blood levels of potassium and the risk for bleeds in the brains of the infants. One study that enrolled 19 patients reported on the use of Albuterol (a medication that helps to move potassium from the blood to the body cells). Albuterol lowered the blood levels of potassium both at 4 and at 8 hours after the treatment had started. Because of the few infants enrolled in the studies to date, no firm recommendations for the treatment of too high blood levels of potassium in neonates can be made. Further research is needed.

Abstract (click to read)

Background:

Non-oliguric hyperkalaemia of the newborn is defined as a plasma potassium level > 6.5 mmol/L in the absence of acute renal failure. Hyperkalaemia is a common complication in the first 48 hours of life in very low birth weight (birth weight < 1500 g) and/or very preterm newborns (< 32 weeks gestational age).

Objectives:

To determine the effectiveness and safety of interventions for non-oliguric hyperkalaemia [for the purpose of this review defined as serum potassium > 6.0 mmol/L ( the clinical setting in which interventions would likely be introduced prior to reaching a grossly abnormal level) and a urine output > 0.5 ml/kg/hour] in preterm or very low birth weight (VLBW) infants during their first 72 hours of life.

Search strategy:

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2006) was searched to identify relevant randomised and quasi-randomised controlled trials. The following data bases were searched in June 2006; MEDLINE from 1966, EMBASE from 1980, CINAHL from 1982.

Selection criteria:

Randomised or quasi-randomised controlled trials conducted in preterm and/or VLBW neonates with a diagnosis of non-oliguric hyperkalaemia. The interventions included were those aimed at redistributing serum potassium (sodium bicarbonate or insulin and glucose) or increasing the elimination of potassium from the body [diuretics (any type) or ion exchange resins (any type), or exchange transfusion, or peritoneal dialysis, or salbutamol, or albuterol] or counteracting potential arrhythmias from hyperkalaemia (calcium) vs. placebo or no intervention; or comparing any two of these interventions. The primary outcome measure was 'All cause mortality during initial hospital stay'. Secondary outcomes included common adverse outcomes seen in infants born preterm.

Data collection and analysis:

The standard review methods of the Cochrane Neonatal Review Group were used. All studies identified as potentially relevant by the literature search were assessed for inclusion in the review by the two authors. The statistical methods included relative risk (RR), risk difference (RD), number needed to treat to benefit (NNTB) or number needed to treat to harm (NNTH) for dichotomous and weighed mean difference (WMD) for continuous outcomes reported with 95% confidence intervals (CI). A fixed effects model was used for meta-analysis. Heterogeneity was assessed using the I squared (I2 ) statistic.

Main results:

Three randomized trials, enrolling 74 preterm infants (outcome data available on 71 infants) evaluated interventions for hyperkalemia. Urine output was ascertained only in one study (Hu 1999). In none of the trials could we ascertain that allocation to the comparison groups was concealed. The sample sizes of the three trials were very small with 12 (Malone 1991), 19 (Singh 2002) and 40 infants enrolled (Hu 1999). The intervention and the outcomes assessments could not be blinded to the clinical staff in two trials (Hu 1999; Malone 1991).

In one study (Malone 1991), glucose and insulin, compared to cation-exchange resin, caused a reduction in all cause mortality that was of borderline statistical significance: RR 0.18 (95% CI 0.03, 1.15); RD -0.66 (95% CI -1.09, -0.22); NNTB 2 (95% CI 1, 5)]. In the study of Hu (Hu 1999), the incidence of intraventricular haemorrhage > grade 2 was significantly reduced [RR 0.30 (95% CI; 0.10, 0.93); RD -0.35 (95% CI; -0.62, -0.08); NNTB 3 (95% CI; 2, 13).

Albuterol inhalation vs. saline inhalation changed serum K+ from baseline at 4 hours [WMD -0.69 mmol/L (95% CI; -0.87, -0.51)] and at 8 hours [WMD -0.59 mmol/L (95% CI; -0.78, -0.40)] after initiation of treatment. No differences were noted in mortality or other clinical outcomes (Singh 2002).

No serious side effects were noted with either the combination of insulin and glucose or albuterol inhalation. Other interventions that we listed in our objectives have not been studied to date.

Authors' conclusions:

In view of the limited information from small studies of uncertain quality, no firm recommendations for clinical practice can be made. It appears that the combination of insulin and glucose is preferred over treatment with rectal cation-resin for hyperkalaemia in preterm infants. Both the combination of insulin and glucose and albuterol inhalation deserve further study. The two interventions could possibly be tested against each other. The effectiveness of other potentially effective interventions for non-oliguric hyperkalaemia (diuretics, exchange transfusion, peritoneal dialysis and calcium) have not been tested in randomized controlled trials.

This record should be cited as:

Vemgal P, Ohlsson A. Interventions for non-oliguric hyperkalaemia in preterm neonates. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD005257. DOI: 10.1002/14651858.CD005257.pub2

Assessed as up to date:

August 30, 2006

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Primary Review Group:

Neonatal Group

Health topics:

Neonatal care > Other

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Independent high-quality evidence for health care decision making

Interventions for non-oliguric hyperkalaemia in preterm neonates

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