Hypokalaemia and its clinical effects among children treated with nebulised salbutamol in Mulago Hospital.

Abstract

Introduction: Potassium imbalance particularly hypokalemia, is a common electrolyte disturbance in sick children. One of the iatrogenic causes of hypokalemia is the use of beta 2 adrenergic drugs like salbutamol. The prevalence and severity of salbutamol induced hypokalemia is not known especially when used in conditions in which children have normal potassium levels. This study has provided data on the prevalence of hypokalemia among children treated with nebulised salbutamol. Objective: To determine the prevalence of hypokalemia, its clinical effects, factors associated and to assess its recovery among children who were treated with nebulised salbutamol between the age 2 months and twelve years in Mulago Hospital. Methods: This was a prospective cohort study. Children who needed to be nebulised with salbutamol aged 2 months to 12 years whose parents consented were consecutively enrolled from December 2013 to June 2014. Data was collected using a structured questionnaire including patient demographic data, clinical data, blood sample results for serum potassium level on pre and post treatment and ECG abnormalities for those with hypokalemia. Subsequently blood samples were taken at 24 hours and 48 hours for those who had hypokalemia to assess the recovery. Results: Three hundred and twenty two children were screened from December 2013 to June 2014. Prevalence of hypokalemia was found to be 39.8% ranging between (34.1 – 45.4) 95% CI. Factors associated with hypokalemia were older age above 5 years (p value of 0.007), salbutamol use within 24 hours (p value of 0.019) and history of steroid use (p value of 0.03). Eight out of 129 (6.2%) children who had hypokalemia developed U waves on ECG. Conclusion: The prevalence of hypokalemia in children who are treated with nebulised salbutamol is high. The factors found to be associated with hypokalemia include being older than 5 years, having a history of salbutamol use within 24 hours and history of use of steroid medication. From the above findings we recommend serum potassium monitoring for children at increased risk. Although no immediate severe adverse outcomes were associated with hypokalemia in this study, caution needs to be taken when nebulizing older children, those who have been pre treated with salbutamol within 24 hours and steroids. We recommend further studies to establish predictors for the presence of hypokalemia.