CLONIDINE INDUCED BRADYCARDIA AND HYPOTENSION ARE FREQUENT IN CRITICALLY ILL CHILDREN, BUT DO NOT APPEAR TO COMPROMISE HEMODYNAMICS

Abstract

Abstract BACKGROUND: Clonidine is licensed as an antihypertensive drug, but is increasingly used as analgo-sedative in the PICU as it does not induce respiratory depression and is deprived of neurotoxicity. For fear of bradycardia and hypotension, many physicians are reluctant to use clonidine, especially in less stable patients. The prevalence of bradycardia and hemodynamic compromise in this population is, however, unknown. OBJECTIVES: The aim of this study was to determine the prevalence of clonidine-associated bradycardia and hypotension, to delineate the hemodynamic effect of a clonidine infusion and to isolate the effect of bradycardia on hemodynamics. DESIGN/METHODS: All children (0-18 yrs of age) who received a clonidine infusion between January 2011 and July 2014 were identified. Patients who received the infusion during ECMO, active cardiac pacing or with a life expectancy of <24 hrs were excluded. Bradycardia was defined as a heart rate (HR) below the 1st percentile for age during three consecutive hours. Hypotension was defined as a systolic (SBP) or mean blood pressure (MBP) below the 5th percentile during one hour. To determine the hemodynamic consequences of the clonidine infusion, pre-infusion values of HR, BP, vasoactive inotropic score (VIS) were compared to post-infusion values using linear mixed models. The effect of bradycardia was explored by comparing BP and VIS before and during bradycardia episodes. RESULTS: Of 226 patients identified with a clonidine infusion, 40 were excluded, leaving 186 eligible patients (median age: 12.9 months, IQR: 3.5-60.6). At start of infusion, 69.3% patients received an IV bolus, the median infusion duration was 61.8 hours (IQR 24.7-154.8) and the median of the maximal infusion rate was 0.7 mcg/kg/h (IQR 0.3-1.5). During the clonidine infusion, 40.2% experienced bradycardia, 58% experienced systolic hypotension while 49.7% had low MBP but VIS decreased and physicians increased the infusion rate (fig 1). During bradycardia episodes no clinically significant change in blood pressure was observed (Figure 2). CONCLUSION: Bradycardia and hypotension are frequent complications after clonidine infusion start but do not appear to compromise hemodynamics as VIS decreased and physicians further increased the infusion rate. Bradycardia episodes seem to be hemodynamically well tolerated.Our results suggest that clonidine IV infusion is safe in this heterogeneous critically ill pediatric population. (Fig 7, 8)