Which inotrope?

'Which inotrope?' for the sick child is a question that suggests the existence of ready answer. But, with critically ill children the 'answer' is context specific. What is the clinical situation? Is the predominant problem systolic myocardial impairment post cardiopulmonary bypass, decreased systemic vascular resistance in sepsis or diastolic dysfunction in restrictive cardiomyopathy? What about age and ethnicity? In fact the optimal reply relies on factors which medical science has not yet entirely elucidated - such as genomic/genetic and developmental variations in inotrope receptor distribution and function and the underlying variability in host responses to varying clinical situations.Overall, the evidence base to guide inotrope use in children is sparse, and extrapolations from adult medicine and physiology predominate. In daily practice a combination of experience, 'usual regimes' and local clinical practice guidelines - often derived from resuscitation courses or international guidelines provide identifiable standards for inotrope use.Inotropes are vasoactive drugs, and the choice of drug and dose is tailored to the haemodynamic, or blood flow/circulatory, state of the patient and frequently adjusted depending on effect.This review provides a background to these agents and offers suggestions to help decision-making regarding their use.