Introduction

Inotropes are medicines that increase the force of cardiac muscle contraction. Inotropes are used to improve cardiac output and so increase oxygen delivery to tissues. There are very few pure inotropes. Most have other effects, which can help or hinder therapy.

Deciding which inotrope to use, and when, is complicated for several reasons.

The evidence base for these medicines is patchy, particularly with respect to how development affects the targets for the medicines and how the body handles the medicines at different ages. The clinical signs and biomarkers we use to guide treatment have not been validated (can we measure them reliably?) nor qualified (do the markers predict important outcomes?). The short-term clinical outcomes and biomarkers we can measure readily may not be the aspects that matter. For example, blood pressure (BP) is readily measured, but what may matter more is blood flow to key organs, which is more difficult to measure.

All are in agreement that it is essential to treat extremely low BP with evidence of poor circulation. However, there is uncertainty about which thresholds should be used to direct management of BP, or any other biomarker, if adverse outcomes such as death are to be minimised.

Nevertheless, these medicines are used widely and a range of professionals need to understand how and when to deploy these medicines.

In all cases where a child is critically ill, or could be critically ill, the standard of care is that an adequately experienced clinician follows a standardised care pathway. In the UK, the Advanced Paediatric Life Support scheme provides a good model.1 With respect to circulation, experienced clinicians need to (1) assess the circulation; (2) actively consider fluid resuscitation and then (3) start an inotrope if they judge the circulation to be insufficient after appropriate fluid resuscitation has been …