Passive leg raising is used to predict who will benefit from fluid therapy in critically ill patients, including children. Patients with a Fontan circulation may have a different haemodynamic response to a fluid challenge by passive leg raising.

The haemodynamic response of 31 paediatric patients with a Fontan circulation from the outpatient clinic (median age 14.0 years) and 35 healthy controls (median age 12.8 years) to passive leg raising was evaluated non-invasively by echocardiography for the assessment of, e.g., velocity time integral across the (neo)aortic valve, blood pressure measurements, and respiration. Participants were considered responders when the velocity time integral increased ≥ 10.0%.

Overall, patients and controls did not differ in the haemodynamic response. Twelve patients (38.7%) and 8 controls (22.9%) were responders, which was not statistically different (P = 0.22). Responders in the patient and control group also had a similar echo-estimated velocity time integral increase of + 18.9% and + 15.2%, respectively (P = 0.91). There was no difference in echo-estimated velocity time integral change between patient and control non-responders with a decrease of −1.4% and −6.4%, respectively (P = 0.70) and no difference in the amount of patients who were negatively affected by passive leg raising, ith a decrease of ≤−10.0% in 7 patients (22.6%) and 9 controls (25.7%)(P = 0.77).

The haemodynamic response of ambulatory paediatric patients with a Fontan circulation to passive leg raising is like that of healthy controls. Patients who did not respond were similarly affected as healthy controls. Whether the haemodynamic response is different in critically ill patients warrants further investigation.

The Netherlands National Trial Register (NTR), Trial: NL6415; date of registration 20-07-2017; Trial information: https://www.trialregister.nl/trial/6415.