Cardiac output measurement in Malawian children ages 2 months-12 years hospitalised with severe anaemia (COM-TRACT).

Background: Little is known about myocardial perturbations in African children hospitalised with severe anaemia.

Methods: An observational study nested within a clinical trial of blood transfusion was conducted on the paediatric ward in Blantyre, Malawi. Children were ages 2 months-12 years hospitalized with uncomplicated severe anaemia (haemoglobin 4-6 g/dl). By randomisation, 13 children received 30 ml/kg whole blood, 13 received 20 ml/kg whole blood and 26 had no immediate transfusion (usual care). We measured standard parameters of cardiac function using ultrasonic cardiac output monitoring (USCOM) at enrolment, 8 and 24 hours and discharge.

Results: Fifty-two children, median age 39 months (interquartile range [IQR] 25-58) and median haemoglobin 5.1 g/dl (IQR 4.8-5.6) were studied. Severe tachycardia and tachypnoea over time corrected faster in the transfused arms than the controls. At enrolment, the stroke volume index was within the normal range and 26/52 (50%) had a cardiac output index (COI) >97.5% the standard centile. The COI decreased in all arms by discharge but was greatest in the transfusion arms (p=0.05 for 20 ml/kg and p=0.009 for 30 ml/kg). A higher volume or receipt of whole blood did not worsen cardiac function. No child required diuretics.

Conclusions: The data generated by this small but granular study of haemodynamic and cardiac function provide reassuring physiological evidence showing the safety of higher doses of blood transfusion than currently recommended. It also supports the findings of a secondary analysis of the Transfusion and Treatment of Severe Anaemia in African Children trial indicating that whole blood transfusions are safe. These data support the new evidence-based paediatric transfusion algorithm for anaemic African children and its recommendation for safe use.