Reduced cardiac index reserve and hypovolemia in severe falciparum malaria

Background: Impaired microvascular perfusion is central to the development of coma and lactic acidosis in severe falciparum malaria. Refractory hypotension is rare on admission but develops frequently in fatal cases. We assessed cardiac function and volume status in severe falciparum malaria and its prognostic significance. Methods: Patients with severe (N=101) or acute uncomplicated falciparum malaria (N=83) recruited two hospitals in India and Bangladesh and healthy participants (N=44) underwent echocardiography. Results Patients with severe malaria had 38% shorter left ventricular (LV) filling times and 25% shorter LV ejection times than healthy participants because of tachycardia, yet stroke volume, LV internal diameter in diastole (LVIDd) and systole (LVIDs) indices were similar. A low endocardial fraction shortening (eFS) was present in 17% (9/52) of severe malaria patients. Adjusting for preload and afterload, eFS was similar in health and severe malaria. Fatal cases had smaller baseline LVIDd and LVIDs indices, more collapsible inferior vena cavae (IVC) and higher heart rates than survivors. LVIDs and IVC collapsibility were independent predictors for mortality, together with base excess and Glasgow Coma Scale. Conclusions: Patients with severe malaria have rapid ejection of a normal stroke volume. Fatal cases had features of relative hypovolemia and reduced cardiac index reserve.