Rationale:

• High parasitemia has been correlated with mortality in P. falciparum malaria.
• Despite appropriate medical treatment, mortality in patients with >10% parasitemia ranges from 20% to 40% when cerebral or renal function is impaired, and up to 80% in the presence of acute respiratory distress syndrome.
• Exchange transfusion may reduce parasite load, remove toxic substances, reduce microcirculatory sludging, and rapidly correct anemia.

Evidence:

• Several case reports and a small case series have described successful exchange transfusion in patients with severe malaria (96; 97; 98).
• Retrospective studies that compared severe malaria cases treated with adjunct exchange transfusion with patients receiving chemotherapy alone have been limited by small numbers of cases and noncomparability of study groups (99; 100).
• One prospective study in Zimbabwe compared survival of eight severe malaria cases randomly assigned to receive either chemotherapy alone or chemotherapy with exchange transfusion. Whereas three out of four patients receiving chemotherapy alone died, all four patients receiving exchange transfusion as adjunct therapy survived. Due to the small number of patients, a statistically significant benefit of exchange transfusion could not be demonstrated (101).
• A recent meta-analysis of eight case-control studies concluded that exchange transfusion was not associated with a higher survival rate than was antimalarial chemotherapy alone (102).
• A case series of six patients showed reductions in parasitemia from 23% to 80% to 13% to 20% following exchange transfusion (103).

Comments:

• In these studies, there were problems with comparability of case and control groups: patients who had exchange transfusion had higher parasitemia and more severe malaria. Furthermore, survival rates were higher among patients with partial immunity when compared with patients with no immunity. No iatrogenic deaths were described in these studies. No sufficiently powered, randomized, controlled study has been reported to date.
• The World Health Organization guidelines for exchange transfusion have been published (55).
• Partial exchange transfusion has been successfully performed in young children (104).