Rationale:

• Vascular permeability resulting in plasma leakage is the main reason for circulatory compromise or shock in patients with severe dengue.
• Administration of adequate crystalloids or colloids should result in normalization of intravascular volume.
• The presence of significant external or internal bleeding is indicated by the failure of the blood pressure to increase despite a decline in hematocrit after adequate crystalloid or colloid administration.

Evidence:

• The specific recommendations are based on WHO guidelines on the management of dengue fever and dengue hemorrhagic fever (55).

Comments:

• Blood transfusion is indicated only in patients with significant hemorrhagic manifestations.
• It may be difficult to recognize internal hemorrhage if there is hemoconcentration.
• A decrease in hematocrit (e.g., from 0.5 [50%] to 0.4 [40%]) without clinical improvement despite the administration of sufficient fluids indicates significant internal hemorrhage.
• Fresh whole blood is preferable, and the volume of blood administered should be sufficient to only increase the erythrocyte concentration to normal (i.e., 10 mL/kg·h).