When is blood transfusion indicated in patients with dengue?

Blood Transfusion Indications in Dengue

Blood transfusion in dengue is indicated for significant active bleeding, particularly when hemoglobin drops below critical thresholds or when bleeding causes hemodynamic compromise, not based solely on platelet count.

Primary Indications for Blood Component Therapy

Packed Red Blood Cells

• Transfuse packed red blood cells when there is a rapid drop in hematocrit or hemoglobin in the setting of active bleeding 1, 2
• Blood transfusion may be necessary in cases of significant bleeding, particularly gastrointestinal hemorrhage 1, 3
• Target hemoglobin >10 g/dL if central venous oxygen saturation (ScvO2) is <70% in patients with shock 1
• Approximately 2.6% of hospitalized dengue patients with hemorrhagic manifestations require packed red blood cell transfusion, with a mean of 3.2 units per patient 4

Platelet Concentrate

• Transfuse platelets when platelet count is <20,000/mm³, especially in high-risk patients with risk of bleeding 5
• For platelet counts between 21,000-40,000/mm³, transfuse only if hemorrhagic manifestations (petechiae, gum bleeding, epistaxis) are present or other superadded conditions exist 5
• Platelet transfusion is indicated in 64.7% of dengue patients requiring blood component therapy, specifically those exhibiting active bleeding 2
• The transfusion requirement correlates significantly with occurrence of bleeding (p<0.008) and gastrointestinal bleeding (p<0.0001), but NOT with platelet count alone (p=0.207) 2

Fresh Frozen Plasma

• Transfuse fresh frozen plasma in patients with circulatory failure (dengue shock syndrome) who do not respond adequately to intravenous fluid resuscitation 2
• FFP is used in 29.4% of dengue patients requiring blood component therapy 2
• Patients with peptic ulcer and recent hemorrhage require more FFP transfusions (p=0.05) than those without recent hemorrhage 6

Critical Clinical Context

When NOT to Transfuse

• Do not transfuse based on platelet count alone without clinical bleeding - the correlation between platelet count and transfusion requirement is not statistically significant 2
• Prophylactic platelet transfusion in the absence of bleeding or very low counts (<20,000/mm³) represents inappropriate use 5
• Among patients receiving platelet transfusions, approximately 32% (31 of 96 patients) received inappropriate transfusions when they had counts >20,000/mm³ without hemorrhagic manifestations 5

High-Risk Bleeding Scenarios

• Gastrointestinal bleeding is the most common type of severe hemorrhage in dengue, occurring in 8.4% of hospitalized patients 6
• Endoscopic findings in dengue patients with upper GI bleeding include hemorrhagic/erosive gastritis (67%), gastric ulcer (57.7%), and duodenal ulcer (26.8%) 6
• Patients with peptic ulcer showing recent hemorrhage on endoscopy require significantly more packed red blood cells (p=0.002) and FFP (p=0.05) 6

Monitoring Parameters to Guide Transfusion Decisions

Laboratory Monitoring

• Track hematocrit serially - rising hematocrit indicates ongoing plasma leakage, while falling hematocrit suggests successful plasma expansion or bleeding 1
• Monitor platelet counts daily, particularly during the critical phase (days 3-7 of illness) 1, 3
• Nearly half of dengue patients with hemorrhagic manifestations develop anemia, with mean lowest platelet count of 26.4×10⁹/L 4

Clinical Indicators Requiring Transfusion Consideration

• Active bleeding from any site (mucosal, gastrointestinal, or other) 1, 5, 2
• Signs of hemodynamic compromise: tachycardia, hypotension, poor capillary refill, altered mental status 3
• Persistent tissue hypoperfusion despite adequate fluid resuscitation 1, 3
• Signs of plasma leakage with cardiopulmonary dysfunction, which correlate with unfavorable outcomes 4

Common Pitfalls to Avoid

• Do not delay blood transfusion in patients with significant active bleeding while waiting for platelet counts to reach arbitrary thresholds - bleeding manifestations, not platelet numbers alone, should guide transfusion decisions 5, 2
• Do not use endoscopic injection therapy for hemostasis in dengue patients with upper GI bleeding - medical treatment with blood transfusion is the mainstay, as endoscopic therapy is not effective and may increase transfusion requirements (p=0.03 for packed red cells, p=0.014 for FFP) 6
• Avoid over-transfusion during the recovery phase when hematological parameters spontaneously normalize within 1-2 weeks after defervescence 7
• Communicate anticipated transfusion requirements to the blood bank early, as approximately 10.6% of DHF patients require blood component therapy 2