17.2 Hematologic Emergencies

A bleeding or anemic patient in a helicopter is a content-of-oxygen problem and a clotting-factor problem at the same time. Domain 4.F of the August 2026 Board of Certification for Emergency Nursing (BCEN) Certified Flight Registered Nurse (CFRN) outline tests hematologic emergencies—coagulopathies and anemias—because you cannot run a full coagulation panel at 3,000 feet, and Dalton's law makes a low hemoglobin (Hb) worse as cabin altitude rises. Reverse what you can, replace what is actually missing, and pick a destination that can exchange plasma, replace factor, or run a bloodless program.

Coagulopathies: reverse the drug, replace the missing factor

Warfarin and the direct oral anticoagulants

Warfarin blocks vitamin K–dependent factors (II, VII, IX, X, and proteins C and S). In life-threatening bleed—especially intracranial hemorrhage (ICH)—the flight reversal is four-factor prothrombin complex concentrate (PCC) plus vitamin K, not a slow plasma infusion as the first move. Fresh frozen plasma (FFP) is a volume load and a delay. Vitamin K turns the liver back on; PCC covers the hours until that happens. A sending international normalized ratio (INR) is useful; do not wait for a repeat INR on the ramp if the patient is herniating.

Direct oral anticoagulants (DOACs) are a different map. Dabigatran has idarucizumab (Praxbind). Oral factor Xa inhibitors (apixaban, rivaroxaban, edoxaban) have andexanet alfa in some centers. Both antidotes are often not on the aircraft and not at the sending hospital. When the specific antidote is missing, most transport protocols use PCC. That is protocol teaching, not a BCEN statute. Write the last ingested dose and time.

Disseminated intravascular coagulation, liver failure, hemophilia, and the platelet traps

Disseminated intravascular coagulation (DIC) consumes platelets and factors while laying down fibrin: oozing lines, a rising prothrombin time (PT) and partial thromboplastin time (PTT), falling fibrinogen, climbing D-dimer. Treat the driver—sepsis (section 17.1), trauma, or obstetric catastrophe—and replace what is missing. DIC is not a reason to withhold antibiotics.

Liver failure looks like DIC because the liver makes most clotting factors. The story is jaundice, ascites, known cirrhosis, or an acetaminophen binge. These patients sequester platelets in a big spleen. They do not need a platelet transfusion as the first thought for every bruise.

Hemophilia is a missing factor, not a missing platelet. Hemophilia A lacks factor VIII; hemophilia B lacks factor IX. A hemarthrosis, psoas bleed, or ICH in a known hemophiliac gets factor replacement (or a bypassing agent if inhibitors are present) before platelets.

Immune thrombocytopenia (ITP) is isolated low platelets. Thrombotic thrombocytopenic purpura (TTP) is microangiopathic hemolysis, thrombocytopenia, and organ ischemia from platelet-rich thrombi. The TTP destination is plasma exchange. Do not transfuse platelets blindly in TTP—you can feed the thrombi. If you cannot tell ITP from TTP in the cabin, withhold prophylactic platelets and fly to a center that can start exchange.

Anemias, sickle cell, transfusion, and the bloodless request

Acute loss versus chronic compensation

Acute blood-loss anemia is Chapter 8 hypovolemia with a falling Hb: replace blood and stop the hole. Chronic anemia has a low Hb the patient has been walking around on until cabin altitude steals the rest of their oxygen content. Arterial oxygen content is roughly 1.34 × Hb × saturation. Dalton lowers inspired oxygen tension; a Hb of 6 g/dL leaves almost no reserve even when the pulse oximeter still reads 94 percent.

Sickle cell disease sickles when the patient is hypoxic, cold, acidotic, or dry. Flight care is oxygen, warmth, and isotonic fluid, not ice packs. Acute chest syndrome—hypoxia, chest pain, a new infiltrate—needs a higher fraction of inspired oxygen (FiO2) or a lower cabin and an exchange-transfusion center, not a clinic that can only give opioids.

Transfusion thresholds and Jehovah's Witness ethics

Transfusion thresholds are program- and picture-specific, not a single CFRN number. Common critical-care teaching uses a restrictive red-cell trigger near 7 g/dL in a stable patient and a higher trigger for active ischemia, acute bleed, or profound hypoxia. That is clinical teaching, not BCEN law. Warm the product. Watch for transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI). Prefer type-specific blood when it is already crossmatched; emergency O-negative or O-positive follows your program.

A Jehovah's Witness patient with a documented refusal of allogeneic blood does not lose that refusal because the aircraft left the ground. Honor the directive. Optimize oxygen delivery: raise FiO2, request a lower cabin, stop bleeding, and fly to a bloodless-medicine program. Do not hide a unit in the pump. Document the refusal and the receiving plan.

• Reverse warfarin with PCC plus vitamin K; treat DOACs with a specific antidote if you have it, otherwise PCC per protocol.
• Give hemophiliacs factor, not platelets first; send TTP to plasma exchange.
• Treat cabin anemia as a Dalton-plus-low-Hb problem; keep sickle-cell patients warm, wet, and oxygenated.

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