Hemophilia

Factor 8

(weight in kg) x (50ml plasma/kg) x (desired F8 level - native F8 level) = total units^

Recommended Factor VIII Therapy for Specific Problems in Hemophilia

TYPE OF BLEEDING INITIAL DOSAGE DURATION COMMENT
Skin
Abrasion None None Treat with local pressure and topical thrombin
Laceration Usually none; if necessary, treat as minor None Local pressure and anesthetic with epinephrine may benefit; watch 4 hours after suturing; reexamine in 24 hours
Superficial


Deep Minor bleeding (12.5 mg/kg) Single-dose coverage May need hospitalization for observation; repeat may be necessary for suture removal
Nasal epistaxis


Spontaneous Usually none; may need to be treated as mild bleeding None Uncommon; consider platelet inhibition; treat in usual manner
Traumatic Moderate bleeding (25 mg/kg) Up to 5–7 days Trauma-related bleeding can be significant
Oral
Mucosa or tongue bites Usually none; treat as minor if persists Single dose Commonly seen
Traumatic (laceration) or dental extraction Moderate (25 U/kg) to severe (50 U/kg) Single dose; may need more Saliva rich in fibrin lytic activity; oral ε-aminocaproic acid (Amicar) may be given at 100 mg every 6 hr for 7 days to block fibrinolysis; check contraindications; hospitalize patients with severe bleeding
Soft tissue/muscle hematomas Moderate (25 U/kg) to severe (50 U/kg) 2–5 days May be complicated by local pressure on nerves or vessels (e.g., iliopsoas, forearm, calf)
Hemarthrosis
Early Mild (12.5 U/kg) Single dose Treat as earliest symptom (pain); knee, elbow, ankle more common
Late or unresponsive cases of early hemarthrosis Mild to moderate (25 U/kg) 3–4 days Arthrocentesis rarely necessary and only with 50% level coverage; immobilization is critical point of therapy
Hematuria Mild (12.5 U/kg) 2–3 days Urokinase, the fibrinolytic enzyme, is in urine; with persistent hematuria an organic cause should be ruled out
Major bleeding Major bleeding (50 U/kg) 7–10 days or 3–5 days after bleeding ceases In head trauma, therapy should be given prophylactically; early CT scan of head recommended for all
Gastrointestinal severe bleeding


Neck/sublingual


Retroperitoneal


Intra-abdominal


Major trauma


Head injury (see text)


Central nervous system bleeding (see text)


Surgical procedure


CT, computed tomography


 Dosage of Factor VIII (Antihemophilic Factor)

BLEEDING RISK DESIRED FACTOR VIII LEVEL (%) INITIAL DOSE (U/KG)
Mild 5–10 12.5
Moderate 20–30 25
Severe 50 or greater 50

Standard Calculation

  1. Patient's plasma volume (50 mL/kg × weight in kg) × (Desired level of factor VIII [percent]) − (Present level of factor VIII [percent]) = Number of units for initial dose.
  2. In emergency therapy, the present level of factor VIII is assumed to be zero.
  3. One unit is the activity of the coagulation factor present in 1 mL of normal human plasma.
  4. Because the half-life of factor VIII is 8–12 hr, the desired level is maintained by giving half the initial dose every 8–12 hr.
  5. Cryoprecipitate is assumed to have 80–100 U of factor VIII:C per bag; factor VIII:C concentrates list the units per bottle on the label.

Factor 9

(weight in kg) x (100ml plasma/kg) x (desired F9 level - native F9 level) = total units^

^half this dose should be readministered in 24 hours

^^DDAVP is not helpful in F9 deficiency

Source

DONALDSON 10/08 (From "Kaji Questions"), Rosen's

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