Patient dose based on BSA from nomogram

6. Patient-based Dose 6.3) Body Surface Area 6.3.1) Body Surface Area

6.3.1.3) Dose via BSA nomogram Normal 1


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If the adult dose of a drug is 250 mg, what would be the dose for a child weighing 51 lb and measuring 2 feet 7 inches in height using the BSA nomogram?


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lb equals 103 mg kg

  • The patient height
    = 2 feet 7 inches
    = ( 2 × 12 + 7 ) inch
    = 31 inch
    = 31 × 2.54 cm
    = 78.74 cm

  • patient weight
    = 51 lb
    = 51 × 0.454 kg
    = 23.2 kg

  • BSA for the patient is

    BSA `= \quad sqrt(( Height (cm) × Weight (Kg) )/(3600))`

    ` \quad \quad \quad = sqrt(( 78.74 \quad cm × 23.2 \quad Kg )/(3600)) = 0.7123 ` m2

  • By nomogram to calculate BSA you will get 0.65 `m^2`
  • Using the formula:
    Patient dose (mg) = `(BSA\quad (m^2)) / (1.73 \quad (m^2)) × ` Adult dose (mg)
  • Therefore, Patient dose` =(0.7123 \quad m^2)/(1.73 \quad m^2) × 250 \quad mg = 103 \quad mg` Ans.