Body-surface-area dosing: many cytotoxic and some paediatric doses are prescribed per square metre of body surface area: dose (mg) = dose per m² × BSA (m²). The Mosteller formula estimates BSA = √(height (cm) × weight (kg)/3600).
ขนาดยา
D = 375·0.6 = 225 mg
คำตอบ
D = 225 mg
4.การคำนวณขนาดยา
คำตอบ: W = 980 mL
Solution strengths: a percentage strength is grams per 100 mL, so 1% = 1 g/100 mL = 10 mg/mL. A ratio strength 1:1000 means 1 g in 1000 mL = 1 mg/mL; 1:10 000 is 0.1 mg/mL. For a dilution the amount of drug stays the same: C₁·V₁ = C₂·V₂.
ปริมาตรของสารละลายตั้งต้น
V₁ = 1·1000/50 = 20 mL
น้ำที่ต้องเติม
W = 1000 − 20 = 980 mL
คำตอบ
W = 980 mL
5.อัตราการให้สารน้ำทางหลอดเลือดดำ
คำตอบ: R = 30 gtt/min
Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.
มิลลิลิตรต่อนาที
30/60 = 0.5 mL/min
อัตราการหยด
R = 0.5·60 = 30 gtt/min
คำตอบ
R = 30 gtt/min
กับชุดไมโครดริป (60 gtt/mL) gtt/min เท่ากับ mL/h
6.อัตราการให้สารน้ำทางหลอดเลือดดำ
คำตอบ: Δ = 28 %
Infusion rates: a pump is set in mL/h = volume/time in hours. A gravity drip is counted in drops per minute: gtt/min = volume (mL) × drop factor (gtt/mL)/time (min). The drop factor is printed on the tubing package: macrodrip sets deliver 10, 15 or 20 gtt/mL (blood sets often 10 gtt/mL in the US, 15 in the UK) and microdrip sets 60 gtt/mL. Always use the drop factor the question or package gives.