[size=6]An adolescent, who weighs 140 kg, sustained a complicated pelvic fracture in a motor vehicle crash. Their pain is not controlled with non-opioid medications. Dosing of morphine should be based on

 

a Lean body weight

 

b Ideal body weight

 

c Actual body weight

 

d Total body weight[/size]

B

B

[size=6]An adolescent, who weighs 140 kg, sustained a complicated pelvic fracture in a motor vehicle crash. Their pain is not controlled with non-opioid medications. Dosing of morphine should be based on

 

a Lean body weight

 

b Ideal body weight

 

c Actual body weight

 

d Total body weight[/size]

B

[b]correct answer

a [/b]Lean body weight

In obese patients, opioid dosing should be based on lean body weight (LBW), which is total body weight (TBW)-fat weight. LBW may be determined based on several gender-specific formulas. LBW is substantially less than TBW in patients with significant obesity and dosing based on TBW would lead to opioid overdosage.

 

Antibiotics, low molecular weight heparin and propofol should be dosed based on adjusted body weight (ABW). ABW=Ideal body weight (IBW) + 0.4 (TBW-IBW). This formula accounts for the greater LBW and volume of distrifestimate by BWaications in obese patients that would be If there is uncertainty regarding appropriate medication dosing for an obese patient a pharmacist should be consulted.