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Medication Dosing in Achondroplasia
Question# 963
Recently had a patient with a rare condition of Primordial Dwarfism (PD). Pt was a 42 YOF with a weight of 31 pounds (14kg) and ~2ft tall. In cases of cardiac arrest would she fall into the weight based category for joule settings and epi administration. Or do we continue with adult dosing for joule setting & Epi as she is greater than 8 & 12 years of age? Would we be faulted for running an adult or pediatric arrest? The mother made a comment on scene that the hospital frequently overdoses the patient. Regarding other medical directive many are weight based but, the ones with the age based should be choose the pediatric dose due to the patients weight and size?
Answer:
Unfortunately, there is no evidence-based answer to this question given how rare it is. There are a handful of case-reports in anesthesia and obstetrical literature but no consensus on appropriate dosing and management in these patients.
This is a challenging scenario as individuals with achondroplasia (dwarfism) have very low body weight proportions but in many scenarios adult size / aged organs. This poses a challenge as their metabolism would equate that of an adult meaning drug kinetics would be similar to that of an adult.
It would be reasonable to use weight based dosing of medications (ie analgesia) and up-titrate as needed to effect. If a patient is conscious, you may even ask them what they typically use at home for analgesia to guide the decision. Contacting BHP in these scenarios is recommended but starting on a lower end of a sliding scale is reasonable.
In a cardiac arrest where drugs are not readily titratable, you would not be faulted in using adult dosing given metabolism matches that of an adult. If running a pediatric arrest, gradual increase in Joules for defibrillation would be reasonable. Given the rarity and lack of evidence in this patient population, either approach would be reasonable but would recommend early call to a BHP to help guide you through this decision.
This is a challenging scenario as individuals with achondroplasia (dwarfism) have very low body weight proportions but in many scenarios adult size / aged organs. This poses a challenge as their metabolism would equate that of an adult meaning drug kinetics would be similar to that of an adult.
It would be reasonable to use weight based dosing of medications (ie analgesia) and up-titrate as needed to effect. If a patient is conscious, you may even ask them what they typically use at home for analgesia to guide the decision. Contacting BHP in these scenarios is recommended but starting on a lower end of a sliding scale is reasonable.
In a cardiac arrest where drugs are not readily titratable, you would not be faulted in using adult dosing given metabolism matches that of an adult. If running a pediatric arrest, gradual increase in Joules for defibrillation would be reasonable. Given the rarity and lack of evidence in this patient population, either approach would be reasonable but would recommend early call to a BHP to help guide you through this decision.