Weight-based dosing question

[ilovebirds]

Hey guys - quick question. Is there ever a reason to use a weight other than the patient's actual weight in weight based dosing?

Last week, I was calculating some drips, and I noticed that none of my calculations matched the MAR. After closer examination, I realized the discrepancy was due to the MAR listing using a different recorded weight - as an example, the heparin was dosed for a person weighing 15kg less than my patient. Is there a good reason for this? My initial thought was risk for bleeding, but my patient's aPTT remained non-therapeutically low.

Thanks! :)

[smf0903]

Was the patient obese? There's a formula for dosing weight for patients over a certain percentage of ideal body weight. I don't remember it off the top of my head but I would suspect that's the case.

Or it could be a stated weight recorded because someone was too lazy to actual weigh the patient ...as just happened at a facility with a tPa patient :/

[chare]

They might be using dry weight if the patient is fluid overloaded, or odeal bodyweight.

Or, the may have not adjsted the doding weight for current admission.

[ilovebirds]

Thank you both for your responses!

The patient wasn't fluid overloaded, but was obese. I'll discuss this further with my instructor and nurses at the facility to see if there's a protocol for dosage calculations of obese patients.

[KelRN215, BSN, RN]

I'm a pedi nurse and all meds are dosed by weight in kids. A frequent problem that we encountered when I worked in the hospital was that the system did not automatically update the "weight for calc" (the weight the system used to calculate medication doses) when new weights were documented. You had to go into a completely different place in the EMR and document a new weight for calc. Most people didn't do this every time a child was weighed. Depending on diagnosis, some children are weighed daily in the hospital. For babies or kids who are in for prolonged periods of time, this can be problematic.