I work in an ICU and we have had as many as 15 to 16 IV drips going on one patient at a time. Some of them are weight based, some not. In the ICU where I work we do not change the weight of the patient in the pump each morning when we weigh the patient. This doesn't seem right to me. I'd like to hear from others. Do you change the weight in your IV pumps to reflect the patients current weight each day?
We do not and the justification I've been provided is that you want to use the patient's dry weight (for consistency and accuracy), instead of a weight that may be higher due to fluid volume, for example. Also, if the titration is based on labs, such as would be with heparin, then you risk changing the dose based not on the lab measurement but on the weight.
As the previous poster alluded to weight change in the critically ill patient is almost always related to fluid retention and would not be accurate for dosing medications, especially vasoactive drugs. Always use the "dry" weight.
You should not be changing the weights programmed into the pumps, weight based dosing is only for guestimating an initial starting dose which should be adjusted based on a more accurate assessment of patient response to the initial dose. For instance, if you have a patient you're starting on a heparin drip you'll often used the patient's weight to estimate their proper dose when starting the drip, but you'll then check ptt's to more accurately figure out the appropriate dose. You might do the same thing when starting a levo drip, you'll use their weight to figure the initial dose, but all adjustment after that are based on more direct measurements of effect; BP, lactates, etc. If you've found the correct dose of levo that provides the optimal effects, why would you change the dose because you get a different weight the next day?
Very good points Muno! You brought to light the most important aspect of medication dosing. The patient's response.
I work on a cardiac telemetry unit. The admitting diagnosis and/or past medical history for the majority of our patient population is CHF exacerbation. Typical admission stays can be anywhere from 5 days to weeks/months. In that period of time, as a result of major diuresis, patients (upon discharge) can weigh 20-40lbs less than when they come in. We administer weight based medications, such as dobutamine (mcg/kg/min.) and adjust the weight in the IV pump every morning based off of their daily weight. My coworker and I are working on a policy for dobutamine infusions, but are getting backlash from the ICU. The ICU bases their dose of dobutamine off of admission weight, and does not change that weight unless there is a significant loss of weight (i.e. Amputation of a limb). The ICU was also concerned that staff on our floor will cause medication errors when adjusting the IV pumps, even though 2 RNs double check the weight and the pump. We believe that our way in the acute care setting is best because of significant drops in weight due to diuresis, and much longer lengths of stay. Any thoughts?
Can I ask, in your previous experience, did you have an actual policy that stated to adjust the weight based medications according to the daily weight?
Your ICU is correct in pushing back since what you are proposing is not good practice. Weight based medications, particularly in the case of CHF patients should be based on a euvolemic or "dry" weight, this does not change as the patient diureses. The purpose of using weight in medication dosing is that you are taking into account the differences in absorption and metabolism in different patients. The extra fluid in a hypervolemic patient does not play into tissue absorption or metabolism of these medications, which is why changes in weight due to changes in fluid status should not be an indication to change the dosage of a medication.
Beyond the lack of justification for adjusting the dosage based on daily weights, it's also potentially dangerous. Documented weights can change drastically from one day to the next, and if the dosage is adjusted based on this then you could be making an unsafe titration. If the dobutamine rate appears appropriate based on the relevant assessment data, why would you change it?
When inquiring my colleagues input, they had similar things to say. They added that often when we have titrated multiple drips, it doesn't matter the weight, they have been titrated to pt.s condition. If we reach a "stable point" with titration then adjust all the weight based meditations, we are making serious changes to drips when the patient is at a point where everything is working well. Then we have to start over with titrating to hemodynamics. Why mess with that just because the weight changed.
Thanks for all the input.
It reminds me of the tidal volume issues that some ICUs have -- just because someone is 5'5 but 400 lbs, their lungs are probably similar in size to a 5'5 who weighs 200 lbs. We've had patients get serious lung issues because our docs improperly calculate and severely overestimate what their tidal volume should be due to ABW instead of IBW.
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