Pharmacology math: Safety related to Pediatric IV infusions

(Microtubing: 60 " long,
displaces 0.3 ml)

Buretrol

Pediatric institutions use some method to safely control the amount of fluid a child receives when medications are necessary. Most Pediatric nursing units have a policy that children under a certain age with IV fluids / IV medications will be placed on an infusion pump.

Fluid overload must be avoided.
Time over which a medication should be administered is a factor and can be a critical factor.
Minimal dilution (end concentration of the medication) is important for medications such as aminoglycosides.
Another critical aspect of administering medications relates to the process of collecting therapeutic blood levels.

Methods:

Microtubing:

In clinical practice, microtubing may be a new concept to students whose practice has been adult-oriented. Microtubing refers to special tubing that has a small diameter and takes a relatively small amount of fluid to fill the tubing (displacement). When using the microtubing, read the packaging to determine what the priming volume for that particular tubing is. The priming volume is the volume of fluid necessary to fill the tubing and becomes important when one needs to determine how much flush to give. One company markets a 60" tubing that displaces only 0.3 ml of fluid, another 0.4 ml, etc. (Hint: always read the packaging.)

Buretrols:

A buretrol or volutrol is an inline receptacle between the client's IV catheter set and the bag of IV fluids. Maximum capacity is 150 ml. The theory behind the use of the buretrol is that the nurse can fill the buretrol to a certain level and if the IV pump malfunctions, then only that volume will flow into the client. Institutional practice varies regarding filling the buretrol with 2 or 3 hours delivery of IV fluids. Institutional practice decides which children will be given a buretrol and an infusion pump (ex: < 15 kg, <10 kg, etc).

INFUSION PUMPS

Example of infusion pump capable of admininstering 3 medications

Calculating flow rate for placement on a volumetric infusion pump

The ml / hr the doctor orders is set on the pump as the "infusion rate".
The amount you calculate as "ml / hr" is set on the pump.
Some pumps deliver " x volume over x time".

Example:

The physician becomes concerned about John’s renal function and orders the Vancomycin dose (60 mg) to be infused over 90 minutes instead of the usual 60 minutes. If the Vancomycin dosage is diluted into 60 ml of IV fluid, what will be the flow rate? (Given on an IV pump for control.)

Critical information:

Volume: 60 ml of fluid
Time: 90 minutes
Method of delivery: syringe pump using ml/hr
Not given: Time factor which is constant: 1 hr = 60 min.

Calculate:

60 ml 90 min	=	X ml 60 min
90 x	=	3600
x	=	40 (ml/hr)

In clinical practice, some brands of infusion pumps, such as a Baxter, have various options to set as needed:

Single dose: Select the correct syringe size, enter volume to be infused, time over which to infuse the medication.
Mcg/kg/min: Select the correct syringe size, enter the client's weight in kg, the ordered dosage in mcg/kg/min, and the concentration of the medication.
Mg/kg: Select the correct syringe size, enter the client's weight in kg, the ordered dosage in mg/kg, and the concentration of the medication.
Ml/hr: Select the correct syringe size, enter the rate of infusion and the volume limit.

Other pumps (typically called infusers) will deliver whatever volume is in the syringe when the time limit from 5 minutes to 1 hour is selected.

**Tip:**
Sometimes critical thinking is required to deliver the medication/fluid in the most expedient, safe manner for the individual child's needs.