A client who is receiving an IV infusion of heparin sodium 25,000 units in 5% dextrose injection 500 mL at 1,000 units/hour has a partial thromboplastin time (PTT) of 10 seconds. The sliding scale prescription reads, “If the PTT is less than 65 seconds, increase the rate by 200 units/hour; and if the PTT is greater than 95 seconds, decrease the rate by 200 units/hour.” The nurse should regulate the infusion pump for how many mL/hour? (Enter numerical value only.)
The correct answer and Explanation is :
To solve this, we first need to figure out how much volume (in mL) is required to deliver the prescribed 1,000 units of heparin per hour and then adjust for the sliding scale.
Step 1: Determine the concentration of the solution
- The total amount of heparin in the IV bag is 25,000 units.
- The total volume of the IV bag is 500 mL.
So, the concentration of heparin in the IV solution is:
[
\frac{25,000 \, \text{units}}{500 \, \text{mL}} = 50 \, \text{units/mL}
]
Step 2: Calculate the initial infusion rate
The current prescribed infusion rate is 1,000 units per hour. To determine how many milliliters per hour (mL/hour) this corresponds to:
[
\frac{1,000 \, \text{units/hour}}{50 \, \text{units/mL}} = 20 \, \text{mL/hour}
]
Step 3: Adjust the infusion rate based on the sliding scale
The patient’s PTT is 10 seconds, which is significantly lower than the target range of 65–95 seconds. According to the sliding scale, if the PTT is less than 65 seconds, the nurse should increase the rate by 200 units/hour.
So, the new infusion rate is:
[
1,000 \, \text{units/hour} + 200 \, \text{units/hour} = 1,200 \, \text{units/hour}
]
Step 4: Calculate the new infusion rate in mL/hour
Now, we calculate the new infusion rate in mL/hour based on the new dose of 1,200 units/hour:
[
\frac{1,200 \, \text{units/hour}}{50 \, \text{units/mL}} = 24 \, \text{mL/hour}
]
Final Answer:
The nurse should set the IV pump to 24 mL/hour.
This adjustment increases the heparin dose to help prolong the PTT to reach the therapeutic range, following the sliding scale protocol.