A patient receives 1 L of dextrose 5% in 1/5 normal saline. For the first 3.5 hours the fluid is delivered at 160 mL/h. The remaining fluid is to run over the next 8 hours. What flow rate (mL/h) is required for the remaining period?

A patient receives 1 L of dextrose 5% in 1/5 normal saline. For the first 3.5 hours the fluid is delivered at 160 mL/h. The remaining fluid is to run over the next 8 hours. What flow rate (mL/h) is required for the remaining period?

• A. 60 mL/h
• B. 55 mL/h
• C. 50 mL/h
• D. 45 mL/h

Answer: (B)

This question tests how to compute the remaining infusion rate needed to finish a prescribed volume in the remaining time. First, determine how much fluid has already been given: 160 mL/h for 3.5 hours equals 160 × 3.5 = 560 mL. Subtract this from the total volume to find what’s left: 1000 mL − 560 mL = 440 mL. The fluid must be delivered over the remaining 8 hours, so the required rate is 440 mL ÷ 8 h = 55 mL/h. Therefore, set the flow rate for the remaining period to 55 mL/h.

This question tests how to compute the remaining infusion rate needed to finish a prescribed volume in the remaining time.

First, determine how much fluid has already been given: 160 mL/h for 3.5 hours equals 160 × 3.5 = 560 mL. Subtract this from the total volume to find what’s left: 1000 mL − 560 mL = 440 mL.

The fluid must be delivered over the remaining 8 hours, so the required rate is 440 mL ÷ 8 h = 55 mL/h.

Therefore, set the flow rate for the remaining period to 55 mL/h.