A 1.5 litre infusion starting at 0430 hours at a rate of 90 mL/h. After 10 hours the pump is reset to 75 mL/h. Calculate the finishing time.

A 1.5 litre infusion starting at 0430 hours at a rate of 90 mL/h. After 10 hours the pump is reset to 75 mL/h. Calculate the finishing time.

• A. 2230 h
• B. 2140 h
• C. 2320 h
• D. 2210 h

Answer: (A)

The calculation uses two infusion phases with different rates. First, the patient needs 1.5 L (1500 mL). At 90 mL/h for 10 hours, the amount delivered is 900 mL, leaving 600 mL to infuse. The new rate is 75 mL/h, so delivering 600 mL takes 600/75 = 8 hours. Start time is 0430. After the first 10 hours, it’s 1430. Adding 8 hours brings it to 2230. Finishing time: 2230 hours (10:30 pm).

The calculation uses two infusion phases with different rates. First, the patient needs 1.5 L (1500 mL). At 90 mL/h for 10 hours, the amount delivered is 900 mL, leaving 600 mL to infuse. The new rate is 75 mL/h, so delivering 600 mL takes 600/75 = 8 hours. Start time is 0430. After the first 10 hours, it’s 1430. Adding 8 hours brings it to 2230. Finishing time: 2230 hours (10:30 pm).