Med Math: Drop Factors Question #9


IV of 1000 mL D5.45NS is ordered to infuse over 8 hours. How many mL per hour will be infused?


  1. 50 mL/hr
    • Rationale:
  2. 100 mL/hr
    • Rationale:
  3. 120 mL/hr
    • Rationale:
  4. 125 mL/hr
    • Rationale:



Normal Saline is to be infused. You would need to know how much volume in ml you need per hour in order to solve. The total volume is set at 1000 ml to be infused. The D5.45 NS is extra information and not needed to solve the problem. The hour is not converted to minutes to solve the problem. The 1000 ml to be infused is divided by 8 hours. There is a simple formula below for calculating the flow rate. The final answer should have ml/hr within.


—– x 1 (understood to be 1 as in 1 hour) = Total volume per hour is ml/hr


1000mL/8 h = x mL/1h = 125 mL/hr

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