Converting Weight, Height, Temperature, and Drop Rate at Urgent Care
A nurse in an urgent care clinic is admitting a 176-pound adult who is 5 feet 9 inches tall and has an oral temperature of 101.3 °F. The provider orders an antipyretic at 10 mg per kilogram of body weight, supplied as 160 mg per 5 mL, and asks the nurse to document the weight in kilograms and the height in centimeters in the chart. The same nurse must also start 1,000 mL of lactated Ringer's over 8 hours using tubing with a drop factor of 15 gtt/mL, and the pump is unavailable, so the rate must be counted by hand as whole drops per minute. The clinic's laminated conversion card lists 1 kg = 2.2 lb, 1 inch = 2.54 cm, 1 foot = 12 inches, and the standard Fahrenheit-to-Celsius formula. A second nurse will double-check each calculation before the medication is given and before the infusion is started.
1. What weight in kilograms should be documented, and what volume of antipyretic will the nurse draw up?
Read the worked answer
Weight: 176 lb ÷ 2.2 lb/kg = 80 kg (exact; no rounding needed).
Dose: 80 kg × 10 mg/kg = 800 mg.
Volume: the suspension is 160 mg per 5 mL, which is 32 mg/mL. So 800 ÷ 32 = 25 mL. Cross-check by proportion: 160/5 = 800/x, so 160x = 4,000 and x = 25 mL.
Answer: document 80 kg and administer 25 mL.
This is a large oral volume for one dose, so the nurse should confirm with the provider whether the dose is to be split or whether a concentrated product is preferred; the arithmetic is correct, but the volume is worth a double-check before administration.
2. What height in centimeters and temperature in Celsius should be entered in the chart?
Read the worked answer
Height: 5 feet = 60 inches; 60 + 9 = 69 inches. Then 69 × 2.54 = 175.26 cm, documented as 175.3 cm (or 1.75 m).
Temperature: °C = (°F − 32) × 5/9.
101.3 − 32 = 69.3; 69.3 × 5 = 346.5; 346.5 ÷ 9 = 38.5 °C.
Answer: 175.3 cm and 38.5 °C.
Back-check the temperature the other way: (38.5 × 9/5) + 32 = 69.3 + 32 = 101.3 °F, which matches the reading, so no transcription error occurred.
3. At how many drops per minute should the nurse count the lactated Ringer's infusion, and what should the nurse note about rounding?
Read the worked answer
Hourly rate: 1,000 mL ÷ 8 h = 125 mL/h.
Per minute: 125 ÷ 60 = 2.0833 mL/min.
Drops: 2.0833 × 15 gtt/mL = 31.25 gtt/min.
Answer: count 31 drops per minute, since quarter-drops cannot be counted.
Rounding matters: 31 gtt/min delivers (31 ÷ 15) × 60 ≈ 124 mL/h, slightly under the ordered 125 mL/h, while 32 gtt/min delivers about 128 mL/h. Over 8 hours the 31-gtt rate finishes roughly 8 mL late, which is clinically acceptable but should be documented. The nurse should verify the count over a full minute, confirm the tubing drop factor on the package rather than assume it, and have the second nurse check the rate before the infusion begins.