Insensible losses are estimated at approximately 10 mL/kg/day. Which of the following values represents this estimate?

• A. 5
• B. 10
• C. 15
• D. 20

Answer: (B)

Insensible losses are the unmeasured water lost through the skin and lungs. The standard baseline used in maintenance fluid calculations is about 10 mL per kilogram of body weight per day. So the value that represents this estimate is 10 mL/kg/day. For example, a person weighing 70 kg would have about 700 mL of insensible losses per day under this baseline. Values lower or higher than this reflect different assumptions or patient conditions (fever, burns, environmental factors) that can increase or decrease these losses, but the typical starting estimate is 10 mL/kg/day.