The Sleep Tight Video©
Help for sleepless parents
fluids, requirement for
Maybe it has crossed your mind - "Hey, I don't know how much fluid my child needs to drink in a day." I know - I get this uneasy feeling every time I put a child in the hospital and have to write IV orders. Here is how we calculate daily fluid requirements:
Example #1 - 20 pound child:
Example #2 - 12 pound child:
Example #3 - 44 pound child:
I know this sounds awfully imprecise, but the body works it out just fine. We have a saying in medicine: "The dumbest kidney is smarter than the smartest doctor."
Now, remember again, this is only basal requirements (see below). If, for example, the body temperature is elevated one degree Celsius (there is that darn metric system again - 1.8 degrees Fahrenheit), for a whole day, increase the fluid requirements by 10%. But don't trouble yourself with this degree of detail; doctors rarely do.
The beauty part is - if you know the fluid requirements, now you know the caloric requirement too! It turns out that for what we call basal metabolism (just running the machine at idle, not walking around, no sports, no allowance for growth, or any other reason to rev up the body machinery), a human burns a calorie for each cc of fluid metabolized, and vice versa.
I admit there is little practical utility in everyday life for this arcane knowledge, but it just might help you someday.
The more precise formula is 100 kcal/kg for an infant 3 to 10 kg; 1000 kcal plus 50 kcal/kg for a child from 10 to 20 kg; 1500 kcal plus 20 kcal/kg over 20 for weights >20 kg. On average, ~40 mL/100 kcals/24 h will replace insensible losses and ~60 mL/100 kcals/24 h will replace urinary losses.