Fluids and Electrolytes

Men’s Fitness Survey 2003 America’s fittest cities: America’s fittest cities: 5. San Diego, CA 4. Colorado Springs, CO 3. San Francisco, CA 2. Seattle, WA 1. Honolulu, HI

Men’s Fitness Survey 2003 America’s FATTEST cities: 5. St. Louis, MO 4. Philadelphia, PA 3. Detroit, MI 2. Chicago, IL 1. Houston, TX

Body Fluids  Total body water (TBW)  50-70% of total body wt  Higher in males and muscle  Decreases with age and higher in newborns  Intracellular fluid (ICF) is 2/3 of TBW  Extracellular fluid (ECF) 1/3 of TBW  Approx % of ECF is intravascular volume

Fluid Requirements  Fluid Balance  Adult Basal requirements: 35cc/kg/d (1500cc/m 2 /d)  Pediatric 1 st 10-20kg = 100 cc/kg/d 2 nd 10 kg = 50 cc/kg/d 3 rd > 20 kg = 20 cc/kg/d  cc/hr rule

Fluid Losses  Fluid losses  GI cc/day  Renal cc/day  Insensible 400 cc/m 2 /d (approx 10 cc/kg/d)  60% lungs, 40% perspiration  Fever: 15% increase in insensible for each degree over 37C  Tachypnea 50%inc. in insensible per doubling of RR

Fluid Losses  Fluid losses cont.  Evaporation: ventilator, open abdominal wounds  Other GI losses: diarrhea, fistulas, drains  “Third space” losses  OR loss: cc/hr in major abdominal operations

Electrolyte Requirements  Electrolytes  Sodium  Primary extracellular cation and primary determinant of tonicity  Requirements: adult mEq/day; pediatric 3-5 mEq/kg/day  Potassium  Primary intracellular cation, used in glucose transport, protein deposition, myoneural conduction  Requirements: adult mEq/day; pediatric 3-5 mEq/kg/day

Electrolyte Requirements Other Electrolyte Requirements Other Electrolyte Requirements Mg: 20 mM/day usually replace 2-4 gram to keep above 2 mg/dL Cl: Adult mEq/d; ped 5-7 mEq/kg/d Ca: 1-3 g/day (po) or 7-10 mmole/day (IV) corrected Ca = (3.5 – alb) * Ca meas. PO 4 : 30 mmole/day

IV Fluid Composition Na(mEq/L)K(mEq/L)Cl(mEq/L)mOsm/LDextrose(g/L) D5W D10W NS % NaCl LR