ABSITE Review - Fluids & Lytes Flashcards
What is the relation of total body water between men, woman and infants?
infants > men > women
How is the total body water divided?
2/3 intracellular + 1/3 extracellular (2/3 interstitial + 1/3 plasma)
What determines the plasma/interstitial osmotic pressure?
Proteins
What determines the intracellular/extracellular osmotic pressure?
Sodium
What is the MCC of volume overload?
Iatrogenic
What are the lytes components of NS?
Na 154 and Cl 154
What are the lytes components of LR?
Na 130, K 4, Ca 2.7, Cl 109, bicarb 28
What is the plasma osmolarity formula?
Posm = (2 x Na) + (glucose/18) + (BUN/2.8)
How is volume replaced depending on weight?
4cc/kg/h for 1st 10kg, 2cc/kg/h for 2nd 10kg, 1cc/kg/h for each additional kg
What is the best indicator of adequate volume replacement?
Urine Output
What is the usual water fluid loss during open abdominal surgery?
0.5/1.0 L/hr
What IVFs should be used postop?
Use LR for 1st 24hrs. After 24hrs, switch to D5W1/2NS w 20mEq K because it stimulates insulin release, resulting in AA uptake and protein synthesis
What is the daily GI fluid volume secretion of the stomach, bile, pancreas and duodenum?
Stomach 1-2L/day
Bile 500-1000mL/day
Pancreas 500-1000mL/day
Duodenum 500-1000mL/day
What is the electrolyte composition of sweat, saliva, stomach, pancreas, bile, small intestine and colon secretions? What should be used for replacement?
Sweat - hypotonic Saliva - K (highest [] in the body) Stomach - H and Cl - D5W1/2NS w 20 K Pancreas - HCO3 - LR w HCO3 Bile - HCO3 - LR w HCO3 Small intestine - HCO3, K - LR w HCO3 Colon - K - LR w K
What EKG changes are seen in hyperK? What is the treatment?
Peaked T waves
Tx - Ca gluconate, Na bicarb, 10U insulin, 1amp 50% glucose, kayexalate, dialysis
What electrolyte can help hypokalemia?
Mg
What is the formula of Total free water deficit?
T FW def = 0.6 x kg x [(Na/140) - 1]
What is the formula of water requirement?
Water req = (desired change in Na over 1 day x TBW)/desired Na after giving the water requirement
What is the maximum Na change over 1 day for hyperNa?
No more than 0.7 mEq/h (16mEq/day)
What can cause rapid correction of hypoNa?
Central pontine myelinosis (no more than 1 mEq/h)
What is the formula to correct Na with hyperglycemia?
Add 2 points to Na for each 100 increment of glucose
Which diuretic is contraindicated in hypercalcemia?
Thiazides
What are the two physical exam signs present in hypocalcemia?
Chvostek’s (tapping on face produces twitching) and Trousseau (carpopedal spasm) sign
What is the correction for hypocalcemia and albumin?
Add 0.8 to Ca for every 1g decrease in albumin
