Calculation of Maintenance Fluids (Medwiki and Surgical Recall)
What is the rule for calculating maintenance fluids for 24 hours?
100/50/20 rule 100mL/kg for the first 10 kg 50mL/kg for the next 10 kg (so really, 1500 is the base) 20mL/kg for every kg over 20 (divide for 24 for hourly rate) 70 kg would need 2,500mL in a day and 104mL/hr for maintenance rate [slightly lower than the 4/2/1 rule)
How many mL are in 1oz?
30mL
What is the minimal urine output for an adult on maintenance IV?
30mL/hr or .5mL/kg/hr
What is the rule for calculating hourly rate for maintenance IV fluid?
4/2/1 Rule 4mL/kg for the first 10 kg 2mL/kg for the next 10 kg (so really, 60 mL is the base) 1mL/kg for every kg over 20
How many kcal per L in D5W?
5% Dextrose = 50g in 1L H2O 4 Kcal/g 50g/1L x 4Kcal/g = 200 kcal/L
What is the minimal UOP of an adult trauma patient
50mL/hr
How many mL are in 1 tsp?
5mL
What is in colloids? Are they expensive? What components in it impair platelets?
Albumin YES impairplatelets: dextran, hexastarct
After a laparotomy when should a patient's fluid be "mobilized"?
Classically, postop day 3; the patient begins to "mobilize" the third-space fluid back into the intravascular space
What is the common adult maintenance fluid?
D5 1/2 NS with 20 mEq KCL/L
What is the common pediatric maintenance fluid? Why is it different than adult maintenance fluid?
D5 1/4 NS with 20 mEqKCL/L Use 1/4 NS b/c of kids decreased ability to concentrate urine
What is the most common postoperative IV fluid after laparotomy?
D5 LR or LR for the first 25-36 hrs (in Fairbanks we always use D5 1/2 NS), followed by maintenance fluid (D5 1/2 NS w/ 20mEq KCl)
What type of fluids should be used for a bolus?
ISOTONIC (LR or NS)
Why should ISOTONIC fluids be given for reuscitation (ie to restore intravascular volume)?
If HYPOtonic fluid (1/2 NS) is given, the tonicity of the intravascular will be decreased and water will freely diffuse into the interstitial and intracellular spaces. Thus, use isotonic fluids to expand the intravascular space.
What is the most common trauma resuscitation fluid?
LR
What IVF is used to replace duodenal or pancreatic fluid loss
LR (bicarb loss) +/- extra bicarb
Why not bolus fluids with a significant amt of potassium? What about a bolus of LR?
LR only contains 4mEq/L. If you bolus with a lot of potassium hyperkalemia can result so don't do this.
Wat are the common ISOTONIC fluids?
NS and LR
What is the best way to assess fluid status? What if the patient has heart or renal failure?
UOP If cardiac or renal failure look at central venous pressure CWP
Why not combine bolus fluids with dextrose?
hyperglycemia may result
What portion of 1L of NS will stay in the intravascular space after a laparotomy?
in 5 hrs only approx 200cc (20%) will remin in the intravascular space!
What is the most common cause of electrolyte abnormalities?
lab error
What ist he possible consequence of hyperglycemia in a patient with HYPOvolemia
osmotic diuresis
Why should dextrose be added to maintenance fluid?
to prevent muscle breakdown