Metabolic

ACID-BASE EQUATIONS

Metabolic

Acidosis:

H⁺= 40 +(1.5 x decrease of [HCO3]) [Range: 80> -- >40]

PaCO2= 40- (1.2 x decrease of [HCO3]) [Range:40> -- >18[

Alkalosis:

H⁺= 40- (0.5 x increase of [HCO3]) [40> -- >30]

PaCO2= 40+ (0.6 x increase of [HCO3]) [55> -- >40]

Respiratory

Acidosis

Acute: H⁺= 40 + (0.8 x increase of PaCO2) [89> -- >40]

Chronic: H⁺= 40 + (0.3 x increase of PaCO2) [60> -- >40]

Alkalosis

Acute: H⁺= 40 - (0.7 x decrease in PaCO2) [40> -- >20]

Chronic: H⁺= 40 - (0.2 x decrease in PaCO2) [40> -- >25]

Acid-base conversion : H⁺ = (24 x PaCO2)/HCO3^-

ELECTROLYTE DISORDERS

Corrected Sodium

Corrected Na = Na⁺ + [1.5 x {Glu - 150}/100]

Water Deficit = 0.6 x body wt. x [1-(140/Na⁺)]

Calcium/albumin correction:

[(Normal Albumin x Patient's Albumin) x 0.8] + Patient's Ca⁺

ANION GAP

Na - (Cl + HCO3) = anion gap [Nl= 12 +2]

PULMONARY

Aa Gradient = [713(FiO2) - {PaCO2/0.8}] - Pa0₂

RENAL

Osmolarity = (2 x Na) + (BUN/2.8) + (Glucose/18)

Osmolar Gap= Measured - Calculated Nl= 0-10

Creatinine Clearance

CrCL = (140-age) x (wt in kg)

(Serum Cr) x 72

* for females multiply x 0.85

Pediatrics

Fluid and Electrolytes

Age Weight [Ml/kg/d]

Neonate 2.5-4kg [75]

1wk - 6mo 3.0-8kg [90-100]

7 - 12mo 8-12kg [80-90]

13 - 24mo 10-15kg [65-75]

OR

100ml/kg for the first 10kg

50ml/kg for the second 10kg

10ml/kg for every 10kg thereafter.

(Best if used for children instead of infants)

Fluid boluses should be 10cc/kg IVP of NS

Rehydration

Condition Na(mEq) K(mEq) Cl(mEq)

--------- ------- ------ -------

Fasting: 5-7, 1-2, 4-6

Isotonic: 8-10, 8-10, 8-10

Hypertonic: 2-4, 0-4, 2-6

Hypotonic: 10-12, 8-10, 10-12

Pyloric Stenosis: 8-10, 10-12, 10-12

DKA: 8-10, 5-7, 6-8

**For hypertonic states, do not give 1/2 replacement during first eight hours as you would with the other states, but give evenly over 48 hours. (Cerebral edema may occur)**