FLUID BALANCE

TOTAL BODY WATER (AS PERCENTAGE OF BODY WEIGHT) IN RELATION TO AGE AND SEX

AGE MALE FEMALE

UNDER 18 65% 55%

18-40 60% 50%

40-60 50-60% 40-50%

OVER 60 50% 40%

Ions

NORMAL VALUES AND MASS CONVERSION FACTORS

Normal Plasma Values Mass Conversion

Sodium (Na+) 135 – 145 meq/L 23 mg = 1 meq

Potassium (K+) 3.5 – 5.0 meq/L 39 mg = 1 meq

Chloride (Cl-) 98 – 107 meq/L 35 mg = 1 meq

Bicarbonate (HCO3-) 22 – 26 meq/L 61 mg = 1 meq

Calcium (Ca2+) 8.5 – 10.5 mg/dL 40 mg = 1 mmol

Phosphorus 2.5 – 4.5 mg/dL 31 mg = 1 mmol

Magnesium (Mg2+) 1.8 – 3.0 mg/dL 24 mg = 1 mmol

Osmolality 285 – 295 mosm/kg265 - 305 mosm/kg

-

Sodium Regulation

NORMAL Na+

INCREASED SODIUM

DECREASED SODIUM

Increased ADH secretion, Decreased urine volume and increased plasma

volume

Decreased aldosterone secretion, decreased sodium reabsorption

DECREASED SODIUM

INCREASED SODIUM

Decreased ADH secretion, Increased urine volume and decreased plasma

volume

Increased aldosterone secretion, increased sodium reabsorption

Potassium Regulation

NORMAL K+

INCREASED POTASSIUM

DECREASED POTASSIUM

Increased aldosterone secretion with increased potassium secretion by the kidneys and increased potassium in

urine

DECREASED POTASSIUM

INCREASED POTASSIUM

Decreased aldosterone secretion with decreased potassium secretion by the

kidney and decreased potassium in the urine

Calcium Regulation

NORMAL Ca++

INCREASED CALCIUM

DECREASED CALCIUM

Increased Calcitonin secretion with decreased bone resorption

Decreased parathyroid hormone secretion with decreased bone resorption, decreased intestinal

calcium absorption, and decreased kidney calcium reabsorption

DECREASED CALCIUM

INCREASEDCALCIUMIncreased parathyroid hormone

secretion with increased bone resorption, increased intestinal

calcium absorption, and increased renal calcium reabsorption

Parenteral Solutions

COMMONLY USED PARENTERAL SOLUTIONS

IV Solutions Osmolality(mosm/kg)

Glucose(g/liter)

Sodium(meq/liter)

Chloride(meq/liter)

5% D/W 252 50 - -

10% D/W 505 100 - -

50% D/W 2525 500 - -

0.45% NaCl 154 - 77 77

0.9% NaCl 308 - 154 154

3% NaCl 1026 - 513 513

Ringer’s lactate 282 - 130 109

5% D/NR 294 50 147 147

5% D/NM 290 50 77 77

Hyponatremia

SERUM OSMOLALITY

Normal Low High

ISOTONICHyponatremia

HyperproteinemiaHyperlipidemia

HYPERTONICHyponatremia

HyperglycemiaMannitol, sorbitol,Glycerol, maltose

HYPOTONICHyponatremia

VOLUME STATUS

Hyponatremia

VOLUME STATUS

Hypovolemic Euvolemic Hypervolemic

Una <10 meq/LExtrarenal saltDehydrationDiarrheaVomiting

Edematous states:Congestive heart failureHepatic diseaseNephrotic syndromeAdvanced CHF

SIADHPostop HypoNaHypothyroidismPsychogenic polydipsiaBeer potomaniaDrug reactions

Una >20 meq/LRenal salt lossDiureticsACE-inhibitorsNephropathiesMineralo-Corticoid lack

Hypokalemia: Treatment

ORAL POTASSIUM REPLACEMENTS

AMOUNT meq OF K ANION NAMES

LIQUIDS 15 ml 10 Cl 5% Potassium chloride

15 ml 20 Cl 10% Potassium chloride

15 ml 40 Cl 20% Potassium chloride

15 ml 20 Gluconate Potassium gluconate

POWDERS Packet 15 Cl K-lor

Packet 20 Cl Potassium chloride

Packet 25 Cl K-lyte

TABLETS 1 8 Cl Slow-K

1 8 Cl Micro-K extencaps

1 10 Cl K-dur 10

1 20 Cl K-dur 20

Hypokalemia: Treatment

POTASSIUM CONTENT OF FOODS

VERY HIGH(12-20 meq)

HIGH(5-12 meq)

BEANS Garbanzo beansSoy beans

Kidney beans Navy beansLima beans Pinto beans

FRUIT (1/2 cup or as stated) Papaya (one medium) Apricots (3 halves)Banana (6”)Cantaloupe (1/4”)Honeydew melon (1/4”)Orange (3”) and orange juicePear (one large)Prunes (4) and prune juiceRhubarb

Hypokalemia: Treatment

POTASSIUM CONTENT OF FOODS

VERY HIGH(12-20 meq)

HIGH(5-12 meq)

VEGETABLES (1/2 cup or as stated)

Artichoke (one)Avocado (1/4)Brussel sproutsCarrot (7 ½”) and chardKetchup (1 tbsp)Potato (one baked, one broiled, 10 fries, ½ cup mashed)Pumpkin and spinachTomato (one) and tomato juice

Hyperkalemia: Treatment

EMERGENCY TREATMENT OF HYPERKALEMIA

MODALITY MECHANISM OF ACTION

ONSET DURATION PRESCRIPTION K REMOVED FROM BODY

Calcium Antagonizes cardiac conduction abnormalities

0-5 min 1 hour Ca gluconate 10%, 5-30 ml IV;CaCl 5%, 5-30 ml IV

None

Bicarbonate Shifts K into cells

15-30 min

1-2 hours NaHCO3 44-88 meq IV

None

Insulin Shifts K into cells

15-60 min

4-6 hours SAI, 5-10 u IV, plus glucose 50%, 25 g IV

None

Albuterol Shifts K into cells

15-30 min

2-4 hours Nebulized albuterol, 10-20 mg in 4 ml saline

None

Hyperkalemia: Treatment

NON-EMERGENCY TREATMENT OF HYPERKALEMIA

MODALITY MECHANISM OF ACTION

DURATION OF TREATMENT

PRESCRIPTION K REMOVED FROM BODY

Loop diuretic Increased renal K excretion

0.5-2 hours Furosemide 40-160 mg IV or orally with or without NaHCO3, 0.5-3 meq/kg daily

Variable

Sodium polystyrene sulfonate (Kayexalate

Ion exchange resin binds K

1-3 hours Oral: 15-30 g in 20% sorbitol (50-100 ml)Rectal: 50 g in 20% sorbitol

0.5-1 meq/g

Hemodialysis Extracorporeal K removal

48 hours Blood flow > 200-300 ml/min; Dialysate K = 0

200-300 meq

Peritoneal dialysis

Peritoneal K removal

48 hours Fast exchange, 3-4 L/hr 200-300 meq

Hypocalcemia: Treatment

TREATMENT OF HYPOCALCEMIA

MODALITY AMOUNT OF CALCIUM ONSET DOSE

Intravenous calcium (Calcium gluconate)

93 mg (4.7 meq) per 10 ml Immediate 93-186 mg over 10-15 mins; then 10-15 mg/kg over 4-6 hours.

Oral calcium (calcium carbonate)

40% elemental calcium;250 mg/624 mg tablet or

500 mg/1250 mg tablet or500 mg/1500 mg tablet

< 1 hour 250-500 mg calcium 3 to 5 times a day.

Hypercalcemia

CAUSES OF HYPERCALCEMIA

INCREASED INTAKE OR ABSORPTION

Milk-alkali syndrome

Vitamin D or vitamin A excess

ENDOCRINE DISORDERS Primary and secondary hyperparathyroidism

Acromegaly

Adrenal insufficiency

NEOPLASTIC DISEASES Tumors producing PTH-related proteins

Metastases to bone

Lymphoproliferative disease

Secretion of prostaglandins and osteolytic factors

MISCELLANEOUS CAUSES Thiazide diuretics and renal transplant complications

Sarcoidosis and Paget’s disease of the bone

Hypophosphatasia, immobilization, iatrogenic

ABG Interpretation

SUMMARY OF EXPECTED COMPENSATION FOR SIMPLE ACID-BASE DISORDERS

DISORDER INITIAL CHANGE COMPENSATORY RESPONSE

Metabolic Acidosis Decrease in HCO3- Decrease in pCO2:

Δ pCO2 = 1.1 – 1.3 (ΔHCO3-)

Metabolic Alkalosis Increase in HCO3- Increase in pCO2:

Δ pCO2 = 0.6 – 0.7 (ΔHCO3-)

Respiratory Acidosis Increase in pCO2 Increase in HCO3-

ACUTE: ΔHCO3-= 0.1 Δ pCO2 + 2

CHRONIC: ΔHCO3-= 0.3 – 0.35 Δ pCO2

Respiratory Alkalosis Decrease in pCO2 Decrease in HCO3-

ACUTE: ΔHCO3-= 0.2 – 0.25 Δ pCO2

CHRONIC: ΔHCO3-= 0.4 – 0.5 Δ pCO2