Fluids, Electrolytes, Acid-Base Disorders, and Nutrition Support

“Normal” daily requirements

Electrolyte

Daily Requirements

Sodium

50–150 mEq (1–2 mEq/kg)

Potassium

0.5–1.5 mEq/kg

Phosphorus

10–30 mmol

Magnesium

8–32 mEq

Calcium

10–15 mEq

Chloridea

80–120 mEq

Acetatea

80–120 mEq

aDepending on the acid-base status of the patient.

Approximate electrolyte content of GI secretions (in milliequivalents per liter) (About Surgery:

A Clinical Approach. Philadelphia: Elsevier Health Sciences, 1996:5-17; Acta Chir Scand Suppl

1963:suppl 306:301-65)

Fluid

Average Daily

Volume (mL)

Sodium

(mEq/L)

Potassium

(mEq/L)

Chloride

(mEq/L)

Bicarbonate

(mEq/L)

Magnesium

(mEq/L)

Stomach

1000–2000

60–90

10–15

100–130

—

0.9

Duodenum

400–600

5–10

90–120

—

Jejunum/Ileum

2000–2500

5–10

90–120

30–40

6–12

Colon

< 300

20–30

—

6–12

Pancreas

600–800

5–10

0.4

Bile

300–600

5–10

1.1

Solutions

Sodium

(mEq/L)

Potassium

(mEq/L)

Chloride

(mEq/L)

Bicarbonate

(mEq/L)

Calcium

(mEq/L)

Magnesium

(mEq/L)

Osmolarity

(mOsm/L)

5% dextrose in water

—

—

—

—

—

—

0.45% sodium chloride

(one-half normal saline)

—

—

—

—

5% dextrose in 0.45%

sodium chloride (5%

dextrose in one-half

normal saline)

—

—

—

—

Lactated Ringer solution

2.7

—

Plasma-Lyte

A/Normosol-R pH 7.4

—

294–295