Page 8 - Critical Care Notes

4223_Tab01_001-044 29/08/14 10:46 AM Page 2

BASICS

Normal Arterial and Venous Blood Gases

Blood Gas
Components Arterial Venous
pH 7.35–7.45 7.31–7.41
80–100 mm Hg 35–40 mm Hg
PO 2
35–45 mm Hg 41–51 mm Hg
PCO 2
HCO 3 - 22–26 mEq/L or mmol/L 22–26 mEq/L or mmol/L
Base excess (BE) –2 to +2 mEq/L or mmol/L –2 to +2 mEq/L or mmol/L
O 2 saturation 95%–100% 68%–77%
Values denoted are at sea level.
Quick Blood Gas Interpretation

Acid-Base Disorder pH PCO 2 ↑ HCO 3 -
Respiratory acidosis ↓ ↑ ↑ if compensating
Respiratory alkalosis ↑ ↓ ↓ if compensating
Metabolic acidosis ↓ and (+) ↓ if ↓
base excess compensating
Metabolic alkalosis ↑ and (–) ↑ if ↑
base excess compensating
Mixed respiratory and ↓ ↑ ↓
metabolic acidosis
Mixed respiratory and ↑ ↓ ↑
metabolic alkalosis
Full or total compensation: pH will be within normal limits.

2