ABG Analysis

Easy and simple explanation of ABG arterial blood gas analysis ..U will be able to solve most of the questions related to ABG

1. ABG Analysis

2. Arterial blood gas Colour- bright Red Pressure- High VBG- Venous Blood Gas Colour- Dark Red Pressure-Low Basic Difference between arterial blood and venous blood

3. SITE- Most Common Site- RADIAL ARTERY Why?? Easily accessible because of its anatomical location Because of collateral circulation OTHERS- Brachial artery Femoral artery

4. Modified Allen’s Test- Close the fist Press both the radial and ulnar artery It will turn pale because of blocked supply Release the ulnar artery Circulation must be restored within 3-15 secs NORMAL CAPILLARY REFILL TIME-<3 secs

5. Positive Allen’s test- Normal Circulation restored within seconds Signifies patency of the radial and ulnar artery Can Cannulate the radial artery Negative Allen’s test- Abnormal Ulnar artery is blocked No collateral circulation **Not adequate to puncture the radial artery as if by some reason the radial artery gets damaged or thrombus formation occurs then whole circulation of the hand will be blocked.

6. Normal values* most important pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg HCO3- 22-26 mEq/L PaO2- 80-100 mm/Hg Rules- pH and PaCO2 moves in same direction Then it’s METABOLIC (both increases /both decreases) 2. pH and PaCO2 moves in opposite direction Then it’s RESPIRATORY (one increases other one decreases) **ROME Respiratory Opposite Metabolic Equal

7. Eg. pH- 7.2 PaCO2- 32 HCO3- 13 PaO2- 92 pH- 7.1 PaCO2- 75 HCO3- 44 PaO2- 88 Metabolic Acidosis Respiratory Acidosis **HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg

8. Eg. pH- 7.5 PaCo2-49 HCO3-24 PaO2-76 pH-7.6 PaCo2- 31 HCO3- 26 PaO2-86 Metabolic Alkalosis Respiratory Alkalosis **HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg

9. Respiratory Acidosis (PaCO2:HCO3) ACUTE- 10:1 CHRONIC-10:4 Respiratory Alkalosis ACUTE- 10:2 CHRONIC-10:4 **Every 10 mm Hg increase in PaCO2 leads to 1 mEq/L increase in HCO3 CO2+ H2O H+ + HCO3-

10. RESPIRATORY ACIDOSIS RULES HCO3- Normal – Uncompensated pH – Normal- Fully Compensated pH- not Normal- Partially Compensated Eg. pH- 7.25 PaCO2- 60 HCO3- 23 Eg. pH- 7.42 PaCo2-31 HCO3-28 Respiratory acidosis Uncompensated Respiratory Alkalosis fully compensated ** HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg HCO3- 22-26 mEq/L

11. pH-7.47 PaCo2-34 HCO3-21 pH-7.32 PaCo2-47 HCO3-29 **HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg HCO3- 22-26 mEq/L pH- not Normal- Partially Compensated Respiratory alkalosis Partially compensated Respiratory acidosis partially compensated

12. METABOLIC PaCO2-Normal- Uncompensated pH- Normal- fully compensated pH-7.37 PaCo2-33 HCO3-17 **HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg Metabolic acidosis Fully compensated

13. pH- 7.52 PaCO2- 37 HCO3- 26 Metabolic alkalosis uncompensated ** HINT pH – 7.35- 7.45 (less than 7.35 is acidosis & more than 7.45 is Alkalosis) PaCO2 – 35-45 mm Hg HCO3- 22-26 mEq/L (Uncompensated)

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