Arterial blood gases. ppt(To detect blood gases)

A test that require a sample from an artery to measure oxygen and carbon dioxide in blood.

1. Interpretation of Arterial Blood Gases

2. ABG’s ABGs is a test that measures the oxygen tension ( PaO ₂), carbon dioxide tension ( PaCO ₂), acidity (pH), oxyhemoglobin saturation ( SaO ₂), and bicarbonate (HCO3) concentration in arterial blood

3. Collection of sample The sample can be obtained either through a catheter placed in an artery, or by using a needle and syringe to puncture an artery . These syringes are pre-heparinized and handled to minimize air exposure that will alter the blood gas values

4. Procedure Site - Radial, brachial, femoral or dorsalispedis artery Transport - on ice cube, within 15 minutes Complications - bleeding, bruises and thrombosis Errors - due to delay, cold chain not maintained, venous sampling, air bubbles, sample clotted, too much heparin, poor calibration of analyzer, inadequate quality control

5. Procedure Insert needle at 45 degree radial, 60 brachial and 90 femoral Withdraw the needle and apply digital pressure Check bubbles in syringe Place the capped syringe in the container of ice immediately Maintain firm pressure on the puncture site for 5 minutes if patient has coagulation abnormalities apply pressure for10 to15 minutes

6. Normal values

7. Acid base disorders

8. Step1 Determine if it is acidosis or alkalosis? Look at pH (pH < 7.35=Acidosis or pH> 7.45=Alkalosis)

9. Step 2 Determine the most likely primary disturbance (i.e. metabolic or respiratory ) Problem is metabolic if change in HCO3- is favoring change in pH (Both in same direction)- Problem is respiratory if change in PaC02 is favoring change in pH

10. Step 3. Identify compensations If the primary disturbance is metabolic , determine whether an appropriate respiratory compensation is present (check PaCO2 level) If primary disturbance is respiratory , determine whether an appropriate metabolic compensation is present (check HCO3 level)

11. Step 4 Determine anion gap • High AG (> 12); organic metabolic acidosis, small elevation may be observed in metabolic alkalosis • Normal AG (4-12); RTA and diarrhea (Metabolic acidosis) • Low AG ( < 3) ; lab error, hypoalbuminemia , severe hyperkalemia and hypercalcemia ,

12. Ospe questions Interpret ABGs PH 7.55, HCO3 38, pCO2 30, Na 139, Cl 99 2. Write three causes of each condition? Respiratory Acidosis : asthma, COPD, pneumonia Respiratiory Alkalosis : anemia, anxiety, liver disease, lung disease Metabolic Acidosis : vomiting, Diarrhea, lactic acidosis diabetes Metabolic Alkalosis : hypokalemia, liver failure, kidney disease