Abg interpretation copy
Download as PPTX, PDF8 likes2,506 views
The document provides guidance on interpreting arterial blood gas (ABG) results through a step-by-step process. It begins by outlining proper techniques for collecting an ABG sample. It then describes the variables provided in an ABG report and how to assess for acid-base disorders by analyzing the pH, PCO2, HCO3, and other values. The document outlines the steps to determine if an acid-base imbalance is respiratory or metabolic in nature and how to evaluate for compensation. It also reviews how to interpret values in specific conditions like respiratory acidosis, alkalosis, and different types of metabolic acidosis.
![STEP 1 - Is your ABG valid?
• Henderson-Hasselbalch equation
• [H+]= 24 X pCO2/HCO3
• 80 – (H+) = Decimals after 7](https://image.slidesharecdn.com/abginterpretation-copy-191230150837/85/Abg-interpretation-copy-8-320.jpg)
![Compensation (Rule of 1,4,2,5)
• Increase in HCO3
• <24 hrs: Expected [HCO3] = 24+[1/10x (PCO2-40)]
10 mmhg increase in PaCO2 increase in HCO3
by 1 mmol/L
• >24 hrs: Expected [HCO3] = 24+[4/10x (PCO2-40)]
10 mmhg increase in PaCO2 increase in HCO3
by 4 mmol/L](https://image.slidesharecdn.com/abginterpretation-copy-191230150837/85/Abg-interpretation-copy-34-320.jpg)
![Compensation (Rule of 1,4,2,5)
• Decrease in HCO3
• <24 hrs: Expected [HCO3] = 24 – [2/10x (40-PCO2)]
10 mmhg decrease in PaCO2 decrease in HCO3 by
2 mmol/L
• >24 hours:Expected [HCO3] = 24 –[5/10 x (40-PCO2)]
10 mmhg decrease in PaCO2 decrease in HCO3 by
5 mmol/L](https://image.slidesharecdn.com/abginterpretation-copy-191230150837/85/Abg-interpretation-copy-39-320.jpg)
Abg interpretation copy
- 1. ABG Interpretation DR ANKIT GAJJAR MBBS, MD, IDCCM, IFCCM, EDIC CONSLUTANT INTENSIVIST
- 2. Collecting ABG • Radial is ideal • Preheparinised syringe • Flush syringe with 0.5 ml heparin and empty • Heparin not emptied adequately - Low HCO3 - Low PCO2
- 3. • 50% of the syringe should be filled by blood • Avoid contact with air – Increase PO2 if PO2 <150 – Decrease in PCO2 • Marked elevation in WBC – Decrease in PO2 • Maintain cold chain
- 4. Know your machine • Measured variables – pH – PCO2 – PO2 • Calculated variables – HCO3 - Lactate - SpO2 - PaO2 - Electrolytes
- 5. What does ABG tells us • Acid Base disorder – Metabolic acidosis – Metabolic alkalosis • Blood gas abnormalities – Respiratory acidosis – Respiratory alkalosis – Hypoxia – Carbon monoxide poisoning – Methemoglobinaemia
- 6. In the end we will be experts
- 7. The Blood Gas Report: The essentials • pH 7.4 (7.35-7.45) • PCO2 40 (35-45) • PO2 80 (80-100) • HCO3 24 (24-28)
- 8. STEP 1 - Is your ABG valid? • Henderson-Hasselbalch equation • [H+]= 24 X pCO2/HCO3 • 80 – (H+) = Decimals after 7
- 9. Ph 7.40 PCO2 40 PO2 88 HCO3 24 Na 137 Cl 102
- 11. • Step 1 - pH • Step 2 – Metabolic / Respiratory • Step 3 – Respiratory acute v/s Chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 Respiratory compensation – Rule of 1,2,4,5 • Step 5 Metabolic compensation – Expected pCO2 = (1.5 x HCO3)+8 – Expected pCO2 = (0.7x HCO3)+21 • Step 6 Anion gap • Step 7 Delta ratio
- 12. STEP – 1 Acidemic or Alkalemic • pH < 7.4 - Acidosis • pH > 7.4 - Alkalosis
- 13. STEP 2 – METABOLIC / RESPIRATORY
- 14. Metabolic Acidosis • Increase acid production • Decrease acid excretion • Increase alkali excretion • In ABG – pH < 7.40 – HCO3 < 24
- 15. Anion gap • Serum AG = Measured cations - measured anions = Unmeasured anions - unmeasured cations • Serum AG = Na - (Cl + HCO3) • Reference range is 8 to 16 mmol/l (an average of 12 mmol/l) • AG falls by 2.5 meq/L for every 1 g/dL reduction in the serum albumin concentration
- 17. pH 7.05 PCO2 31 PO2 88 HCO3 10 Na 137 Cl 102
- 18. Increase anion gap • Increase unmeasured anions (MUD-PILES) – Methanol – Uremia – DKA – Paraldehyde – Isoniazid – Lactic Acidosis (shock, sepsis, metformin, linezolid, drugs) – Ethylene Glycol – Salicylates • Decrease unmeasured cations – Ca, Mg, K
- 19. Normal anion gap acidosis • Loss of bicarb (HARD UP) – Hyperchloremic acidosis (Excessive normal saline) – Acetazolamide – RTA – Diarrhea – Ureterosigmoidostomy / colonic fistula – Post hypocapnia
- 21. Delta gap • AG – Normal AG = Δ Gap • Δ gap SHOULD BE = Δ Bicarbonate • Δ gap/ Δ Bicarbonate = Delta Ratio • Δ ratio < 1 – Another metabolic acidemia • Δ ratio > 1 – Another metabolic alkalemia
- 23. Look for compensation • Expected pCO2 = (1.5 x HCO3) + 8 ± 2 • If CO2 is higher then expected concomitant respiratory acidosis • If CO2 is lower then expected concomitant respiratory alkalosis
- 24. Ph 7.05 7.43 PCO2 32 16 PO2 88 88 HCO3 10 10 Na 137 137 Cl 102 102
- 25. Management of metabolic acidosis • Identify underlying etiology • Treat according to underlying etiology • HCO3 – HCO3 losing pathology – severe acidosis • If inadequate respiratory compensation INTUBATION AND HYPERVENTILATION
- 26. Metabolic alkalosis • Ph > 7.40 • HCO3 > 26
- 27. Look for compensation • Expected pCO2 = (0.7 x HCO3) + 21 ± 2 • PCO2 higher then expected associated respiratory acidosis • PCO2 lower then expected respiratory alkalosis
- 28. Ph 7.58 PCO2 50 PO2 88 HCO3 44 Na 145 Cl 88
- 29. Causes • Chloride responsive (U Chloride < 20) – Vomiting / Gastric suction – Prior use of diuretics – Posthypercapnia • Chloride resistant (U Chloride > 20) – Severe hypokalemia – Hyperaldosteronism – Active use of diuretics – Milk alkali syndrome
- 30. Treatment of metabolic alkalosis • Normal saline • Potassium replacement • Acetazolamide
- 31. Respiratory acidosis • pH < 7.35 • PCO2 > 45
- 32. Acute v/s Chronic • Expect change in pH = 0.008 x PCO2 • If pH is higher then expected pH it is chronic
- 33. Ph 7.31 PCO2 76 PO2 68 HCO3 38 Na 137 Cl 94
- 34. Compensation (Rule of 1,4,2,5) • Increase in HCO3 • <24 hrs: Expected [HCO3] = 24+[1/10x (PCO2-40)] 10 mmhg increase in PaCO2 increase in HCO3 by 1 mmol/L • >24 hrs: Expected [HCO3] = 24+[4/10x (PCO2-40)] 10 mmhg increase in PaCO2 increase in HCO3 by 4 mmol/L
- 35. Ph 7.31 PCO2 76 PO2 68 HCO3 38 Na 137 Cl 94
- 37. Respiratory alkalosis • Ph > 7.45 • PCO2 > 45
- 38. Acute v/s Chronic • Expect change in pH = 0.008 x PCO2 • If pH is lower then expected pH it is chronic
- 39. Compensation (Rule of 1,4,2,5) • Decrease in HCO3 • <24 hrs: Expected [HCO3] = 24 – [2/10x (40-PCO2)] 10 mmhg decrease in PaCO2 decrease in HCO3 by 2 mmol/L • >24 hours:Expected [HCO3] = 24 –[5/10 x (40-PCO2)] 10 mmhg decrease in PaCO2 decrease in HCO3 by 5 mmol/L
- 40. Ph 7.52 PCO2 30 PO2 66 HCO3 22 Na 130 Cl 100
- 41. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio
- 42. ARE WE READY FOR THE CHALLENGE
- 44. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.39 PCO2 93.8 PO2 69.6 HCO3 55.7 Na 145 Cl 86
- 45. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.18 PCO2 16 PO2 114 HCO3 6 Na 135 Cl 95
- 46. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.25 PCO2 80 PO2 46 HCO3 20 Na 134 Cl 104
- 47. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.23 PCO2 23 PO2 64 HCO3 14 Na 130 Cl 94
- 48. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.14 PCO2 59.1 PO2 66.3 HCO3 18 Na 138 Cl 102
- 49. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.23 PCO2 23 PO2 110 HCO3 14 Na 130 Cl 100
- 50. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.26 PCO2 18 PO2 128 HCO3 7 Na 136 Cl 113
- 51. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.31 PCO2 33 PO2 88 HCO3 16 Na 134 Cl 113
- 52. • Step 1 - pH • Step 2 – metabolic/respiratory • Step 3 – resp acute v/s chronic – change in pH = 0.08 x PCO2 / 10 • Step 4 resp compensation – Rule of 1,2,4,5 • Step 5 metabolic compensation – Expected pCO2 = (1.5 x HCO3) + 8 – Expected pCO2 = (0.7x HCO3) + 21 • Step 6 Anion gap • Step 7 delta ratio Ph 7.64 PCO2 32 PO2 75 HCO3 33 Na - Cl -
- 53. One more gap – Saturation gap • ABG machiene gives SaO2 from PaO2 – SaO2 chart • In case of Methemoglobinemia ABG will give SaO2 higher then SpO2 • ABG machine with co oxymetry will give measured – SaO2 – Meth HB – Carboxy Hb
- 55. THANK YOU