Basics In Arterial Blood Gas Interpretation

1. Basics in Arterial Blood Gas Interpretation Crisbert I. Cualteros, M.D.

9. Ventilatory/ Acid-Base Status

10. Henderson-Hasselbach Parameters & their normal laboratory ranges pH= [HCO 3 ]p P C02 > 26 < 35 > 7.45 Alkalotic < 22 > 45 < 7.35 Acidotic 22-26 35-45 7.35-7.45 Normal [HCO3]p (mmol/L) PCO2 (mmHg) pH

11. Traditional Metabolic Acid-Base Nomenclature  (+)   N Compensated (chronic)  (+)    Partly compensated (subacute)  (+)  N  Uncompensated (acute) Metabolic alkalosis  (-)   N Compensated (chronic)  (-)     Partly compensated (subacute)  (-)   N  Uncompensated (acute) Metabolic acidosis BE [HCO3]p PCO 2 pH Nomenclature

12. Traditional Respiratory Acid-Base Nomenclature    N Compensated (chronic)     Partly compensated (subacute) N N   Uncompensated (acute) Respiratory alkalosis    N Compensated (chronic)     Partly compensated (subacute) N N   Uncompensated (acute) Respiratory acidosis BE [HCO3]p PCO2 pH Nomenclature

31. Causes of Metabolic Alkalosis Hypokalemia* Ingestion of large amounts of alkali or licorice Gastric fluid loss: Vomiting, NG suctioning* Hyperaldosteronism 2 0 to nonadrenal factors Bartter’s syndrome Inadequate renal perfusion diuretics (inhibiting NaCl reabsorption)* Bicarbonate administration Sodium bicarbonate overcorrection Blood transfusion Adrenocortical hypersecretion (e.g tumor) Steroids* Eucapnic ventilation posthypercapnia * Common in the ICU

32. Limits of Compensation  0.5- 1/ 1 meq/L [HCO 3 - ]  Metabolic Alkalosis  1- 1.5/ 1 meq/L [HCO 3 - ]  Metabolic Acidosis  2- 5/ 10 mmHg PCO 2  Chronic  0- 2/ 10 mmHg PCO 2  Acute Respiratory Alkalosis  1- 3.5/ 10 mmHg PCO 2  Chronic  0.1- 1/ 10 mmHg PCO 2  Acute Respiratory Acidosis PCO 2 mmHg [HCO 3 - ] meq/L Imbalance

34. Oxygenation Status

36. Steps for Analyzing Oxygenation Status

40. 3. If normoxemic, is oxygenation adequate or more than adequate?

41. Thank you !