UOC laboratory medicine: ABGs analysis

3/11/18

ABGs analysis

ABG analysis made easy

ABGs analysis

Look initialy at patient's pH Is it [[Alkalotic]] OR [[Acidic]] ?

Patients has [[Alkalosis with Increased pCO2]] [[Alkalosis with Decreased pCO2]]

Patients has [[Acidosis with Increased pCO2]] [[Acidosis with Decreased pCO2]]

Respiratory Acidosis Check compensation by finding the expected HCO3 First calculate chronicity index = ΔpH/ΔpCO2 If closer to 0,008 then there is an acute Respiratory Acidosis => ExpHCO3 = 0.1 X ΔpCO2 +/- 2 If closer to 0,003 then there is an chronic Respiratory Acidosis => ExpHCO3 = 0.35 X ΔpCO2 +/- 2 . If Measured HCO3 = Expexted HCO3 => the patient only has Respiratory Acidosis and you should go to [[DDx Respiratory Acidosis]] . [[.If Measured HCO3 > Expected HCO3 => concomitant Metabolic Alkalosis]] [[.If Measured HCO3 < Expected HCO3 => concomitant Metabolic Acidosis]] .

Metabolic Acidosis . Check compensation by finding the expected pCO2 ExppCO2=1.5 X HCO3 + 8 +/- 2 . If Measured pCO2 = Expexted pCO2 => the patient only has Metabolic Acidosis . If Measured pCO2 > Expected pCO2 => concomitant Respriratory Acidosis so also look at [[DDx Respiratory Acidosis]] If Measured pCO2 < Expected pCO2 => concomitant Respiratory Alkalosis so also look at [[DDx Respiratory Alkalosis]] . Write down the info regardinh a concomitant respiratory acid-base disorder and continue with [[the Anion Gap]]

Metabolic Alkalosis Check compensation by finding the expected pCO2 ExppCO2=0.8 X HCO3 + 21 +/- 2 If Measured pCO2 = Expexted pCO2 => the patient only has Metabolic Alkalosis [[DDx Metabolic Alkalosis]] . [[If Measured pCO2 > Expected pCO2 => concomitant Respriratory Acidosis]] [[If Measured pCO2 < Expected pCO2 => concomitant Respiratory Alkalosis]] .

Respiratory Alkalosis Check compensation by finding the expected HCO3 First calculate chronicity index = ΔpH/ΔpCO2 If closer to 0,008 then there is an acute Respiratory Alkalosis => ExpHCO3 = 0.2 X ΔpCO2 +/- 2 If closer to 0,003 then there is an chronic Respiratory Alkalosis => ExpHCO3 = 0.5 X ΔpCO2 +/- 2 . If Measured HCO3 = Expexted HCO3 => the patient only has Respiratory Alkalosis and you go to [[DDx Respiratory Alkalosis]] . [[If Measured HCO3 > Expected HCO3 => concomitant Metabolic Alkalosis]] [[If Measured HCO3 < Expected HCO3 => concomitant Metabolic Acidosis]]

Measure Urine Cl [[Urine Cl <10mEq/L]] [[Urine Cl >20mEq/L]] ?

Chlorine Independent Metabolic Alkalosis DDx -Εξωγενής χορήγηση διτανθρακικών -Υπεραλδοστερονισμός -Σ. Bartter -Σ. Liddle -Έλλειψη 11-β-υδροξυλάσης ή 17-α-υδροξυλάσης -Sleep Apnea Syndrome (patient awake after overnight hypercapnia)

Chlorine Dependent Metabolic Alkalosis DDx -Έμετοι -Υποκαλιαιμία/Υπονατριαιμία -Volume Depletion alkalosis (+διουρητικά)

Πνευμονική Εμβολή Σύνδρομο συστηματικής φλεγμονώδους αντίδρασης (Systemic inflammatory-response syndrome -SIRS) και σήψη Acute respiratory distress syndrome (ARDS) Πνευμονία – υποξυγοναιμία Καρδιογενές shock – Πνευμονικό οίδημα Ισχαιμικό ή αιμοραγικό ΑΕΕ Δηλητηρίαση από σαλικυλικά Κρίση Πανικού Εγκυμοσύνη Ήπια κρίση βρογχικού άσθματος

Περιοριστικά σύνδρομα • ΧΑΠ • Άσθμα • Παχυσαρκία • νοσήματα του θωρακικού κλωβού (π.χ. κυφοσκωλίωση) Λοιμώξεις πνεύμονα Πλευριτική συλλογή ή πνευμοθώρακας (σε προχωρημένο στάδιο) Απόφραξη αεραγωγών από ξένο σώμα Κατασταλτικά φάρμακα και ουσίες (ναρκωτικά, αλκοόλ, αναισθητικά) Υπερβολική οξυγονοθεραπεία σε ΧΑΠ Βλάβες ΚΝΣ (ένφρακτα, αιμοραγίες, τραύματα, λοιμώξεις) Ανεπαρκής μηχανικός αερισμός

Calculate the anion gap AG=Na-(Cl+HCO3) . [[The AG is increased (>12mEq/L)]] [[The AG is normal(=<12mEq/L)]] . NOTE think AG correction in hypoproteinemia (2.5mEq/L lower for each unit of albumin below 4.5mg/dl)

Increased AG Metabolic Acidosis . Calculate ΔΔAG = (AG-12)/(24-HCO3) [[1<ΔΔAG<2]] [[ΔΔAG <1]] [[ΔΔAG >2]]

[[DDx non-AG Metabolic Acidosis]]

MUDPILES -Methanol -Uremia -Diabetic Ketoacidosis -Paraldehyde -Iron/Isoniazide -Lactic Acidosis -Ethanol/Ehtylen glycol -Salicylates

AG metabolic acidosis without other concomitant metabolic dosrder [[DDx AG Metabolic Acidosis]]

AG metabolic acidosis with concomitant non-AG metabolic acidosis [[DDx AG Metabolic Acidosis]] AND [[DDx non-AG Metabolic Acidosis]]

AG metabolic acidosis with concomitant metabolic alkalosis [[DDx AG Metabolic Acidosis]] AND [[DDx Metabolic Alkalosis]]

USED CAR(P) -Ureteroenterostomy -Saline Hydration/spironolactone -Endocrinopathies (Hypoaldosteronism, Hyperparathyroidism) -Diarrhea -Carbonyl Anhydrase Inhibitors -Ammonium chloride -Renal tubular acidosis -Pancreatic Fistula

[[DDx Respiratory Alkalosis]] and [[DDx Metabolic Alkalosis]]

[[DDx Respiratory Alkalosis]] and measure [[the Anion Gap]] and follow the metabolic acidosis algorithm

[[DDx Metabolic Alkalosis]] and [[DDx Respiratory Acidosis]]

[[DDx Metabolic Alkalosis]] and [[DDx Respiratory Alkalosis]]

[[DDx Respiratory Acidosis]] and [[DDx Metabolic Alkalosis]]

[[DDx Respiratory Acidosis]] AND Measure the [[the Anion Gap]] and follow further instructions regarding Metabolic acidosis from there