مقاربة غازات الدم الشرياني2(الحماض الاستقالبي عالي الفجوة)

1. ABG series ANAS SAHLE , MD DAMASCUSE HOSPITAL

2. Acid-Base Disorders and the ABG 2

3. Corrected equations in ABG1 AG= NA - (HCO3+CL) cAG = AG + ((2,5(4 –albu)) GAP:gap ratio…..

5. BREIF PREVIEW

6. Summary of the Approach to ABGs Check the pH Check the pCO2 Select the appropriate compensation formula Determine if compensation is appropriate Check the anion gap AG=NA – (HCO3 + CL):12 If the anion gap is elevated, check the delta-delta G:G Ratio =Δ AG (12-AG) HCO3 (24-HCO3) If a metabolic acidosis is present, check urine pH Generate a differential diagnosis

7. EXPECTED CHANGES IN ACID-BASE DISORDERS From: THE ICU BOOK - 2nd Ed. (1998) [Corrected]

9. Gap:gap ratio??

11. Osmolal gap = measured serum osmolality - (2 NA + gluco8 + bun,8) Corrected osmolal gap = measured serum osmolality - (2 NA + gluco8 + bun,8 + ETOH,6)

13. High normal

14. Comparision Diabetic ketoacidosis Glucose >250 mgl Hco3 <15 meq High AG metabolic acisosis . ph <7,3 Ketonemia ketonuria. Alcoholic ketoacidosis Decreased ndetectable ETOH level. Variable glucose level. High AG metabolic acidosis. Ketonemia etonuria.

15. Case reportAcid-base disturbances A 42 year old diabetic female

16. A 42 year old diabetic female Has been on insulin since the age of 13 Presents with a 4 day history of dysuria which has progressed to severe right flank pain Body temperature: 38.8C WBC of 14 000 cells/L

17. Electrolytes and ABG Na+ 135 mmol/L (136-145).. cNA=?? K+ 4.8 mmol/L (3.5-5.0) HCO3- 12 mmol/L (22-26) Cl- 99 mmol/L (98-106) Gluco 300 mg/dl pH 7.23 (7.38-7.42) PaCO2 25 mmHg (38-42) PaO2 118 mmHg (90-105) Urine: w.c:20,r.c:2,prot(-),hb(-),keton(++) DiabeticF 42 year old

20. PCO2mmHg 90 pH=7,1 pH=7,2 pH=7,37 pH=7,3 pH=7,43 80 pH=7,5 Stabilized respiratory acidosis Acute respiratory acidosis 70 pH=7,6 60 stabilizedmetabolic alkalosis 50 Acute metabolic alkalosis Acute metabolic acidóza 40 pH=7.23 pCO2=25 mmHg HCO3-=12 mmol/l 30 stabilizedmetabolic acidosis Acute respiratory alkalosis stabilizedrespiratory alkalosis 20 10 4 9 14 39 19 46 24 51 34 29 41 HCO3-mmol/l DiabeticF 42 year old HCO3- 12 mmol/L ABG 7.23 /25/118

21. Metabolic acidosis - anion gap Is calculated as the difference between the sodium concentration and the sum of chloride and bicarbonate concentrations.

22. Increased anion-gap acidosis Ingestion of: Methanol, ethanol, ethylene glycol, aspirin, paraldehyde, salicylates, cyanide Uremia or renal failure Lactic acidosis Alcoholic ketoacidosis or diabetic ketoacidosis

23. A 23 year old man presents with confusion

24. A 23 year old man presents with confusion A 23 year old man presents with confusion. He has had diabetes since age 12, and has been suffering from an intestinal flu for the last 24 hours. He has not been eating much, has vague stomach pain, stopped taking his insulin, and has been vomiting. His glucoseis high M 23 year old with confusion

25. Electrolytes and ABG Na+ 130 mmol/L (136-145) Cl- 78 mmol (98-106) HCO3- 10 mmol/L (22-26) pH 7.20 (7.38-7.42) PaCO2 25 mm Hg (38-42) PaO2 68 mm Hg (90-105) M 23 year old with confusion

26. Interpretation of the ABG values PaO2 =68 mm Hg Expected PaO2 for a 22 year old man PaO2 = 100 – (1/3 x 22)~ 93 mmHg Patient is hypoxemic for age M 23 year old with confusion

28. Ventilation Is hypoxia caused by hypoventilation or primary pulmonary problem? PaCO2 Hypoventilation = high PaCO2 The A-a 02 gradient (PA-a02) Hypoventilation = normal A-a 02 gradient Primary pulmonary problem = PA-a02 increased PAO2 = FiO2 x (PB – PH2O) – PaCO2/0.8 Expected A-a gradient < (Age/4) + 4

29. Equation for derivation of alveolar PO2 (PAO2) M 23 year old with confusion

30. The A-a 02 gradient (pA-a02) pAO2 = FiO2 x (PB – PH20) – PaCO2/R PA-a02 = PAO2 - PaO2=[150 – (1.25 x 25)] – 68 = 51 mmHg Expected A-a gradient < (Age/4) + 4 = 23/4 + 4 = 9.75 mmHg M 23 year old with confusion

31. Primary lung problem Hypoventilation can be excluded Low PaCO2 High PA-a02 Hypoxia is related to primary lung defect ? aspiration in the confusional state

33. Case 1 A 21 y.o. male presents to the ER with confusion. Over the past several days his family reports that he had complained of nausea and anorexia. The PMH is negative. On PE the BP is 122/60, HR 110, T 37.8, RR 28. Chest is clear. Abdomen is benign. In the ED he begins to vomit and subsequent develops respiratory distress. He is intubated, and one hour later the following labs are obtained:

34. Case 1 CORRECTED SODIUM=M.NA+((M.GL-100)00)*2,4 =159,12

36. Case 2 46 y.o. female with a history of alcohol abuse presents with progressive nausea, confusion and labored breathing over 5 days. The past medical history is significant for chronic migraines and hypertension. Medications include enalapril 10 mg daily, Premarin(HRT) 0.625 mg daily and DarvocetN-100(narcotic) as needed for pain. Physical exam showed respiratory distress and postural hypotension.

37. Case 2 Labs

39. Case 2 Labs

40. High normal

41. From http://www.merck.com/mmpe/sec21/ch326/ch326c.html

42. Case 3 A 44 y.o. female with cirrhosis is admitted with fever and abdominal pain. Medications include spironolactone, furosemide, and lactulose. On exam the BP is 74/55, HR 72, T 38.3, RR 24. She is cachectic. The abdomen is tense and diffusely tender. There is 1+ leg edema.

43. Case 3 Labs

45. NEXT LECTURE NORMAL AG METABOLIC ACIDOSIS MEXED DISORDERS (PH normal)