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Acid-base questions

Acid-base questions. Charles J. Foulks, M.D., FACP Professor of Medicine October 12, 2011. A 16 yo type I diabetic is admitted to the ICU. Serum ketones are positive, glucose is 394 mg/dL, Na 134 mEq/L, K 5.2 mEq/L, Cl 98 mEq/L, HCO3 10 mEq/L, pH 7.17, pCO2 is 28 torr. Is there compensation?

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Acid-base questions

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  1. Acid-base questions Charles J. Foulks, M.D., FACP Professor of Medicine October 12, 2011

  2. A 16 yo type I diabetic is admitted to the ICU. Serum ketones are positive, glucose is 394 mg/dL, Na 134 mEq/L, K 5.2 mEq/L, Cl 98 mEq/L, HCO3 10 mEq/L, pH 7.17, pCO2 is 28 torr.

  3. Is there compensation? NO What is the primary acid-base disturbance and its etiology? DIABETIC KETOACIDOSIS. If there wasn’t compensation, what is the other primary disorder? PRIMARY RESPIRATORY ACIDOSIS What is the anion gap? 26 Is there compensation? YES

  4. A 67 yo man is 12 hours post-operatively from coronary artery bypass grafting. While being extubated, he aspirated, became septic, and developed shock. His BP is 80/50 mm Hg. on multiple pressors. Na 145 mEq/L, Cl 98 mEq/L, K 4 mEq/L, ph 7.14torr, pCO2 12. What is the primary acid-base disorder and its etiology? LACTIC ACIDOSIS SECONDARY TO EITHER SHOCK OR SEPSIS. Is there compensation? YES. What is the anion gap? 43

  5. 4. A 23 yo woman was admitted with nausea and vomiting for several days. Intake has been poor. Na 128 mEq/L, Cl 80 mEq/L, K 2.9 mEq/L, HCO3 32 mEq/L, pCO2 44 torr, pH 7.47. What is the primary acid-base disorder and its etiology? PRIMARY METABOLIC ALKALOSIS SECONDARY TO VOMITING. Is there compensation? Yes

  6. 5. A 60 yo male with chronic obstructive pulmonary disease has been on naso-gastric suction for 3 days. You have been asked to see him for a diagnosis of lethargy. Labs Na 142 mEq/L, Cl 88 mEq/L, k 2.8 mEq/L, HCO3 40 mEq/L, pCO2 62 torr, pH 7.42.

  7. What was the initial acid-base disturbance and its etiology? PRIMARY METABOLIC ALKALOSIS SECONDARY TO NASOGASTRIC SUCTION. Was there compensation? NO If there wasn’t compensation, what is the other primary disorder? PRIMARY RESPIRATORY ACIDOSIS.

  8. A 32 yo male was found comatose at home in his garage. He is a known heavy drinker. Lab values Na 138 mEq/L, Cl 96 mEq/L, K 3.2 mEq/L, HCO3 4 mEq/L, pCO2 16 torr, pH 7.00, BUN 20 mg/dL, glucose 122, serum osmolarity 363 mosm/kg.

  9. What is the primary acid-base disturbance and its etiology? PRIMARY METABOLIC ACIDOSIS SECONDARY TO EITHER METHANOL OR ETHYLENE GLYCOL POISONING. Was there compensation? YES.

  10. A46 yo male has undergone bowel resection for Crohn’s disease. He is now 5 days post-operative and is on nasogastric suction. Lab values Na 132 mEq/L, HCO3 26 mEq/L, pCO2 32 torr, pH 7.50.

  11. What is the primary acid-base disturbance? THERE ARE TWO PRIMARY DISORDERS. EITHER CAN BE THE ANSWER HERE: PRIMARY METABOLIC ALKALOSIS (FROM NG SUCTIONING) OR PRIMARY RESPIRATORY ALKALOSIS (FROM PAIN). Was there compensation: NO

  12. CASE 1 Objective: 1. Recognize data base items needed to diagnose and treat acid base abnormalities. An asymptomatic patient is found to have the following laboratory values:                        Na+     138 mEq/L              Cl-        112 mEq/L             K+      3.9 mEq/L              HCO3-  14 mEq/L Intravenous NaHCO3 is infused to raise the plasma HCO3- concentration. Is this the correct form of therapy?

  13. CASE 2 Objectives:       1. To diagnose an acid base disorder given necessary data. 2. To recognize this acid base disorder. A 64 year old disoriented woman is brought to the emergency room. No history is obtainable. She is tachypneic (respiratory rate 35/min) and confused, but physical examination is otherwise not remarkable.  Laboratory studies include: Na+ 144 mEq/L  Arterial blood  pH 7.24   K+ 4.4 mEq/L    HCO3 9 mEq/L  Cl- 107 mEq/L      pCO2    22 mmHg

  14. 1. What is her acid base abnormality? 2. What are the possible causes? She has a normal serum creatinine concentration and plasma ketone level which is undetectable. 3. What diagnoses are now plausible? 4. What additional tests might you order to establish to correct diagnosis? 5. What if her pCO2 were 16 torr?

  15. CASE 3 Objectives:  1. To review acid/base abnormalities with GI fluid loss.                       2. To calculate blood gas data. A 70 year old man has had repeated diarrheal stools for the past 3 days. Blood studies include: Na+      132 mEq/L         Arterial  pH   7.39 K+        2.7 mEq/L         HCO3 22 mEq/L Cl- 90 mEq/L pCO2 37 torr HCO3 9 mEq/L

  16. CASE 4 Objective: To recognize this acid base disturbance - its generation, maintenance, and therapy. A 50 year old man is more successful as a lawyer than as a husband. His recent divorce and the financial settlement have pushed his cigarette and Cutty Sark consumption to unreasonable levels, and flared his long-standing peptic ulcer disease. "Doc, I've about had it. I've been vomiting for four days". You admit him to the hospital. His BP is 110/70, falling to 70/60 when he sits up. Resting pulse rate is 98/min. Skin turgor is poor, and he has obviously lost weight.

  17. His Hct is 46%, BUN 28 mg/dl, serum creatinine 1.4 mg/dl. Urinalysis shows S.G. 1.028, no protein, and a normal sediment. Other laboratory studies include: Na+    135  mEq/L            arterial  pH   7.60    K+     3.0 mEq/L                    HCO3    42 nEq/L            Cl-       83 mEq/L                    pCO2  42 torr          

  18. Hyponatremia • 85 yo male presents to ED with pneumonia, fever, prod cough • Mod distress, 120/86, 74, 24, 101.8 • Dec. breath sounds, L base • Na 120 K 3.9 Cl 87 Bicarb 24 • Bun 10 Creat 0.8 Glu 90 • Urine Na 60, K+ 30, Osmolality 500

  19. Hyponatremia • 1. What is hyponatremia? • 2. Is it synonymous with hypo-osmolality? • 3. What is the calc osm? 4. What is pseudohyponatremia? 5. Cause of his hyponatremia? 6. Why?

  20. Hard Problems • 44 yo man, hx chronic pancreatitis, adm for vomiting over 4 days. BP 100/70, P 120, light headed. • What disorders do you predict? • Na+ • K+ • Acid-base • Answers?

  21. Hard Problems • 54 yo female, cerv ca 20 years ago, rec. external beam irradiation. Has HTN, chronic kidney disease, weight loss over several months. Presents to ED with c/o severe dyspnea, RR 40, shallow. • Exam: 88/60, 130, 40, 97.7, O2 sat 96% • RN tells you she can’t lift her head and she had spasm of her R had when BP taken

  22. Hard Problems Exam: strength 0-1+/5, clear chest, no S3, loss of muscle mass in hands, cheeks, hair pulls out easily, loss of lunulae, tongue pale You repeat the BP and she has spasm of that hand. Lab? Diagnoses?

  23. Hard Cases • Na 122, K 1.4, Cl 86, Bicarb 12, Phos 0.6, • Ca 4.4 mg/dL, alb 3.0, Mg++ 0.8, hct 24%, mcv 70, pH 6.94 • Predict the QT interval • Why? • How to fix?

  24. Hard Cases • 5 mo old male, normal birth, brought in by mom for lethargy. No fever, cough. Wets diapers, has been fussy for 5-6 days. • Lethargic child, but not limp. BP 98/70, looks fat. Temp 98.4. Remainder of exam totally normal. LP negative. No evidence of trauma. No focal findings

  25. Hard Cases • What lab tests do you want and why? • Any more history needed?

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