Acid Base Work Book 2019

Section One 1. Medical student draws ABG and put it in her pocket for 6 hours. Then she sends it to the lab.

Normal Values Case 7.35-7.45 pH 7.26 40 pCO2 61

140 Na 138 4 K 3.8 80-26 = 54 = 24 x 61/31 = 47. 54=/= 47. Not valid. Redraw labs. 100 Cl 100 24 HCO3 31 8-16 BUN 17 0.6-1.4 Cr 1.2 12 Anion Gap

2. 36 year old man with history of depression found down in his garage

Normal Values Case 7.35-7.45 pH 7.28 40 pCO2 26 Acidemia. Metabolic, ingestion? 80-28 = 52 = 24x26/12 = 52 (valid) 140 Na 140 AG 25 - AGMA 4 K 3.9 pCO2 = 1.5 x 12 + 8 +/- 2 = 24-28 (pCO2 fits) - approp compensation 100 Cl 103 Delta gap/delta bicarb = 13/12 = 1.1 - pure AGMA 24 HCO3 12 8-16 BUN 10 AGMA with appropriate respiratory compensation 0.6-1.4 Cr 0.8 12 Anion Gap

3. 68 year old man with stable COPD in for routine PFT’s

Normal Values Case 7.35-7.45 pH 7.34 40 pCO2 60 acidemia , resp? Stable and chronic? 140 Na 140 80-34 = 46 = 24 x 60/32 = 45 (valid) AG 10 4 K 3.9 pCO2 increases by 10 = bicarb increase by 3.5 100 Cl 98 60-40 = 20. 20/10 = 2. 2 x 3.5 = 7. 24 + 7 = 31 (approp met comp) 24 HCO3 32 Chronic respiratory acidosis with appropriate metabolic compensation 8-16 BUN 20 0.6-1.4 Cr 1.2 12 Anion Gap Acid Base Work Book 2019

4. 22 year old G2P1 woman in the 33rd week of pregnancy Normal Values Case 7.35-7.45 pH 7.46 Alkalemia. Chronic due to pregnancy? 40 pCO2 29 80-46 = 34 = 24 x 29/20 = 34 (valid) AG 10 140 Na 138 Decrease bicarb by 4 for every decrease in pCO2 by 10 4 K 3.7 40-29 = 11 24-20 = 20 100 Cl 108 Chronic respiratory alkalosis with metabolic compensation 24 HCO3 20 8-16 BUN 6 Cirrhotics get this for the same reason - progesterone increases respiratory drive/causes hyperventilation 0.6-1.4 Cr 0.5 12 Anion Gap

5. 18 year old wrester with recent rapid weight loss

Normal Values Case 7.35-7.45 pH 7.50 40 pCO2 48 Alkalemia. Diuretics and contraction alkalosis? 140 Na 137 80-50 = 30 = 24 x 48/38 = 30 (valid) 4 K 3.2 pCO2 = 0.9 x 38 + 16 +/- 2 = 48-52 (pCO2 in this range) appropr 100 Cl 92 compensation 24 HCO3 38 Metabolic alkalosis with appropriate respiratory compensation 8-16 BUN 23 0.6-1.4 Cr 1.0 12 Anion Gap

6. In a man undergoing surgery, it was necessary to aspirate the contents of the upper gastro-intestinal tract.

Normal Values Case 7.35-7.45 pH 7.50 40 pCO2 52

140 Na 140 alkalemia . metabolic. GI losses. 4 K 3.0 80-50 = 30 = 24 x 52/40 = 31 (valid) pCO2 = 0.9 x 40 +16 +/- 2 = 50-54 (within this range) approp comp 100 Cl 90

24 HCO3 40 Metabolic alkalosis with appropriate respiratory compensation 8-16 BUN 22 0.6-1.4 Cr 1.4 12 Anion Gap

Acid Base Work Book 2019

7. A person was admitted to hospital in a coma. Normal Values Case 7.35-7.45 pH 7.10 40 pCO2 16 BAD acidemia. Ingestion! H+ = 40 x 1.25 x 1.25 x 1.25 = 78.125 = 24 x 16/5 = 80 (valid - see reference 140 Na 138 sheet for formula for pH less than 7.2) 4 K 3.7 AG 33 - AGMA 100 Cl 100 pCO2 1.5 x 5 + 8 +/- 2 = 13.5-17.5 ( pco2 within this range) appropr comp 24 HCO3 5 Delta gap/delta bicarb = 21/9 = 1.1 - pure AGMA 8-16 BUN 36 AGMA with appropriate respiratory compensation 0.6-1.4 Cr 0.5 12 Anion Gap

8. 39 year old man with heartburn

Normal Values Case 7.35-7.45 pH 7.50 40 pCO2 50 Alkalemia. Too much tums 140 Na 141 80 - 50 = 30 = 24 x 50/37 = 32 (valid) 4 K 3.5 AG 12 100 Cl 92 pCO2 = 0.9 x 37 + 16 +/- 2 = 47-52 (pco2 in this range) - appropr comp 24 HCO3 37 Metabolic alkalosis with appropriate respiratory compensation 8-16 BUN 10 0.6-1.4 Cr 0.8 12 Anion Gap

9. Nurse gets blood gas because patient has been breathing hard for the past 3 hours.

Normal Values Case 7.35-7.45 pH 7.46 40 pCO2 30 alkalemia . acute resp alk? 140 Na 134 80-30 = 50 =/= 24x 30/22 --may not be relevant in acute resp issue AG 12 4 K 4.1 Bicarb decreases by 2 for every decrease in pCO2 by 10 100 Cl 100 40-30 = 10 so 24-1 = 23 - close enough 24 HCO3 22 Acute respiratory alkalosis 8-16 BUN 22 0.6-1.4 Cr 1.4 12 Anion Gap

Acid Base Work Book 2019

10. A 44 year old moderately dehydrated man was admitted with a two day history of acute severe diarrhea. Normal Values Case 7.35-7.45 pH 7.31 40 pCO2 33 Acidemia. Bicarb loss? 140 Na 134 80 - 31 = 49 = 24 x 33/16 = 49.5 (valid) 4 K 2.9 AG 10 NAGMA 100 Cl 108 pCO2 = 1.5 x 16 + 8 +/- 2 = 30-34 (within range) appropr comp 24 HCO3 16 NAGMA with appropriate respiratory compensation 8-16 BUN 31 0.6-1.4 Cr 1.5 12 Anion Gap

11. A 22 year old female with type I DM, presents to the emergency department with a 1 day history of nausea, vomiting, polyuria, polydypsia and vague abdominal pain. Exam noted for deep sighing breathing, orthostatic hypotension, and dry mucous membranes Normal Values Case 7.35- pH 7.27 7.45 Acidemia. ?DKA 40 pCO2 23 80-27= 53= 24 x (23/11) = 50 (valid)

AG 26 140 Na 132 pCO2 = (1.5 x 11) + 8 +/- 2 = 22.5-26.5 (pCO2 within this range) 4 K 6.0 delta gap/ delta bicarb = 1.1 100 Cl 93

24 HCO3 11 pure AGMA with appropriate respiratory compensation 8-16 BUN 38 0.6-1.4 Cr 2.6 12 Anion Gap

12. A previously well 55 year old woman is admitted with a complaint of severe vomiting for 5 days. Physical examination reveals postural hypotension, tachycardia, and diminished skin turgor. The laboratory finding include the following. Normal Values Case 7.35-7.45 pH 7.23 Acidemia. ?lactic acidosis? 40 pCO2 22 80 – 23 = 57 = 24 x 22/9 = 58 (valid) AG 54 140 Na 140 pCO2 = 1.5 x 9 +8 +/- 2 = 19.5 – 23. 5 (pCO2 within range) 4 K 3.4 delta gap/delta bicarb = 2.8 100 Cl 77 24 HCO3 9 pure AGMA with respiratory compensation with concomitant metabolic 8-16 BUN 48 alkalosis

0.6-1.4 Cr 2.1 12 Anion Gap Acid Base Work Book 2019

13. A 70 year old man with history of CHF presents with 6 days of shortness of breath and leg swelling. Normal Values Case 7.35-7.45 pH 7.30 40 pCO2 60 acidemia. 80 – 30 = 50 = 24 x 60/30 = 48 (valid) 140 Na 140 AG 9 4 K 4.0 ?Chronic? 6 days. 100 Cl 101 60 – 40 = 20. 20/10 = 2. 2 x 3.5 = 7. 24 + 7 = 31 (compensated bicarb for 24 HCO3 30 pco2 of 60) 8-16 BUN 21 Chronic respiratory acidosis with appropriate metabolic compensation 0.6-1.4 Cr 1.0 12 Anion Gap

14. A 50 year old insulin dependent diabetic woman was brought to the ED by ambulance. She was semi-comatose and had been ill for several days. Normal Values Case 7.35-7.45 pH 7.41 nl pH. Mixed? 40 pCO2 32 80 – 41 = 39 = 24 x 32/19 = 40 (valid)

AG 34 - AGMA 140 Na 132 1.5 x 19 + 8 +/- 2 = 34.5 – 38.5 (pCO2 too low) – resp alk 4 K 2.7 Delta gap/delta bicarb = 22/5 = 4.4 – met alk 100 Cl 79 AGMA with respiratory alkalosis with concomitant 24 HCO3 19 metabolic alkalosis 8-16 BUN 30

0.6-1.4 Cr 2.1 12 Anion Gap

15. A 19 year old pregnant insulin dependent diabetic patient was admitted with a history of polyuria and thirst. She now felt ill and presented to hospital. Normal Values Case Nl pH. Mixed? 7.35-7.45 pH 7.39 80-39 = 41 = 24 (16/10) = 38.4 (valid) 40 pCO2 16 AG 25 – AGMA 140 Na 136 4 K 4.8 pCO2 = 1.5 x 10 + 8 +/- 2 = 21 – 25 (pCO2 too low) – resp alk 100 Cl 101 delta gap/ delta bicarb = 13/14 = 1 – pure AGMA 24 HCO3 10 8-16 BUN 28 0.6-1.4 Cr 2.2 pure AGMA with concomitant respiratory alkalosis 12 Anion Gap Acid Base Work Book 2019

16. 72 year old woman taking oil of wintergreen, Bayer and ECASA for pain, fever, and heart. Normal Values Case Nl pH. Mixed? 7.35-7.45 pH 7.38 40 pCO2 26 80- 38 = 42 = 24 x 26/15 = 42 (valid)

140 Na 141 AG 25 – AGMA 4 K 4.0 1.5 x 15 + 8 +/- 2 = 28.5-32.5 (pCO2 too low) – resp alk 100 Cl 101 24 HCO3 15 Delta gap / delta bicarb = 13/9 = 1.4 – pure AGMA 8-16 BUN 17 0.6-1.4 Cr 0.8 AGMA with concomitant respiratory alkalosis 12 Anion Gap

17. 43 year old male with cirrhosis, gangrene of the foot, and hypotension

Normal Values Case 7.35-7.45 pH 7.41 Nl pH, mixed? 40 pCO2 21 80 – 41 = 39 = 24 x 21/13 = 39 (valid)

AG 21 – AGMA 140 Na 139 pCO2 = 1.5 x 13 + 8 +/- 2 = 25.5 – 29.5 (pCO2 too low) – resp alk 4 K 3.0 delta gap/delta bicarb = 9/11 = 0.8 (<1, high AGMA plus NAGMA) 100 Cl 105

24 HCO3 13 AGMA and NAGMA with concomitant respiratory alkalosis 8-16 BUN 6

0.6-1.4 Cr 0.6 12 Anion Gap

18. 81 year old male with renal insufficiency and longstanding COPD presenting with respiratory difficulty.

Normal Values Case Acidemia – high pCO2 and low bicarb – mixed 7.35-7.45 pH 7.19 40 pCO2 50 H+ = 40 x 1.25 x 1.25 = 62.5 = 24 (50/18) = 66 (close enough to be valid)

140 Na 137 AG 19 – AGMA 4 K 5.2 pCO2 = 1.5 x 18 + 8 +/- 2 = 33 – 37 (pcO2 too high) – resp acidosis 100 Cl 100 24 HCO3 18 AGMA plus respiratory acidosis 8-16 BUN 68 0.6-1.4 Cr 4.3 12 Anion Gap

Acid Base Work Book 2019

19. 72 year old female with CHF on diuretics. FEV1 = 1.30. Normal Values Case 7.35-7.45 pH 7.37 40 pCO2 64 Nl pH. Mixed? Diuretics - met alk? 140 Na 139 80-37 = 43 = 24 x 64/36 = 42 (valid) 4 K 3.4 AG 10 100 Cl 93 pCO2 = 0.9 x 36 + 16 +/- 2 = 46 - 50 (pco2 too high) 24 HCO3 36 respiratory acidosis with concomitant metabolic alkalosis 8-16 BUN 25 0.6-1.4 Cr 1.3 12 Anion Gap

20. 25 year old type I diabetic patient presents feeling poorly. FSBS is 650. He is given 10 units of IV insulin, then the following labs are drawn

Normal Values Case

7.35-7.45 pH 7.40

40 pCO2 40 Normal pH. mixed ? DKA? 80 - 40 = 40 = 24 x 40/25 = 38 (valid) 140 Na 140 AG 25 AGMA 4 K 5.1 pCO2 = 1.5 x 25 + 8 +/- 2 = 43-47 (pCO2 too low) - concomitant resp 100 Cl 90 alkalosis 24 HCO3 23 Delta gap/delta bicarb = 13/1 = 13 - metabolic alkalosis 8-16 BUN 25 AGMA plus metabolic alkalosis plus concomitant respiratory alkalosis

0.6-1.4 Cr 0.8

12 Anion Gap

21. 39 year old type I diabetic with ESRD has nausea and vomiting for three days. Still taking all of her meds, but little food or fluid. Receives lorazepam in ED for agitation.

Normal Values Case 7.35-7.45 pH 7.51 40 pCO2 46 Alkalemic. 140 Na 142 80-51 = 29 = 24 x 46/36 = 30 (valid) AG 17 4 K 5.1 pCO2 = 0.9 x 36 +16 +/- 2 = 46-50 pcO2 within range - resp compensation 100 Cl 89 Metabolic alkalosis with appropriate respiratory compensation and 24 HCO3 36 concomitant small anion gap metabolic acidosis 8-16 BUN 67 0.6-1.4 Cr 7.8 12 Anion Gap Acid Base Work Book 2019

22. 79 year old female with a history of pancreatic cancer status post Whipple procedure, admitted for seizure and mental status change.

Normal Values Case 7.35-7.45 pH 7.14 40 pCO2 47 Acidemia 140 Na 139 H+ = 40 x 1.25 x 1.25 x 1.25 = 78.1 = 24 x 47/13 = 86 (close enough) AG 14 baby AGMA 4 K 5.7 pCO2 = 1.5 x 13 + 8 +/- 2 = 25.5-29.5 (pCO2 too high) - concom resp acidosis 100 Cl 112 Delta gap/delta bicarb = 2/11 = 0.18 - NAGMA 24 HCO3 13 AGMA, NAGMA, with concomitant respiratory acidosis 8-16 BUN 38 0.6-1.4 Cr 2.8 12 Anion Gap

Section 2

23. 68 year old male with dilated cardiomyopathy presents with hypotension and pulmonary edema on CXR Normal Values Case 7.35-7.45 pH 7.39 40 pCO2 25 80-39 = 41 = 24 x 25/15 = 40 (valid) 140 Na 123 AG 23 (AGMA) 4 K 5.1 pCO2 = 1.5 x 15 +8 +/- 2 = 28.5-32.5, pCO2 too low (respiratory alkalosis) 100 Cl 85 delta gap/delta bicarb = 11/9 = 1.2 - pure AGMA 24 HCO3 15 AGMA with concomitant respiratory alkalosis 8-16 BUN 42 0.6-1.4 Cr 2.1 12 Anion Gap

The patient above is given 2 liters of normal saline and promptly goes into respiratory distress. He is paralyzed and intubated. The ventilator is set at AC, RR = 10. TV = 500, FIO2 = 100%. His next blood gas is: pH = 7.20 pCO2 = 40 pO2 = 320

What do you do now? Increase the RR on the vent if you want to normalize the pH - would need to target a minute ventilation to obtain pCO2 28-32 (determine by winter’s formula) Acid Base Work Book 2019

24. 18 year old male with asthma attack. Three hours of dyspnea. Respiratory rate = 36.

Normal Values Case 7.35-7.45 pH 7.52 40 pCO2 25

140 Na 140 4 K 4.0 Acute respiratory alkalosis 100 Cl 105 24 HCO3 27 8-16 BUN 10 0.6-1.4 Cr 1.0 12 Anion Gap

Forty-five minutes later, after O2 and nebulizers his respiratory rate is 38. His ABG is now pH = 7.40, pCO2 = 40, pO2 = 180. What do you do? Tiring out - intubate him

What is the most likely acid-base disorder(s) in the following examples? Give a clinical example that could cause the disturbance.

25.

Normal Values Case 7.35-7.45 pH 7.47 40 pCO2 29 80-47 = 33 = 24x 29/22 = 32 (valid) AG 12 40-29 = 11, 11/10 = 1.1, 24-1 = 23 140 Na 140 Acute respiratory alkalosis 4 K 4.0 100 Cl 106 Asthma exacerbation 24 HCO3 22 12 Anion Gap

26.

Normal Values Case 7.35-7.45 pH 7.42 80-42 = 38 = 24 x 29/19 = 37 (valid) 40 pCO2 29 AG 11 pCO2 = 1.5 x 19 + 8 +/- 2 = 34.5-38.5, pCO2 too low, resp alk NAGMA plus resp alk 140 Na 140

4 K 4.0 Diamox after falling down mountain 100 Cl 110 Cirrhotic with diarrhea from lactulose 24 HCO3 19 12 Anion Gap Acid Base Work Book 2019

27.

Normal Values Case 7.35-7.45 pH 7.26 40 pCO2 60 80-26 = 54 = 24 x 60/26 = 55 (valid) Acute respiratory acidosis 140 Na 140

4 K 4.0 Heroin OD 100 Cl 104 24 HCO3 26 12 Anion Gap

28.

Normal Values Case 7.35-7.45 pH 7.34 40 pCO2 60 80-34 = 46 = 24 x 60/30 = 48 60-40 = 20, 20/10 = 2, 2x3.5 = 7, 24+7 = 31 Chronic respiratory acidosis with chronic metabolic compensation 140 Na 140 (alkalosis) 4 K 4.0

100 Cl 100 COPD, OHS 24 HCO3 30 12 Anion Gap

29.

Normal Values Case 7.35-7.45 pH 7.44 40 pCO2 60 80 - 44 = 36 = 24 x 60/38 = 38 (valid) pCO2 = 0.9 x 38 +16 +/- 2 = 48-52 - pCO2 too high - resp acidosis 140 Na 140 4 K 4.0 Met alk with respiratory acidosis 100 Cl 95 COPD on diuretics 24 HCO3 38 12 Anion Gap

Acid Base Work Book 2019

Two patients present with the following data H+ = 61 PCO2 = 24

Patient A 140 Na 140 4 K 5.0 100 Cl 96 24 HCO3 9

Patient B 140 Na 140 4 K 5.0 100 Cl 121 24 HCO3 9

30. Based on the data presented for patient A, which one of the following diagnoses would most likely explain the lab findings?

A. Diarrhea B. Respiratory acidosis C. Ketosis

31. Based on the data presented for patient B, which one of the following diagnoses would most likely explain the lab findings?

A. Diarrhea B. Respiratory acidosis C. Ketosis

32. A 60 year old homeless man presents with nausea, vomiting and poor oral intake 2 days prior to admission. The patient reports a 3 day history of binge drinking prior to symptoms. Labs : Serum chemistry: Na 139, K 5.0, Cl 104, HCO3- 16 , BUN 25, Cr 1.3, Glu 75 ABG: pH 7.30, PCO2 29, HCO3- 16, PO2 92 Serum albumin 1.0

Does the patient have an abnormal anion gap? Yes, 19

What calculation do you need to perform? 4-1 = 3 3x 2.5 = 7.5, 12-7.5 = 4.5 - in a patient with an albumin of 1, their normal AG is 4.5 not 12

Acid Base Work Book 2019

33. A 28 year old female with history of Sjogren’s syndrome presents to her PCP for a checkup visit. She is doing well. Physical examination is unremarkable. She is noted to have the following serum chemistry: Na 138, K 4.2, Cl 108, HCO3- 18 AG 12 Because of her history, the physician decides to check her urine electrolytes. Urine chemistry: K 30, Na 75, Cl 105 UAG 0 What is the most likely diagnosis? RTA

34. A 58 year old male is admitted with a 2 day history of ______Na 138, K 3.2, Cl 108, HCO3- 18 AG 12 Because of her history, the physician decides to check her urine electrolytes. Urine chemistry: K 30, Na 100, Cl 200 UAG -70 What is the most likely diagnosis? Diarrhea

35. A suicidal auto mechanic presents with mental status changes. He has the following lab values.

Normal Values Case 7.35-7.45 pH 7.28 40 pCO2 26 80-28 = 52 = 24 x 26/12 = 52 valid AG 25 (AGMA) 140 Na 140 pCO2 = 1.5x12+8 +/- 2 = 24-28 4 K 3.9 AGMA with appropr resp compensation 100 Cl 103 delta/delta = 13/12 1.1 pure AGMA 24 HCO3 12 Calculated osm 289

8-16 BUN 10 80-100 GLUCOSE 104 12 Anion Gap

What test should you order next? Measured osm

36. 21-year-old type I diabetic discontinues insulin because of sore throat and difficulty swallowing. Which of the following is the most likely acid-base disorder to develop? a) metabolic acidosis, normal anion gap b) metabolic acidosis, increased anion gap c) acute respiratory alkalosis d) no acid-base disorder is likely to develop

37. 24-year-old asthmatic has acute onset of wheezing and nonproductive cough. Which of the following is the most likely acid-base disorder to develop? a) chronic respiratory alkalosis b) acute respiratory acidosis c) acute respiratory alkalosis Acid Base Work Book 2019 d) no acid-base disorder is likely to develop

38. 22-year-old morbidly obese patient adheres to 600 calorie diet, 2000ml water intake daily for 10 consecutive days. Which of the following is the most likely acid-base disorder to develop? a) metabolic acidosis, normal anion gap b) metabolic acidosis, increased anion gap c) acute respiratory alkalosis d) no acid-base disorder is likely to develop

39. 57-year-old male with COPD, home oxygen dependence, daily chronic sputum production, is treated with several types of metered dose inhalers. No other medications. He is in his usual state. Which of the following is the most likely acid-base disorder to be present? a) chronic respiratory alkalosis b) acute respiratory acidosis c) chronic respiratory acidosis d) no acid-base disorder is likely to develop

40. The patient described in problem 39 develops worsening respiratory failure and requires mechanical ventilation. He is placed on a ventilator with tidal volume 800 cc, 100 percent FIO2, and rate of 24/min. Arterial blood gas is performed after 30 minutes of these ventilator settings. Which of the following is the most likely acid-base disorder to be present at this time? a) acute respiratory alkalosis and metabolic alkalosis b) acute respiratory alkalosis and metabolic acidosis c) chronic respiratory acidosis d) acute respiratory alkalosis e) no acid-base disorder is likely to develop

41. 55-year-old male with ischemic cardiomyopathy, ejection fraction 25 percent receives outpatient treatment including lisinopril, digoxin, low-salt diet, furosemide 80 mg twice daily, and potassium supplement. Blood pressure is 110/ 70. He has one plus ankle edema and feels well. Serum creatinine concentration is 0.9 mg/dl. Which of the following is most likely to be present? a) chronic respiratory alkalosis related to impaired cardiac output b) metabolic alkalosis c) respiratory acidosis and metabolic acidosis related to impaired cardiac output

Acid Base Work Book 2019

Section 3

42. A 26 year old man with unknown past medical history is brought in to the ER by ambulance, after friends found him unresponsive in his apartment. He had last been seen at a party four hours prior.

Acute resp acidosis – bicarb nl, pCO2 elevated

ABG: pH 7.25 Chem 7: Na+ 137

+ PCO2 60 K 4.5

- - HCO3 26 Cl 100

- PO2 55 HCO3 25

43. A 67 year old man with diabetes and early diabetic nephropathy (without overt renal failure) presents for a routine clinic visit. He is currently asymptomatic. Because of some abnormalities on his routine blood chemistries, you elect to send him for an ABG.

AG 9 pCO2 = 1.5 x 16 + 8 +/- 2 = 30-34 NAGMA with appropriate resp compensation

ABG: pH 7.33 Chem 7: Na+ 135

+ PCO2 34 K 5.1

- - HCO3 18 Cl 110

- PO2 92 HCO3 16

Cr 1.4

44. A 68 year old woman with metastatic colon cancer presents to the ER with 1 hour of chest pain and shortness of breath. She has no known previous cardiac or pulmonary problems.

ABG: pH 7.49 Chem 7: Na+ 133

+ PCO2 28 K 3.9

- - HCO3 21 Cl 102

- PO2 52 HCO3 22 Acid Base Work Book 2019

pCO2 low with elevated pH and normal bicarb

acute respiratory alkalosis

45. A 6 year old girl with severe gastroenteritis is admitted to the hospital for fluid rehydration, and is noted to have a - high [HCO3 ] on hospital day #2. An ABG is ordered:

ABG: pH 7.47 Chem 7: Na+ 130

+ PCO2 46 K 3.2

- - HCO3 32 Cl 86

- PO2 96 HCO3 33

Elevated pH, bicarb, and pCO2 pCO2 = 0.9 x metabolic alkalosis with appropriate respiratory compensation 33 + 16 +/- 2 = 43.7- 45.7 (pCO2 within range)

46. A 75 year old man with morbid obesity is sent to the ER by his skilled nursing facility after he developed a fever of 103° and rigors 2 hours ago. In the ER he is lucid and states that he feels “terrible”, but offers no localizing symptoms. His ER vitals include a heart rate of 115, and a blood pressure of 84/46.

AG 15 – AGMA pCO2 = 1.5 x 15 + 8 +/- 2 = 30.5 – 34.5 (pCO2 too high) – resp acidosis delta gap/delta bicarb= 12/9 = 1.3 – AGMA AGMA and respiratory acidosis

ABG: pH 7.12 Chem 7: Na+ 138

+ PCO2 50 K 4.2

- - HCO3 13 Cl 99

- PO2 52 HCO3 15 Acid Base Work Book 2019

47. A 25 year old man with type I diabetes presents to the ER with 24 hours of severe nausea, vomiting, and abdominal pain.

ABG: pH 7.15 Chem 7: Na+ 138

+ PCO2 30 K 5.6

- - HCO3 10 Cl 88

- PO2 88 HCO3 11

Cr 1.1

AG 39 – AGMA pCO2 = 1.5 x 11 + 8 +/- 2 = 22.5-26.5 (pCO2 too high) – resp acidosis delta gap/delta bicarb = 27/13 = 2.1 (AGMA plus met alkalosis) AGMA plus metabolic alkalosis plus respiratory acidosis

48. A 62 year old woman with severe COPD comes to the ER complaining of increased cough and shortness of breath for - the past 12 hours. There are no baseline ABGs to compare to, however, her HCO3 measured during a routine clinic visit 3 months ago was 34 mEq/L.

ABG: pH 7.21 Chem 7: Na+ 135

+ PCO2 85 K 4.0

- - HCO3 33 Cl 90

- PO2 47 HCO3 34

AG 9

Every inc in pco2 by 10, bicarb increases by 3.5

85-40 = 45/10 = 4.5 4.5 x 3.5 = 16ish, 24+16 = 40 (if baseline pCO2 were 85, bicarb would be 40 to be compensated)

Either has chronic respiratory acidosis with chronic metabolic compensation and NOW with superimposed metabolic acidosis OR has chronic resp acidosis with chronic metabolic compensation and NOW acute respiratory acidosis (the latter fits with the clinical scenario, plus we know that her baseline bicarb was 34 from the question stem)

If bicarb is 34, change is bicarb is 10. 10/3.5 = 2.8. 2.8x 10 is 28, 40 (nl pcO2) + 28 = 68 – her baseline pcO2 is probably around 68.

Acute on chronic respiratory acidosis with a chronic compensatory metabolic alkalosis