Monday, May 20, 2013

Case studies electrolyte and acid-base disorder

Case 1

Mr. Frank is a 60 year-old with pneumonia. He is admitted with dyspnea, fever, and chills. His blood gas is below:
pH 7.28
CO2 56
PO2 70
HCO3 25
SaO2 89%
What is your interpretation?
  • Uncompensated respiratory acidosis

Case 2

Ms. Strauss is a 24 year-old college student. She has a history of Crohn's disease and is complaining of a four day history of bloody-watery diarrhea. A blood gas is obtained to assess her acid/base balance:
pH 7.28
CO2 43
pO2 88
HCO3 20
SaO2 96%
What is your interpretation?
  • Uncompensated metabolic alkalosis

Case 3

Mr. Karl is a 80 year-old nursing home resident admitted with urosepsis. Over the last two hours he has developed shortness of breath and is becoming confused. His ABG shows the following results:
pH 7.02
CO2 55
pO2 77
HCO3 14
SaO2 89%
What is your interpretation?
  • Combined respiratory and metabolic acidosis

Case 4

Mrs. Lauder is a thin, elderly-looking 61 year-old COPD patient. She has an ABG done as part of her routine care in the pulmonary clinic. The results are as follows:
pH 7.37
CO2 63
pO2 58
HCO3 35
SaO2 89%
What is your interpretation?
  • Fully compensated respiratory acidosis

Case 5

Ms. Steele is a 17 year-old with intractable vomiting. She has some electrolyte abnormalities, so a blood gas is obtained to assess her acid/base balance.
pH 7.50
CO2 36
pO2 92
HCO3 27
SaO2 97%
What is your interpretation?
  • Hypochloremic metabolic alkalosis (anion gap)

Case 6

Mr. Longo is a 18 year-old comatose, quadriplegic patient who has the following ABG done as part of a medical workup:
pH 7.48
CO2 22
pO2 96
HCO3 16
SaO2 98%
What is your interpretation?
  • Respiratory alkalosis with metabolic acidosis

Case 7

Mr. Casper is a 55 year-old with GERD. He takes about 15 TUMS antacid tablets a day. An ABG is obtained to assess his acid/base balance:
pH 7.46
CO2 42
pO2 86
HCO3 29
SaO2 97%
What is your interpretation?
  • Uncompensated Metabolic alkalosis 

Case 8

Mrs. Dobins is found pulseless and not breathing this morning. After a couple minutes of CPR she responds with a pulse and starts breathing on her own. A blood gas is obtained:
pH 6.89
CO2 70
pO2 42
HCO3 13
SaO2 50%
What is your interpretation?
  • Combined respiratory acidosis with metabolic acidosis

Case 9

After resuscitating Mrs. Dobins, you find Mr. Simmons to be in respiratory distress. He has a history of Type-I diabetes mellitus and is now febrile. His ABG shows:
pH 7.00
CO2 59
pO2 86
HCO3 14
SaO2 91%
What is your interpretation?
  • Combined respiratory acidosis with metabolic acidosis

Case 10

Ms. Berth was admitted for a drug overdose. She is being mechanically ventilated and a blood gas is obtained to assess her for weaning. The results are as follows:
pH 7.54
CO2 19
pO2 100
HCO3 16
SaO2 98%
What is your interpretation?
  • Respiratory alkalosis with metabolic acidosis

Case 11

Mrs. Puffer is a 35-year-old single mother, just getting off the night shift. She reports to the ED in the early morning with shortness of breath. She has cyanosis of the lips. She has had a productive cough for 2 weeks. Her temperature is 102.2, blood pressure 110/76, heart rate 108, respirations 32, rapid and shallow. Breath sounds are diminished in both bases, with coarse rhonchi in the upper lobes. Chest X-ray indicates bilateral pneumonia.
ABG results are:
pH= 7.44
PaCO2= 28
HCO3= 24
PaO2= 54

  • Compensated respiratory alkalosis

Case 12

Mr. Worried is a 52-year-old widower. He is retired and living alone. He enters the ED complaining of shortness of breath and tingling in fingers. His breathing is shallow and rapid. He denies diabetes; blood sugar is normal. There are no EKG changes. He has no significant respiratory or cardiac history. He takes several antianxiety medications. He says he has had anxiety attacks before. While being worked up for chest pain an ABG is done:
ABG results are:
pH= 7.48
PaCO2= 28
HCO3= 22
PaO2= 85

  • Uncompensated respiratory alkalosis

Case 13

Mr. Sweet, a 24-year-old DKA (diabetic ketoacidosis) patient from the ED. The medical diagnosis tells you to expect acidosis. In report you learn that his blood glucose on arrival was 780. He has been started on an insulin drip and has received one amp of bicarb. You will be doing finger stick blood sugars every hour.
ABG results are:
pH= 7.33
PaCO2= 25
HCO3=12
PaO2= 89
  • Metabolic acidosis with respiratory alkalosis

Case 14

A 24 year-old woman is found down in Pioneer Square by some bystanders. The medics are called and, upon arrival, find her with an oxygen saturation of 88% on room air and pinpoint pupils on exam. She is brought into the Harborview ER where a room air arterial blood gas is performed and reveals: pH 7.25, PCO2 60, PO2 65, HCO3 -  26. On his chemistry panel, her sodium is 137, chloride 100, bicarbonate 26.

  • Acute Uncompensated respiratory acidosis 

Case 15

A 60 year-old man with amyotrophic lateral sclerosis is brought into clinic by his family who are concerned that he is more somnolent than normal. On further history, they report that he has been having problems with morning headaches and does not feel very refreshed when he wakes up. An arterial blood gas is performed and reveals:  pH 7.37, PCO2 57, PO2 70, HCO3- 32.

  •  Chronic Compensated respiratory acidosis

Case 16

A 65 year-old man is brought into the VA hospital with complaints of severe nausea and weakness. He has had problems with peptic ulcer disease in the past and has been having similar pain for the past two weeks. Rather than see a physician about this, he opted to deal with the problem on his own and, over the past week, has been drinking significant quantities of milk and consuming large quantities of TUMS (calcium carbonate).  On his initial laboratory studies, he is found to have a calcium level of 11.5 mg/dL, a creatinine of 1.4 and bicarbonate of 35. The resident working in the ER decides to draw a room air blood gas that reveals: pH 7.45, PCO2 49, PO2 68, HCO3- 34. On his chemistry panel, the sodium is 139, chloride 95, HCO3- 34.
  • Compensated metabolic alkalosis

Case 17

A 45 year-old woman with a history of inhalant abuse presents to the emergency room complaining of dyspnea. She has an SpO2 of 99% on room air and is obviously tachypneic on exam with what appears to be Kussmaul’s respirations. A room air arterial blood gas is performed and reveals: pH 6.95, PCO2 9, PO2 128, HCO3- 2. A chemistry panel revealed sodium of 130, chloride 98, HCO3- 2.

  • Increased Anion gap metabolic acidosis with respiratory alkalosis

Case 18

A 68 year-old man with a history of very severe COPD (FEV1 ~ 1.0L,  < 25% predicted) and chronic carbon dioxide retention (Baseline PCO2 58) presents to the emergency room complaining of worsening dyspnea and an increase in the frequency and purulence of his sputum production over the past 2 days. His oxygen saturation is 78% on room air. Before he is place on supplemental oxygen, a room air arterial blood gas is drawn and reveals: pH 7.25, PCO2 68, PO2 48, HCO3-  31.

  • Respiratory acidosis with metabolic compensation

Case 19

A 47 year-old man with a history of heavy alcohol use presents with a two-day history of severe abdominal pain, nausea and vomiting. On exam, his blood pressure is 90/50 and he is markedly tender in his epigastrum. His initial laboratory studies reveal sodium of 132, chloride 92, HCO3- 16, creatinine 1.5, amylase 400 and lipase 250. A room air arterial blood gas is drawn and reveals pH 7.28, PCO2 34, PO2 88, HCO3- 16.


  • Increased anion gap metabolic acidosis with respiratory compensation

Case 20

A climber is coming down from the summit of Mt. Everest. At an altitude of 8,400 m (PB ~ 272 mmHg), he has a blood gas drawn while breathing ambient air as part of a research project. The blood gas reveals pH 7.55, PCO2 12, PO2 30 and HCO3- 10.5.


  • Respiratory alkalosis with metabolic compensation

Case 21

A 57 year-old woman presents with 2 days of fevers, dyspnea and a cough productive of rust-colored sputum. Her room air oxygen saturation in the emergency room is found to be 85% and the intern decides to obtain a room air arterial blood gas while they are waiting for the chest x-ray to be done. The blood gas reveals: pH 7.54, PCO2 25, PO2 65, HCO3- 22


  • Acute uncompensated respiratory alkalosis

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