Case Vignettes in Acid-Base Balance
Case Vignettes in Acid-Base Balance
Due Saturday, March 16 th Choose three of the four vignettes and BRIEFLY answer the questions that follow.
Normal Levels of Substances in the Arterial Blood: pH 7.40 + 0.05 pCO2 (partial pressure of carbon dioxide) 40 mm Hg pO2 (partial pressure of oxygen) 90 - 100 mm Hg
Hemoglobin - O2 saturation 94 - 100 %
[HCO3-] 24 meq / liter
Vignette #1:
A 14-year-old girl with cystic fibrosis has complained of an increased cough productive of green sputum over the last week. She also complained of being increasingly short of breath, and she is noticeably wheezing on physical examination. Arterial blood was drawn and sampled, revealing the following values: pH 7.30 pCO2 50 mm Hg pO2 55 mm Hg
Hemoglobin - O2 saturation 45 %
[HCO3-] 24 meq / liter
Questions:
1. How would you classify this girl's acid-base status?
2. How does cystic fibrosis cause this acid-base imbalance?
3. How would the kidneys try to compensate for the girl's acid-base imbalance?
4. List some other causes of this type of acid-base disturbance.
Vignette #2:
A 76-year-old man complained to his wife of severe sub-sternal chest pains that radiated down the inside of his left arm. Shortly afterward, he collapsed on the living room floor. Paramedics arriving at his house just minutes later found him unresponsive, not breathing, and without a pulse. CPR and electroconvulsive shock were required to start his heart beating again. Upon arrival at the Emergency Room, the man started to regain consciousness, complaining of severe shortness of breath (dyspnea) and continued chest pain. On physical examination, his vital signs were as follows:
Systemic blood 85 mm Hg / 50 mm pressure Hg
Heart rate 175 beats / minute
Respiratory rate 32 breaths / minute
Temperature 99.2o
F
His breathing was labored, his pulses were rapid and weak everywhere, and his skin was cold and clammy. An ECG was done, revealing significant "Q" waves in most of
Due Saturday, March 16 th Choose three of the four vignettes and BRIEFLY answer the questions that follow.
Normal Levels of Substances in the Arterial Blood: pH 7.40 + 0.05 pCO2 (partial pressure of carbon dioxide) 40 mm Hg pO2 (partial pressure of oxygen) 90 - 100 mm Hg
Hemoglobin - O2 saturation 94 - 100 %
[HCO3-] 24 meq / liter
Vignette #1:
A 14-year-old girl with cystic fibrosis has complained of an increased cough productive of green sputum over the last week. She also complained of being increasingly short of breath, and she is noticeably wheezing on physical examination. Arterial blood was drawn and sampled, revealing the following values: pH 7.30 pCO2 50 mm Hg pO2 55 mm Hg
Hemoglobin - O2 saturation 45 %
[HCO3-] 24 meq / liter
Questions:
1. How would you classify this girl's acid-base status?
2. How does cystic fibrosis cause this acid-base imbalance?
3. How would the kidneys try to compensate for the girl's acid-base imbalance?
4. List some other causes of this type of acid-base disturbance.
Vignette #2:
A 76-year-old man complained to his wife of severe sub-sternal chest pains that radiated down the inside of his left arm. Shortly afterward, he collapsed on the living room floor. Paramedics arriving at his house just minutes later found him unresponsive, not breathing, and without a pulse. CPR and electroconvulsive shock were required to start his heart beating again. Upon arrival at the Emergency Room, the man started to regain consciousness, complaining of severe shortness of breath (dyspnea) and continued chest pain. On physical examination, his vital signs were as follows:
Systemic blood 85 mm Hg / 50 mm pressure Hg
Heart rate 175 beats / minute
Respiratory rate 32 breaths / minute
Temperature 99.2o
F
His breathing was labored, his pulses were rapid and weak everywhere, and his skin was cold and clammy. An ECG was done, revealing significant "Q" waves in most of