Answers to the ABG Practice Examples:

1. Mr. Frank has an uncompensated respiratory acidosis with hypoxemia as a result of his pneumonia. This is due to inadequate ventilation and perfusion. The treatment goals for Mr. Frank would be to improve both ventilation and oxygenation. Ventilation may improve with the use of bronchodilators and pulmonary hygiene. If not, Mr. Frank may require CPAP, BiPAP, or intubation and mechanical ventilation. Oxygen therapy should consist of only the minimal amount necessary to increase his oxygen saturation to normal (95%).

2. Ms. Strauss has an uncompensated metabolic acidosis. This is due to excessive bicarbonate loss from her diarrhea. It is interesting to note that she has no compensation. Normally, the respiratory center compensates quickly for metabolic disorders. However, in Ms. Strauss' case she would have to hyperventilate in order to compensate. This may not be possible in her present condition, and should be evaluated further. Treatment would consist of control of the diarrhea and bowel rest. It should not be necessary to administer bicarbonate in her present condition.

3. Mr. Karl has a metabolic and respiratory acidosis with hypoxemia. The metabolic acidosis is caused by his sepsis. The respiratory acidosis is secondary to respiratory failure. This presentation of sepsis and associated respiratory failure is consistent with ARDS. Treatment must be aggressive, because his acidosis is severe. His respiratory status needs to be stabilized, and would probably require mechanical ventilation. If hypotension exists, aggressive fluid and vasopressor support would be warranted. This patient is at high risk for further complications and should be managed in an ICU. Bicarbonate should not be administered until the underlying sepsis and respiratory failure is treated.

4. Mrs. Lauder has a fully-compensated respiratory acidosis with hypoxemia. Full compensation is evidenced by the normal pH in spite of her acid/base disorder. This is her baseline and doesn't require treatment.

5. Ms. Steele has an uncompensated metabolic alkalosis. This is due to vomiting that results in excessive loss of stomach acid. Treatment consists of fluids, anti-emetics, and management of her electrolyte disorders.

6. As a result of his neurologic condition, Mr. Longo has chronic hyperventilation syndrom. His blood gas shows a fully-compensated respiratory alkalosis. This is a chronic and stable condition for him and probably requires no treatment.

7. Mr. Casper has overmedicated himself with TUMS, effectively absorbing too much stomach acid. His ABG shows a partially-compensated metabolic alkalosis. Treatment consists of better control of his GERD, possibly with H2-blockers (Pepcid®) or proton-pump inhibitors (Prilosec®).

8. Mrs. Dobins has a severe metabolic and respiratory acidosis with hypoxemia. The metabolic component comes from her decreased perfusion, and the respiratory component comes from inadequate ventilation. Treatment would consist of intubation, mechanical ventilation, blood pressure and circulatory support.

9. Wow, Mr. Simmons too! He, like Mrs. Dobbins, has a metabolic and respiratory acidosis with hypoxemia. However, the cause is different. His respiratory acidosis is probably the result of pneumonia (also causing the fever). His pneumonia has altered his glucose metabolism, causing hyperglycemia and diabetic ketoacidosis. Treatment should be three-pronged: 1) increase his oxygenation with oxygen therapy; CPAP, BiPAP, or mechanical ventilation, 2) treat his pneumonia with antibiotics, antipyretics, and good pulmonary hygiene, and 3) administer insulin and IV fluids to decrease his blood glucose and treat his DKA.

10. Mrs. Berth is being overventilated which caused a partially-compensated respiratory alkalosis. Treatment would consist of decreasing ventilatory support, or trying other modes of ventilation to decrease her minute volume. She will be difficult to wean from the ventilator in this condition due to the metabolic compensation. Therefore attempts should be made to allow her CO2 to increase back to normal before weaning can proceed.

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