Final answer:
Bob's arterial blood gases suggest respiratory acidosis with renal compensation. This condition is typically associated with a retention of CO2 due to obstructive pulmonary disease, such as asthma, leading to increased blood carbonic acid levels and a compensatory rise in bicarbonate.
Step-by-step explanation:
The subject of the question relates to Medicine, particularly focusing on the interpretation of arterial blood gases (ABGs) and the understanding of acid-base balance in the context of pulmonary function. In the scenario provided, Bob, a 64-year-old patient with asthma, has altered ABG results. His arterial blood gas shows a pH of 7.31, indicating a lower-than-normal pH (normal range is 7.35-7.45), a pCO2 level higher than normal (suggesting hypoventilation), and an elevated bicarbonate level (HCO3−). This combination is consistent with respiratory acidosis, as it indicates an accumulation of CO2, which forms carbonic acid in the blood. The elevated bicarbonate suggests that renal compensation is occurring, with the kidneys attempting to preserve acid-base balance by retaining bicarbonate. In cases of asthma, airway obstruction and decreased gas exchange lead to the retention of CO2 and subsequent respiratory acidosis.