In a client with histoplasmosis presenting with pH 7.30 and PCO2 of 58 mm Hg, which acid-base disturbance is likely?

The situation described involves a client with histoplasmosis, presenting a pH of 7.30 and a PCO2 (partial pressure of carbon dioxide) of 58 mm Hg. This combination of findings indicates an acid-base disturbance.

In this context, the pH value of 7.30 suggests acidemia, as a normal pH range is typically between 7.35 and 7.45. The elevated PCO2 of 58 mm Hg points to respiratory issues, as it indicates that there is an accumulation of carbon dioxide (CO2) in the blood, leading to an increase in carbonic acid and thus contributing to the acidity of the blood.

Respiratory acidosis occurs when the lungs cannot remove enough CO2, which leads to an increase in acidity. In cases of respiratory distress, common in conditions like histoplasmosis (a fungal infection that can affect the lungs), patients may retain CO2. Given these factors, the findings clearly indicate that the acid-base disturbance is due to respiratory acidosis.

Therefore, the identification of respiratory acidosis as the likely acid-base disturbance aligns perfectly with both the low pH and the high PCO2 values observed in the patient.