Respiratory regulation of acid-baseDownloads

A 60-year-old woman is brought to the emergency department by her husband because of worsening shortness of breath over the past 2 days. Last week, she had a sore throat and a low-grade fever. She has coughed up white sputum each morning for the past 2 years. She has hypertension and type 2 diabetes mellitus. She has smoked 2 packs of cigarettes daily for 35 years. Current medications include metformin and lisinopril. On examination, she occasionally has to catch her breath between sentences. Her temperature is 38.1°C (100.6°F), pulse is 85/min, respirations are 16/min, and blood pressure is 140/70 mm Hg. Expiratory wheezes with a prolonged expiratory phase are heard over both lung fields. Arterial blood gas analysis on room air shows: pH 7.33 PCO2 53 mm Hg PO2 68 mm Hg An x-ray of the chest shows hyperinflation of bilateral lung fields and flattening of the diaphragm. Which of the following additional findings is most likely in this patient?

A 39-year-old woman is brought to the emergency room by her husband because of severe dyspnea and dizziness. Her symptoms started suddenly 30 minutes ago. She appears distressed. Arterial blood gas shows a pH of 7.51, pO2 of 100 mm Hg, and a pCO2 of 30 mm Hg. Which of the following is the most likely cause?