Q70) A 40-year-old man presents to your office for regular follow up. He has history of hypertension for which he has been on Hydrochlorthiazide and Lisinopril. Lately, his blood pressure has not been well controlled and this has been documented both in the office and outside during several visits. The patient says he has had increasing fatigue and irritability over the last few months and has difficulty concentrating at work. He thinks his boss has never been supportive and he attributes his irritability to this. He has smoked 2 packs of cigarettes per day for the past 15 years. On physical examination he is a obese male with a neck circumference of 18 inches. He has a ruddy complexion. His vitals reveal a HR of 90 and a BP of 152/92. Reminder of the physical exam is normal. EKG reveal changes consistent with long standing hypertension. A CBC, electrolyes and creatinine are normal. Which of the following is the most important investigation that can identify the cause of his uncontrolled hypertension?
( A ) Ambulatory blood pressure monitoring
( B ) Pulmonary function studies
( C ) Polysomnography
( D ) Arterial blood gases
(E) Urine drug screen