Q. A 60-year-old man presents to the emergency department with worsening shortness of breath and chest tightness from the morning. He has had a history of chronic pulmonary disease (COPD) for the past 8 years. His temperature is 98.6°F ( 37°C), pulse is 90 beats per minute, blood pressure is 140/90 mmHg while he is breathing quietly and respiratory rate is 20 per minute. However, during inspiration, his blood pressure drops to 120/80 mmHg. He appears anxious and is using accessory muscles to breathe. On physical examination, widespread, high-pitched, musical wheezes were heard all over the lung fields with normal heart sounds. What is the most likely explanation for this patient’s drop in blood pressure during inspiration?