NREMT Paramedic Exam 2025 – 400 Free Practice Questions to Pass the Exam

Paroxysmal nocturnal dyspnea is a sudden episode of shortness of breath that occurs during the night, often causing the individual to wake up gasping for air. The primary mechanism behind this phenomenon is associated with fluid overload in the lungs, which frequently occurs due to left-sided heart failure.

In left-sided heart failure, the heart's inability to pump blood effectively leads to increased pressure in the pulmonary circulation. This results in the accumulation of fluid in the pulmonary interstitial spaces and alveoli, especially when the patient is in a supine position during sleep. This fluid accumulation triggers the sensation of dyspnea, making it difficult for the person to breathe comfortably while lying flat.

Other conditions, such as asthma, chronic kidney disease, or pulmonary embolism, can cause dyspnea but are less commonly associated with the classic presentation of paroxysmal nocturnal dyspnea. In chronic kidney disease, fluid overload can also occur, but it does not typically present specifically as episodes during the night. Asthma is characterized by bronchoconstriction and wheezing rather than fluid excess, and while pulmonary embolism may cause dyspnea, it usually does not present in this episodic nocturnal manner. The distinct night-time episodes