Paroxysmal Nocturnal Dyspnea
and other irregular respiratory rates

Abnormal respiratory rates, such as paroxysmal nocturnal dyspnea, are among the first things a physician assesses during examination of the lungs. A pulmonary exam requires comparison of the findings on both sides of the chest. The examiner first inspects movements of chest to confirm the estimate of the patient’s respiratory rate when the vital signs’ examination was performed, and carefully observes the pattern of breathing (the rate, the rhythm and the depth).

  • Tachypnea is rapid breathing, usually greater than 25 breaths per minute.

  • Bradypnea is slow breathing, usually less than 8 breaths per minute.

  • Hyperpnea is deep breathing.

  • Hypopnea is shallow breathing

  • Apnea is lack of breathing over 20 seconds in an awake patient or 30 seconds in a sleeping patient.

  • Orthopnea is difficulty in breathing when one assumes the recumbent position and improvement on sitting up – often seen in left heart failure as well as in lung disease.

  • Paroxysmal nocturnal dyspnea (PND) is severe shortness of breath while sleeping requiring the patient to rise up and seek more air as by opening a window. It is seen in patients with left heart failure.

  • Platypnea is difficulty in breathing in the upright position, which improves when the patient lies down. It may be seen in patients with cirrhosis of the liver.Orthodeoxia is a decrease in arterial oxygen saturation in the upright position, which improves in the recumbent position. It may be seen in cirrhosis of the liver.

  • Trepopnea is difficulty breathing when lying in the one lateral decubitus position and with improvement in the upright or recumbent positions. It may be seen in unilateral lung disease, congestive heart failure from a dilated cardiomyopathy, or an endobronchial or mediastinal tumor.

  • Paradoxical respiration is characterized by the abdomen falling on inspiration where normally the abdomen would rise with the chest on inspiration. It is often a sign of diaphragmatic abnormality.

  • Cheyne-Stokes breathing is a form of breathing wherein periods of apnea are punctuated with periods of crescendo-decrescendo alterations in breathing. It has multiple causes including congestive heart failure.

  • Biot’s breathing is a form of breathing wherein short periods of rapid shallow breathing alternate with periods of apnea. It is often present in patients with meningitis or increased intracranial pressure.

  • Kussmal’s breathing is a form of breathing that is rapid and deep. It occurs in patients with metabolic acidosis, especially diabetic ketoacidosis.

    Return to Dypsnea

    Return to Human Respiratory System

    Return from Paroxysmal Nocturnal Dyspnea to Medical Exam Essentials homepage


  • Don’t Miss
    A Primer in Adult
    Physical Diagnosis

    With a 30-Day Money Back Guarantee, there is no risk involved in trying this handy new eBook.

    Download the PDF now and start mastering the skills necessary for Physical Diagnosis.


    Sign up for Periodic Site Updates

    Add your name and e-mail address, and we’ll send you periodic site updates when we add other valuable documents for Medical Students.