What are the underlying physiologic mechanisms that result in dyspnea?
How can a physician elicit a patient's personal description of shortness of breath in order to gain insight into the underlying diagnosis?
What physical exam findings are concerning for impending respiratory failure?
What are the key diagnostic studies a physician should order to further elucidate the cause of a patient's dyspnea?
How can the disease states associated with dyspnea be organized into a clinical framework?
A 63-year-old woman describes shortness of breath on postoperative day 3 after a hip replacement. At 3 AM, the patient starts complaining that she “can't catch her breath” and feels as though she is suffocating. she appears in acute distress upright with rapid, shallow breathing and expiratory grunting. Her blood pressure is 210/95 mm Hg with a heart rate of 120 beats per minute and an oxygen saturation of 92% while using supplemental oxygen at 6 liters/min by nasal cannula. On physical exam, auscultation of the lungs reveals rales over the lower one-third of the lung fields with dullness at the bases, as well as significant peripheral pitting edema. Since the patient has been receiving intravenous normal saline at100 cc/hour since the surgery, she is likely suffering from pulmonary edema. A chest radiograph (CXR) demonstrates increased interstitial markings and bilateral costophrenic angle blunting, which explain her clinical presentation. Increased interstitial edema activates a variety of receptors that stimulate the respiratory controller and cause air hunger, while pleural eff usions cause an increase in work of breathing by affecting the body's ventilatory pump.
The history, exam findings of hypertension, orthopnea, and rales, and the CXR findings help to confirm the diagnosis of volume overload. Other potential causes of dyspnea in an older patient who has undergone major surgery include myocardial ischemia, aspiration, and pulmonary embolism. In addition to treating congestive heart failure (CHF), it is important to seek out any underlying error that may have caused the condition and effect a system change that can improve quality of care for future patients. In the above case, indiscriminant use of maintenance fluids was the culprit; focused provider education and adjustment of existing order sets may be needed.
Dyspnea, or “shortness of breath,” is a common problem affecting up to half of patients in acute, tertiary care hospitals and one quarter of ambulatory outpatients. This sensation of breathlessness can be associated with anxiety, fear, or depression and, thereby, cause substantial disability. The American Thoracic Society consensus statement on dyspnea describes it as “an uncomfortable sensation of breathing,” which encompasses several qualitatively distinct sensations that reflect the subjective nature of the experience as well as the psychological, social, and environmental factors that contribute to the symptoms. ...