Patients in acute respiratory distress require rapid assessment of the cause of dyspnea. We have observed that many of those patients who are in congestive heart failure (CHF) exhibit rounding of the abdominal cross-section during expiration. We sought to evaluate the diagnostic utility of this breathing pattern in dyspneic patients presenting to an emergency department. Twenty-six subjects with dyspnea due to a variety of conditions were recruited from the emergency department at Beth Israel Deaconess Medical Center. Subjects ranged in age from 21 to 94 years and 81% were female. We measured variation in the anteroposterior and transverse diameters of the rib cage and abdomen using respiratory magnetometers and determined phase of respiration with a pneumotachometer. Investigators blinded to the subjects' identities and diagnoses interpreted measurements as indicating normal respiratory movement without expiratory abdominal rounding, slight expiratory rounding, or pronounced expiratory rounding. The likely cause of dyspnea was determined from discharge diagnoses in the medical record. Expiratory rounding was observed in 12/14 subjects with CHF and 5/12 subjects without CHF (p = 0.0186), and pronounced expiratory rounding was present in 11/14 patients with CHF and 2/12 patients without CHF (p = 0.0016). Test characteristics for the association of CHF with pronounced expiratory rounding were sensitivity 79%, specificity 83%, and predictive accuracy 81%. In patients with acute respiratory distress, expiratory abdominal rounding suggests CHF as the primary cause of dyspnea; a greater degree of rounding suggests a greater likelihood of CHF. The clinical utility of this diagnostic sign remains to be determined in a prospective study.
