Abstract
We retrospectively reviewed the charts of 474 patients (627 visits) presenting with symptoms of hyperventilation syndrome at the emergency department of Kobe City Medical Center West Hospital between April 2004 and March 2010. The average age of the patients was 35 ± 16 years. The number of female patients (389 patients and 525 visits) was markedly higher than that of male patients (85 patients and 102 visits). Moreover, the number of visits in summer was higher than in winter, and the number of night visits was found to be higher. The patients often suffered from psychiatric disorders. F4 (neurotic, stress-related and somatoform disorders) in the International Classification of Disease 10 was confirmed in 104 patients (21.9%). Bronchial asthma was the most frequently observed physical complication and was confirmed in 64 patients (13.5%). In all, 348 patients required transportation by ambulance; these patients often developed psychiatric complications resulting in a longer stay at the emergency department. During the period of investigation, 15% of the patients revisited the emergency department for hyperventilation syndrome and developed psychiatric disorders more frequently than those who consulted the emergency department only once during this period. Furthermore, re-consultation for hyperventilation syndrome within a month was observed in 11.5% of the patients. For the purposes of treatment, paper bag rebreathing and sedative drugs were used in 19.5% and 51.4% of the patients, respectively. These patients required a significantly longer stay at the emergency department. Posthyperventilation apnea accompanied by significant decrease of SpO2 levels was observed in 5.6% of the patients; however, only 7 patients (1.1%) were hospitalized. The prognosis of hyperventilation syndrome was very good. Nevertheless, other serious diseases presenting as hyperventilation should be carefully differentiated from hyperventilation syndrome, and hypoxemia caused by posthyperventilation apnea should also be considered when treating these patients.
