Ambulatory monitoring of respiration in anxiety.

An ambulatory monitor, body suit, and calibration procedure were developed to compare the respiration of seven patients with panic disorder and twelve normal volunteers. Subjects wore a body suit with Respitrace bands, connected to a portable respiratory monitor for a period of 24 hours. Breath by breath values for respiratory rate and tidal volume were computed every two minutes. There was a significant difference between patients and controls in their patterns of minute ventilation during sleep. Tidal volume, rather that respiratory rate increases characterized the periods of anxiety and limited symptom attacks.