Thorax and Abdomen Motion Analysis in Patients with Obstructive Diseases

Objective: We evaluated changes in bronchoconstriction by a new approach based on respiratory inductive plethysmography (RIP) signal analysis. Methods: Thoracic and abdominal motions were recorded (5 min) by uncalibrated RIP in 44 adult subjects with a diagnosis of moderate bronchial obstruction (Obstructive group) and 50 healthy adult controls (Healthy group). In the Obstructive group, two series of measurements were performed before (Obstructive PRE) and after (Obstructive POST) a bronchodilation protocol. Airway resistance (Raw) and lung function data (forced vital capacity (FVC), forced expiratory volume in one second (FEV1 ) and FEV1 /FVC) were measured with a body plethysmograph. A breath-bybreath analysis was performed to calculate distances between normalized thorax and abdomen RIP signals and a mean distance (D) was calculated for each recording. Results: D and Raw were higher in the Obstructive group than in the Healthy group in both PRE and POST conditions. Both D and Raw significantly decreased after bronchodilation in the Obstructive group. D and Raw were also positively and significantly correlated in the Obstructive group in both PRE and POST conditions. Conclusion: D, as calculated from signals recorded by RIP, appears to be a useful non-invasive parameter for continuous monitoring of changes in bronchoconstriction.