Respiratory Dysfunction in Individuals With Thoracic Outlet Syndrome

The purpose of this study was to compare pulmonary function and respiratory muscle strength and endurance in individuals with thoracic outlet syndrome (TOS) and healthy participants. Sixty-two individuals with TOS (mean age 30.81 ± 10.69 years; 10 male, 52 female) and 47 healthy individuals (mean age 30.64 ± 9.16 years; 14 male, 33 female) participated in this study. Pulmonary function testing was performed using a spirometer. Respiratory muscle strength (maximal inspiratory pressure [MIP] and maximal expiratory pressure [MEP]) were measured using a mouth pressure device. Respiratory muscle endurance was tested at 35% MIP and measured as the time in seconds from the start of the test to voluntary exhaustion. Age distribution and physical characteristics were similar between the groups (P > .05). All pulmonary function parameters except for peak expiratory flow rate were similar in patients with TOS and healthy controls (P > .05). Patients with TOS had significantly lower peak expiratory flow rate, MIP, MIP%, MEP, MEP%, and respiratory muscle endurance compared with controls (P < .05). Forty-six patients with TOS (74.2%) had MIP values below the lower limit of the 95% CI of the control group (97.05-113.88 cmH2O), and 53 patients with TOS (85.2%) had MEP values below the lower limit of the 95% CI of the control group (124.74-146.49 cmH2O). Expiratory flow rate and respiratory muscle strength and endurance may be adversely affected in TOS. Trunk muscles perform both postural and breathing functions. Therefore, disruption in one function may negatively affect the other.