Association Between Respiratory Muscle Performance and Functional Capacity in Patients With Primary Stage IIIb & IV Lung Cancer

Background and Purpose: Respiratory muscle function is important in sustaining the levels of physical activity required for daily life. The purpose of our study is to investigate the association between respiratory muscle performance, functional capacity, dyspnea, anxiety/depression symptom, 1-year respiratory morbidity rate, and 1-year mortality in patients with primary stage IIIb and IV lung cancer.

Methods: A total of 120 patients with newly diagnosed primary stage IIIb and IV lung cancer will be recruited from the National Taiwan University Hospital. Demographic and clinical signs/syndromes will be obtained from the chart. Pain and dyspnea will be measured using visual analog scale. Respiratory muscle strength will be tested by measuring maximal inspiratory and expiratory pressure (PImax and PEmax, respectively). Spirometric variables, forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) will be measured. Functional capacity will be measured using Karnofsky performance status and Simmonds functional assessment. Anxiety/depression symptom will be measured using Hospital Anxiety and Depression Scale. One year respiratory complication morbidity and 1-year mortality will be recorded in prospective nature. Spearman's and Pearson correlation coefficient will be used to test the relationship between respiratory muscle performance and multiple variables. Univariate and stepwise multiple regression analyses will be used to identify factors associated with respiratory muscle performance, functional capacity, one-year respiratory morbidity and one-year mortality rate in patients with primary stage IIIb and IV lung cancer.

Clinical relevance: The prevalence of lung cancer is increasing in the recent years. The attempt to understand the relations between respiratory muscle performance, functional capacity and associated clinical courses will shed light on whether chest physical therapy intervention will be beneficial for patients with primary IIIb and IV lung cancer.