Dimensions of dyspnea in lung cancer

Dyspnea is a subjective symptom with a sensory component of labored breathing and an affective reaction expressed as distress. The purpose of this study was to characterize the dimensions of dyspnea from the perspective of a sample of individuals with lung cancer. The aims of the study were (a) to explore qualitatively and quantitatively the dimensions of Breathing Effort and Breathing Distress; (b) to examine the relationships among Breathing Effort and Distress and functional health; and (c) to examine the influence of individual factors on Breathing Effort and Breathing Distress. Thirty-seven outpatients with a diagnosis of advanced or locally advanced lung cancer who reported Level 2 or higher on the Medical Research Council dyspnea scale were enrolled. Participants underwent one assessment completing 1) separate visual analog scales for Breathing Effort and Breathing Distress at three temporal perspectives 2) The Medical Outcomes Survey (SF-36v2), and 3) the State Trait Anxiety Inventory. The initial 30 participants underwent semistructured interviews. Results show that individuals with lung cancer related dyspnea discriminated between Breathing Effort and Breathing Distress. The dyspnea dimensions occurred along a continuum. Unique and shared characteristics of Breathing Effort and Distress were generated. When participants were separated into those experiencing high («= 15) and low (n=\5) Breathing Effort, the high Breathing Effort group reported significantly higher Breathing Distress on all 3 measures (range of t values: 2.40 - 4.84,/? <.02). Breathing Effort was a contributor to decreased physical component of functional health (7?2 =.16). Breathing Distress had no impact on functional health. There were significant associations among two variables (opioid use and state anxiety) with respective Breathing Effort and Distress measures. State anxiety and opioid use were significant predictors, Accounting;; for 28% of the variance in Breathing Effort. Opioid use was the sole predictor, Accounting;; for 16% of the variance of Breathing Distress. The participants taking opioids (n = 9) reported less dyspnea (p = .01) than the group not taking opioids. Trait anxiety was not significantly associated with either breathing dimension. This study's findings provide information to further explain the subjective dyspnea experience and define factors associated with dyspnea in lung cancer.