The purposes of this study were (a) to explore associations among theoretical dimensions of dyspnea. (Intensity, Distress, Sensory Quality, and Duration) in adults with COPD who present to an emergency department (ED) with exacerbated dyspnea, and (b) to determine whether a dyspnea, measure reflecting those dimensions could predict visit disposition. A non-experimental cross- sectional design was used.
A convenience sample of patients with COPD (N = 104) participated while in the ED. The questionnaire included visual analog scales (VAS) for global Intensity and Distress, an item about exacerbation duration, and 16 Sensory Quality descriptors with numerical rating scales (NRS) for descriptor Intensity. VAS and NRS items pertained to how breathing felt when patients decided to come to the ED (DECISION) and one week before (WEEK BEFORE).
The majority (54%) reported a duration of dyspnea at DECISION of two days or less. Duration and VAS ratings were not associated with admission. Within each time frame, VAS ratings were virtually identical, reflecting only one dimension (Distress). Principal axis factor analysis of descriptor NRS; scores for DECISION resulted in three orthogonal factors with good internal consistency: (1) Smothering /Suffocation / Hunger for air (α = .87); (2) Effort / Work (α = .87); and (3) Tight / Constricted (α = .74). Concordance between time frames was low. A difference (DECISION - WEEK BEFORE) of at least four scale points for the first factor was associated with visit disposition for subjects with shorter (≤2 days) duration (Sensitivity = .67, Specificity = .64; OR = 3.6, 95% CI 1.1 to 11.8). Two clinical indicators had comparable sensitivity and specificity: initial heart rate (≤100 vs. ≥101 beats/min); and the number of nebulized bronchodilator treatments in the ED (≤1 vs. ≥2 treatments).
Results suggest that changes in sensory quality of dyspnea in the week preceding an ED visit may contribute to the perception of greater dyspnea intensity when patients with relatively brief exacerbations (≤2 days) decide to come to the ED. Numerical ratings of dyspnea descriptors were reliable, content valid, and demonstrated predictive validity in COPD patients with relatively brief exacerbations.
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