Dyspnea in hospitalized advanced cancer patients: subjective and physiologic correlates.

BACKGROUND AND
OBJECTIVE: It is unclear if physiologic measures are useful for assessing dyspnea. We examined the association among the subjective rating of dyspnea according to patients with advanced cancer, caregivers and nurses, and various physiologic measures.
METHODS: We conducted a cross-sectional survey of patients with cancer hospitalized at MD Anderson Cancer Center. We asked patients, caregivers, and nurses to assess the patients' dyspnea at the time of study enrollment independently using a numeric rating scale (0=none, 10=worst). Edmonton Symptom Assessment Scale (ESAS) ratings, causes of dyspnea, vitals, and Respiratory Distress Observation Scale [RDOS] ratings were collected.
RESULTS: A total of 299 patients were enrolled in the study: average age 62 (range 20-98), female 47%, lung cancer 37%, and oxygen use 57%. The median RDOS rating was 2/16 (interquartile range 1-3) and the number of potential causes was 3 (range 2-4), with pleural effusion (n=166, 56%), pneumonia (n=144, 48%), and lung metastasis (n=125, 42%) being the most common. The median intensity of patients' dyspnea at the time of assessment was 3 (interquartile range 0-6) for patients, 4 (interquartile range 1-6) for caregivers, and 2 (interquartile range 0-3) for bedside nurses. Patients' expression of dyspnea correlated moderately with caregivers' (r=0.68, p<0.001) and nurses' (r=0.50, p<0.001) assessments, and weakly with RDOS (r=0.35, p<0.001), oxygen level (r=0.32, p<0.001), and the number of potential causes (r=0.19, p=0.001). In multivariate analysis, patients' dyspnea was only independently associated with ESAS dyspnea (p=0.002) and dyspnea as assessed by caregivers (p<0.001).
CONCLUSION: Patients' level of dyspnea was weakly associated with physiologic measures. Caregivers' perception may be a useful surrogate for dyspnea assessment.