Booth, S., Kelly, M.J., Cox, N.P., Adams, L., & Guz, A. (1996). Does oxygen help dyspnea in patients with cancer? American Journal of Respiratory and Critical Care Medicine, 153(5), 1515–1518.
Oxygen and air were administered via nasal cannula at 4 liters per minute for 15 minutes to hospice patients reporting dyspnea at rest. Order of treatment was randomly determined.
The study reported on a sample of 38 patients. Forty-five patients were entered into the study, but two were excluded because of equipment failure, one becuase of cough, and four because they did not understand the use of VAS and Borg scales.
The mean age was 71 years, with a range of 54–90 years.
Sixteen patients were women, 20 had a primary diagnosis of lung cancer, two had mesothelioma, and the rest had other primary cancers with metastases to the lung. Thirteen patients had significant chronic obstructive pulmonary disease, and four had cardiac disease.
The study was conducted on two inpatient hospice units.
The study was a single-blind, randomized, placebo-controlled trial.
No significant difference in mean baseline score for VAS was observed for those receiving air first versus those receiving oxygen first.
Mean baseline VAS levels (on room air 59 mm) were significantly reduced after administration of either air (48 mm, p = < 0.001) or oxygen (45 mm, p = < 0.001).
No statistically significant difference was noted in order of treatment effect. No difference in the response to oxygen or air in patients with history of cardiopulmonary disease was observed, and the improvement in dyspnea with oxygen could not be predicted from a subject’s initial level of hypoxia.
No correlation was found between the effect of oxygen on dyspnea and oxygen saturation while on air; oxygen administration corrected hypoxemia when present.
In a qualitative subset of 28
The VAS score changed significantly from baseline with both oxygen and air in the subgroup of patients who were receiving morphine plus benzodiazepine compared to subgroups receiving morphine alone, benzodiazepine alone, or neither morphine nor benzodiazepine.
Both oxygen and air can have a significant effect in reducing dyspnea at rest in persons with advanced cancer.
The sample size was small but larger than most dyspnea studies. There was no formal washout period between the two test gases, so there may have been a carryover effect in those who received the oxygen first. Comparison of subgroups of patients on drug therapy was based on very limited numbers of subjects, and the authors' conclusion regarding usefulness of benzodiazepines to potentiate effect of oxygen is taken with caution and should be redemonstrated with a larger number of subjects.
Findings are different than the Bruera et al. (1993) study regarding the beneficial effect of oxygen for hypoxic patients.