SYMPTOMATIC BENEFIT OF SUPPLEMENTAL OXYGEN IN HYPOXEMIC PATIENTS WITH TERMINAL CANCER - THE USE OF THE N OF 1 RANDOMIZED CONTROLLED TRIAL

The symptomatic effects of oxygen on the dyspnea of terminally ill cancer patients have not been clearly established. Therefore, the decision to administer oxygen is frequently made on an individual basis. We report on the use of N of 1 randomized clinical trial to compare the symptomatic benefit of respiratory failure due to terminal ovarian cancer. A 53-yr-old female patient underwent 6 randomized double-blind crossover trials between oxygen 5 L/mm delivered by mask and air 5 L/min delivered by mask. Each treatment period lasted 5 min. The mean saturation of oxygen during the baseline period was 84% +/- 3%, versus 84% +/- 4% on air (P, NS) and 94% +/- 4% on oxygen (P < 0.001). The mean visual analogue scale (VAS) for dyspnea was 77 +/- 4 during the baseline period as compared to 51 +/- 7 after air (P < 0.001), and 40 +/- 5 after oxygen (P < 0.001). The patient and the investigator chose oxygen badly in 5 of 5 cases, air in 0 and 1 case, and no choice was made in 1 and 0 case, respectively. In 4 cases the patient considered the difference between oxygen and air to be of "much importance," and in one case to be of "moderate importance." No significant treatment, period, or interaction between period and treatment was detected for the difference in the VAS. We conclude that oxygen was significantly better than air for symptomatic improvement in the patient. The N of 1 technique is a simple and reliable method for the assessment of individual patients' response to oxygen.