COX-2: a link between airway inflammation and disordered chloride secretion in cystic fibrosis?

9 By the end of the training programme, the duration of a constant work rate treadmill task was increased by 79% in patients receiving bronchodilator treatment compared with those receiving placebo. Finally, in this issue of Thorax, Peters et al report that 50% oxygen breathing acts synergistically with bronchodilator therapy (ipratropium bromide) to reduce hyperinflation and improve exercise tolerance in patients with COPD. 10 In a crossover study in 16 patients, the mean tolerance of a constant work rate increased by 57% and 31% when inhaling oxygen or receiving bronchodilator, respectively. The combination of oxygen and ipratropium increased exercise tolerance by an average of 87% over the control condition, demonstrating an approximately additive response. The mathematically inclined among us will note that only four of six possible permutations of these four interventions have so far been reported. The successful combinations of heliox with exercise training and of bronchodilators with heliox are waiting to be achieved. Further, can studies of the simultaneous application of three interventions be far behind? Four studies of this kind could be planned, the requirement being the necessity to prove the superiority of the exercise tolerance improvements in response to three interventions over that of three groups in which combinations of two of the three interventions are applied. Will we see the day when a study appears in which simultaneous application of all four of these physiological manoeuvres are combined to ameliorate exercise intolerance and are proved to be superior to three groups in which three of the four interventions are given? One can only dream. 1 Somfay A, Porszasz J, Lee SM, et al. Dose-response effect of oxygen on hyperinflation and exercise endurance in non-hypoxemic COPD patients. Effect of heliox on lung dynamic hyperinflation, dyspnea and exercise endurance capacity in COPD patients. Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients. 7 Casaburi R. Factors determining constant work rate exercise tolerance in COPD and their role in dictating the minimal clinically important difference in response to interventions. The effect of helium and oxygen on exercise performance in COPD: a randomised crossover trial. Improvement in exercise tolerance with the combination of tiotropium and pulmonary rehabilitation in patients with COPD. L ung disease in cystic fibrosis (CF) continues to be the major cause of morbidity and mortality, with the mechanisms whereby the biochemical defect causes lung disease receiving considerable attention. CF is caused …