Re-evaluation of Mist Therapy in Children with Cystic Fibrosis Using Maximum Expiratory Flow-volume Curves

Abstract

The measurement of maximum expiratory flow rates (Vmax) on MEFV curves is a simple yet sensitive method for detecting peripheral airway obstruction. In order to re-examine the efficacy of mist therapy (MT) in cystic fibrosis, MEFV curves as well as vital capacity (VC) and timed vital capacity (FEV1.0) were measured in 16 patients every two weeks for a period of 4 to 5 months. In half of the patients, all of whom had been in mist tents at night for at least 6 months, the studies were done during an initial 8 to 12 week period out of mist and then a similar period in mist; in the other half the test conditions were reversed. The results were expressed as percent of predicted values. During the period without MT, 4 patients improved and 2 worsened as indicated by changes in all 4 parameters studied. As a group, FEV1.0 was significantly (p<0.025) better when they were without MT. VC and Vmax at 25% VC and 50% VC were also closer to normal without MT but the difference was not signifant. Thus, these studies failed to show any beneficial effect of mist therapy in cystic fibrosis. (Supported by PHS HD00989, NCFRF and the state of Conn.)