EFFECTS OF A MANUAL BREATHING ASSIST TECHNIQUE UPON FLOW-VOLUME LOOPS IN PERSONS WITH AND WITHOUT ASTHMA. A M. Bohmiller*; E Geenty; D Aizaga; C Costello; P Nelson; S Prihoda; Lawrence P. Cahalin Physical Therapy, Northeastern University, Boston, MA PURPOSE: To examine the effects of manual breathing assist techniques (BAT) on the flow-volume loops of persons with asthma (PA) and persons without asthma (PNA). BACKGROUNDS/SIGNIFICANCE: Minimal research has been conducted on the effects of BAT upon flow-volume loops in PA and PNA. SUBJECTS: Ten PA between the ages of 21-26 were age- and gender-matched to 10 PNA. METHODS AND MATERIALS: One facilitated expiration/inspiration BAT (gentle, but progressively increasing diagonal compressive pressure on the anterior- lateral lower ribs during end expiration followed by a quick release of the compressive pressure at end-expiration) was provided in the supine position to subjects in both groups by one physical therapy student trained in BAT. Baseline measurements were taken seated after which supine measurements were taken pre-BAT, during BAT, and 5 minutes post-BAT. A Jones Spirometer using American Thoracic Society guidelines was used to measure and record the flow-volume loops. ANALYSES: Repeated measures ANOVA with post hoc analysis using Dunnett's procedure and t-tests were used to analyze the data. The level of significance was set at p<0.05. RESULTS: BAT produced several significant improvements to the flow-volume loops of PA including improvements in PIFR and PEFR/PIFR (p<0.05) that were not observed in PNA. FEF measures of PA and PNA during and after BAT were not significantly different from baseline measures. However, both PA and PNA were observed to have a significant increase in FIF25 and FIF50 during BAT (with only PNA experiencing a significant increase in FIF75). Five minutes post-BAT the PA and PNA were observed to have a significant decrease in FIF 25 and only the PA experienced a significant decrease in FIF50. CONCLUSIONS: The increase in FIF of PA and PNA during BAT is likely due to the elastic recoil of the chest wall from the quick release of the BAT compressive pressure at end-expiration. However, the BAT compressive pressure on the anterior-lateral lower ribs during end expiration appeared to have little effect upon the FEF values. Although the significant decrease in the post-BAT FIF25 of PNA is difficult to understand, the decrease in the post-BAT FIF25 and FIF50 of PA is likely due to progressive hyperinflation from the increase in FIF during BAT. The results of this study suggest that BAT has potential therapeutic utility for PA by improving PIFR, PEFR/PIFR, and several measures of FIF. However, post-BAT data suggests the possiblity of dynamic hyperinflation with subsequent reductions in inspiratory flow. A larger sample of PA and PNA should decrease the likelihood of a possible type II error in the FEF results and better clarify the effects of BAT. Further investigation is needed to determine the effects of multiple consecutive BAT maneuvers on the flow-volume loop, ventilation, and oxygen consumption, as well as to explore the effects of chronic adminstration of BAT to younger and older PA. FUNDING SOURCE: Not Applicable KEYWORDS: manual breathing assist, asthma, flow-volume loop Copyright 2009 by the American Physical Therapy Association. Requests for reprints should be directed to the corresponding author of the article. Educators, students, and other academic customers may receive permission to reprint copyrighted material from Physical Therapy (ISSN 1538-6724) by contacting the Copyright Clearance Center Inc, 222 Rosewood Dr, Danvers, MA 01923. Other types of customers who want permission to reprint should contact the APTA Editorial Office, Attn: Physical Therapy.