SESSION TITLE: Physiology/PFTs/Rehabilitation Posters
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 30, 2013 at 01:30 PM - 02:30 PM
PURPOSE: Breathing Reserve (BR) is a parameter for evaluating ventilatory limitation to exercise during Cardiopulmonary Exercise Testing (CPET). It is obtained by subtracting Maximal Ventilation at peak exercise (VEmax) from Maximal Voluntary Ventilation (MVV). MVV used in calculating BR can be directly measured or calculated. The objective of this study was to determine if BR using calculated MVV (cMVV) correlates with BR using measured MVV (mMVV).
METHODS: We retrospectively studied 44 patients who underwent CPET for evaluation of dyspnea of unclear itiology on routine testing. Age, gender, FEV1, mMVV, VEmax, BR using mMVV and BR% using mMVV was obtained from records. MVV was calculated for each patient by multiplying FEV1 by 35. BR using cMVV (cBR) was derived by subtracting VEmax from cMVV. BR% using cMVV (cBR%) was calculated by using the formula: BR%=cMVV-VEmax/cMVV x100. Pearson's correlation coefficient (r) was calculated to determine if there was any significant correlaton between measured and calculated parameters- namely cMVV and mMVV; cBR and mBR and cBR% and mBR% respectively.
RESULTS: Of 44 patients studied, 34 were males; mean age was 52±14 years. Mean FEV1 was 2.5±0.6 L. Mean VEmax was 59±17L/min. mMVV was 94±25L; cMVV was 88±21 L (r=0.8; p<0.001). mBR was 35±16L/min; cBR was 281±6 L/min (r=0.62; p<0.001). mBR% was 36±12%; cBR% was 32±16% (r=0.64; p<0.001). These results indicate that calculated values of MVV, BR and BR% correlate well with directly measured values.
CONCLUSIONS: BR obtained by calculating MVV correlates well with BR derived by directly measuring MVV. There is no significant difference in BR obtained by calculating MVV versus directly measuring MVV.
CLINICAL IMPLICATIONS: As calculated values of MVV and BR correlate well with measured values, in patients who have difficulty performing maneuvers for measuring MVV, calculated values can be a reliable substitute.
DISCLOSURE: The following authors have nothing to disclose: Shine Raju, D. Datta
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