COMPARISON OF BREATHING RESERVE OBTAINED FROM MEASURED AND ESTIMATED MAXIMAL VOLUNTARY VENTILATION IN CARDIOPULMONARY EXERCISE TESTING

Abstract

SESSION TITLE: Pulmonary Physiology SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2018 01:00 PM - 02:00 PM PURPOSE: Breathing Reserve (BR) which is an indicator of ventilatory limitation to exercise during Cardiopulmonary Exercise Testing (CPET), is the difference between Maximal Voluntary Ventilation (MVV) and maximal ventilation at peak exercise (VEmax). MVV used in calculating BR can be directly measured or calculated. The objective of this study was to determine if BR and BR% derived from calculated MVV (cMVV) correlate with BR and BR% derived from measured MVV (mMVV). METHODS: We retrospectively studied 121 patients who underwent CPET for evaluation of dyspnea. Age, gender, mMVV, VEmax, BR using mMVV and BR% using mMVV were 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. Calculated BR% using cMVV (cBR%) was calculated by using the formula: BR% = cMVV-VEmax/cMVV x100. Pearson’s correlation analysis was performed to determine if there was any significant difference between, respectively, cBR% and mBR%. Standard error of estimate was determined to assess agreement between measured and calculated values of BR%. RESULTS: Of 121 patients studied, 62% were males; mean age was 54+14.6 years. Mean VEmax was 62.52+17.8 L/min; mean cMVV was 89.7+27 L/min. Mean mBR was 32.2+17; mean cBR was 27+27.5. Mean BR% was 32+1. Mean cBR% was 24+34%. The results of Pearson’s correlation analysis were as follows: cMVV vs. mMVV: r= 0.43; p <0.001;cBR vs. mBR: r= 0.471; p <0.001; cBR% vs. mBR%: r= 0.53; p <0.001 Standard error of estimate of measured and calculated values of BR% was 0.24, which is quite low and indicates that the calculated BR% is an accurate representation of measured BR%. CONCLUSIONS: There is significant correlation between cMVV and mMVV. BR obtained from calculated MVV also strongly correlates to BR derived from directly measured MVV. CLINICAL IMPLICATIONS: During CPET, MVV may not need to be measured as calculated values correlate well with measured values. This will make CPET less labor-intensive for both the patient and test personnel. DISCLOSURES: No relevant relationships by Debapriya Datta, source=Web Response no disclosure on file for Talal Kaiser; No relevant relationships by Sophie Korzan, source=Web Response No relevant relationships by Nancy McLellan, source=Web Response No relevant relationships by Aniket Sharma, source=Web Response