SESSION TYPE: Physiology/PFTs/ Rehabilitation Posters
PRESENTED ON: Wednesday, October 24, 2012 at 01:30 PM - 02:30 PM
PURPOSE: Dyspnea on Exertion (DOE) is commonly encountered in clinical practice and is usually assessed by resting tests such as pulmonary function test and echo-cardiogram. These routinely performed tests for DOE evaluation can at times be non-diagnostic. Cardiopulmonary Exercise Test (CPExT) measures physiologic parameters during exercise which may accurately identify cause of dyspnea. Despite this, CPExT remains underutilized. The objective of this study was to determine the effectiveness of CPExT in determining the etiology of dyspnea in patients in whom routine evaluation had failed to reveal a cause.
METHODS: Medical records of 54 patients who underwent CPExT for dyspnea evaluation were reviewed. Age, gender and physiologic parameters obtained during CPExT including maximal /peak oxygen uptake (VO2max/peak), O2 pulse, Anaerobic threshold (AT),% predicted heart rate (%HR), Heart Rate Reserve (HRR), Work performed, Maximal respiratory rate (RRmax), Peak O2 saturation (peakO2 sat), Breathing reserve (BR), Maximal ventilation (VEmax), Maximal voluntary ventilation (MVV), Respiratory quotient (RQ), Dead space (Vd/Vt at rest and exertion), and VO2/work slope were obtained from records. The number of patients in whom CPExT was diagnostic and their specific cause of exercise-limitation was determined.
RESULTS: Of 54 patients, 22 (40%) were male. Mean age was 50±14.7 years. Duration of DOE ranged from 2 to 60 months. Mean values(%predicted) of studied parameters were as follows: Work performed 80 ± 23.5; VO2 max/peak 61.2± 21.3 ; % HR 84.2 ± 18.5; O2 Pulse 93 ±35.3; AT 52 ±14.3; MVV 83.4 ± 17.8; VEmax 65.9 + 16.3. Mean numeric values of some other studied parameters were as follows: HRR(beats/minute) 23.5 ± 34; RRmax (breaths/minute) 33.7 ± 7; PkO2 sat (%) 95 ± 2; RQ 1.08 ± 0.12; Vd/Vt (rest) 0.30 ± 0.07; Vd/Vt (exertion) 0.17 ± 0.06; VO2/Work(ml/min/watt) 9.7±3. Exercise capacity was normal with a normal VO2max in 8/54 (14%) patients complaining of DOE. Cause of DOE was determined to be obesity in 6/54(11%); deconditioning in 13/54 (24%); cardiac limitation in 5/54 (9%); respiratory limitation in 5/54 (9%). Test was sub-optimal in 16/54 (26%). No cause of DOE was found in 17/54 (33%), including those with suboptimal tests.
CONCLUSIONS: CPExT is an effective mode of evaluation of dyspnea of unclear etiology, able to determine the cause in 2/3rds of such cases.
CLINICAL IMPLICATIONS: CPExT should be performed to determine the etiology of DOE in patients in whom routine evaluation has failed to reveal a cause.
DISCLOSURE: The following authors have nothing to disclose: Anupam Kumar, D. Datta
No Product/Research Disclosure InformationUniversity of CT Health Center, Farmington, CT