RehabMove 2018: VENTILATORY THRESHOLD ASSESSMENT IN CARDIOPULMONARY EXERCISE TEST RESULTS OF PEOPLE AFTER STROKE

PURPOSE: Assessment of ventilatory threshold (VT) in people after stroke could provide valuable information for daily life participation, since VT identifies the workload below which activities can be sustained for a long period of time. This study aimed to give insight in the VT of people after stroke. The purpose was twofold: 1) to assess the inter- and intra-rater reliability of VT assessment by experienced assessors, 2) to report on VT values of sub-acute stroke patients in rehabilitation. METHODS: 59 cardiopulmonary exercise tests (CPET) from sub-acute stroke patients (14F/44M, 59±11 years, 16±56 weeks since stroke) were selected from the Heliomare database. Tests were presented in a random order to two experienced sports-physicians, who independently determined VT by a combination of the V-slope method1 and the ventilatory equivalents method, to assess inter-rater reliability. One physician repeated this sequence one week later to assess intra-rater reliability. Intra-class correlation coefficients (ICC) type 2,1 and standard error of measurement (SEM) were calculated to establish reliability for oxygen uptake values at VT (VO2-VT). If a good reliability (ICC>0.8) was established, the average values of the experienced rater were presented to describe VO2-VT in this cohort. RESULTS: VT was determined by both raters in 55/59 tests. Inter- and intra-rater reliability of VO2-VT determination were good (ICC 0.88 and 0.98, SEM 1.15 and 0.47 ml/kg/min resp.). Average VO2-VT values were 9.4±2.5 ml/kg/min, corresponding to 43.1±8.5% of peak oxygen uptake. CONCLUSION: The VT can be determined reliably for people after stroke from CPET data, by experienced raters. Relative VO2-VT values in this cohort are comparable to those reported in other cohorts of people after stroke. However, both relative and absolute VO2-VT are (very) low in comparison to the healthy population. This low VT could be limiting daily life functioning for people after stroke2.