Oxygen uptake response to cycle ergometry in post-acute stroke patients with different severity of hemiparesis

The validation of oxygen uptake efficiency slope in patients with stroke

To evaluate the real aerobic capacity is difficult due to impaired limbs function in stroke patients. Oxygen uptake efficiency slope (OUES) could represent the aerobic capacity in submaximal exercise test. Hence, we designed this observational study to investigate the application of the OUES for evaluating aerobic capacity in these patients.Thirty-seven stroke patients were classified into 2 groups according to their Brunnstrom stage of affected lower limbs. Patients underwent cardiopulmonary exercise testing to assess cardiorespiratory fitness. Minute ventilation and oxygen consumption were measured, and OUES was calculated, compared with healthy reference values, and correlated with the peak oxygen consumption. The predictive validity of submaximal OUES was derived.Study participants' OUES (median 566.2 [IQR, 470.0-711.6]) was 60% of healthy reference values and correlated positively with the peak oxygen consumption (r = 0.835) (P < .01). The predictive validity of oxygen uptake efficiency slope at 50% of maximal exercise duration (OUES50) and oxygen uptake efficiency slope at 75% of maximal exercise duration (OUES75) for oxygen uptake efficiency slope at 100% of maximal exercise duration (OUES100) was 0.877 and 0.973, respectively (P < .01). The OUES50, OUES75, and OUES100 groups were not significantly different; agreement of submaximal and maximal OUES values was strong.OUES is a valuable submaximal index for evaluating cardiorespiratory fitness in stroke patients. Moderate-to-high concurrent validity of this parameter with peak oxygen consumption and the high predictive validity of OUES50 and OUES75 for OUES100 suggest maximal exercise testing in stroke patients who cannot reach maximal exercise is unnecessary.

Assessment for cardiovascular fitness in patients with stroke: which cardiopulmonary exercise testing method is better?

Background: Assessment for cardiovascular disease (CVD) is important in stroke patients, both being one of the main factors limiting success in stroke rehabilitation and its increased risk in stroke patients. Reduced exercise capacity after stroke decreases patients' functionality and further increases the risk of CVD. Carefully selected cardiopulmonary exercise testing (CPET) can be safely used to determine the risk of CVD and to prescribe exercise program in stroke rehabilitation.Objectives: The primary purpose of this study is to determine the most appropriate CPET in patients with stroke. The secondary aim is to determine the relationship between cardiorespiratory fitness and functional status of the patients.Methods: Two CPETs using treadmill and bicycle ergometer protocols determined with a preliminary study were performed on participants. The main outcome measure was VO_2peak. Patients were also evaluated according to Brunnstrom motor staging, Modified Ashworth Scale, Berg Balance Scale, and Functional Independence Measure.Results: In total, 38 patients reached higher VO_2peak values at treadmill test compared to bicycle test (p < 0.001). The mean VO₂peak reached at treadmill CPET was 62% of the control group where mean VO_2peak reached at bicycle was 76% of the control group. No significant correlation was found between Brunnstrom staging, spasticity, Berg Balance Scale, and VO_2peak .Discussion: The results of this study indicate that CPET can be performed safely in stroke patients when appropriate protocol was selected and that treadmill was more appropriate to determine cardiorespiratory fitness in this study population.

Physiological responses and perceived exertion during robot-assisted treadmill walking in non-ambulatory stroke survivors

PURPOSE

To examine physiological responses and perceived exertion during robot-assisted treadmill walking in non-ambulatory stroke survivors; compare these outcomes with aerobic exercise recommendations; and investigate the effect of robotic assistance.

MATERIALS AND METHODS

Twelve non-ambulatory stroke survivors (67 ± 11 years-old, 84 ± 38 d post-stroke) participated. Subjects walked three times 20 min (1 session/day) in the Lokomat: once with conventional exercise parameters, once with 60% robotic assistance and once with 100% robotic assistance. Gas exchange and heart rate were monitored continuously. Perceived exertion was assessed every 3 min during walking.

RESULTS

During conventional robot-assisted treadmill walking, net perceived exertion (0-14 scale) significantly increased between minute 6 (median = 2, interquartile range = 4) and 18 (median = 5, interquartile range = 4). Net physiological responses did not significantly change over time. Throughout exercise, percentage of predicted heart rate reserve was significantly below the 40% threshold (medians: 11-14%) and percentage of predicted maximum heart rate reached the 55% threshold (medians: 59-60%). Perceived exertion reached the 11-point threshold halfway. Net physiological responses and perceived exertion did not significantly differ between 60% and 100% robotic assistance.

CONCLUSIONS

The assistance level that non-ambulatory stroke survivors require at their highest tolerable walking speed seems too high to sufficiently stress the cardiorespiratory system during robot-assisted treadmill walking.Implications for rehabilitationThe exercise intensity of 20-minute conventional robot-assisted treadmill walking can be low, and might be too low to challenge the cardiorespiratory system of non-ambulatory stroke survivors.Lowering the level of robotic assistance from 100% to 60% does not seem to increase the exercise intensity of 20-minute robot-assisted treadmill walking.

Early functional improvement after stroke correlates with cardiovascular fitness

Cardiovascular fitness exerts directly beneficial effects on functional and cognitive outcomes in patients of chronic stroke. However, the effect of early rehabilitation on cardiovascular function has not yet been thoroughly examined. We tested whether complementary rehabilitation program could influence cardiovascular fitness in an early stage of stroke patients. The associations for post-acute stroke functional recovery with cardiovascular fitness were explored. Thirty-seven patients with mean poststroke interval of 8.6 ± 3.8 days underwent inpatient rehabilitation of 22.8 ± 3.8 days. Functional outcomes of 15.3 points (17.2%) in functional independence measure improved after rehabilitation program. The therapeutic cardiovascular fitness was determined in ramp exercise test on a cycling ergometer. Peak oxygen uptake (V˙O_2peak) significantly increased by 24.8% after early stroke rehabilitation. Multivariate regression analysis was performed to assess for associations of functional improvement with respect to change in V˙O_2peak and extremities motor impairment. V˙O_2peak gain accounted for more functional recovery than extremities motor improvement (R² = 0.42). In conclusion, these results suggest that cardiovascular fitness appears to increase after complementary program in early stroke rehabilitation, and better cardiovascular fitness may be associated with greater functional improvement.

Optimizing a Treadmill Ramp Protocol to Evaluate Aerobic Capacity of Hemiparetic Poststroke Patients

Bernardes, WL, Montenegro, RA, Monteiro, WD, de Almeida Freire, R, Massaferri, R, and Farinatti, P. Optimizing a treadmill ramp protocol to evaluate aerobic capacity of hemiparetic poststroke patients. J Strength Cond Res 32(3): 876-884, 2018-A correct assessment of cardiopulmonary capacity is important for aerobic training within motor rehabilitation of poststroke hemiparetic patients (PSHPs). However, specific cardiopulmonary exercise testing (CPET) for these patients are scarce. We proposed adaptations in a protocol originally developed for PSHPs by Ovando et al. (CPET1). We hypothesized that our adapted protocol (CPET2) would improve the original test, by preventing early fatigue and increasing patients' peak performance. Eleven PSHPs (52 ± 14 years, 10 men) performed both protocols. CPET2 integrated changes in final speed (100-120% vs. 140% maximal speed in 10-m walking test), treadmill inclination (final inclination of 5 vs. 10%), and estimated test duration (10 vs. 8 minutes) to smooth the rate of workload increment of CPET1. Peak oxygen uptake (V[Combining Dot Above]O2peak) (20.3 ± 6.1 vs. 18.6 ± 5.0 ml·kg·min; p = 0.04), V[Combining Dot Above]O2 at gas exchange transition (V[Combining Dot Above]O2-GET) (11.5 ± 2.9 vs. 9.8 ± 2.0 ml·kg·min; p = 0.04), and time to exhaustion (10 ± 3 vs. 6 ± 2 minutes; p < 0.001) were higher in CPET2 than in CPET1. Slopes and intercepts of regressions describing relationships between V[Combining Dot Above]O2 vs. workload, heart rate vs. workload, and V[Combining Dot Above]O2 vs. heart rate were similar between CPETs. However, standard errors of estimates obtained for regressions between heart rate vs. workload (3.0 ± 1.3 vs. 3.8 ± 1.0 b·min; p = 0.004) and V[Combining Dot Above]O2 vs. heart rate (6.0 ± 2.1 vs. 4.8 ± 2.4 ml·kg·min; p = 0.05) were lower in CPET2 than in CPET1. In conclusion, the present adaptations in Ovando's CPET protocol increased exercise tolerance of PSHPs, eliciting higher V[Combining Dot Above]O2peak and V[Combining Dot Above]O2-GET, preventing earlier fatigue, and providing better physiological relationships along submaximal workloads.

Biliary stenting for unresectable cholangiocarcinoma: A population-based study of long-term outcomes and hospital costs in Taiwan

Few studies have compared percutaneous biliary stenting (PBS) and endoscopic biliary stenting (EBS) in terms of long-term effects on cholangiocarcinoma (CC), and few have systematically evaluated outcome associations in Taiwan. This study aimed to compare long-term outcomes between two treatments for unresectable CC: PBS and EBS. After propensity score matching (PSM) to reduce the effect of selection bias, 1002 CC patients were included in this analysis: 501 in the PBS group and 501 in the EBS group. The Kaplan-Meier method was used to construct the survival curve for all CC patients, and the Cox proportional hazards model was used for multivariate assessment of outcome predictors. After PSM, group comparisons revealed a significantly longer length of stay in the PBS group compared to the EBS group (25 days vs. 19 days, respectively; p < 0.001). Hospital costs were also significantly higher in the PBS group than in the EBS group (US$126,575 vs. US$89,326, respectively; p < 0.001). The median survival time was 3.7 months in all CC patients, 3.5 months in the PBS group, and 4.0 months in the EBS group. The 1-year, 3-year, and 5-year survival rates were 17.6%, 6.1%, and 3.2% in all CC patients; 16.6%, 4.8%, and 3.2% in the PBS group; and 18.6%, 7.27%, and 3% in the EBS group, respectively. The most important predictor of survival is extrahepatic CC. Medical professionals and healthcare providers should carefully consider the use of EBS for initial treatment of obstructive jaundice in patients with unresectable CC.