Oxygen Desaturation and Persistence of Symptoms During Activities of Daily Living in Patients Following Hospital Discharge for COVID-19.

BACKGROUND: COVID-19 can cause respiratory and multisystemic impairments, which lead to impaired activities of daily living (ADL). Telemonitoring after discharge from the hospital may help identify the persistence of such limitations during ADLs simulations. The aim of this study was to compare SpO2 , fatigue, and dyspnea through telemonitoring during a battery of 4 ADLs in patients following hospital discharge for COVID-19. METHODS: An observational cross-sectional study was conducted by using teleconferencing for patients 30 d after hospital discharge for COVID-19. The subjects were assessed and performed a simulated ADL battery (ie, walking, bathing and dressing, floor sweeping, and folding towels). SpO2 , fatigue, and dyspnea were monitored immediately after the end of each ADL; also, the subjects were asked to show the pulse oximeter on camera and grade their symptoms by using the Borg scale score (0-10). RESULTS: Sixty-six subjects were evaluated, all of whom were normoxic at rest. No significant difference in SpO2 was found among the ADLs. A portion of the subjects experienced desaturation on at least 1 ADL, which allowed subject grouping into the desaturated group, with highest portion of subjects who desaturated found during the walking task (18%), and the non-desaturated group. The subjects who desaturated were found to have more cardiovascular diseases (P = .031) and diabetes mellitus (P = .005) compared with those who did not desaturate. Both groups experienced mild symptoms; however, a percentage of the subjects with desaturation presented moderate-to-intense symptoms, with higher fatigue scores during walking, bathing and dressing, and floor sweeping. Increased dyspnea was also found during walking and during bathing and dressing in the subjects with desaturation. CONCLUSIONS: SpO2 was similar among the ADLs but walking triggered desaturation in a larger number of subjects. The subjects presented with mild-to-intense fatigue and dyspnea during ADLs 30 d after discharge after hospitalization for COVID-19 regardless of desaturation status, which demonstrated that the persistence of symptoms is independent of hypoxemia during exercise.

Respiratory and peripheral muscle strength influence recovery of exercise capacity after severe exacerbation of COPD? An observational prospective cohort study.

BACKGROUND: Patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) have decreased exercise tolerance, which may persist for months. In this context, little is known about the associations between muscle strength and recovery of exercise capacity. OBJECTIVE: To assess whether respiratory and peripheral muscle strength influence recovery of exercise capacity in patients hospitalized due to AECOPD. METHODS: Twenty-seven AECOPD patients (aged 69 ± 7 years, 56% male) were included. The following assessments were performed within 24 to 72 h of hospital admission: (i) respiratory muscle strength, measured by maximal inspiratory and expiratory pressures (MIP and MEP); (ii) peripheral muscle strength, assessed by handgrip and quadriceps muscle strength; and (iii) exercise capacity, measured by 6-min walking distance (6MWD). The 6MWD was reassessed 30 days later to determine the recovery of exercise capacity. RESULTS: After 30 days, while 63% of the patients showed clinically important improvement in the 6MWD (recovery ≥ 30 m), 37% showed no change (recovery < 30 m). During hospital stay, the non-recovered group had lower quadriceps muscle strength compared to the recovered group (15 ± 5 vs. 22 ± 6 kgf; P = 0.006), with no significant difference for MIP, MEP and handgrip strength. Only quadriceps muscle strength was associated with recovery of exercise capacity (r = 0.56; P = 0.003). CONCLUSION: AECOPD patients with quadriceps muscle weakness during hospitalization have poor recovery of exercise capacity after 30 days. This finding suggests the importance of early rehabilitation to improve quadriceps strength and accelerate functional recovery after AECOPD.

Incremental shuttle walk test: is it able to detect exercise-induced bronchospasm in young adult asthmatics?

OBJECTIVE: To determine the accuracy of incremental Shuttle Walking Test (ISWT) in detecting exercise-induced bronchospasm (EIB) in adults with asthma and to verify whether there is an association of the drop in FEV1 between ISWT and cardiopulmonary exercise testing with constant-load CPET-CL. METHODS: In this cross-sectional study 32 individuals with asthma performed two ISWTs, an incremental cardiopulmonary exercise test (CPET-I) and a constant-load cardiopulmonary exercise test (CPET-CL) with na interval of 48 h between tests. Spirometric measurements were obtained 5, 10, 15, 20 and 30 min after exercise; an FEV1 decline > 10% was considered EIB. RESULTS: Fifteen individuals had EIB in both tests [χ2 = 9.41; κ = 0.46 p < 0.002 (95% CI: 0.201-0.708)], with moderate agreement. There was a significant correlation between the greatest variation in the drop in FEV1 between the ISWT and the CPET-CL (r = 0.48; p < 0.01). There was a significant difference for ventilation maintenance time above 40% of Maximum Voluntary Ventilation between the groups of positive EIB (p = 0.001) and negative EIB (p = 0.001) and for ventilatory demand (positive EIB group) (p = 0.008) between ISWT vs CPET-CL. Moreover, assuming CPET-CL as the criterion test, ISWT presented a sensitivity of 62.5% and specificity was 100%. CONCLUSION: ISWT showed moderate accuracy in detecting EIB in adults with asthma and was able to show similar metabolic and ventilatory demand presented in CPET-CL.

Validity and Reliability of the 6-Minute Step Test in Healthy Individuals: A Cross-sectional Study.

OBJECTIVE: To determine the 6-minute step test's (6MST) reliability and validity and to establish reference performance values of this test. DESIGN: Prospective observational cross-sectional study. SETTING: Spirometry and Respiratory Physiotherapy Laboratory, Federal University of São Carlos (institutional). PARTICIPANTS: Ninety-one individuals [42 men and 49 women, mean age = 39 years (SD, 17 years)] without any diagnosed diseases and with normal exercise capacity [6-minute walk test (6MWT) >75% of the predicted normal]. INDEPENDENT VARIABLES: Participants underwent two 6MST on 1 day and two 6MWT on another day in randomized order. Furthermore, age, gender, height, weight, lower limbs length, abdominal circumference, percentage of body fat, and fat-free mass were obtained. MAIN OUTCOME MEASURES: Test-retest reliability was assessed by comparing the findings of the two 6MST using the intraclass correlation coefficient (ICC) and Bland-Altman plot. Validity was assessed by comparing outcomes of the 6MST to outcomes of 6MWT using the Pearson correlation coefficient. A multiple regression analysis was conducted using the stepwise method to develop an equation to predict reference values. RESULTS: The performance (mean steps ± SD) in the first and second test was 149 ± 34 and 149 ± 36 steps, respectively, which was correlated to distance (in meters) in 6MWT (r = 0.72; P < 0.05). Six-minute step test performance was reliable (ICC = 0.9; 95% confidence interval: 0.85-0.93). The equation to predict reference values for the first 6MST was significant (P < 0.001 and R = 0.48): Performance(steps) = 174 to 1.05 × Age(years) to women and Performance(steps) = 209 to 1.05 × Age(years) to men. CONCLUSIONS: Six-minute step test is a reliable and valid test. Moreover, the number of steps may be predicted by demographic and anthropometric variables with moderate strength of prediction. CLINICAL RELEVANCE: Six-minute step test is an exercise test that is easy to be conducted, more tolerable than a graded exercise test, requires fewer equipments and space, and permits better monitoring of the participants. The assessment of the reliability, validity, and reference values will provide a better interpretability for clinicians to use it, especially in primary care.