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PurposeThe Test of Incremental Respiratory Endurance (TIRE) provides a comprehensive assessment of inspiratory muscle performance by measuring maximal inspiratory pressure (MIP) over time. The integration of MIP over inspiratory duration (ID) provides the sustained maximal inspiratory pressure (SMIP). Evidence on the reliability and validity of these measurements in COPD is not currently available. Therefore, we assessed the reliability, responsiveness and construct validity of the TIRE measures of inspiratory muscle performance in subjects with COPD.Patients and methodsTest–retest reliability, known-groups and convergent validity assessments were implemented simultaneously in 81 male subjects with mild to very severe COPD. TIRE measures were obtained using the portable PrO2 device, following standard guidelines.ResultsAll TIRE measures were found to be highly reliable, with SMIP demonstrating the strongest test–retest reliability with a nearly perfect intraclass correlation coefficient (ICC) of 0.99, while MIP and ID clustered closely together behind SMIP with ICC values of about 0.97. Our findings also demonstrated known-groups validity of all TIRE measures, with SMIP and ID yielding larger effect sizes when compared to MIP in distinguishing between subjects of different COPD status. Finally, our analyses confirmed convergent validity for both SMIP and ID, but not MIP.ConclusionThe TIRE measures of MIP, SMIP and ID have excellent test–retest reliability and demonstrated known-groups validity in subjects with COPD. SMIP and ID also demonstrated evidence of moderate convergent validity and appear to be more stable measures in this patient population than the traditional MIP.

Blood flow restricted (BFR) exercise has recently been promoted in the United States as a novel method to restore skeletal muscle strength and hypertrophy in primarily athletic and healthy populations. A specialized tourniquet restricts blood flow after which brief and intermittent exercise is performed with low to moderate loads of resistance. A hypertensive blood pressure (BP) response during BFR exercise has been identified as a potential adverse effect, which may be particularly concerning for patients who are hypertensive. Because of the possibility that a substantial proportion of older adults undergoing orthopedic surgery may have hypertension as well as the possibility of a hypertensive BP response from BFR exercise, we performed a comprehensive search for studies examining the acute and chronic BP response to BFR exercise in hypertensive subjects resulting in 6 studies with which a meta-analysis and systematic review were performed. The meta-analysis results found nonsignificant, slight increases in systolic BP and diastolic BP. The results of the systematic review found that BFR exercise seems to be safe in patients with hypertension with no adverse events reported in the 86 patients who participated in the 6 reviewed studies. The cardiovascular response to BFR exercise seems to vary depending on the muscle group being exercised as well as the method of BFR, but, in general, these measures are greater during BFR exercise compared with non-BFR exercise.

Study design This work is a systematic review with meta-analysis Objective Evaluate the effect of electrical stimulation (ES) on skeletal muscle volume and spasticity in individuals with spinal cord injury (SCI). Setting University of Brasilia, Brazil Methods Searches were conducted of the Cochrane Library, MEDLINE, CINAHL, PEDro, PsycINFO and EMBASE electronic databases for relevant articles published up to June 2018. No restrictions were imposed regarding the year of publication. The inclusion criteria were randomized controlled trials involving adults with SCI comparing ES to an active or passive control. Two independent reviewers extracted the data from the selected studies and methodological quality was assessed using the PEDro scale. Results The initial search led to the retrieval of 164 studies, seven of which met the eligibility criteria, but only six were included in the meta-analysis. The six studies comprised 104 patients with complete or incomplete SCI. In the two studies that investigated the use of ES on muscle volume of the lower limbs, the overall effect was statistically significant in patients with acute SCI (mean difference: 0.86; 95% CI: 0.04 to 1.69; p < 0.04). Among the four studies that examined the use of ES for spasticity of the lower limb, the overall effect was non-significant (mean difference: 0.55; 95% CI: −0.31 to 1.41; p = 0.21). Conclusions Electrical stimulation was found to be an effective method for increasing muscle volume in SCI patients, but had no effect on spasticity. Further investigation of the effect of ES on spasticity in SCI is needed.

BACKGROUND: Smoking has potential deleterious effects on respiratory muscle function. Smokers may present with reduced inspiratory muscle strength and endurance. We compared inspiratory muscle performance of nonsmokers with that of former smokers without overt respiratory problems via the Test of Incremental Respiratory Endurance. METHODS: This study was performed on 42 healthy subjects between the ages of 30 and 79 y (mean ؎ SD of 56.5 ؎ 14.4 y). Fourteen male and 7 female former smokers were matched to nonsmokers based on sex, age, height, and weight. Subjects completed a questionnaire about their health and current smoking status. Testing included the best of 3 or more consistent trials. The Test of Incremental Respiratory Endurance measurements included maximal inspiratory pressure measured from residual volume as well as sustained maximal inspiratory pressure and inspiratory duration measured from residual volume to total lung capacity during a maximal sustained inhalation. RESULTS: No significant difference in inspiratory performance of the entire group of former smokers compared with nonsmokers was found. However, separate sex analyses found a significant difference in sustained maximal inspiratory pressure between male former smokers and nonsmokers (518.7 ؎ 205.0 pressure time units vs 676.5 ؎ 255.2 pressure time units, P ‫؍‬ .041). CONCLUSIONS: We found similar maximal inspiratory pressure between former smokers and nonsmokers via the Test of Incremental Respiratory Endurance, but the significant difference in sustained maximal inspiratory pressure between male former smokers and nonsmokers suggests that the sustained maximal inspiratory pressure may have greater discriminatory ability in assessing the effects of smoking on inspiratory muscle performance. Further investigation of the effects of smoking on inspiratory performance via the Test of Incremental Respiratory Endurance is warranted.

Background: Inspiratory muscle function in COPD has been traditionally described in terms of maximal inspiratory pressure (MIP). Arguably, however, is the day-to-day relevance of MIP, given that individuals rarely need maximal inspiratory forces to perform general tasks, but rather repeated breathing muscle contractions which demand endurance. The sustained maximal inspiratory pressure (SMIP) reflects the ability of the respiratory muscles to maintain force over time (i.e. single-breath work capacity). We investigated the relationships between SMIP and COPD-related clinical outcomes, hypothesizing that SMIP would have superior correlational and discriminatory value when compared to MIP. Methods: 61 males with mild-to-very severe airflow obstruction underwent measures of spirometry, whole-body plethysmography, symptomatology, comorbidity, quality of life, exacerbations and mental health. MIP and SMIP were obtained via the Test of Incremental Respiratory Endurance. Results: The mean ± SD MIP and SMIP were 77.2 ± 22.9 cmH 2 O and 407.9 ± 122.8 PTU. Both MIP and SMIP positively correlated with pulmonary function, with SMIP displaying the highest correlations. We found significant differences in spirometry, hyperinflation, symptomatology, exacerbation frequency, comorbidity, quality of life and anxiety in subjects grouped as having reduced or normal single-breath work capacity. Finally, significantly lower SMIP values were found in individuals with an IC/TLC ratio ≤25%. Conclusions: The assessment of SMIP appears to have superior clinical value than MIP in COPD. Our analyses revealed that subjects whose SMIP was reduced experienced more severe airflow obstruction, greater hyperinflation, as well as worse health and mental status with increased symptomatology and impaired quality of life.

Objectives:The Test of Incremental Respiratory Endurance is a novel testing method that provides a unique examination of one’s inspiratory muscle strength, work and endurance. Little is known about the relationship between inspiratory muscle performance and mortality risk in obstructive lung disease. We examined the relationship between the Test of Incremental Respiratory Endurance measures and the Body-mass index, airflow Obstruction, Dyspnea and Exercise index in chronic obstructive pulmonary disease.Methods:In all, 70 males with mild-to-very severe chronic obstructive pulmonary disease (mean ± standard deviation of 70.2 ± 5.9 years) underwent measurements of body-mass index, spirometry, dyspnea and a 6-min walk test from which the Body-mass index, airflow Obstruction, Dyspnea and Exercise score was calculated. The Test of Incremental Respiratory Endurance provided measures of maximal inspiratory pressure, sustained maximal inspiratory pressure and inspiratory duration.Results:All Test of Incremental Respiratory Endurance parameters inversely correlated with the Body-mass index, airflow Obstruction, Dyspnea and Exercise score: maximal inspiratory pressure (r = −0.355, p = 0.00), sustained maximal inspiratory pressure (r = −0.426, p = 0.00) and ID (r = −0.278, p = 0.02), with sustained maximal inspiratory pressure displaying the highest correlation. Independent significant correlations were also observed between the sustained maximal inspiratory pressure and all Body-mass index, airflow Obstruction, Dyspnea and Exercise score components, except for body-mass index. Finally, sustained maximal inspiratory pressure was significantly different among the Body-mass index, airflow Obstruction, Dyspnea and Exercise index quartiles.Discussion:The significant association between the Body-mass index, airflow Obstruction, Dyspnea and Exercise score and inspiratory muscle performance, in particular sustained maximal inspiratory pressure, suggests that these measures may have a potential prognostic value in the evaluation of chronic obstructive pulmonary disease.

Background Chronic obstructive pulmonary disease (COPD) is associated with an inflammatory response that becomes more pronounced in acute exacerbations. Considerable attention has recently focused on the value of several inflammatory mediators in predicting worsening of COPD‐related symptoms. Whereas respiratory muscle dysfunction is also widely present in this population, little is known about how systemic inflammation relates to inspiratory muscle dysfunction in COPD. Methods Fifty‐three males with mild‐to‐very severe airflow obstruction underwent blood sampling for 23 inflammatory markers, including acute‐phase proteins, cytokines and adipokines. Inspiratory muscle performance was assessed via the test of incremental respiratory endurance, providing measures of maximal (MIP) and sustained maximal (SMIP) inspiratory pressures. Results The mean ± SD MIP and SMIP were 75.32 ± 19.62 cmH2O and 406.15 ± 124.55 PTU. MIP negatively correlated with CRP, SAA and cystatin C (r‐values from −0.333 to −0.378, P < 0.02), while SMIP was inversely related to SAA and cystatin C (r = −0.534 and r = −0.396, P = 0.00). Significant differences in CRP, SAA, cystatin C and PARC were also found between subjects with and without inspiratory muscle weakness. No additional significant relationships were observed between either MIP or SMIP and other inflammatory markers in the study. Conclusions MIP and SMIP are markedly reduced with greater degrees of inflammation in COPD as expressed by higher levels of CRP, SAA and cystatin C. Future research is needed to further examine the above findings and determine the impact of systemic inflammation along with its underlying mechanisms on inspiratory muscle function in COPD.