Maximum Expiratory Research Articles

Runners maintain locomotor-respiratory coupling following isocapnic voluntary hyperpnea to task failure.

Evidence has long suggested that mammalian ventilatory and locomotor rhythms are linked, yet determinants and implications of locomotor-respiratory coupling (LRC) continue to be investigated. Anecdotally, respiratory muscle fatigue seen at the end of heavy exercise may result in an uncoupling of movement-ventilation rhythms; however, there is no scientific evidence to substantiate this claim. We sought to determine whether or not fatigue of the respiratory muscles alters locomotor-respiratory coupling patterns typically observed in highly trained individuals while running. A related query was to examine the relationship between the potential changes in LRC and measures of running economy. Twelve male distance runners ran at four submaximal workloads (68-89 % VO2peak) on two separate days while LRC was quantified. One LRC trial served as a control (CON), while the other was performed following an isocapnic voluntary hyperpnea to task failure to induce respiratory muscle fatigue (FT+). LRC was assessed as stride-to-breathing frequency ratios (SF/fB) and degree of LRC (percentage of breaths occurring during the same decile of the step cycle). Hyperpnea resulted in significant declines in maximal voluntary inspiratory (MIP) and expiratory (MEP) mouth pressures (ΔMIP = -10 ± 12 cm H2O; ΔMEP = -6 ± 9 cm H2O). There were no differences in minute ventilation between CON and FT+ (CON, all speeds pooled = 104 ± 25 L min(-1); FT+ pooled = 106 ± 23 L min(-1)). Stride frequency was not different between trials; however, breathing frequency was significantly greater during FT+ compared to CON at all speeds (CON pooled = 47 ± 10 br min(-1); FT+ pooled = 52 ± 9 br min(-1)), resulting in smaller corresponding SF/fB. Yet, the degree of LRC was the same during CON and FT+ (CON pooled = 63 ± 15 %; FT+ pooled = 64 ± 18 %). The results indicate that trained runners are able to continue entraining breath and step cycles, despite marked changes in exercise breathing frequency, after a fatiguing hyperpnea challenge.

Blood urea nitrogen to creatinine ratio is associated with congestion and mortality in heart failure patients with renal dysfunction

Renal dysfunction (RD) and venous congestion are related and common in heart failure (HF). Studies suggest that venous congestion may be the primary driver of RD in HF. In this study, we sought to investigate retrospectively the relationship between common measures of renal function with caval congestion and mortality among outpatients with HF and RD. We reviewed data from 103 HF outpatients (45 males, mean age 74 years, ejection fraction 41.8 ± 11.6 %) with estimated glomerular filtration rate (eGFR) of < 60 ml/min in a single centre. During an ambulatory visit, all patients underwent blood test and ultrasonography of the inferior vena cava (IVC). Caval congestion was defined as IVC with both dilatation and impaired collapsibility. The best values of renal metrics in predicting caval congestion were determined with receiver-operating characteristic analysis. The BUN/Cr ratio is moderately correlated with IVC expiratory maximum diameter (r = 0.31, p < 0.0007). In a multiple logistic regression model, BUN/Cr > 25.5 (adjusted OR 2.98, p 0.015) and eGFR ≤ 45.8 (adjusted OR 5.38, p 0.002) identify patients at risk for caval congestion; a BUN/Cr > 23.7 was the best predictor of impaired collapsibility (adjusted OR 4.41, p 0.001). a BUN/Cr > 25.5 (HR 2.19, 95 % CI 1.21-3.94, p < 0.001) and NYHA class 3 (HR 2.91, 95 % CI 1.60-5.31, p < 0.0005) were independent risk factors associated with all-cause death during a median follow-up of 31 months. In outpatients with HF and RD, a higher BUN/Cr and lower eGFR are reliable renal biomarkers for caval congestion. The BUN/Cr is associated with long-term mortality and may help to stratify HF severity.

Respiratory Muscle Training Improves Dyspnea and Exercise Performance in Cancer Survivors

It is estimated that up to 70% of survivors experience dyspnea at some point in their recovery. Dyspnea is correlated with functional performance (6 minute walk test, 6MWT) and peak exercise (VO2PEAK), both of which predict survival in lung cancer. Respiratory muscle weakness represents one of the primary mechanisms contributing to exertional dyspnea and reduced exercise performance in cancer survivors. Respiratory muscle training (RMT) protocols have been used to reduce dyspnea in patients with non-malignant lung disease; however, no studies have explored respiratory muscle training to alleviate dyspnea in cancer survivors. PURPOSE: Implement a RMT program to reduce the sensation of dyspnea, as well as to improve exercise capacity, functional performance and QoL in breast and lung cancer survivors. METHODS: Eight participants who have completed all therapies (57.3 ± 6.8 years) performed RMT, 3 sets of 15 repetitions against spring loaded inspiratory and expiratory valves, 3 days/week, for 4 weeks. Pre- and Post-RRMT, subjects performed maximal expiratory (MEP) and inspiratory pressures (MIP), exercise tests (VO2Peak, sub-maximal cycling endurance at 70% of peak and 6MWT) and questionnaires related to dyspnea (Baseline Dyspnea Index) and quality of life (SF-36). RESULTS: Four breast and four lung cancer survivors completed the protocol (mean years ± SD from treatment = 4.1±3.0). At baseline, FVC and FEV1 were 80.3±18.5 and 77.2±18.2% of predicted. MIP and MEP were 51.8±20.0% and 94.8±19.2% of predicted. Post-RMT, MIP and MEP increased 26.5±21.2% and 40.1±32.7%, respectively (p<0.005). Time to peak (8.5±3.5 min vs. 10.1±3.2 min, p=0.015) and submaximal endurance (16.5±7.7 vs. 32.4±8.7 min, p=0.007) exercise and the distance covered in the 6MWT (414±91 m vs. 441±97 m, p=0.03) were all significantly longer. Finally, baseline dyspnea index (p=0.02) and quality of life (p=0.04) improved post-RMT. CONCLUSION: These results suggest that a progressive resistance inspiratory and expiratory respiratory muscle training program helps to improve respiratory muscle strength, the sensation of dyspnea, as well as exercise performance and QoL in cancer survivors.

Lower Limb and Respiratory Muscle Oxygenation During 800-m Running

800-m running is supramaximal exercise, which naturally require oxygen supply to lower limbs muscle. In addition, respiratory muscle work specifically is severe to prevent acidosis attributing to lactate because of increasing by prompting CO2 output. Therefore, the event is performed with tolerating severe strain of both lower limb and respiratory muscles. However, how to changes in lower limb and respiratory muscles oxygenation during 800-m running remains unclear. We hypothesized that during 800-m running, respiratory muscle oxygenation would be reduced by redistribution of blood flow giving priority to lower limb muscles. PURPOSE: To investigate changes in lower limb and respiratory muscles oxygenation during 800-m running. METHODS: Nine male 800-m runners (age; 20±2.1 yrs, record; 115.7±4.9s) performed 800-m running with maximal effort during on outdoor track. Maximal inspiratory (MIP) and expiratory (MEP) pressure were measured before and after 800-m running. OxyHb/Mb and totalHb/Mb of vastus lateralis and of intercostal muscle were evaluated using portable near-infrared spectroscopy (NIRS) during 800-m running. Two-way ANOVA (distance×muscle) with repeated measures was used to identify statistically significant differences in NIRS parameters across each 50-m distance interval. RESULTS: The running speed peaked at 100-m interval (7.4±0.4 m/s), and then gradually decreased until the finish (6.0±0.3 m/s). After 800-m running, MIP was significantly decreased (-47 %; p<0.0001), although MEP was no significant (-8 %; p=0.095). OxyHb/Mb of vastus lateralis was significantly decreased immediately after start and followed by maintaining until finish. By contrast, OxyHb/Mb of intercostal muscle was gradually decreased from start and followed by further decreasing in latter half (from 450-m to finish) of 800-m running. In addition, although totalHb/Mb of intercostal muscle was gradually decreased from start until finish, totalHb/Mb of vastus lateralis was maintaining at resting level. CONCLUSIONS: Our findings in NIRS data suggest that the decrease in respiratory muscle oxygenation maybe greater than lower limbs muscle oxygenation in latter half of 800-m running. No grant for this study.

The Effect of Different Respiratory Muscle Training Protocols on Health Outcomes in Patients with COPD

PURPOSE: Inspiratory muscle training (IMT) has been shown to improve dyspnoea, exercise tolerance and respiratory muscle strength in patients with chronic obstructive pulmonary disease (COPD), however the efficacy of expiratory muscle training (EMT) is equivocal. Respiratory muscle training (RMT) protocols are strenuous, therefore the purpose was to determine the effects of a modified IMT protocol or EMT protocol compared to standard IMT on respiratory health outcomes in patients with COPD. METHODS: 11 COPD patients enrolled in pulmonary rehabilitation completed a randomised controlled pilot trial involving either: eight breaths of IMT (IMT8), 30 breaths of IMT (IMT30) or 30 breaths of EMT (EMT30). RMT was performed twice daily, six days a week for six weeks, commencing at 25% of respiratory muscle strength and progressing by 5% per week up to 50% in the final week. Maximal inspiratory (PImax) and expiratory (PEmax) mouth pressures, Body mass index, airway Obstruction (FEV1), Dyspnoea (modified MRC scale) and Exercise capacity (6 minute walk test; 6MWD), for the calculation of BODE index, and anxiety and depression (hospital anxiety and depression scale; HADS) were recorded before and after the intervention. Data are presented as mean difference ± SD and percentage change while Cohen’s d were applied to determine small (≥0.2), moderate (≥0.5) and large (≥0.8) effect sizes. RESULTS: BODE index decreased in all groups (IMT8: 22% [d = -1.00], IMT30: 7% [d = -0.25] & EMT30: 36.5% [d = -1.08]), with IMT8 (-1.3 ± 1.3) and EMT30 (-1.3 ± 1.2) being the most meaningful. IMT8 & EMT30 were more effective in improving BODE index (d = 0.75 & d = 0.87, respectively) and reducing anxiety (d = -0.83 and d = -0.95, respectively) compared to IMT30. 6MWD increased in all groups: 17% in IMT8 (d = 0.85), 22% in IMT30 (d = 0.38) and 32% in EMT30 (d = 0.75). Both PImax (+15.4 ± 13.1 [d = 1.04] & 11.3 ± 21.4 cmH2O [d = 0.94] and PEmax (+4.0 ± 16.2 [d = 0.16] & 4.0 ± 13.5 cmH2O [d = 0.22]) increased following IMT8 and IMT30, respectively, whereas EMT30 had no positive effect on PImax/PEmax. Compliance was greater during IMT8 (98±2%) compared to IMT30 (85±14%; d = 1.33) and EMT30 (65±31%; d = 1.83). CONCLUSION: Both IMT protocols demonstrated similar improvements in respiratory muscle strength, however only IMT8 and EMT30 showed meaningful reductions in BODE index and HADS.

Lower limb muscle strength is associated with functional performance and quality of life in patients with systemic sclerosis.

Background: Complaints of peripheral muscle weakness are quite common in patients with systemic sclerosis (SSc). It is likely that the muscle impairments may reduce the patients' exercise performance, which in turn may decrease their functional capacity and exert a direct impact on their quality of life. Objectives:To assess the peripheral and respiratory muscle strength in individuals with SSc and to investigate their correlation with the 6-min walk distance (6MWD) and quality of life measurements. Moreover, we aimed to characterize their nutritional status, pulmonary function, functional capacity, and quality of life compared to the controls. Method:The present cross-sectional study included 20 patients with SSc and 20 control subjects. All of the participants were subjected to isometric dynamometry, surface electromyography, bioelectrical impedance analysis, pulmonary function testing, and the 6-min walk test. Patients with SSc also responded to the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and the Health Assessment Questionnaire Disability Index (HAQ-DI). Results:The individuals with SSc exhibited a reduction in quadriceps strength (p=0.0001), increased quadriceps fatigability (p=0.034), impaired pulmonary function, and a reduced 6MWD (p=0.0001) compared to the controls. Quadriceps strength was significantly correlated with the 6MWD (Rho=0.719; p=0.0004) and the HAQ-DI (Rho=-0.622; p=0.003). We also found significant correlations between quadriceps fatigability and maximal inspiratory (Rho=0.684; p=0.0009) and maximal expiratory (Rho=0.472; p=0.035) pressure. Conclusions:Patients with SSc exhibited reduced respiratory muscle and quadriceps strength and an increase in its fatigability. In these individuals, there was a relationship between quadriceps strength, functional capacity, and quality of life.

Does respiratory muscle training improve cough flow in acute stroke? Pilot randomized controlled trial.

Cough protects the lungs from aspiration. We investigated whether respiratory muscle training may improve respiratory muscle and cough function, and potentially reduce pneumonia risk in acute stroke. We conducted a single-blind randomized placebo-controlled trial in 82 patients with stroke (mean age, 64±14 years; 49 men) within 2 weeks of stroke onset. Participants were masked to treatment allocation and randomized to 4 weeks of daily expiratory (n=27), inspiratory (n=26), or sham training (n=25), using threshold resistance devices. Primary outcome was the change in peak expiratory cough flow of maximal voluntary cough. Intention-to-treat analyses were conducted using ANCOVA, adjusting for baseline prognostic covariates. There were significant improvements in the mean maximal inspiratory (14 cmH2O; P<0.0001) and expiratory (15 cmH2O; P<0.0001) mouth pressure and peak expiratory cough flow of voluntary cough (74 L/min; P=0.0002) between baseline and 28 days in all groups. Peak expiratory cough flow of capsaicin-induced reflex cough was unchanged. There were no between-group differences that could be attributed to respiratory muscle training. There were also no differences in the 90-day incidence of pneumonia between the groups (P=0.65). Respiratory muscle function and cough flow improve with time after acute stroke. Additional inspiratory or expiratory respiratory muscle training does not augment or expedite this improvement. http://www.controlled-trials.com. Unique identifier: ISRCTN40298220.

Childhood mouth-breathing consequences at adult age: ventilatory function and quality of life

Introduction Mouth breathing can affect the functions of the respiratory systems and quality of life. For this reason, children who grow up with this stimulus may have implications on physical and psychological aspects at adult age.Objective To evaluate childhood mouth-breathing consequences for the ventilatory function and quality of life at adult age.Materials and methods Prospective, observational and cross-sectional study with 24 adults, between 18 and 30 years old, mouth breathers during childhood, comprised the childhood mouth-breathing group (CMB). The childhood nasal-breathing (CNB) group was composed of 20 adults of the same age, without history of respiratory disease during all their lives. Measurements of maximal respiratory pressures, peak expiratory flow and 6-minute walk test were assessed. In addition, all the volunteers answered the Short Form-36 questionnaire (SF-36).Results The maximal inspiratory (p = 0.001) and expiratory (p = 0.000) pressures as well as the distance in the walk test (p = 0.003) were lower in the COB. The COB also presented lower score in the General Health domain of the SF-36 Questionnaire (p = 0.002).Conclusion Childhood mouth-breathing yields consequences for the ventilatory function at adult age, with lower respiratory muscle strength and functional exercise capacity. Conversely, the quality of life was little affected by the mouth breathing in this study.

Efeitos do treinamento aeróbio sobre a capacidade muscular e funcional em pacientes com diabetes mellitus tipo 2

Introduction: Diabetes Mellitus leads to reduced aerobic capacity as well as the reduction of respiratory muscle strength. Objective: To evaluate the impact of aerobic training (AT) on respiratory muscle strength (RMS) measured by maximal inspiratory (MIP) and expiratory (MEP) pressures, thoracic expansibility (TEx), submaximal functional capacity (SFC) by 6-min walk test (6MWT) and muscular endurance (ME) of the lower limbs and flexibility in subjects with type 2 diabetes mellitus (T2DM). Materials and Methods: Prospective trial, non-randomized with 27 subjects with T2DM, which were allocated into AT group (G1) and control group (G2). Evaluations were performed before and after the RMS, TEx, 6MWT, lower limb ME and flexibility interventions. The AT lasted 8 weeks, three times a week, 60 minutes each. The prescription of AT was performed at 60-70% of maximum heart rate monitored by analog Borg scale. Results: The study shows that occurred an increase in the RMS (49% of the MIP and MEP), 6MWT, ME and flexibility in the G1 group. Conclusion: The TA was effective in improving respiratory muscle strength and functional capacity in patients with T2DM.

E-43 Free Communication/Poster - Military Physiology

PURPOSE: It has been established that top-level race walkers require a high fitness level. Fitness characters have been reported to play major roles in race walking performance, but there is still a lack of information about the physical characteristics and performance of the referees. The aim of this study was to characterize the anthropometric and flexibility of Chinese elite and subelite race walkers, establish selection methods and standards for different levels of race walking athletes. METHODS: 118 race walking athletes were involved in the study (75 male and 43 female) and divided into Elite group (38 male and 19 female) and subelite group (37 male and 24 female) according to their Personal Best Records. We evaluated anthropometric and body composition variables, among them: height, body mass, body mass index (BMI) and body fat (%), lower limb length, chest circumference, waist-hip ratio; and flexibility and mobility performance: ankle flexion, trunk rotation, hip rotation, sit and reach, cross jump in 30 seconds. RESULTS: (1) There were significant differences between E and S group in the levels of sitting height, leg ratio (lower limb length H/calf length B), lower limb H/height*100, waist circumference, waist-hip ratio (P<0.05) in female race walkers, the same consequence were seen in male race walkers, and there were very significant differences in chest circumference (Maximal expiratory and calm circumference) and waistline (P<0.01). (2) For female race walkers, E group had bigger hip rotation angle degree than S (P <0.05). And for the male race walkers E group had better abilities in trunk rotation (P<0.01) and hip rotation angle (P<0.01for left and P<0.05 for right). No significant differences were seen in sit and reach test, cross jump in 30 seconds test between E and C group whether in male or female. CONCLUSION: Elite race walkers have better ratio of lower limbs and chest circumference, and more flexible joints rotation capacity in trunk and hip, which is helpful to keep perfect walking technical and aerobic endurance, but sit and reach flexibility for the assessment methodology is no different.

B-17 Thematic Poster - Physical Activity and Cognition

PURPOSE: Ultra-marathon running offers the unique possibility to investigate the human body when pushed towards its endurance limitations. From investigations looking at locomotor muscle fatigue it is well established that central fatigue (i.e. a reduced drive to a muscle) is a major contributor to the loss in leg muscle strength found after ultra-endurance exercise. Only limited data is available on respiratory muscle strength after an ultra-marathon showing a large variability in the reduction of maximal voluntary inspiratory (MIP) and expiratory (MEP) pressures. Whether this reduction is caused by peripheral and/or central fatigue is currently unknown. METHODS: We assessed respiratory muscle strength by measuring MIP and MEP (n=22) as well as mouth twitch pressure (Pm,tw) and voluntary activation ratio (VAR, n=16) measured by cervical magnetic stimulation before and after a 103 km mountain ultra-marathon with ∼6000 m of positive and negative elevation. Lung function parameters and maximal voluntary ventilation (MVV) were also obtained at similar time points. RESULTS: Both MIP (-16±13%) and MEP (-21±14%) were significantly reduced after the race likely due to substantial peripheral fatigue (reduction in Pm,tw: -19±15%, p<0.01) while VAR (-3±6%, p=0.09) only tended to be decreased suggesting no or only modest levels of central fatigue. No change was observed for forced vital capacity while forced expiratory volume in the 1st second, peak expiratory and inspiratory flow as well as MVV were markedly reduced (p<0.05). CONCLUSIONS: Ultra-endurance running induces respiratory muscle fatigue with significant peripheral inspiratory muscle fatigue but no central fatigue in contrast to results obtained in locomotor muscles. Whether this is due to inherent differences between these muscle groups, their specific load pattern or methodological considerations remains to be clarified.

Respiratory muscle strength in healthy infants and those with surgically correctable anomalies

Assessment of respiratory muscle strength provides important diagnostic and prognostic information. Normative data in healthy, term infants is, however, limited. Surgically correctable birth defects, congenital diaphragmatic hernia (CDH) and abdominal wall defects (AWD), commonly have impaired diaphragm function. The study aims were to obtain normative data for respiratory muscle strength in healthy, term born infants at birth and at 6 weeks postnatal age (PNA) and to investigate the influence of growth and maturation on inspiratory muscle strength in CDH/AWD infants. Maximal inspiratory (cPimax) and expiratory (cPemax) pressures during crying were measured at birth in 67 healthy, term born infants (mean (SD) gestational age (GA) 39.4 (1.7) weeks) and reassessed in 27 at 6 weeks PNA. cPimax and functional residual capacity (FRC) (22.3 (4.2) ml/kg) were also measured in 23 infants with AWD/CDH (mean (SD) GA 36.9 (2.1) weeks) and reassessed in 16 at median (range) 6.5 (1.5-15) months PNA. In healthy infants, mean (SD) cPimax was 88.8 (19.33) cmH2 O and cPemax 61.8 (13.5) cmH2 O at birth, increasing significantly at followup to 100.9 (15.2) cmH2 O (P < 0.05) and 82.6 (19.4) cmH2 O (P < 0.001) respectively. Mean (SD) cPimax was significantly lower (47.5 (22.4) cmH2 O, P < 0.0001) in AWD/CDH infants compared to healthy infants at birth but had increased significantly to 88.1 (27.6) cmH2 O (P < 0.0001) at followup which correlated significantly with increases in FRC (r(2) = 0.33, P = 0.0263). Infants with AWD and CDH have significantly reduced inspiratory muscle strength compared to healthy term born infants but strength increases markedly in early life.

Thoracic load carriage-induced respiratory muscle fatigue

We investigated the effect of carrying a 25 kg backpack upon exercise-induced respiratory muscle fatigue, pulmonary function and physiological and perceptual responses to exercise. Nineteen healthy males performed 60 min walking at 6.5 km h(-1) and 0 % gradient with a 25 kg backpack (load carriage; LC). Following 15 min recovery participants then completed a 2.4 km time trial with the load (LCTT) and on a different day, repeated the trials without the load [control trial (CON) and control time trial (CONTT), respectively]. Respiratory muscle fatigue was determined by the transient change in maximal inspiratory (P Imax) and expiratory (P Emax) pressure prior to and immediately following exercise. P Imax and P Emax were reduced from baseline by 11 and 13 % (P < 0.05), respectively, post-LC but remained unchanged post-CON. Following the time trial P Imax and P Emax were reduced 16 and 19 %, respectively, post-LCTT (P < 0.05) and by 6 and 10 %, respectively (P < 0.05), post-CONTT compared to baseline. Both forced vital capacity and forced expiratory volume in 1 s were reduced by 4 ± 13 and 1 ± 9 %, respectively, during LC when compared to CON. Relative to CON all physiological and perceptual responses were greater in LC, both post-LC and -LCTT (P < 0.01). Time trial performance was faster during CONTT (11.08 ± 1.62 min) relative to LCTT (15.93 ± 1.91 min; P < 0.05). This study provides novel evidence that constant speed walking and time trial exercise with 25 kg thoracic load carriage induces significant inspiratory and expiratory muscle fatigue and may have important performance implications in some recreational and occupational settings.

Ventilatory muscle strength and quality of life in obese patients undergoing bariatric surgery. Prelimianry results

Introduction Obesity is one of the public health problems more relevant in modern society, leading to a series of changes in mechanical ventilation. Obesity treatment is aimed at improving the health and quality of life. Materials and methods The study included 13 female patients, obese grade III, recruited from two bariatric surgery services and referred to the Sleep Laboratory at the Nove de Julho University. Inclusion criteria included patients who were obese grade III (BMI ⩾ 40 ) or grade II (BMI 35.0–39.9), age between 18 and 65years, accepting voluntarily to participate in the study by reading and signing the informed consent form. Results Mean age was 40.08 ± 9.86, after bariatric surgery the mean body mass index was 36.91 ± 6.67, with p =0.004 and maximum inspiratory pressures were 84.12 ± 9.36 and 82.36 ± 12.21 the maximum expiratory, with a p ?0.001 and p ?0.001 respectively. With the BAROS questionnaire there was an report of good to excellent response to surgery in terms of quality of life in 75% of patients. Conclusion After bariatric surgery an optimization in maximum inspiratory and expiratory pressures was observed. The BAROS questionnaire is standardized and easily applied to evaluate the results after bariatric surgery. Acknowledgements The Sleep Laboratory receives funding from the Universidade Nove de Julho (Brazil) and research projects approved by the Brazilian fostering agencies Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) and Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP). LVFO received a grant from CNPq (Research Productivity modality - PQID, process number 307618/2010–2).

Strength of the respiratory and lower limb muscles and functional capacity in chronic stroke survivors with different physical activity levels

The assessment of strength and its relationships with functional capacity could contribute to more specific and effective disability management of stroke survivors. To compare and investigate associations between measures of strength and functional capacity of 98 chronic stroke survivors, stratified into three groups, according to their physical activity levels. The physical activity levels were classified as impaired, moderately active, and active, based on their Human Activity Profile (HAP) scores. Strength was assessed by the maximal inspiratory (MIP) and expiratory (MEP) pressures and by the residual deficits (RDs) of work of the lower limb and trunk muscles, whereas functional capacity was evaluated by the distance covered during the six-minute walking test (6MWT). One-way analyses of variance revealed significant differences between the groups, except between the active and moderately active groups regarding the RDS of the hip and knee flexors/extensors and ankle dorsiflexors (2.91<F<8.62; 0.001<p<0.01). Differences between the groups were found for the 6MWT (F=10.75; p<0.001), but no differences were found for the MIP and MEP measures (0.92<F<2.13; 0.13<p<0.40). Significant, negative, and fair correlations were observed between the RDS of the hip and knee muscles and the 6MWT (0.30<r<-0.43; p<0.01) and the HAP (-0.28<r<-0.41; p<0.01). Moderate to good correlations were found between the 6MWT and the HAP (r=0.50; p<0.0001). There were no significant correlations between measures of respiratory strength and any of the investigated variables (-0.11<r<0.12; 0.26<p<0.56). Lower strength deficits and higher functional capacity were associated with higher physical activity levels. However, the moderately active and active groups demonstrated similar strength deficits.

Abstract 605: ICU Blood Pressure Variability Correlates With The Nadir Of Respiratory Depression After Cardiac Surgery

Objective. Coronary artery bypass graft surgery (CABG) is associated with postoperative respiratory depression. The primary endpoint of this study was the determination whether the blood pressure variability during the intensive care unit (ICU) is correlated with the nadir of postoperative respiratory function impairment. Methods. This prospective study evaluated 44 patients subjected to CABG with cardiopulmonary bypass (CPB). Mean arterial pressure (MAP) was monitored every 30 min for 3 days at the ICU. MAP variability was evaluated through: standard deviation (SD), coefficient of variation (CV), variation independent of mean (VIM), average successive variability (ASV) and SD of ASV. Respiratory function was assessed through maximal inspiratory (MIP) and expiratory (MEP) pressures and expiratory peak flow rate (EPFR) determined 1 day before surgery and on the postoperative days 3rd to 7th. Results. Respiratory parameters MIP, MEP and EPFR were significantly depressed postoperatively for 4, 4 and 5 days respectively. Patient adherence to EPFR monitoring was higher than for MIP and MEP. None of the perioperative parameters (volume of cardioplegia, CPB duration, aortic cross-clamp time, number of grafts) had any correlation with the postoperative respiratory depression. Of all MAP variability parameters, the ASV and SD of ASV had a significant good positive Spearman correlation (rho coefficients ranging from 0.45 to 0.65, p&lt;0.01) with the nadir depression of EPFR for 5 days after cardiac surgery. Conclusion. Variability parameters ASV and SD of ASV of the MAP monitored at ICU may have predictive value for the depression of respiratory function after cardiac surgery as determined by EPFR.

Inspiratory and Expiratory Respiratory Muscle Training as an Adjunct to Concurrent Strength and Endurance Training Provides No Additional 2000 m Performance Benefits to Rowers

The purpose of this study was to examine respiratory muscle training (RMT) combined with 9 weeks of resistance and endurance training on rowing performance and cardiopulmonary responses. Twenty-seven rowers (mean ± SD: age = 27 ± 9 years; height = 176.9 ± 10.8 cm; and body mass = 76.1 ± 12.6 kg) were randomly assigned to an inspiratory only (n = 13) or expiratory only (n = 14) training group. Both RMT programs were 3 sets of 10 reps, 6 d/wk in addition to an identical 3 d/wk resistance and 3 d/wk endurance training program. Both groups showed similar improvements in 2000 m rowing performance, cardiorespiratory fitness, strength, and maximum inspiratory (PImax) and expiratory (PEmax) pressures (p < .05). It was concluded that there were no additional benefits of 9 weeks of inspiratory or expiratory RMT on simulated 2000 m rowing performance or cardiopulmonary responses when combined with resistance and endurance training in rowers.

Maximum respiratory pressure alterations after spinal manipulation

Objective: To verify the immediate effect of spinal manipulation in rotation of the third cervical vertebra (C3) and the 12th thoracic vertebra (T12) in maximum inspiratory (MIP) and expiratory (MEP) pressure in healthy people. Methodology: Healthy university students, sedentary, of both sexes (n = 59), were randomly divided into four groups: placebo group (PG/n = 14/21 ± 1.4 years/mobilization of ankle); cervical manipulation group (CMG/n = 15/21 ± 2.4 years); thoracic manipulation group (TMG/n = 15/21 ± 1.7 years); and cervical and thoracic manipulation group (CTMG/n = 15/21 ± 1.5 years). The MIP and MEP were measured by manometer immediately before and after intervention and the highest value was used as the value of valid tests. The data was normalized by dividing the obtained values on the lower limit of normal range predicted by gender and age for each variable. Results: There was a significant increase in intragroup comparisons of the variables in the CMG (MIP-pre: 0.72/post: 0.76/p < 0.05, MEP-pre: 1.09/post: 1.15/p < 0.01) and CTMG (MIP-pre: 0.64/post: 0.72/p < 0.01; MEP-pre: 0.90/post: 1.01/p < 0.05) in post-intervention compared with baseline, which was not observed in PG and in TMG. There was no difference in intergroup comparisons. Conclusion: Manipulation of C3 alone or combined with manipulation of T12 increased maximum inspiratory and expiratory pressure.

Monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of pulmonary function evaluation in amyotrophic lateral sclerosis

It was study the relationship between respiratory muscle strength and forced vital capacity (FVC) in patients with amyotrophic lateral sclerosis (ALS) versus healthy subjects. Pulmonary function and respiratory muscle strength [maximal inspiratory (PImax), maximal expiratory (PEmax) and sniff nasal inspiratory pressure (SNIP)] were assessed in patients with ALS and healthy subjects, matched using cutoffs established in the literature for impaired pulmonary function and respiratory muscle weakness. Twenty-eight ALS patients and 28 healthy subjects were studied. We found sensitivity and specificity for PImax, PEmax and SNIP of 75/58%, 81/67% and 75/67%. The Receiver Operating Characteristic curve (ROC curve) indicated that the variables PImax, PEmax and SNIP can identify differences in respiratory muscle strength between ALS and healthy individuals at 0.89, 0.9 and 0.82, respectively. A positive correlation was recorded between FVC (%) versus SNIP, PImax and PEmax. In ALS, monitoring respiratory muscle strength assists in early diagnosis of respiratory dysfunction as opposed to the isolated use of FVC.

P229 Nocturnal Noninvasive Ventilation Improves Muscle Strength in Stable COPD Patients with Respiratory Failure

Introduction/ObjectivesNon-Invasive ventilation (NIV) is established for treatment of patients with COPD and respiratory failure (RF). Respiratory muscle weakness has been reported in these patients. Aim of the study is to...