Lower Maximal Inspiratory Pressure Research Articles

The Influence of Lung Function and Respiratory Muscle Strength on Quadriceps Muscle Fatigability in COPD Patients Under Long-term Oxygen Therapy

BackgroundThis research investigates quadriceps muscle fatigability (MF) in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure (CRF) at different levels of lung obstruction [severe obstruction (SO)=FEV1 <50% and >30% versus very severe obstruction (VSO)=FEV1 ≤30%]. It explores the relationships between quadriceps MF and lung function, respiratory muscles, and oxygenation status. MethodsA post hoc cross-over analysis in 45 COPD patients (20 SO and 25 VSO) undergoing long-term oxygen therapy was performed. Delta change in quadriceps maximum voluntary contraction (MVC) (absolute value and percentage) before and after a constant workload was calculated. Associations between quadriceps MF and lung function, respiratory muscles, and gas exchange were examined using Pearson's correlation and multivariate linear regression analysis. ResultsSO patients experience a more substantial reduction in MVC compared to VSO (−15.15±9.13% vs −9.29±8.90%, p=0.0357), despite comparable resting MVC. Dyspnea is more pronounced in VSO at the beginning and end of the exercise. Correlations were found between MF and maximal inspiratory pressure (MIP) (r=−0.4412, p=0.0056), maximal expiratory pressure (MEP) (r=−0.3561, p=0.0282), and a tendency for FEV1% (r=−0.2931, p=0.0507). The regression model (R2=0.4719) indicates that lower MIP and FEV1 and high total lung capacity are significant factors in reducing quadriceps muscle fatigability after a fatiguing task. ConclusionCOPD patients with more severe pulmonary obstruction and hyperinflation and lower respiratory muscle strength have lower quadriceps MF but higher dyspnea both at rest and during exercise.

Long COVID – respiratory symptoms in non-hospitalised subjects – a cross-sectional study

Background The aim of this study was to describe and analyse the variety of respiratory appearances in Long COVID subjects who were not hospitalised during the acute phase of the infection. Methods A consecutive series of 60 subjects participated 10.8 months (SD 4.5) after the acute phase of the infection. Respiratory function was tested concerning lung volumes, expiratory flow, muscle strength, physical capacity including concurrent oxygen saturation, chest expansion, lung sounds, pain and breathing pattern. Differences between those with or without positive test and duration of symptoms more or less than 6 months were analysed with T-test, Chi-square test and Fisher’s exact test. Results Decreased forced vital capacity was found in 6/60 (10%), and forced expiratory volume in 1 s and 7/60 (12%), low maximal inspiratory pressure in 38/58 (54%) and low maximal expiratory pressure in 10/58 (17%). Decreased physical capacity was registered in 36/52 (69%), and thoracic expansion in 26/46 (56%). Pathologic lung sounds had 15/58 (26%) and six patients desaturated during the test of physical capacity. A majority (36/58, 67%) presented pain in the ribcage. All but three patients (95%) showed a dysfunctional breathing pattern in sitting and standing. Only poor and fair correlations were found between age, duration and level of physical capacity compared to spirometry, respiratory muscle strength and thoracic expansion. Conclusion Abnormal breathing pattern and respiratory movements as well as pain, and reduced lung volumes, flow, respiratory muscle strength, physical capacity and thoracic expansion may be involved in Long COVID. The breathing symptoms should therefore be looked for in a wider picture beyond spirometry and oximetry.

Postoperative Pulmonary Complications in Patients With Transcatheter Tricuspid Valve Implantation-Implications for Physiotherapists.

ObjectivesTo investigate the incidence of postoperative pulmonary complications (PPCs) and short-term recovery after transcatheter tricuspid valve implantation (TTVI).MethodsA total of 17 patients diagnosed with severe tricuspid regurgitation who received a LuX-valve TTVI were included in this study. Spirometry lung function, maximal inspiratory pressure (MIP), and 6-min walk test distance (6MWD) were recorded. Prior to surgery, patients were stratified into high or low pulmonary risk groups based on published predefined criteria. A physiotherapist provided all patients with education on thoracic expansion exercises, effective cough and an inspiratory muscle training protocol at 50% of MIP for 3 days preoperatively. All patients received standard post-operative physiotherapy intervention including positioning, thoracic expansion exercises, secretion removal techniques and mobilization. Patients were assessed for PPCs as defined by the Melbourne-Group Score-version 2. Clinical characteristics and hospital stay, cost, functional capacity, and Kansas City Cardiomyopathy Questionnaire (KCCQ) heart failure score were recorded at admission, 1-week, and 30-days post-op.ResultsThe mean (SD) age of the 17 patients was 68.4 (8.0) years and 15 (88%) were female. Pre-surgical assessment identified 8 patients (47%) at high risk of PPCs. A total of 9 patients (53%) developed PPCs between the 1st and 3rd day post-surgery, and 7 of these 9 patients were amongst the 8 predicted as “high risk” prior to surgery. One patient died before the 30 day follow up. Pre-operative pulmonary risk assessment score, diabetes mellitus, a low baseline MIP and 6MWD were associated with a high incidence of PPCs. Compared to those without PPCs, patients with PPCs had longer ICU and hospital stay, and higher hospitalization cost. At 30 days post-surgery, patients without PPCs maintained higher MIP and 6MWD compared to those with PPCs, but there were no significant between-group differences in other lung function parameters nor KCCQ.ConclusionThis is the first study to report the incidence of PPCs post TTVI. Despite a 3-day prehabilitation protocol and standard post-operative physiotherapy, PPCs were common among patients after TTVI and significantly impacted on hospital and short-term recovery and outcomes. In the majority of patients, PPCs could be accurately predicted before surgery. A comprehensive prehabilitation program should be considered for patients prior to TTVI.Clinical Trial Registration[www.ClinicalTrials.gov], identifier [ChiCTR2000039671].

Are oxidative stress biomarkers and respiratory muscles strength associated with COPD-related sarcopenia in older adults?

Patients with chronic obstructive pulmonary disease (COPD) often present with sarcopenia, a condition marked by the loss in quality and quantity of muscle mass that can affect the strength of respiratory muscles. COPD and sarcopenia are also independently associated with oxidative stress. This study aimed to investigate whether oxidative stress biomarkers and respiratory muscle strength are associated with sarcopenia in COPD patients. In a cross-sectional study, 86 elderly subjects, including subjects with and without COPD were assessed for body composition, maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) and oxidative stress parameters [substances reactive to thiobarbituric acid (TBARS), ferric reducing ability of plasma (FRAP), superoxide dismutase (SOD), and catalase (CAT)]. The sample was mainly composed by males (72.1%) and eutrophic subjects. COPD-related sarcopenia was evidenced in 51.1% (22/43) of subjects with COPD. The highest TBARS and CAT, and lower MIP and MEP were associated with a high probability of having COPD-related sarcopenia. In the multivariate analysis, TBARS (OR: 4.89, 95% CI 1.52 to 15.54, p=0.006), CAT (OR: 1.22, 95% CI 1.03 to 1.45, p=0.020) and MEP (OR: 0.97, 95% CI 0.95 to 0.99, p=0.020) were independent determinants of COPD-related sarcopenia. The increase in oxidative stress-related factors and the reduction of respiratory muscle strength are associated with COPD-related sarcopenia.

Effect of upright and slouched postures on the diaphragm strength and chest expansion in obese young adults – An Observational Study

Context: Obese individuals are at high risk of adopting slouched posture because of their excessive body fat distribution. Moreover, excess body fat limits the action of the respiratory muscles and restricts diaphragm mobility and rib movement.Aims: The aim of this study was to study the influence of upright versus slouched posture on respiratory muscle strength and chest expansion in obese young adults.Settings and Design: The participants included in the study were young adults of all genders between the age group of 18 and 25 years with a body mass index above 27.5.Methods and Materials: It is an observational study. Thirty participants were recruited from health-care institutions. Screening was done according to the inclusion and exclusion criteria. Diaphragm strength and chest expansion were assessed in upright sitting and slouched sitting postures.Statistical analysis used: SPSS statistical package version 23 was used to analyze the data. Normality of the baseline data was checked using Student's t-test. To summarize the data, descriptive statistics (mean and standard deviation) were employed. To discover variations in maximal inspiratory pressure (MIP) scores and chest expansion between slouched and upright sitting positions, a paired t-test analysis was performed.Results: The participants showed a lower MIP score in slouched sitting as compared to an upright sitting posture. The mean difference in the MIP scores was 20.99 mmHg (P = 0.04). Chest expansion measurements also showed a significant difference between the two sitting postures.Conclusions: The lower maximal inspiratory pressure and chest expansion measures observed in this study indicate that in obese individuals, slouched sitting posture can adversely affect the diaphragm strength and the chest wall mechanics during breathing.

Relationship of Lung Function and Inspiratory Strength with Exercise Capacity and Prognosis in Heart Failure.

ResumoFundamento A espirometria é subutilizada na insuficiência cardíaca (IC) e não está claro o grau de associação de cada defeito com a capacidade de exercício e com o prognóstico desses pacientes.Objetivo Determinar a relação da %CVF prevista (ppCVF) e do VEF1/CVF contínuos com: 1) pressão inspiratória máxima (PImáx), fração de ejeção do ventrículo esquerdo (FEVE) e desempenho ao exercício; e 2) prognóstico, para o desfecho composto de morte cardiovascular, transplante cardíaco ou implante de dispositivo de assistência ventricular.Métodos Coorte de 111 participantes com IC (estágios AHA C/D) sem pneumopatia; foram submetidos a espirometria, manovacuometria e teste cardiopulmonar máximo. As magnitudes de associação foram verificadas por regressões lineares e de Cox (HR; IC 95%), ajustadas para idade/sexo, e p <0,05 foi considerado significativo.Resultados Com idade média 57±12 anos, 60% eram homens, 64% em NYHAIII. A cada aumento de 10% no VEF1/CVF [β 7% (IC 95%: 3-10)] e no ppCVF [4% (2-6)], foi associado à reserva ventilatória (VRes); no entanto, apenas o ppCVF associado à PImáx [3,8cmH2O (0,3-7,3)], à fração de ejeção do ventrículo esquerdo (FEVE) [2,1% (0,5-3,8)] e ao VO2 pico [0,5mL/kg/min (0,1-1,0)], considerando idade/sexo. Em 2,2 anos (média), ocorreram 22 eventos; tanto FEV1/FVC (HR 1,44; IC 95%: 0,97-2,13) quanto ppCVF (HR 1,13; 0,89-1,43) não foram associados ao desfecho. Apenas no subgrupo FEVE ≤50% (n=87, 20 eventos), VEF1/CVF (HR 1,50; 1,01-2,23), mas não ppCVF, foi associado a risco.Conclusão Na IC crônica, ppCVF reduzido associou-se a menor PImáx, FEVE, VRes e VO2 pico, mas não distinguiu pior prognóstico em 2,2 anos de acompanhamento. Entretanto, VEF1/CVF associou-se apenas com VRes, e, em participantes com FEVE ≤50%, o VEF1/CVF reduzido mostrou pior prognóstico proporcional. Portanto, VEF1/CVF e ppFVC contribuem para melhor fenotipagem de pacientes com IC.

Cut-off Values of the Respiratory Muscle Power and Peak Cough Flow in Post-Stroke Dysphagia.

Background and objectives: This study aimed to determine the cut-off values of the following three respiratory pressure meters; the voluntary peak cough flow (PCF), maximal expiratory pressure (MEP) and maximal inspiratory pressure (MIP); associated with post-stroke dysphagia and assess which of these parameters show good diagnostic properties associated with post-stroke dysphagia. Materials and Methods: Retrospective analysis of a prospectively maintained database. Records of patients with first-ever diagnosed dysphagia attributable to cerebrovascular disease, who had performed spirometry measurements for the PCF, MIP and MEP. Results: From a total of 237 stroke patients, 163 patients were diagnosed with dysphagia. Those with dysphagia had significantly lower PCF values than those without dysphagia (116.3 ± 75.3 vs. 219.4 ± 91.8 L/min, p < 0.001). In addition, the former group also had lower MIP (30.5 ± 24.7 vs. 41.6 ± 25.7 cmH2O, p = 0.0002) and MEP (41.0 ± 27.9 vs. 62.8 ± 32.3 cmH2O, p < 0.001) values than the latter group. The receiver operating characteristic curve analysis showed that the PCF cut-off value of 151 L/min (area under the receiver operating characteristic curve [AUC] 0.81; sensitivity 72%; specificity 78.8%) was associated with post-stroke dysphagia. The optimum MEP and MIP cut-off were 38 cmH2O (AUC 0.70, sensitivity 58%; specificity 77.7%) and 20 cmH2O (AUC 0.65, sensitivity 49%; specificity 84%). PCF showed the highest AUC results. Results from the univariate analysis indicated that PCF values of ≤151 L/min increased risk of dysphagia by 9.51-fold (4.96–18.23). Multivariable analysis showed that after controlling of other clinical factor, the PCFs at this cut-off value still showed increased risk of by 4.19 (2.02–83.69) but this was not observed with the MIPs or MEPs. Conclusions: Our study has provided cut-off values that are associated with increased risk of dysphagia. Among the three parameters, PCF showed increased association with post-stroke dysphagia.

Exercise training increases respiratory muscle strength and exercise capacity in patients with chronic obstructive pulmonary disease and respiratory muscle weakness

BackgroundHow respiratory muscle strength influences the effectiveness of pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD) is unclear. ObjectiveTo investigate the benefits of PR in subjects with COPD according to respiratory muscle strength. MethodsNinety-seven subjects with COPD were evaluated using maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), pulmonary function tests, the cardiopulmonary exercise test (CPET), and the St. George's Respiratory Questionnaire (SGRQ). Subjects were divided into four groups: 1 (normal MIP and MEP); 2 (low MIP); 3 (low MEP); and 4 (low MIP and MEP). Subjects underwent PR for 3 months; MIP, MEP, SGRQ, and CPET were evaluated post-PR. ResultsSubjects with both poor MIP and MEP had the highest dyspnea score, lowest exercise capacity, and poorest health-related quality of life (HRQoL). PR improved exercise capacity and HRQoL in all groups, with more improvement in MIP, MEP, tidal volume (on exercise), and dyspnea (at rest) in subjects with both low MIP and MEP. ConclusionsPatients with respiratory muscle weakness had worse dyspnea, lower exercise capacity, and poorer HRQoL at baseline. Exercise training improved respiratory muscle strength with concurrent improvement of exercise capacity, HRQoL, and dyspnea score. Subjects with both poor baseline MIP and MEP showed greater benefits of PR.

Serum neurofilament light chain at time of diagnosis is an independent prognostic factor of survival in amyotrophic lateral sclerosis.

The prognostic value of serum neurofilament light chain (sNfL), a biomarker of neurodegeneration, compared to other prognostic factors of amyotrophic lateral sclerosis (ALS) at the time of diagnosis, remains unclear. Sera from ALS patients were prospectively collected at the first diagnostic visit in our centre. sNfL levels were determined by single molecule array in 207 ALS patients and in 21 healthy controls. The prognostic value of sNfL was compared with that of other known clinical prognostic factors using a Cox regression model and multivariate analysis. Serum neurofilament light chain levels were higher in ALS patients than in controls (P<0.0001). Seven parameters were predictive of death in ALS: older age, bulbar onset, higher ALS Functional Rating Scale revised (ALSFRS-R) score, greater weight loss, lower maximal inspiratory pressure, forced vital capacity and higher sNfL levels. A Cox regression model showed that sNfL (P<0.0001), weight loss (P=0.040) and site at onset (P=0.048) were independent predictive factors of death. In a sub-cohort restricted to 139 patients with complete spirometry data, sNfL level (P<0.005) and forced vital capacity (P=0.022) were independent factors predictive of death. In a subgroup of 142 patients in whom ALSFRS-R score was available at several time points, sNfL levels positively correlated with ALSFRS-R rate of decline (r=0.571, P<10-12 ). Higher sNfL concentration is a strong and independent prognostic factor of death in ALS as early as the time of diagnosis.

Effects of inspiratory muscle strength and inspiratory resistance on neck inspiratory muscle activation during controlled inspirations.

What is the central question of this study? What factors influence the onset and magnitude of activation of the neck inspiratory muscles during inspiration? What is the main finding and its importance? Recruitment of the sternocleidomastoid and scalene muscles during inspiration, measured by means of surface EMG, was strongly correlated with maximal inspiratory pressure. This result indicates that muscle recruitment depends on the capacity of an individual to generate inspiratory pressure. Surface measurements of neck inspiratory muscle EMG activity might complement tests currently used for the screening of respiratory-related disease. The aims of the present study were as follows: (i) to examine the relationship between the onset of recruitment of the neck inspiratory muscles and inspiratory muscle strength; and (ii) to clarify the effect of inspiratory resistance on neck inspiratory muscle activation during inspiration at specific flow rates and to specific lung volumes. Inspiratory muscle strength, as indicated by maximal inspiratory pressure (MIP), and peak inspiratory flow rate (PFR) were measured in healthy participants. Subsequently, participants inspired at target inspiratory flow rates between 20 and 100% of PFR as closely as possible, with and without artificial inspiratory resistance. Electromyographic activity (EMGRMS ) of the sternocleidomastoid and scalene muscles was measured from surface electrodes at each target flow rate for each 10% increment of forced vital capacity (FVC) between 20 and 50% of FVC. Recruitment onset for each muscle was determined from %PFR-EMGRMS curves at each lung volume (%FVC). Finally, linear regression analyses were performed for MIP and recruitment onset for each muscle at each %FVC. Recruitment onset during inspiration without inspiratory resistance was strongly correlated with MIP (r>0.60, P<0.040). Specifically, a lower MIP was associated with earlier muscle recruitment (i.e. recruitment at a lower flow rate), especially for the sternocleidomastoid muscle (r>0.75, P<0.005). Recruitment of both neck inspiratory muscles at a given flow rate was also earlier when inspiratory resistance was added (P=0.002). These results indicate that the recruitment and activation of the neck inspiratory muscles depends on both inspiratory muscle strength and inspiratory resistance.

Pontos de corte da função pulmonar e capacidade funcional determinantes para sarcopenia e dinapenia em pacientes com DPOC

ABSTRACTObjectiveTo establish a cut-off point for clinical and functional variables to determinate sarcopenia and dynapenia in COPD patients, and to analyze the impact of skeletal muscle dysfunction (SMD) on these variables.MethodsCross-sectional study, screened COPD patients for sarcopenia or dynapenia through low muscle mass and hand grip strength (HGS). Clinical variables: pulmonary function, respiratory muscle strength and functional capacity (FC). The precision of the variables in determining points of predictive cut-off for sarcopenia or dynapenia were performed using the Receiver Operating Characteristic curve and two-way analysis of variance.Results20 COPD patients stratified for sarcopenia (n = 11) and dynapenia (n = 07). Sarcopenia group presented lower lean mass and lower maximal inspiratory pressure (MIP), decreased HGS, reduced FC (p<0.050). Dynapenia group presented reduced MIP, lower HGS and walked a shorter distance at Incremental shuttle walk test (ISWT) (p<0.050). We found cut-off points of forced expiratory volume in one second (FEV1), MIP and maximal expiratory pressure (MEP) and ISWT. It is possible to identify sarcopenia or dynapenia in these patients. We found the coexistence of the conditions (SMD effect) in COPD – reduction in the distance in the ISWT (p = 0.002) and %ISWT (p = 0.017).ConclusionIn moderate to very severe COPD patients the sarcopenia could be predicted by FEV1 (%predicted) < 52, MIP < 73 cmH2O, MEP < 126 cmH2O and distance traveled of < 295 m in ISWT. Whereas dynapenia could be predicted by FEV1 < 40%, MIP < 71 cmH2O, MEP < 110 cmH2O and distance of < 230 m traveled in ISWT.

Nutritional status and pulmonary outcome in children and young people with cystic fibrosis.

Nutrition is closely related to mortality and pulmonary and respiratory muscle function in cystic fibrosis (CF) patients. We initially validated results from a bioelectrical impedance device against dual energy x-ray absorptiometry (DEXA). We then determined whether fat free mass assessed by a portable impedance device rather than body mass index (BMI) better correlated with pulmonary function, respiratory muscle strength and exercise capacity in CF patients. Eighteen young people and adults (median age 19, range 12-39 years) with CF had dual energy X-ray absorptiometry and direct segmental multi-frequency impedance analysis. Body composition, pulmonary function, respiratory muscle function and exercise tolerance using the impedance device were measured in 29 young people with CF with median age 15 (range 12-19) years. There was a significant correlation between impedance and absorptiometry results (r2 = 0.947). Fat free mass correlated with the forced vital capacity z-score (r = 0.442, p = 0.016), maximal inspiratory pressure (r = 0.451, p = 0.014) and exercise tolerance (r = 0. 707, p < 0.001). BMI z-scores did not significantly correlate with pulmonary or respiratory muscle function. Subjects with a fat free mass z-score of ≤2 had a lower forced expiratory volume in 1 s z-score (p = 0.007), lower forced vital capacity z-score (p = 0.001), higher residual volume z-score (p = 0.042), lower maximal inspiratory pressure (p = 0.039), more days of intravenous antibiotics per year (p = 0.016) and a higher rate of chronic infections (p = 0.006). Fat-free mass measured by impedance correlated better with pulmonary and respiratory muscle function and exercise capacity than BMI.

Establishing failure predictors for the planned extubation of overweight and obese patients.

We investigated failure predictors for the planned extubation of overweight (body mass index [BMI] = 25.0–29.9) and obese (BMI ≥ 30) patients. All patients admitted to the adult intensive care unit (ICU) of a tertiary hospital in Taiwan were identified. They had all undergone endotracheal intubation for > 48 h and were candidates for extubation. During the study, 595 patients (overweight = 458 [77%]); obese = 137 [23%]) with planned extubation after weaning were included in the analysis; extubation failed in 34 patients (5.7%). Their mean BMI was 28.5 ± 3.8. Only BMI and age were significantly different between overweight and obese patients. The mortality rate for ICU patients was 0.8%, and 2.9% for inpatients during days 1–28; the overall in-hospital mortality rate was 8.4%. Failed Extubation group patients were significantly older, had more end-stage renal disease (ESRD), more cardiovascular system-related respiratory failure, higher maximal inspiratory pressure (MIP), lower maximal expiratory pressure (MEP), higher blood urea nitrogen, and higher ICU- and 28-day mortality rates than did the Successful Extubation group. Multivariate logistic regression showed that cardiovascular-related respiratory failure (odds ratio [OR]: 2.60; 95% [confidence interval] CI: 1.16–5.80), ESRD (OR: 14.00; 95% CI: 6.25–31.35), and MIP levels (OR: 0.94; 95% CI: 0.90–0.97) were associated with extubation failure. We conclude that the extubation failure risk in overweight and obese patients was associated with cardiovascular system-related respiratory failure, ESRD, and low MIP levels.

Significant Clinical Factors Associated with Long-term Mortality in Critical Cancer Patients Requiring Prolonged Mechanical Ventilation

Studies about prognostic assessment in cancer patients requiring prolonged mechanical ventilation (PMV) for post-intensive care are scarce. We retrospectively enrolled 112 cancer patients requiring PMV support who were admitted to the respiratory care center (RCC), a specialized post-intensive care weaning facility, from November 2009 through September 2013. The weaning success rate was 44.6%, and mortality rates at hospital discharge and after 1 year were 43.8% and 76.9%, respectively. Multivariate logistic regression showed that weaning failure, in addition to underlying cancer status, was significantly associated with an increased 1-year mortality (odds ratio, 6.269; 95% confidence interval, 1.800–21.834; P = 0.004). Patients who had controlled non-hematologic cancers and successful weaning had the longest median survival, while those with other cancers who failed weaning had the worst. Patients with low maximal inspiratory pressure, anemia, and poor oxygenation at RCC admission had an increased risk of weaning failure. In conclusion, cancer status and weaning outcome were the most important determinants associated with long-term mortality in cancer patients requiring PMV. We suggest palliative care for those patients with clinical features associated with worse outcomes. It is unknown whether survival in this specific patient population could be improved by modifying the risk of weaning failure.

Weakness acquired in the intensive care unit. Incidence, risk factors and their association with inspiratory weakness. Observational cohort study.

ObjectiveThis paper sought to determine the accumulated incidence and analyze the risk factors associated with the development of weakness acquired in the intensive care unit and its relationship to inspiratory weakness.MethodsWe conducted a prospective cohort study at a single center, multipurpose medical-surgical intensive care unit. We included adult patients who required mechanical ventilation ≥ 24 hours between July 2014 and January 2016. No interventions were performed. Demographic data, clinical diagnoses, the factors related to the development of intensive care unit -acquired weakness, and maximal inspiratory pressure were recorded.ResultsOf the 111 patients included, 66 developed intensive care unit -acquired weakness, with a cumulative incidence of 40.5% over 18 months. The group with intensive care unit-acquired weakness were older (55.9 ± 17.6 versus 45.8 ± 16.7), required more mechanical ventilation (7 [4 - 10] days versus 4 [2 - 7.3] days), and spent more time in the intensive care unit (15.5 [9.2 - 22.8] days versus 9 [6 - 14] days). More patients presented with delirium (68% versus 39%), hyperglycemia > 3 days (84% versus 59%), and positive balance > 3 days (73.3% versus 37%). All comparisons were significant at p < 0.05. A multiple logistic regression identified age, hyperglycemia ≥ 3 days, delirium, and mechanical ventilation > 5 days as independent predictors of intensive care unit-acquired weakness. Low maximal inspiratory pressure was associated with intensive care unit-acquired weakness (p < 0.001), and the maximum inspiratory pressure cut-off value of < 36cmH2O had sensitivity and specificity values of 31.8% and 95.5%, respectively, when classifying patients with intensive care unit-acquired weakness.ConclusionThe intensive care unit acquired weakness is a condition with a high incidence in our environment. The development of intensive care unit-acquired weakness was associated with age, delirium, hyperglycemia, and mechanical ventilation > 5 days. The maximum inspiratory pressure value of ≥ 36cmH2O was associated with a high diagnostic value to exclude the presence of intensive care unit -acquired weakness.

Evaluation of the Maximal Respiratory Pressure in Children and Adolescents with Asthma between 7 and 14 Years Old

Objectives: To evaluate the respiratory muscle strength among children (<10 years old) and adolescents with asthma. Methods: This is a cross-sectional, retrospective study, among children and adolescents (7 years to 14 years of age) with asthma. Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) [in cmH2O] were measured through digital manometer. The variables evaluated were: gender, age, BMI (body mass index), severity of asthma, use of inhaled corticosteroid (IC). Results: A total of 48 individuals were studied. MIP values were according: a) normal weight=69.5 ± 22.6; overweight=81.6 ± 25.4 (p<0.088); b) use of inhaled corticosteroid=70.5 ± 23.0; no use=25.1 ± 86.3 (p<0.045). MEP values according: a) ages 7-9 years=78.8 ± 19.4; 10-14 years=68.1 ± 22.7 (p<0.097); b) normal weight=66.1 ± 18.9; overweight=80.3 ± 23.3 (p<0.024); c) use of inhaled corticosteroid=68.3 ± 18.3; no use=83.1 ± 27.5 (p<0.036); d) with bronchiectasis=61.8 ± 19.2; without bronchiectasis=83.1 ± 27.5 (p<0.069). Conclusions: Patients who used inhaled corticosteroid had MIP and MEP lower than the others; patients with normal BMI tended to have lower MEP than the overweight group and lower MIP in the group of normal weight. There was a tendency of adolescents to present lower MEP than children.

Maximal Inspiratory Pressure: Does the Choice of Reference Values Actually Matter?

Single-point measurements of maximal inspiratory pressure (MIP) are frequently used to suggest muscle weakness in clinical practice. Although there is a large variability in "mean" predicted MIP depending on the chosen reference values, it remains unclear whether those discrepancies actually impact on the prevalence of weakness, that is, MIP below the lower limit of normal. A total of 1,729 subjects (50.1%men, aged 20 to 94 years) who underwent MIP measurements in a clinical laboratory comprised the study group. MIP was predicted according to the most frequently cited regression equations as of August 2015. Pretest probability of weakness was defined by a cluster of clinical and physiologic variables. Prevalence of weakness ranged from 33.4 to 66.9%. Set 2 equations agreed well in indicating weakness (κ [95%CI] ranging from 0.81 [0.79-0.83] to 0.83 [0.81-0.85]; P< .01). There was closer agreement between higher pretest probability of weakness and low MIP according to set 2 equations compared with set 1 equations. Thus, a significant fraction of subjects with abnormal MIP according to set 1 equations but preserved MIP according to set 2 equations had higher pretest probability of weakness (P< .05). The choice of MIP reference values strongly impacts on the prevalence of weakness. Some specific equations relate better to clinical and physiologic indicators of weakness, suggesting that they might be particularly useful to screen subjects for advanced respiratory neuromuscular assessment.

Respiratory weakness after mechanical ventilation is associated with one-year mortality - a prospective study.

BackgroundDiaphragm dysfunction in mechanically ventilated patients is associated with poor outcome. Maximal inspiratory pressure (MIP) can be used to evaluate inspiratory muscle function. However, it is unclear whether respiratory weakness is independently associated with long-term mortality. The aim of this study was to determine if low MIP is independently associated with one-year mortality.MethodsWe conducted a prospective observational cohort study in an 18-bed ICU. Adults requiring at least 24 hours of mechanical ventilation with scheduled extubation and no evidence of pre-existing muscle weakness underwent MIP evaluation just before extubation. Patients were divided into two groups: low MIP (MIP ≤30 cmH2O) and high MIP (MIP >30 cmH2O). Mortality was recorded for one year after extubation. For the survival analysis, the effect of low MIP was assessed using the log-rank test. The independent effect of low MIP on post mechanical ventilation mortality was analyzed using a multivariable Cox regression model.ResultsOne hundred and twenty-four patients underwent MIP evaluation (median age 66 years (25th–75th percentile 56–74), Simplified Acute Physiology Score (SAPS) 2 = 45 (33–57), duration of mechanical ventilation 7 days (4–10)). Fifty-four percent of patients had low MIP. One-year mortality was 31 % (95 % CI 0.21, 0.43) in the low MIP group and 7 % (95 % CI 0.02, 0.16) in the high MIP group. After adjustment for SAPS 2 score, body mass index and duration of mechanical ventilation, low MIP was independently associated with one-year mortality (hazard ratio 4.41, 95 % CI 1.5, 12.9, p = 0.007). Extubation failure was also associated with low MIP (relative risk 3.0, 95 % CI 1, -9.6; p = 0.03) but tracheostomy and ICU length of stay were not.ConclusionLow MIP is frequent in patients on mechanical ventilation and is an independent risk factor for long-term mortality in ICU patients requiring mechanical ventilation. MIP is easily evaluated at the patient’s bedside.Trial RegistrationThis study was retrospectively registered in www.clinicaltrials.gov (NCT02363231) in February 2015.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-016-1418-y) contains supplementary material, which is available to authorized users.

Identification and comparison of the predictors of maximal inspiratory force and handgrip in a healthy elderly population. The proof study

A severe weakness of peripheral muscles occurs in half of the persons aged 80 years or older. The common factors between muscle depletion and reduced respiratory strength have not yet been established. In the subjects of the Proof cohort, we aimed to identify, among body composition, pulmonary function and energy expenditure parameters, the predictors of maximal inspiratory pressure (MIP) as an index of respiratory muscle strength and handgrip (HG) as an index of peripheral muscle strength. In 375 healthy elderly subjects aged 72±1 years, fat mass (FM) and fat free mass (FFM) were assessed by DEXA, the last being also indexed to height (FFMI). Spirometry was performed and daily energy expenditure (DEE) was estimated by a questionnaire. After three years, MIP and HG of the dominant arm were determined and the predicting value of pulmonary function tests, body composition and DEE on these parameters was tested. Mean MIP and HG were 77±26% and 106±19% of the predicted value (%pred) with 90 (24%) and 30 (8%) subjects below standards, respectively. There was a significant but weak correlation between MIP%pred and HG%pred (r=0.175, p<0.001). Logistic regression showed that low MIP was predicted by trunk FFM and FFMI in women, and DEE in men. Low HG was predicted by trunk FM in men only. The predictors of a reduction of MIP in the elderly differ from those of HG, suggesting a differential regulation of respiratory muscle and arm strength.

Exercise capacity of cirrhotic patients with hepatopulmonary syndrome

Introduction. Hepatopulmonary syndrome (HPS) is characterized by a clinical triad of liver disease and/or portal hypertension, intrapulmonary vascular dilatation and abnormal arterial oxygenation. These conditions can worsen muscle strength, exercise capacity and functionality in the affected population.Objective. The objective of this study was to compare exercise capacity, functional condition and respiratory muscle strength in cirrhotic patients diagnosed with HPS and cirrhotic patients without this diagnosis.Material and methods. This cross-sectional study used a convenience sample consisting of 178 patients (92 patients with HPS and 86 patients without HPS) with a diagnosis of liver cirrhosis caused by either alcohol consumption or the hepatitis C virus (HCV). Peak oxygen consumption (VO2 peak) was used to verify exercise capacity, the six-minute walk test (6MWT) was used to test functionality, and manovacuometry was used to evaluate the strength of the respiratory muscles. The Kolmogorov-Smirnov test and Student’s t-test were used for the statistical analysis. The data were analyzed using SPSS 16.00, and p < 0.05 was considered significant.Results. The group of patients with the diagnosis of HPS exhibited a lower VO2 peak (14.2 ± 2.3 vs. 17.6 ± 2.6, p < 0.001), shorter distance walked in the 6MWT (340.8 ± 50.9 vs. 416.5 ± 91.4, p < 0.001), lower maximal inspiratory pressure (-49.1 ± 9.8 vs. -74.2 ± 13.9, p = 0.001) and lower maximum expiratory pressure (60.1 ± 12.2 vs. 76.8 ± 14.7, p = 0.001).Conclusion. The group of cirrhotic patients diagnosed with HPS exhibited lower values for VO2 peak, distance walked in the 6MWT and respiratory muscle strength than the cirrhotic patients not diagnosed with HPS.