Correlação entre capacidade funcional, força muscular respiratória e força de preensão palmar em candidatos a transplante de fígado / Correlation of functional capacity, respiratory muscle strength, and hand grip strength in liver transplant candidates

Introdução: O transplante de fígado (TxF) é o procedimento padrão recomendado para pacientes com doença hepática terminal. Muitos, enquanto aguardam o TxF apresentam como deterioração funcional a diminuição da força muscular respiratória, força de preensão palmar e capacidade funcional. O objetivo deste estudo foi correlacionar a capacidade funcional, força muscular respiratória e força de preensão palmar em candidatos a transplante de fígado. Métodos: Trata-se de um estudo observacional, prospectivo, quantitativo. Participaram do estudo pacientes candidatos ao TxF que estavam em tratamento na unidade de transplante de fígado em um hospital de referência no noroeste paulista. Os pacientes foram avaliados por meio de: teste de caminhada de seis minutos, manovacuometria e dinamometria. Para análise dos dados foi utilizado o teste de correlação linear de Pearson. Valores de p ≤ 0,05 foram considerados significantes. Resultados: Foram avaliados 38 pacientes cirróticos no pré-operatório de TxF. A média de idade dos pacientes foi de 54,34 ± 8,18 anos, com predominância do gênero masculino (68%), a média do MELD e do IMC foram de 20,84 ± 6,26 pontos e 27,75 ± 5,0 kg/m2, respectivamente. Na força muscular respiratória verificou-se que os pacientes apresentaram média de pressão inspiratória máxima (PImáx) 75,89% e pressão expiratória máxima (PEmáx) 76,82% do predito. Nas análises de correlações entre as variáveis do estudo verificou-se correlação diretamente proporcional, significativa (p ≤ 0,0001) e forte entre preensão manual vs força muscular respiratória, moderada entre preensão manual vs capacidade funcional e moderada entre força muscular respiratória vs capacidade funcional. Conclusão: Os pacientes candidatos a TxF apresentaram correlação positiva entre capacidade funcional, força muscular respiratória e força de preensão palmar. Alterações na força muscular respiratória e de preensão palmar se correlacionaram a redução na capacidade funcional nestes pacientes.

Introduction: Liver transplantation (TxF) is the standard procedure recommended for patients with terminal liver disease. Many, while waiting for the TxF present as functional deterioration the decrease in respiratory muscle strength, hand grip strength, and functional capacity. The aim of this study was correlate functional capacity, respiratory muscle strength, and hand grip strength in liver transplant candidates. Methods: This is an observational, prospective, quantitative study. Candidates for TxF who were being treated at the liver transplant unit in a referral hospital in northwest São Paulo participated in the study. The patients were evaluated using: six- minute walk test, manovacuometry, and dynamometry. Pearson's linear correlation test was used for data analysis. Values of p ≤ 0.05 were considered significant. Results: A total of 38 cirrhotic patients were evaluated in the preoperative period of TxF. The mean age of the patients was 54.34 ± 8.18 years, with a predominance of males (68%), the mean MELD and BMI were 20.84 ± 6.26 points and 27.75 ± 5.0 kg/m2, respectively. Regarding respiratory muscle strength, it was found that patients had a mean maximum inspiratory pressure (PImax) 75.89% and maximum expiratory pressure (PEmax) 76.82% of the predicted. In the analysis of correlations between the study variables, there was a directly proportional, significant (p ≤ 0.0001) and strong correlation between hand grip vs respiratory muscle strength, moderate between hand grip vs functional capacity and moderate between respiratory muscle strength vs functional capacity. Conclusion: Candidate patients for TxF showed a positive correlation between functional capacity, respiratory muscle strength, and hand grip strength. Changes in respiratory muscle strength and hand grip was correlated with the reduction in functional capacity in these patients.

Expiratory muscle dysfunction in critically ill patients: towards improved understanding.

INTRODUCTION: This narrative review summarizes current knowledge on the physiology and pathophysiology of expiratory muscle function in ICU patients, as shared by academic professionals from multidisciplinary, multinational backgrounds, who include clinicians, clinical physiologists and basic physiologists. RESULTS: The expiratory muscles, which include the abdominal wall muscles and some of the rib cage muscles, are an important component of the respiratory muscle pump and are recruited in the presence of high respiratory load or low inspiratory muscle capacity. Recruitment of the expiratory muscles may have beneficial effects, including reduction in end-expiratory lung volume, reduction in transpulmonary pressure and increased inspiratory muscle capacity. However, severe weakness of the expiratory muscles may develop in ICU patients and is associated with worse outcomes, including difficult ventilator weaning and impaired airway clearance. Several techniques are available to assess expiratory muscle function in the critically ill patient, including gastric pressure and ultrasound. CONCLUSION: The expiratory muscles are the "neglected component" of the respiratory muscle pump. Expiratory muscles are frequently recruited in critically ill ventilated patients, but a fundamental understanding of expiratory muscle function is still lacking in these patients.

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

BACKGROUND: Diaphragm 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. METHODS: We 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. RESULTS: One hundred and twenty-four patients underwent MIP evaluation (median age 66 years (25(th)-75(th) 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. CONCLUSION: Low 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 REGISTRATION: This study was retrospectively registered in www.clinicaltrials.gov (NCT02363231) in February 2015.

Efectividad de la estimulación eléctrica en los músculos respiratorios / Effectiveness of electrical stimulation of the respiratory muscles

El buen funcionamiento de los músculos respiratorios es de vital importancia para el mantenimiento de un sistema ventilatorio correcto. Una de las técnicas que se viene utilizando de manera novedosa para el tratamiento de las disfunciones respiratorias es la electroterapia. Por ello, el objetivo de esta revisión es evaluar la efectividad de la estimulación eléctrica aplicada en los músculos respiratorios, en cuanto a la mejora en la función pulmonar, en términos de fuerza muscular y capacidades pulmonares. Para ello se ha realizado una búsqueda bibliográfica en las bases de datos MEDLINE, PUBMED, CINHAL y SCOPUS y en S-CIELO de los artículos publicados entre 2009 y 2014. Se analizaron 13 artículos que superaron los criterios de inclusión y exclusión. Se concluye que se necesita una investigación más profunda para sacar conclusiones definitivas, pero la estimulación eléctrica de los músculos respiratorios parece ser una técnica eficaz en la mejora de la función ventilatoria (AU)

Good respiratory muscle function is vital to maintain a correctly functioning respiratory system. Electrotherapy has been used as a novel technique for the treatment of respiratory disorders. The aim of this review was to evaluate the effectiveness of electrical stimulation applied to the respiratory muscles, in terms of improvement in function lung, muscle strength and lung capacity. A literature search was conducted in MEDLINE, PUBMED, CINAHL and SCOPUS and S-CIELO for articles published between 2009 and 2014. Thirteen articles were analysed that met the inclusion and exclusion criteria. Further research is needed to draw definitive conclusions, but electrical stimulation of the respiratory muscles appears to be an effective technique in improving respiratory function (AU)

Pulmonary hypoplasia in the myogenin null mouse embryo.

Although fetal breathing movements are required for normal lung development, there is uncertainty concerning the specific effect of absent fetal breathing movements on pulmonary cell maturation. We set out to evaluate pulmonary development in a genetically defined mouse model, the myogenin null mouse, in which there is a lack of normal skeletal muscle fibers and thus skeletal muscle movements are absent in utero. Significant decreases were observed in lung:body weight ratio and lung total DNA at embryonic days (E)14, E17, and E20. Reverse transcriptase/polymerase chain reaction, in situ immunofluorescence, and electron microscopy revealed early lung cell differentiation in both null and wild-type lungs as early as E14. However at E14, myogenin null lungs had decreased 5'-bromo-2-deoxyuridine incorporation compared with that of wild-type littermates, whereas at E17 and E20, increased Bax immunolabeling and terminal deoxyribonucleotidyl transferase-mediated dUTP-biotin nick-end labeling staining were detected in the myogenin null mice but not in the wild-type littermates. These observations highlight the importance of skeletal muscle contractile activity in utero for normal lung organogenesis. Null mice lacking the muscle-specific transcription factor myogenin exhibit a secondary effect on lung development such that decreased lung cell proliferation and increased programmed cell death are associated with lung hypoplasia.

Autosomal dominant myopathy with proximal weakness and early respiratory muscle involvement maps to chromosome 2q.

Two Swedish families with autosomal dominant myopathy, who also had proximal weakness, early respiratory failure, and characteristic cytoplasmic bodies in the affected muscle biopsies, were screened for linkage by means of the human genome screening set (Cooperative Human Linkage Center Human Screening Set/Weber version 6). Most chromosome regions were completely excluded by linkage analysis (LOD score <-2). Linkage to the chromosomal region 2q24-q31 was established. A maximum combined two-point LOD score of 4.87 at a recombination fraction of 0 was obtained with marker D2S1245. Haplotype analysis indicated that the gene responsible for the disease is likely to be located in the 17-cM region between markers D2S2384 and D2S364. The affected individuals from these two families share an identical haplotype, which suggests a common origin.

Involvement of respiratory muscles in cytoplasmic body myopathy--a pathology study.

A muscle biopsy and autopsy study of a child who died at 14 months of respiratory failure is described. A diagnosis of infantile cytoplasmic body myopathy was made due to the high percentage of cytoplasmic bodies (CBs), particularly in respiratory muscles. No pathological abnormalities were found in the central nervous system, peripheral nerves or visceral organs. Immunohistochemical studies suggested that the central core of CBs was stained for fibrillary actin, being surrounded by a positive signal for desmin. A differential diagnosis as to other conditions involving proliferation of CBs is discussed.

A case of the scalenus anterior muscle passing behind the left subclavian artery.

The scalenus anterior muscle was found to pass behind the left subclavian artery and the first thoracic nerve in a 95-year-old Japanese woman. The scalenus anterior muscle originates from the fifth and sixth cervical vertebrae and inserts on the first rib more dorsal than typical. It is innervated by the fifth and seventh cervical nerves. The muscle belly is thin. The scalenus minimus was not found. The left vertebral artery originates from the aortic arch and enters the transverse foramen of the fifth cervical vertebra. The primary vertebral artery arises from the costocervical artery. The internal thoracic artery originates from the subclavian artery more distally than typical. The axillary artery crosses the brachial plexus between the eighth cervical and first thoracic nerves. Because the first thoracic nerve joins the brachial plexus more distally than usual, the plexus has no typical inferior trunk. Comparative anatomy shows that the muscles, nerves and arteries of the lateral cervical region of the present case maintains primitive characteristics. From the functional viewpoint, the mechanical efficiency of the scalenus anterior muscle is probably lower than usual due to the lower point of origin and the dorsal shift of the insertion.