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1.
J Sports Med Phys Fitness ; 60(8): 1101-1109, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32955836

RESUMO

BACKGROUND: Minimizing the energy required for breathing muscles is based on the adaptation of the respiratory muscles which is reflected in the reduction of breathing frequency (BF) and tidal volume (VT) increase. This may be influenced through a targeted BE and the quality of breathing may be linked to endurance performance. Aim of this study was assess dynamic ventilation parameters at different load intensities and their changes due to the systematic breathing exercise (BE). METHODS: Study recruit 36 runners of both sexes with a mean age 16.8±1.6 years. A random distribution was performed. The intervention program consisted of a set of BE aimed at the activation of the diaphragm. We monitored the dynamics of ventilation parameters at intensities 2, 3, 4 W/kg during a stepped test on a bicycle ergometer. RESULTS: The BE was focused on the activation of the diaphragm for a 12.2±3.6 minutes per day, sixteen weeks. After eight weeks, there were significant changes in VT and BF (P<0.05). After sixteen weeks there was a significant increase in VT of 5.7-18.3% (P<0.01), depending on the load level, BF values decreased significantly by 5.4-14.4% (P<0.01). VE and VO2 values were without changes. There were no significant changes in the control group. CONCLUSIONS: It was confirmed that the two-month BE intervention focused on the activation of the diaphragm is sufficient and resulted in a significant change in the values of dynamic ventilation parameters. After four months of intervention, the changes are significantly greater compared with values found after a two-month intervention period.


Assuntos
Exercícios Respiratórios/métodos , Resistência Física/fisiologia , Respiração , Músculos Respiratórios/fisiologia , Adolescente , Diafragma/fisiologia , Teste de Esforço , Feminino , Humanos , Masculino , Corrida/fisiologia , Volume de Ventilação Pulmonar
2.
Am J Respir Crit Care Med ; 202(7): 1005-1012, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32614246

RESUMO

Rationale: Tissue Doppler imaging (TDI) is an echocardiographic method that measures the velocity of moving tissue.Objectives: We applied this technique to the diaphragm to assess the velocity of diaphragmatic muscle motion during contraction and relaxation.Methods: In 20 healthy volunteers, diaphragmatic TDI was performed to assess the pattern of diaphragmatic motion velocity, measure its normal values, and determine the intra- and interobserver variability of measurements. In 116 consecutive ICU patients, diaphragmatic excursion, thickening, and TDI parameters of peak contraction velocity, peak relaxation velocity, velocity-time integral, and TDI-derived maximal relaxation rate were assessed during weaning. In a subgroup of 18 patients, transdiaphragmatic pressure (Pdi)-derived parameters (peak Pdi, pressure-time product, and diaphragmatic maximal relaxation rate) were recorded simultaneously with TDI.Measurements and Main Results: In terms of reproducibility, the intercorrelation coefficients were >0.89 for all TDI parameters (P < 0.001). Healthy volunteers and weaning success patients exhibited lower values for all TDI parameters compared with weaning failure patients, except for velocity-time integral, as follows: peak contraction velocity, 1.35 ± 0.34 versus 1.50 ± 0.59 versus 2.66 ± 2.14 cm/s (P < 0.001); peak relaxation velocity, 1.19 ± 0.39 versus 1.53 ± 0.73 versus 3.36 ± 2.40 cm/s (P < 0.001); and TDI-maximal relaxation rate, 3.64 ± 2.02 versus 10.25 ± 5.88 versus 29.47 ± 23.95 cm/s2 (P < 0.001), respectively. Peak contraction velocity was strongly correlated with peak transdiaphragmatic pressure and pressure-time product, whereas Pdi-maximal relaxation rate was significantly correlated with TDI-maximal relaxation rate.Conclusions: Diaphragmatic tissue Doppler allows real-time assessment of the diaphragmatic tissue motion velocity. Diaphragmatic TDI-derived parameters differentiate patients who fail a weaning trial from those who succeed and correlate well with Pdi-derived parameters.


Assuntos
Estado Terminal , Diafragma/diagnóstico por imagem , Contração Muscular/fisiologia , Ultrassonografia Doppler/métodos , Desmame do Respirador , Idoso , Idoso de 80 Anos ou mais , Procedimentos Cirúrgicos Cardíacos , Coma/fisiopatologia , Coma/terapia , Diafragma/fisiologia , Diafragma/fisiopatologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismo Múltiplo/fisiopatologia , Traumatismo Múltiplo/terapia , Procedimentos Neurocirúrgicos , Período Pós-Operatório , Pressão , Reprodutibilidade dos Testes , Insuficiência Respiratória/fisiopatologia , Insuficiência Respiratória/terapia , Sepse/fisiopatologia , Sepse/terapia , Resultado do Tratamento
3.
Artigo em Inglês | MEDLINE | ID: mdl-32428575

RESUMO

Olesoxime is a cholesterol-like neuroprotective compound that targets to mitochondrial voltage dependent anion channels (VDACs). VDACs were also found in the plasma membrane and highly expressed in the presynaptic compartment. Here, we studied the effects of olesoxime and VDAC inhibitors on neurotransmission in the mouse neuromuscular junction. Electrophysiological analysis revealed that olesoxime suppressed selectively evoked neurotransmitter release in response to a single stimulus and 20 Hz activity. Also olesoxime decreased the rate of FM1-43 dye loss (an indicator of synaptic vesicle exocytosis) at low frequency stimulation and 20 Hz. Furthermore, an increase in extracellular Cl- enhanced the action of olesoxime on the exocytosis and olesoxime increased intracellular Cl- levels. The effects of olesoxime on the evoked synaptic vesicle exocytosis and [Cl-]i were blocked by membrane-permeable and impermeable VDAC inhibitors. Immunofluorescent labeling pointed on the presence of VDACs on the synaptic membranes. Rotenone-induced mitochondrial dysfunction perturbed the exocytotic release of FM1-43 and cell-permeable VDAC inhibitor (but not olesoxime or impermeable VDAC inhibitor) partially mitigated the rotenone-driven alterations in the FM1-43 unloading and mitochondrial superoxide production. Thus, olesoxime restrains neurotransmission by acting on plasmalemmal VDACs whose activation can limit synaptic vesicle exocytosis probably via increasing anion flux into the nerve terminals.


Assuntos
Colestenonas/farmacologia , Fármacos Neuroprotetores/farmacologia , Nervo Frênico/efeitos dos fármacos , Vesículas Sinápticas/efeitos dos fármacos , Canais de Ânion Dependentes de Voltagem/fisiologia , Animais , Colesterol , Diafragma/efeitos dos fármacos , Diafragma/inervação , Diafragma/fisiologia , Exocitose/efeitos dos fármacos , Camundongos , Nervo Frênico/fisiologia , Potenciais Sinápticos/efeitos dos fármacos , Canais de Ânion Dependentes de Voltagem/antagonistas & inibidores
4.
Pediatr Pulmonol ; 55(8): 1969-1973, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32470214

RESUMO

OBJECTIVES: This study aimed to describe postnatal physiological changes in maximum values of peak electrical activity of the diaphragm (Edi) in extremely preterm infants during the preterm period. WORKING HYPOTHESIS: The amplitude and frequency of neural sigh are different at each postmenstrual age in extremely preterm infants. STUDY DESIGN: A retrospective, observational study. PATIENT-SUBJECT SELECTION: Edi values were evaluated in 14 extremely preterm infants with neurally-adjusted ventilatory assist. METHODOLOGY: Data of Edi peak and Edi minimum were collected from a ventilator. Edi-sigh was defined as the Edi peak value that was more than twice as large as the median Edi peak at each postmenstrual week in each patient. The frequency of Edi-sigh, and median values of Edi-sigh, Edi peak, and Edi minimum were evaluated at each postmenstrual week. The Jonckheere-Terpstra test was used to analyze the trend between postmenstrual weeks and Edi values. RESULTS: From 26 to 35 postmenstrual weeks, the number of Edi-sighs per hour significantly increased as postmenstrual weeks increased (P < .001). Furthermore, the median values of Edi-sigh significantly increased as postmenstrual weeks increased (16.9 µV at 26 weeks to 25.4 µV at 35 weeks, P < .001). There were no significant changes in the median values of Edi peak and Edi minimum at each week. CONCLUSIONS: The amplitude and frequency of neural sigh in extremely preterm infants increase with the number of postmenstrual weeks.


Assuntos
Diafragma/fisiologia , Lactente Extremamente Prematuro/fisiologia , Feminino , Humanos , Recém-Nascido , Suporte Ventilatório Interativo , Masculino , Estudos Retrospectivos , Ventiladores Mecânicos
5.
Indian J Gastroenterol ; 39(2): 196-203, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32436177

RESUMO

BACKGROUND: The diagnosis of rumination syndrome is frequently overlooked, and under-recognized; children are subjected to unnecessary testing and inappropriate treatment for a condition which can be diagnosed clinically and managed easily. In the first ever systematic exploration of this condition from India, we present a prospective study on children with chronic vomiting in which rumination emerged as the predominant cause. METHODS: This was a prospective study in which all consecutive children (5-18 years) presenting with chronic or recurrent vomiting of at least 2-month duration were enrolled. Clinical history was assessed by a physician-administered questionnaire. All subjects underwent standard testing followed by additional investigations as required. The ROME III criteria were used. RESULTS: Fifty children (28 boys, age 12.2 + 3 years) were enrolled. Diagnosis was rumination syndrome 30, cyclical vomiting 8, functional vomiting 6, intestinal tuberculosis 4, intestinal malrotation 1, and superior mesenteric artery syndrome 1. Children with rumination syndrome had a relapsing and remitting (12, 40%) or a chronically symptomatic course (18, 60%). These children received incorrect diagnoses (26, 87%) or no diagnosis (3, 10%) and extensive investigation before referral. Before referral, children with rumination syndrome were treated with a median of four drugs (range 1 to 9); two underwent surgery (appendectomy) for their symptoms while one child was subjected to electroconvulsive therapy. Overall, resolution after treatment was seen in 26 (87%) with a relapse in 8 (27%) children. CONCLUSION: The diagnosis of rumination syndrome is delayed and these children are often inappropriately treated. Therapy in the form of diaphragmatic breathing has a good success rate.


Assuntos
Síndrome da Ruminação/complicações , Síndrome da Ruminação/terapia , Vômito/etiologia , Adolescente , Exercícios Respiratórios/métodos , Criança , Doença Crônica , Diagnóstico Tardio , Erros de Diagnóstico , Diafragma/fisiologia , Feminino , Humanos , Prescrição Inadequada , Masculino , Estudos Prospectivos , Recidiva , Síndrome da Ruminação/diagnóstico , Procedimentos Desnecessários
6.
Br J Anaesth ; 125(1): e148-e157, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32386831

RESUMO

BACKGROUND: Bedside measures of patient effort are essential to properly titrate the level of pressure support ventilation. We investigated whether the tidal swing in oesophageal (ΔPes) and transdiaphragmatic pressure (ΔPdi), and ultrasonographic changes in diaphragm (TFdi) and parasternal intercostal (TFic) thickening are reliable estimates of respiratory effort. The effect of diaphragm dysfunction was also considered. METHODS: Twenty-one critically ill patients were enrolled: age 73 (14) yr, BMI 27 (7) kg m-2, and Pao2/Fio2 33.3 (9.2) kPa. A three-level pressure support trial was performed: baseline, 25% (PS-medium), and 50% reduction (PS-low). We recorded the oesophageal and transdiaphragmatic pressure-time products (PTPs), work of breathing (WOB), and diaphragm and intercostal ultrasonography. Diaphragm dysfunction was defined by the Gilbert index. RESULTS: Pressure support was 9.0 (1.6) cm H2O at baseline, 6.7 (1.3) (PS-medium), and 4.4 (1.0) (PS-low). ΔPes was significantly associated with the oesophageal PTP (R2=0.868; P<0.001) and the WOB (R2=0.683; P<0.001). ΔPdi was significantly associated with the transdiaphragmatic PTP (R2=0.820; P<0.001). TFdi was only weakly correlated with the oesophageal PTP (R2=0.326; P<0.001), and the correlation improved after excluding patients with diaphragm dysfunction (R2=0.887; P<0.001). TFdi was higher and TFic lower in patients without diaphragm dysfunction: 33.6 (18.2)% vs 13.2 (9.2)% and 2.1 (1.7)% vs 12.7 (9.1)%; P<0.0001. CONCLUSIONS: ΔPes and ΔPdi are adequate estimates of inspiratory effort. Diaphragm ultrasonography is a reliable indicator of inspiratory effort in the absence of diaphragm dysfunction. Additional measurement of parasternal intercostal thickening may discriminate a low inspiratory effort or a high effort in the presence of a dysfunctional diaphragm.


Assuntos
Esôfago/fisiologia , Respiração com Pressão Positiva/métodos , Músculos Respiratórios/fisiologia , Ultrassonografia/métodos , Trabalho Respiratório/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Cuidados Críticos/métodos , Estado Terminal , Diafragma/fisiologia , Esôfago/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Músculos Respiratórios/diagnóstico por imagem
7.
NeuroRehabilitation ; 46(3): 381-389, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32250328

RESUMO

BACKGROUND: Neurodevelopmental treatment (NDT) and Dynamic neuromuscular stabilization (DNS)-based exercise is effective for improving core stability and postural control in stroke patients. OBJECTIVE: To compare the effects of DNS and conventional NDT exercises on diaphragm movement, abdominal muscle thickness, and postural control in stroke patients. METHODS: The participants were randomly allocated into DNS (n = 16) and NDT (n = 15) for 30 minutes each per day, 3 days a week for 4 weeks. Diaphragm movement and abdominal muscle thickness were determined using ultrasonography. The trunk impairment scale (TIS) and Berg Balance Scale (BBS) were used to measure postural control. The functional ambulation category (FAC) was used to evaluate gait ability. Analysis of covariance (ANCOVA) was used to evaluate post-test differences in the DNS and NDT exercise groups. RESULTS: ANCOVA revealed the superior effects of DNS in diaphragm movement and abdominal muscle thickness (transversus abdominis, internal oblique), as well as clinical BBS and FAC tests, compared with those of NDT (p < 0.05). CONCLUSIONS: This novel clinical trial suggests that DNS training was more effective than NDT training in improving postural movement control and gait ability via a balanced co-activation of the diaphragm and TrA/IO in stroke patients.


Assuntos
Músculos Abdominais/fisiologia , Diafragma/fisiologia , Equilíbrio Postural/fisiologia , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/fisiopatologia , Exercício Físico/fisiologia , Terapia por Exercício , Humanos
9.
Cancer Res ; 80(9): 1861-1874, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32132110

RESUMO

Skeletal muscle wasting is a devastating consequence of cancer that contributes to increased complications and poor survival, but is not well understood at the molecular level. Herein, we investigated the role of Myocilin (Myoc), a skeletal muscle hypertrophy-promoting protein that we showed is downregulated in multiple mouse models of cancer cachexia. Loss of Myoc alone was sufficient to induce phenotypes identified in mouse models of cancer cachexia, including muscle fiber atrophy, sarcolemmal fragility, and impaired muscle regeneration. By 18 months of age, mice deficient in Myoc showed significant skeletal muscle remodeling, characterized by increased fat and collagen deposition compared with wild-type mice, thus also supporting Myoc as a regulator of muscle quality. In cancer cachexia models, maintaining skeletal muscle expression of Myoc significantly attenuated muscle loss, while mice lacking Myoc showed enhanced muscle wasting. Furthermore, we identified the myocyte enhancer factor 2 C (MEF2C) transcription factor as a key upstream activator of Myoc whose gain of function significantly deterred cancer-induced muscle wasting and dysfunction in a preclinical model of pancreatic ductal adenocarcinoma (PDAC). Finally, compared with noncancer control patients, MYOC was significantly reduced in skeletal muscle of patients with PDAC defined as cachectic and correlated with MEF2c. These data therefore identify disruptions in MEF2c-dependent transcription of Myoc as a novel mechanism of cancer-associated muscle wasting that is similarly disrupted in muscle of patients with cachectic cancer. SIGNIFICANCE: This work identifies a novel transcriptional mechanism that mediates skeletal muscle wasting in murine models of cancer cachexia that is disrupted in skeletal muscle of patients with cancer exhibiting cachexia.


Assuntos
Caquexia/complicações , Proteínas do Citoesqueleto/metabolismo , Proteínas do Olho/metabolismo , Glicoproteínas/metabolismo , Músculo Esquelético/metabolismo , Doenças Musculares/metabolismo , Síndrome de Emaciação/etiologia , Animais , Composição Corporal , Caquexia/metabolismo , Carcinoma Ductal Pancreático/complicações , Carcinoma Ductal Pancreático/metabolismo , Proteínas do Citoesqueleto/deficiência , Proteínas do Citoesqueleto/genética , Diafragma/fisiologia , Modelos Animais de Doenças , Regulação para Baixo , Proteínas do Olho/genética , Feminino , Glicoproteínas/deficiência , Glicoproteínas/genética , Xenoenxertos , Humanos , Fatores de Transcrição MEF2/metabolismo , Masculino , Camundongos , Músculo Esquelético/patologia , Atrofia Muscular , Doenças Musculares/etiologia , Proteínas de Neoplasias/metabolismo , Neoplasias Pancreáticas/complicações , Neoplasias Pancreáticas/metabolismo , RNA Mensageiro/metabolismo , Regeneração , Corrida , Sarcolema , Síndrome de Emaciação/metabolismo , Síndrome de Emaciação/prevenção & controle
10.
Cochrane Database Syst Rev ; 3: CD012935, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32176939

RESUMO

BACKGROUND: Diaphragm-triggered non-invasive respiratory support, commonly referred to as NIV-NAVA (non-invasive neurally adjusted ventilatory assist), uses the electrical activity of the crural diaphragm to trigger the start and end of a breath. It provides variable inspiratory pressure that is proportional to an infant's changing inspiratory effort. NIV-NAVA has the potential to provide effective, non-invasive, synchronised, multilevel support and may reduce the need for invasive ventilation; however, its effects on short- and long-term outcomes, especially in the preterm infant, are unclear. OBJECTIVES: To assess the effectiveness and safety of diaphragm-triggered non-invasive respiratory support in preterm infants (< 37 weeks' gestation) when compared to other non-invasive modes of respiratory support (nasal intermittent positive pressure ventilation (NIPPV); nasal continuous positive airway pressure (nCPAP); high-flow nasal cannulae (HFNC)), and to assess preterm infants with birth weight less than 1000 grams or less than 28 weeks' corrected gestation at the time of intervention as a sub-group. SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2019, Issue 5), MEDLINE via PubMed (1946 to 10 May 2019), Embase (1947 to 10 May 2019), and CINAHL (1982 to 10 May 2019). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials (RCTs) and quasi-randomised trials. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials that compared diaphragm-triggered non-invasive versus other non-invasive respiratory support in preterm infants. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials, assessed trial quality and extracted data from included studies. We performed fixed-effect analyses and expressed treatment effects as mean difference (MD), risk ratio (RR), and risk difference (RD) with 95% confidence intervals (CIs). We used the generic inverse variance method to analyse specific outcomes for cross-over trials. We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: There were two small randomised controlled trials including a total of 23 infants eligible for inclusion in the review. Only one trial involving 16 infants included in the analysis reported on either of the primary outcomes of the review. This found no difference in failure of modality between NIV-NAVA and NIPPV (RR 0.33, 95% CI 0.02 to 7.14; RD -0.13, 95% CI -0.41 to 0.16; 1 study, 16 infants; heterogeneity not applicable). Both trials reported on secondary outcomes of the review, specific for cross-over trials (total 22 infants; 1 excluded due to failure of initial modality). One study involving seven infants reported a significant reduction in maximum FiO2 with NIV-NAVA compared to NIPPV (MD -4.29, 95% CI -5.47 to -3.11; heterogeneity not applicable). There was no difference in maximum electric activity of the diaphragm (Edi) signal between modalities (MD -1.75, 95% CI -3.75 to 0.26; I² = 0%) and a significant increase in respiratory rate with NIV-NAVA compared to NIPPV (MD 7.22, 95% CI 0.21 to 14.22; I² = 72%) on a meta-analysis of two studies involving a total of 22 infants. The included studies did not report on other outcomes of interest. AUTHORS' CONCLUSIONS: Due to limited data and very low certainty evidence, we were unable to determine if diaphragm-triggered non-invasive respiratory support is effective or safe in preventing respiratory failure in preterm infants. Large, adequately powered randomised controlled trials are needed to determine if diaphragm-triggered non-invasive respiratory support in preterm infants is effective or safe.


Assuntos
Diafragma/fisiologia , Recém-Nascido Prematuro , Pressão Positiva Contínua nas Vias Aéreas , Humanos , Recém-Nascido , Suporte Ventilatório Interativo , Ventilação com Pressão Positiva Intermitente , Ensaios Clínicos Controlados Aleatórios como Assunto
11.
Am J Respir Crit Care Med ; 201(10): 1218-1229, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32150440

RESUMO

Rationale: Tidal expiratory flow limitation (tidal-EFL) is not completely avoidable by applying positive end-expiratory pressure and may cause respiratory and hemodynamic complications in ventilated patients with lungs prone to collapse. During spontaneous breathing, expiratory diaphragmatic contraction counteracts tidal-EFL. We hypothesized that during both spontaneous breathing and controlled mechanical ventilation, external expiratory resistances reduce tidal-EFL.Objectives: To assess whether external expiratory resistances 1) affect expiratory diaphragmatic contraction during spontaneous breathing, 2) reduce expiratory flow and make lung compartments more homogeneous with more similar expiratory time constants, and 3) reduce tidal atelectasis, preventing hyperinflation.Methods: Three positive end-expiratory pressure levels and four external expiratory resistances were tested in 10 pigs after lung lavage. We analyzed expiratory diaphragmatic electric activity and respiratory mechanics. On the basis of computed tomography scans, four lung compartments-not inflated (atelectasis), poorly inflated, normally inflated, and hyperinflated-were defined.Measurements and Main Results: Consequently to additional external expiratory resistances, and mainly in lungs prone to collapse (at low positive end-expiratory pressure), 1) the expiratory transdiaphragmatic pressure decreased during spontaneous breathing by >10%, 2) expiratory flow was reduced and the expiratory time constants became more homogeneous, and 3) the amount of atelectasis at end-expiration decreased from 24% to 16% during spontaneous breathing and from 32% to 18% during controlled mechanical ventilation, without increasing hyperinflation.Conclusions: The expiratory modulation induced by external expiratory resistances preserves the positive effects of the expiratory brake while minimizing expiratory diaphragmatic contraction. External expiratory resistances optimize lung mechanics and limit tidal-EFL and tidal atelectasis, without increasing hyperinflation.


Assuntos
Diafragma/fisiologia , Expiração/fisiologia , Contração Muscular/fisiologia , Respiração com Pressão Positiva/métodos , Síndrome do Desconforto Respiratório do Adulto/terapia , Animais , Diafragma/fisiopatologia , Modelos Animais de Doenças , Pulmão/diagnóstico por imagem , Respiração com Pressão Positiva/efeitos adversos , Atelectasia Pulmonar/diagnóstico por imagem , Ventilação Pulmonar , Respiração Artificial/métodos , Síndrome do Desconforto Respiratório do Adulto/fisiopatologia , Mecânica Respiratória/fisiologia , Suínos , Tomografia Computadorizada por Raios X
12.
PLoS One ; 15(3): e0229972, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32163474

RESUMO

OBJECTIVES: Bedside ultrasound techniques have the unique ability to produce instantaneous, dynamic images, and have demonstrated widespread utility in both emergency and critical care settings. The aim of this article is to introduce a novel application of this imaging modality by utilizing an ultrasound based mathematical model to assess respiratory function. With validation, the proposed models have the potential to predict pulmonary function in patients who cannot adequately participate in standard spirometric techniques (inability to form tight seal with mouthpiece, etc.). METHODS: Ultrasound was used to measure diaphragm thickness (Tdi) in a small population of healthy, adult males at various points of the respiratory cycle. Each measurement corresponded to a generated negative inspiratory force (NIF), determined by a handheld meter. The data was analyzed using mixed models to produce two representative mathematical models. RESULTS: Two mathematical models represented the relationship between Tdi and NIFmax, or maximum inspiratory pressure (MIP), both of which were statistically significant with p-values <0.005: 1. log(NIF) = -1.32+4.02×log(Tdi); and 2. NIF = -8.19+(2.55 × Tdi)+(1.79×(Tdi2)). CONCLUSIONS: With validation, these models intend to provide a method of estimating MIP, by way of diaphragm ultrasound measurements, thereby allowing evaluation of respiratory function in patients who may be unable to reliably participate in standard spirometric tests.


Assuntos
Diafragma/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Pressões Respiratórias Máximas/métodos , Modelos Biológicos , Adulto , Diafragma/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia/métodos
13.
Zhonghua Jie He He Hu Xi Za Zhi ; 43(2): 132-135, 2020 Feb 12.
Artigo em Chinês | MEDLINE | ID: mdl-32062883

RESUMO

Objective: To evaluate the condition of the diaphragm in patients with long-term mechanical ventilation using ultrasound technology and to analyze its relationship with ventilation time and muscle atrophy in order to clarify the reasons for diaphragm dysfunction in long-term mechanical ventilation patients. Methods: Patients admitted to the respiratory department at the Chinese PLA General Hospital between June 2018 and April 2019 with mechanical ventilation were included in this study. The enrolled patients were divided into a short-term mechanical ventilation group (7 days ≤ ventilation time<1 month) and a long-term mechanical ventilation group (mechanical ventilation time ≥ 1 month). The diaphragmatic excursion, inspiratory time, contraction rate, E-T index, diaphragm thickness, diaphragm thickness fraction (DTF), and tibialis anterior thickness were compared between the two groups. The correlation between ventilation time and diaphragm thickness was analyzed in all patients. Results: The mean diaphragm thickness and DTF were significantly lower in the long-term mechanical ventilation group than in the short-term mechanical ventilation group [(0.13±0.036) vs (0.17±0.05) cm and (0.22±0.045) vs (0.27±0.075)](all P<0.05). However, there was no significant difference in diaphragmatic excursion, inspiratory time, contraction rate, E-T index or tibialis anterior thickness between the two groups (all P>0.05). There was a significant linear correlation between ventilation time and diaphragm thickness (P<0.01). Tibialis anterior thickness was not significantly correlated with ventilation time (P>0.05). Conclusion: Diaphragm thickness and function were significantly reduced in patients with long-term mechanical ventilation, which was correlated with the duration of ventilation. Nutritional status was not the main factor affecting diaphragm thickness.


Assuntos
Diafragma/diagnóstico por imagem , Diafragma/fisiopatologia , Atrofia Muscular , Respiração Artificial/efeitos adversos , Ultrassonografia/métodos , Diafragma/fisiologia , Humanos , Contração Muscular/fisiologia , Debilidade Muscular/diagnóstico por imagem , Estudos Prospectivos , Respiração , Fatores de Tempo
15.
Anesthesiology ; 132(5): 1114-1125, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32084029

RESUMO

BACKGROUND: The assessment of diaphragm function with diaphragm ultrasound seems to bring important clinical information to describe diaphragm work and weakness. When the diaphragm is weak, extradiaphragmatic muscles may play an important role, but whether ultrasound can also assess their activity and function is unknown. This study aimed to (1) evaluate the feasibility of measuring the thickening of the parasternal intercostal and investigate the responsiveness of this muscle to assisted ventilation; and (2) evaluate whether a combined evaluation of the parasternal and the diaphragm could predict failure of a spontaneous breathing trial. METHODS: First, an exploratory evaluation of the parasternal in 23 healthy subjects. Second, the responsiveness of parasternal to several pressure support levels were studied in 16 patients. Last, parasternal activity was compared in presence or absence of diaphragm dysfunction (assessed by magnetic stimulation of the phrenic nerves and ultrasound) and in case of success/failure of a spontaneous breathing trial in 54 patients. RESULTS: The parasternal was easily accessible in all patients. The interobserver reproducibility was good (intraclass correlation coefficient, 0.77 (95% CI, 0.53 to 0.89). There was a progressive decrease in parasternal muscle thickening fraction with increasing levels of pressure support (Spearman ρ = -0.61 [95% CI, -0.74 to -0.44]; P < 0.0001) and an inverse correlation between parasternal muscle thickening fraction and the pressure generating capacity of the diaphragm (Spearman ρ = -0.79 [95% CI, -0.87 to -0.66]; P < 0.0001). The parasternal muscle thickening fraction was higher in patients with diaphragm dysfunction: 17% (10 to 25) versus 5% (3 to 8), P < 0.0001. The pressure generating capacity of the diaphragm, the diaphragm thickening fraction and the parasternal thickening fraction similarly predicted failure or the spontaneous breathing trial. CONCLUSIONS: Ultrasound assessment of the parasternal intercostal muscle is feasible in the intensive care unit and provides novel information regarding the respiratory capacity load balance.


Assuntos
Diafragma/diagnóstico por imagem , Músculos Intercostais/diagnóstico por imagem , Respiração Artificial/métodos , Ultrassonografia de Intervenção/métodos , Desmame do Respirador/métodos , Adulto , Diafragma/fisiologia , Feminino , Humanos , Músculos Intercostais/fisiologia , Masculino , Adulto Jovem
16.
Br J Radiol ; 93(1106): 20190549, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31778311

RESUMO

OBJECTIVE: To test the hypothesis that there is a measureable upward motion of the diaphragm during prolonged breath-holds that could have a detrimental effect on image quality in liver MRI and to identify factor that potentially influence the magnitude of this motion. METHODS: 15 healthy volunteers underwent MRI examination using prolonged breath-holds in the maximum inspiratory position and a moderate inspiratory position. Coronal T1 weighted three-dimensional gradient echo sequences of the entire thorax were acquired every 6 s during breath-holding allowing the calculation of total lung volume and the measurement of the absolute position of the dome of the liver. The potential impact of subject's gender, body mass index, and total lung capacity on the change in lung volume/diaphragmatic motion was assessed using random coefficient regression. RESULTS: All volunteers demonstrated a slow reduction of the total lung volume during prolonged breath-holding up to 123 ml. There was a measurable associated upward shift of the diaphragm, measuring up to 5.6 mm after 24 s. There was a positive correlation with female gender (p = 0.037) and total lung volume (p = 0.005) and a negative association with BMI (p = 0.012) for the maximum inspiratory position only. CONCLUSION: There is a measureable reduction of lung volumes with consecutive upward shift of the diaphragm during prolonged breath-holding which likely contributes to motion artifacts in liver MRI. ADVANCES IN KNOWLEDGE: There is a measureable gas exchange-related reduction of lung volumes with consecutive upward shift of the diaphragm during prolonged breath-holding which likely contributes to motion artifacts in liver MRI. Correcting for this predictable upward shift has potential to improve image quality.The magnitude of this effect does not seem to be related to gender, BMI or total lung capacity if a moderate inspiratory position is used.


Assuntos
Abdome/fisiologia , Suspensão da Respiração , Fígado , Adulto , Artefatos , Diafragma/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Inalação/fisiologia , Medidas de Volume Pulmonar , Imagem por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Movimento/fisiologia , Troca Gasosa Pulmonar/fisiologia , Adulto Jovem
17.
Pediatr Pulmonol ; 55(2): 354-359, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31765520

RESUMO

OBJECTIVE: To determine the effect of changing electrode positions on vital signs and respiratory effort parameters measured with transcutaneous electromyography of the diaphragm (dEMG) in preterm infants. METHODS: In this observational study, simultaneous dEMG measurements were performed at the standard position and at one alternative electrode position (randomly assigned to lateral, superior, medial, inferior to the standard placement, or dorsal). The activity of the diaphragm was measured for 1 hour at both positions. Main outcome measures were the agreement in heart rate (HR), respiratory rate (RR), and percentage difference in dEMG parameters of respiratory effort (peak and tonic activity, amplitude, area under the curve, and frequency content) between the standard and alternative electrode positions. RESULTS: Thirty clinically stable preterm infants (gestational age 30.1 ± 3.0 weeks) with either no or noninvasive respiratory support were included. Agreement in HR was excellent at all positions (ICC > 0.95) while RR agreement showed more diversity (ICC range 0.40-0.86). Mixed modeling of dEMG parameters revealed that medial and inferior placement measured the weakest signals (median 75.5% and 64.5% lower dEMG amplitude). Lateral electrode placement showed the highest similarity to standard positioning (median 23.5% lower amplitude). CONCLUSION: Measuring HR showed high similarity at all positions. However, registration of RR and respiratory effort is clearly influenced by the electrode position. Electrodes in the same transversal plane as the diaphragm, and at sufficient distance from each other, provide the best agreement with the standard positioning.


Assuntos
Diafragma/diagnóstico por imagem , Eletromiografia , Recém-Nascido Prematuro , Diafragma/fisiologia , Eletrodos , Feminino , Idade Gestacional , Frequência Cardíaca/fisiologia , Humanos , Lactente , Recém-Nascido , Masculino , Estudos Prospectivos , Taxa Respiratória/fisiologia
18.
Curr Opin Crit Care ; 26(1): 18-25, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31876624

RESUMO

PURPOSE OF REVIEW: To review the clinical problem of diaphragm function in critically ill patients and describes recent advances in bedside monitoring of diaphragm function. RECENT FINDINGS: Diaphragm weakness, a consequence of diaphragm dysfunction and atrophy, is common in the ICU and associated with serious clinical consequences. The use of ultrasound to assess diaphragm structure (thickness, thickening) and mobility (caudal displacement) appears to be feasible and reproducible, but no large-scale 'real-life' study is available. Diaphragm ultrasound can also be used to evaluate diaphragm muscle stiffness by means of shear-wave elastography and strain by means of speckle tracking, both of which are correlated with diaphragm function in healthy. Electrical activity of the diaphragm is correlated with diaphragm function during brief airway occlusion, but the repeatability of these measurements exhibits high within-subject variability. SUMMARY: Mechanical ventilation is involved in the pathogenesis of diaphragm dysfunction, which is associated with severe adverse events. Although ultrasound and diaphragm electrical activity could facilitate monitoring of diaphragm function to deliver diaphragm-protective ventilation, no guidelines concerning the use of these modalities have yet been published. The weaning process, assessment of patient-ventilator synchrony and evaluation of diaphragm function may be the most clinically relevant indications for these techniques.


Assuntos
Diafragma , Respiração Artificial , Estado Terminal , Diafragma/anatomia & histologia , Diafragma/diagnóstico por imagem , Diafragma/fisiologia , Humanos , Unidades de Terapia Intensiva , Respiração Artificial/efeitos adversos , Ultrassonografia
19.
Med Sci Sports Exerc ; 52(5): 1126-1134, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-31876666

RESUMO

INTRODUCTION: We aimed to compare acute mechanical and metabolic responses of the diaphragm and rib cage inspiratory muscles during two different types of respiratory loading in patients with chronic obstructive pulmonary disease. METHODS: In 16 patients (age, 65 ± 13 yr; 56% male; forced expiratory volume in the first second, 60 ± 6%pred; maximum inspiratory pressure, 82 ± 5%pred), assessments of respiratory muscle EMG, esophageal pressure (Pes) and gastric pressures, breathing pattern, and noninvasive assessments of systemic (V˙O2, cardiac output, oxygen delivery and extraction) and respiratory muscle hemodynamic and oxygenation responses (blood flow index, oxygen delivery index, deoxyhemoglobin concentration, and tissues oxygen saturation [StiO2]), were performed during hyperpnea and loaded breathing. RESULTS: During hyperpnea, breathing frequency, minute ventilation, esophageal and diaphragm pressure-time product per minute, cardiac output, and V˙O2 were higher than during loaded breathing (P < 0.05). Average inspiratory Pes and transdiaphragmatic pressure per breath, scalene (SCA), sternocleidomastoid, and intercostal muscle activation were higher during loading breathing compared with hyperpnea (P < 0.05). Higher transdiaphragmatic pressure during loaded breathing compared with hyperpnea was mostly due to higher inspiratory Pes (P < 0.05). Diaphragm activation, inspiratory and expiratory gastric pressures, and rectus abdominis muscle activation did not differ between the two conditions (P > 0.05). SCA-blood flow index and oxygen delivery index were lower, and SCA-deoxyhemoglobin concentration was higher during loaded breathing compared with hyperpnea. Furthermore, SCA and intercostal muscle StiO2 were lower during loaded breathing compared with hyperpnea (P < 0.05). CONCLUSION: Greater inspiratory muscle effort during loaded breathing evoked larger rib cage and neck muscle activation compared with hyperpnea. In addition, lower SCA and intercostal muscle StiO2 during loaded breathing compared with hyperpnea indicates a mismatch between inspiratory muscle oxygen delivery and utilization induced by the former condition.


Assuntos
Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Músculos Respiratórios/fisiologia , Trabalho Respiratório/fisiologia , Músculos Abdominais/fisiologia , Idoso , Exercícios Respiratórios , Diafragma/fisiologia , Esôfago/fisiologia , Feminino , Hemodinâmica , Humanos , Masculino , Pessoa de Meia-Idade , Pressão , Doença Pulmonar Obstrutiva Crônica/terapia , Ventilação Pulmonar , Estômago/fisiologia
20.
Pediatr Pulmonol ; 55(3): 616-623, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31868983

RESUMO

OBJECTIVE: To investigate the relationship between applied flows of nasal high flow (NHF) and physiological outcomes and work of breathing (WOB), to identify an optimal delivery flow which results in reduced WOB in preterm infants. DESIGN: A prospective observational clinical study with randomly applied NHF rates. PATIENTS AND SETTING: Preterm infants within 72 hours of commencement of NHF respiratory support. INTERVENTIONS: Infants were initially placed on 8 L/min of NHF and flows of 2, 4, and 6 L/min were then applied in random order. MEASUREMENTS AND RESULTS: WOB was measured using transcutaneous electromyography and respiratory inductance plethysmography. Physiological variables were also recorded. Measurements taken 10 minutes after each flow change were compared with 8 L/min. Sixteen infants with a median gestational age of 28 (range 24-31) weeks and postnatal age of 14 (2-55) days were included in the study. The median flow rate before the study was 6 (4-8) L/min and a fraction of inspired oxygen (FiO2 ) was 0.21 (0.21-0.26). Changes in flow resulted in changes in activity in the front diaphragm (P = .027) and intercostals (P = .034). The electrical activity of the front diaphragm at 8 L/min was significantly lower than that at 2 L/min (P = .016). Respiratory rate was lowest at 6 L/min (P = .002) and SpO2 /FiO2 was highest at 8 L/min (P < .04). CONCLUSION: In preterm infants, changes in WOB resulting from randomly applied levels of NHF can be demonstrated by measuring the electrical activity of the diaphragm and intercostal muscles with transcutaneous electromyography. In combination with physiological measurements, the similarities in electrical activity between 4, 6, and 8 L/min suggest that these three flows may be equally as effective.


Assuntos
Recém-Nascido Prematuro/fisiologia , Nariz/fisiologia , Oxigenoterapia , Diafragma/fisiologia , Eletromiografia , Feminino , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Masculino , Pletismografia , Taxa Respiratória , Trabalho Respiratório
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