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Rationale: Pediatric-specific ventilator liberation guidelines are lacking despite the many studies exploring elements of extubation readiness testing. The lack of clinical practice guidelines has led to significant and unnecessary variation in methods used to assess pediatric patients' readiness for extubation. Methods: Twenty-six international experts comprised a multiprofessional panel to establish pediatrics-specific ventilator liberation clinical practice guidelines, focusing on acutely hospitalized children receiving invasive mechanical ventilation for more than 24 hours. Eleven key questions were identified and first prioritized using the Modified Convergence of Opinion on Recommendations and Evidence. A systematic review was conducted for questions that did not meet an a priori threshold of ⩾80% agreement, with Grading of Recommendations, Assessment, Development, and Evaluation methodologies applied to develop the guidelines. The panel evaluated the evidence and drafted and voted on the recommendations. Measurements and Main Results: Three questions related to systematic screening using an extubation readiness testing bundle and a spontaneous breathing trial as part of the bundle met Modified Convergence of Opinion on Recommendations criteria of ⩾80% agreement. For the remaining eight questions, five systematic reviews yielded 12 recommendations related to the methods and duration of spontaneous breathing trials, measures of respiratory muscle strength, assessment of risk of postextubation upper airway obstruction and its prevention, use of postextubation noninvasive respiratory support, and sedation. Most recommendations were conditional and based on low to very low certainty of evidence. Conclusions: This clinical practice guideline provides a conceptual framework with evidence-based recommendations for best practices related to pediatric ventilator liberation.
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Respiração Artificial , Sepse , Humanos , Criança , Respiração Artificial/métodos , Desmame do Respirador/métodos , Ventiladores Mecânicos , Extubação/métodosRESUMO
INTRODUCTION: Many people experience persistent symptoms for more than 12 weeks following SARS-CoV-2 infection, which is known as post-COVID-19 condition (PCS) or Long COVID (LC). PCS can impair people's quality of life and daily functioning. However, there is a lack of in-depth research exploring the PCS patient journey, as well as gendered aspects of patients' experiences. METHODS: Nineteen semi-structured qualitative interviews were conducted with people living with PCS in the United Kingdom (13 women, 6 men). Interviews were transcribed verbatim and analysed inductively using reflexive thematic analysis. RESULTS: Five main themes were identified: 'Symptom dismissal', 'Lack of information and support', 'Life before and after Long COVID', 'Psychological impact' and 'Acceptance'. A shift overtime to self-management of symptoms was evident. These themes represent different stages of patients' PCS journey. Narratives indicated that women highlighted dismissal by healthcare professionals (HCPs), which was not as prominent in men's narratives. In addition, women went into more detail about the psychological impact of PCS compared to men. CONCLUSION: Women with PCS reported symptom dismissal by HCPs, which may have delayed their diagnosis and negatively affected their well-being. We were not able to explore the experiences of people from non-conforming gender groups. Raising awareness of these issues among HCPs, particularly general practitioners, could improve patient care in PCS. PATIENT OR PUBLIC CONTRIBUTION: Patient and public involvement consisted of people who took part in the interviews and commented on the themes' interpretation and study conclusions.
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COVID-19 , Pesquisa Qualitativa , Qualidade de Vida , Humanos , Feminino , Masculino , COVID-19/psicologia , Pessoa de Meia-Idade , Adulto , Reino Unido , Idoso , Síndrome de COVID-19 Pós-Aguda , Entrevistas como Assunto , SARS-CoV-2 , Fatores SexuaisRESUMO
This study aims to investigate noninvasive indices of neuromechanical coupling (NMC) and mechanical efficiency (MEff) of parasternal intercostal muscles. Gold standard assessment of diaphragm NMC requires using invasive techniques, limiting the utility of this procedure. Noninvasive NMC indices of parasternal intercostal muscles can be calculated using surface mechanomyography (sMMGpara) and electromyography (sEMGpara). However, the use of sMMGpara as an inspiratory muscle mechanical output measure, and the relationships between sMMGpara, sEMGpara, and simultaneous invasive and noninvasive pressure measurements have not previously been evaluated. sEMGpara, sMMGpara, and both invasive and noninvasive measurements of pressures were recorded in twelve healthy subjects during an inspiratory loading protocol. The ratios of sMMGpara to sEMGpara, which provided muscle-specific noninvasive NMC indices of parasternal intercostal muscles, showed nonsignificant changes with increasing load, since the relationships between sMMGpara and sEMGpara were linear (R2 = 0.85 (0.75-0.9)). The ratios of mouth pressure (Pmo) to sEMGpara and sMMGpara were also proposed as noninvasive indices of parasternal intercostal muscle NMC and MEff, respectively. These indices, similar to the analogous indices calculated using invasive transdiaphragmatic and esophageal pressures, showed nonsignificant changes during threshold loading, since the relationships between Pmo and both sEMGpara (R2 = 0.84 (0.77-0.93)) and sMMGpara (R2 = 0.89 (0.85-0.91)) were linear. The proposed noninvasive NMC and MEff indices of parasternal intercostal muscles may be of potential clinical value, particularly for the regular assessment of patients with disordered respiratory mechanics using noninvasive wearable and wireless devices.
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Diafragma , Músculos Intercostais , Eletromiografia , Voluntários Saudáveis , Humanos , Mecânica RespiratóriaRESUMO
NEW FINDINGS: What is the central question of this study? What are the mechanisms underlying impaired muscular endurance and accelerated fatigue during acute hypoxia? What is the main finding and its importance? Hypoxia had no effect on the electrochemical latency associated with muscle contraction elicited by supramaximal electrical motor nerve stimulation in vivo. This provides greater insight into the effects of hypoxia and fatigue on the mechanisms of muscle contraction in vivo. ABSTRACT: Acute hypoxia impairs muscle endurance and accelerates fatigue, but the underlying mechanisms, including any effects on muscle electrical activation, are incompletely understood. Electromyographic, mechanomyographic and force signals, elicited by common fibular nerve stimulation, were used to determine electromechanical delay (EMDTOT ) of the tibialis anterior muscle in normoxia and hypoxia ( FIO2 0.125) at rest and following fatiguing ankle dorsiflexor exercise (60% maximum voluntary contraction, 5 s on, 3 s off) in 12 healthy participants (mean (SD) age 27.4 (9.0) years). EMDTOT was determined from electromyographic to force signal onset, electrical activation latency from electromyographic to mechanomyographic (EMDE-M ) and mechanical latency from mechanomyographic to force (EMDM-F ). Twitch force fell significantly following fatiguing exercise in normoxia (46.8 (14.7) vs. 20.6 (14.3) N, P = 0.0002) and hypoxia (52.9 (15.4) vs. 28.8 (15.2) N, P = 0.0006). No effect of hypoxia on twitch force at rest was observed. Fatiguing exercise resulted in significant increases in mean (SD) EMDTOT in normoxia (Δ 4.7 (4.57) ms P = 0.0152) and hypoxia (Δ 3.7 (4.06) ms P = 0.0384) resulting from increased mean (SD) EMDM-F only (normoxia Δ 4.1 (4.1) ms P = 0.0391, hypoxia Δ 3.4 (3.6) ms P = 0.0303). Mean (SD) EMDE-M remained unchanged during normoxic (Δ 0.6 (1.08) ms) and hypoxic (Δ 0.25 (0.75) ms) fatiguing exercise. No differences in percentage change from baseline for twitch force, EMDTOT , EMDE-M and EMDM-F between normoxic and hypoxic fatigue conditions were observed. Hypoxia in isolation or in combination with fatigue had no effect on the electrochemical latency associated with electrically evoked muscle contraction.
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Exercício Físico , Hipóxia , Fadiga Muscular , Músculo Esquelético/fisiologia , Adulto , Feminino , Humanos , Masculino , Contração Muscular , Adulto JovemRESUMO
BACKGROUND: The clinical effectiveness of neurally adjusted ventilatory assist (NAVA) has yet to be demonstrated, and preliminary studies are required. The study aim was to assess the feasibility of a randomized controlled trial (RCT) of NAVA versus pressure support ventilation (PSV) in critically ill adults at risk of prolonged mechanical ventilation (MV). METHODS: An open-label, parallel, feasibility RCT (n = 78) in four ICUs of one university-affiliated hospital. The primary outcome was mode adherence (percentage of time adherent to assigned mode), and protocol compliance (binary-≥ 65% mode adherence). Secondary exploratory outcomes included ventilator-free days (VFDs), sedation, and mortality. RESULTS: In the 72 participants who commenced weaning, median (95% CI) mode adherence was 83.1% (64.0-97.1%) and 100% (100-100%), and protocol compliance was 66.7% (50.3-80.0%) and 100% (89.0-100.0%) in the NAVA and PSV groups respectively. Secondary outcomes indicated more VFDs to D28 (median difference 3.0 days, 95% CI 0.0-11.0; p = 0.04) and fewer in-hospital deaths (relative risk 0.5, 95% CI 0.2-0.9; p = 0.032) for NAVA. Although overall sedation was similar, Richmond Agitation and Sedation Scale (RASS) scores were closer to zero in NAVA compared to PSV (p = 0.020). No significant differences were observed in duration of MV, ICU or hospital stay, or ICU, D28, and D90 mortality. CONCLUSIONS: This feasibility trial demonstrated good adherence to assigned ventilation mode and the ability to meet a priori protocol compliance criteria. Exploratory outcomes suggest some clinical benefit for NAVA compared to PSV. Clinical effectiveness trials of NAVA are potentially feasible and warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01826890. Registered 9 April 2013.
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Suporte Ventilatório Interativo/normas , Respiração Artificial/métodos , Fatores de Tempo , Adulto , Estudos de Viabilidade , Feminino , Humanos , Unidades de Terapia Intensiva/organização & administração , Unidades de Terapia Intensiva/estatística & dados numéricos , Suporte Ventilatório Interativo/estatística & dados numéricos , Tempo de Internação/estatística & dados numéricos , Londres , Masculino , Pessoa de Meia-Idade , Respiração Artificial/estatística & dados numéricosRESUMO
Our aim was to compare the work of breathing (WOB) during synchronised nasal intermittent positive pressure ventilation (SNIPPV) and heated humidified high flow nasal cannula (HHHFNC) when used as post-extubation support in preterm infants. A randomised crossover study was undertaken of nine infants with a median gestational age of 27 (range 24-31) weeks and post-natal age of 7 (range 2-50) days. Infants were randomised to either SNIPPV or HHHFNC immediately following extubation. They were studied for 2 h on one mode and then switched to the other modality and studied for a further 2-h period. The work of breathing, assessed by measuring the pressure time product of the diaphragm (PTPdi), and thoracoabdominal asynchrony (TAA) were determined at the end of each 2-h period. The infants' inspired oxygen requirement, oxygen saturation, heart rate and respiratory rate were also recorded. The median PTPdi was lower on SNIPPV than on HHHFNC (232 (range 130-352) versus 365 (range 136-449) cmH2O s/min, p = 0.0077), and there was less thoracoabdominal asynchrony (13.4 (range 8.5-41.6) versus 36.1 (range 4.3-50.4) degrees, p = 0.038).Conclusion: In prematurely born infants, SNIPPV compared to HHHFNC post-extubation reduced the work of breathing and thoracoabdominal asynchrony. What is Known: ⢠The work of breathing and extubation failure are not significantly different in prematurely-born infants supported by HHHFNC or nCPAP. ⢠SNIPPV reduces inspiratory effort and increases tidal volume and carbon dioxide exchange compared to nCPAP in prematurely born infants. What is New: ⢠SNIPPV, as compared to HHHFNC, reduced the work of breathing in prematurely-born infants studied post-extubation. ⢠SNIPPV, as compared to HHHFNC, reduced thoracoabdominal asynchrony in prematurely born infants studied post-extubation.
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Extubação/métodos , Ventilação com Pressão Positiva Intermitente/métodos , Ventilação não Invasiva/métodos , Trabalho Respiratório/fisiologia , Gasometria , Cânula , Estudos Cross-Over , Feminino , Frequência Cardíaca/fisiologia , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Taxa Respiratória/fisiologiaRESUMO
INTRODUCTION: Contemporaneous measures of muscle architecture and force have not previously been conducted during critical illness to examine their relationship with intensive care unit (ICU)-acquired weakness. METHODS: Ankle dorsiflexor muscle force (ADMF) with high-frequency electrical peroneal nerve stimulation and skeletal muscle architecture via ultrasound were measured in 21 adult, critically ill patients, 16 at ICU admission. RESULTS: Thirteen patients were measured on 2 occasions. Among these, 10 who were measured at ICU admission demonstrated muscle weakness. Despite significant reductions in tibialis anterior (Δ = -88.5 ± 78.8 mm2 , P = 0.002) and rectus femoris (Δ = -126.1 ± 129.1 mm2 , P = 0.006) cross-sectional areas between occasions, ADMF did not change (100-HZ ankle dorsiflexor force 9.8 [IQR, 8.0-14.4] kg vs. 8.6 (IQR, 6.7-19.2) kg, P = 0.9). DISCUSSION: Muscle weakness was evident at ICU admission. No additional decrements were observed 7 days later despite significant reductions in muscle size. These data suggest that not all ICU weakness is truly "acquired" and questions our understanding of muscle function during critical illness. Muscle Nerve 57: 964-972, 2018.
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Estado Terminal , Força Muscular/fisiologia , Debilidade Muscular/diagnóstico , Músculo Esquelético/fisiopatologia , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Debilidade Muscular/diagnóstico por imagem , Debilidade Muscular/fisiopatologia , Músculo Esquelético/diagnóstico por imagem , UltrassonografiaRESUMO
BACKGROUND: Maternal smoking, substance misuse in pregnancy and prone sleeping increase the risk of sudden infant death syndrome (SIDS). We examined the effect of maternal smoking, substance misuse and sleeping position on the newborn response to hypoxia. METHODS: Infants born between 36 and 42 weeks of gestational age underwent respiratory monitoring in the prone and supine sleeping position before and during a hypoxic challenge. Minute ventilation (MV) and end-tidal carbon dioxide (ETCO2) levels were assessed. RESULTS: Sixty-three infants were studied: 22 controls, 23 whose mothers smoked and 18 whose mothers substance-misused and smoked. In the supine position, baseline MV was higher and ETCO2 levels were lower in infants of substance-misusing mothers compared to controls (p = 0.015, p = 0.017, respectively). Infants of substance-misusing mothers had a lower baseline MV and higher ETCO2 levels in the prone position (p = 0.005, p = 0.004, respectively). When prone, the rate of decline in minute ventilation in response to hypoxia was greater in infants whose mothers substance-misused and smoked compared to controls (p = 0.002) and infants of smoking mothers (p = 0.016). CONCLUSION: The altered response to hypoxia in the prone position of infants whose mothers substance-misused and smoked in pregnancy may explain their increased vulnerability to SIDS.
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Hipóxia/diagnóstico , Exposição Materna/efeitos adversos , Efeitos Tardios da Exposição Pré-Natal , Decúbito Ventral , Sono , Fumar/efeitos adversos , Transtornos Relacionados ao Uso de Substâncias/complicações , Feminino , Humanos , Recém-Nascido , Masculino , Mães , Gravidez , Complicações na Gravidez , Respiração , Fatores de Risco , Morte Súbita do Lactente/prevenção & controle , Decúbito Dorsal , Volume de Ventilação PulmonarRESUMO
BackgroundWe tested the hypotheses that caffeine therapy would increase the ventilatory response to hypercarbia in infants above the effect of maturation and those with a weaker ventilatory response to hypercarbia would be more likely to subsequently develop apnea that required treatment.MethodsInfants born at less than 34 weeks of gestation underwent a steady-state hypercarbic challenge using 0, 2, and 4% carbon dioxide soon after birth that was repeated at weekly intervals. The results of the initial study were compared between infants who did or did not subsequently develop apnea requiring treatment with caffeine.ResultsTwenty-six infants born at a median gestation of 32 (range 31-33) weeks were assessed. Caffeine administration was associated with an increase in CO2 sensitivity, and the mean increase was 15.3 (95% CI: 1-30) ml/kg/min/% CO2. Fourteen infants subsequently developed apnea treated with caffeine. After controlling for gestational age and birth weight, they had significantly lower carbon dioxide sensitivity at their initial study compared with those who did not require treatment.ConclusionCaffeine administration was associated with an increase in the ventilatory response to hypercarbia. An initial weaker ventilatory response to hypercarbia was associated with the subsequent development of apnea requiring treatment with caffeine.
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Apneia/tratamento farmacológico , Cafeína/uso terapêutico , Dióxido de Carbono/metabolismo , Hipercapnia/terapia , Respiração/efeitos dos fármacos , Peso ao Nascer , Feminino , Idade Gestacional , Humanos , Lactente , Recém-Nascido , Recém-Nascido Prematuro/fisiologia , Doenças do Prematuro , Masculino , PolissonografiaRESUMO
OBJECTIVE: Respiratory muscle weakness frequently develops during mechanical ventilation, although in children there are limited data about its prevalence and whether it is associated with extubation outcomes. We sought to identify risk factors for pediatric extubation failure, with specific attention to respiratory muscle strength. DESIGN: Secondary analysis of prospectively collected data. SETTING: Tertiary care PICU. PATIENTS: Four hundred nine mechanically ventilated children. INTERVENTIONS: Respiratory measurements using esophageal manometry and respiratory inductance plethysmography were made preextubation during airway occlusion and on continuous positive airway pressure of 5 and pressure support of 10 above positive end-expiratory pressure 5 cm H2O, as well as 5 and 60 minutes postextubation. MEASUREMENTS AND MAIN RESULTS: Thirty-four patients (8.3%) were reintubated within 48 hours of extubation. Reintubation risk factors included lower maximum airway pressure during airway occlusion (aPiMax) preextubation, longer length of ventilation, postextubation upper airway obstruction, high respiratory effort postextubation (pressure rate product, pressure time product, tension time index), and high postextubation phase angle. Nearly 35% of children had diminished respiratory muscle strength (aPiMax ≤ 30 cm H2O) at the time of extubation, and were nearly three times more likely to be reintubated than those with preserved strength (aPiMax > 30 cm H2O; 14% vs 5.5%; p = 0.006). Reintubation rates exceeded 20% when children with low aPiMax had moderately elevated effort after extubation (pressure rate product > 500), whereas children with preserved aPiMax had reintubation rates greater than 20% only when postextubation effort was very high (pressure rate product > 1,000). When children developed postextubation upper airway obstruction, reintubation rates were 47.4% for those with low aPiMax compared to 15.4% for those with preserved aPiMax (p = 0.02). Multivariable risk factors for reintubation included acute neurologic disease, lower aPiMax, postextubation upper airway obstruction, higher preextubation positive end-expiratory pressure, higher postextubation pressure rate product, and lower height. CONCLUSIONS: Neuromuscular weakness at the time of extubation was common in children and was independently associated with reintubation, particularly when postextubation effort was high.
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Extubação/efeitos adversos , Unidades de Terapia Intensiva Pediátrica/estatística & dados numéricos , Força Muscular/fisiologia , Músculos Respiratórios/fisiopatologia , Desmame do Respirador/estatística & dados numéricos , Obstrução das Vias Respiratórias , Feminino , Humanos , Lactente , Masculino , Manometria , Pletismografia , Respiração com Pressão Positiva , Fatores de Risco , Fatores de TempoRESUMO
NEW FINDINGS: What is the central question of this study? The parasternal intercostal electromyogram (EMGpara) is known to provide an accurate, non-invasive index of respiratory load-capacity balance. Although relationships between EMGpara and both airflow obstruction and hyperinflation have been shown, the independent contribution of each factor has not been examined. What is the main finding and its importance? Reductions in airway calibre and inspiratory capacity along with increases in EMGpara were induced via methacholine challenge. A strong inverse relationship was observed between EMGpara and airway obstruction, with no influence of inspiratory capacity. These data suggest that EMGpara is more strongly influenced by airway calibre than by changes in end-expiratory lung volume during airway challenge testing. Neural respiratory drive, measured via the parasternal intercostal electromyogram (EMGpara), provides a non-invasive index of the load-capacity balance of the respiratory muscle pump. Previous studies in patients with obstructive lung disease have shown strong relationships between EMGpara and the extent of both airflow obstruction and hyperinflation. The relative influence of the two factors has not, however, been described. Airflow obstruction was induced via methacholine challenge testing in 25 adult humans. Forced expiratory volume in 1 s (FEV1 ) and surface EMGpara during tidal breathing were measured after each dose, with 20 of the participants also undergoing measurements of inspiratory capacity (IC) at each stage. Linear mixed model analysis was used to assess dose-wise changes in FEV1 and EMGpara, and thereafter to determine the influence of changes in FEV1 and IC on change in EMGpara. Median (interquartile range) FEV1 decreased significantly [from 96.00 (80.00-122.30) to 67.80 (37.98-92.27)% predicted, P < 0.0001] and EMGpara increased significantly [from 5.37 (2.25-8.92) to 6.27 (3.37-19.60) µV, P < 0.0001] from baseline to end of test. Linear mixed model analysis showed a significant interaction between methacholine dose and induced change in EMGpara, with an increase in EMGpara of 0.24 (95% confidence interval 0.11-0.37) µV per methacholine dose2 . Change in FEV1 further influenced this relationship [increase in slope of 0.002 (0.004-0.001) µV dose-2 per % predicted fall in FEV1 , P = 0.011], but not with change in IC. These data suggest that bronchoconstriction exerts a more potent influence on levels of EMGpara than changes in end-expiratory lung volume during methacholine challenge.
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Broncoconstrição/efeitos dos fármacos , Músculos Intercostais/efeitos dos fármacos , Cloreto de Metacolina/farmacologia , Músculos Respiratórios/efeitos dos fármacos , Adulto , Testes de Provocação Brônquica/métodos , Feminino , Volume Expiratório Forçado/efeitos dos fármacos , Humanos , Capacidade Inspiratória/efeitos dos fármacos , Pulmão/efeitos dos fármacos , Medidas de Volume Pulmonar/métodos , Masculino , Volume de Ventilação Pulmonar/efeitos dos fármacos , Adulto JovemRESUMO
BACKGROUND AND OBJECTIVE: Peak aerobic capacity (VO2 peak) is an important outcome measure in cystic fibrosis (CF), but measurement is not widely available and can be influenced by patient motivation, pain and fatigue. Alternative markers of disease severity would be helpful. Neural respiratory drive, measured using parasternal intercostal muscle electromyography (EMGpara), reflects the load to capacity balance of the respiratory system and provides a composite measure of pulmonary function impairment in CF. The aim of the study was to investigate the relationship between exercise capacity, EMGpara and established measures of pulmonary function in clinically stable adult CF patients. METHODS: Twenty CF patients (12 males, median (range) age: 22.3 (17.0-43.1) years) performed the 10-m incremental shuttle walk test (ISWT) maximally with contemporaneous measures of aerobic metabolism. EMGpara was recorded from second intercostal space at rest and normalized using peak electromyogram activity obtained during maximum respiratory manoeuvres and expressed as EMGpara%max (EMGpara expressed as a percentage of maximum). RESULTS: VO2 peak was strongly correlated with ISWT distance (r = 0.864, P < 0.0001). Lung gas transfer (TL CO) % predicted was best correlated with VO2 peak (r = 0.842, P < 0.0001) and ISWT distance (r = 0.788, P < 0.0001). EMGpara%max also correlated with VO2 peak (-0.757, P < 0.0001), while the relationships between exercise outcome measures and forced expiratory volume in 1 s (FEV1 ) % predicted and forced vital capacity (FVC) % predicted were less strong. A TL CO% predicted of <70.5% was the strongest predictor of VO2 peak <32 mL/min/kg (area under the curve (AUC): 0.96, 100% sensitivity, 83.3% specificity). ISWT distance and EMGpara%max also performed well, with other pulmonary function variables demonstrating poorer predictive ability. CONCLUSION: TL CO% predicted and EMGpara%max relate strongly to exercise performance markers in CF and may provide alternative predictors of lung disease progression.
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Fibrose Cística/complicações , Eletromiografia/métodos , Tolerância ao Exercício/fisiologia , Pneumopatias/diagnóstico , Adolescente , Adulto , Biomarcadores , Fibrose Cística/fisiopatologia , Progressão da Doença , Teste de Esforço , Feminino , Volume Expiratório Forçado , Humanos , Músculos Intercostais/fisiopatologia , Pneumopatias/complicações , Masculino , Pessoa de Meia-Idade , Sensibilidade e Especificidade , Índice de Gravidade de Doença , Teste de CaminhadaRESUMO
BACKGROUND: Exercise capacity in chronic obstructive pulmonary disease (COPD) is limited by both breathlessness and leg muscle fatigue. Neural respiratory drive, measured as diaphragm electromyogram (EMGdi) activity expressed as a proportion of maximum (EMGdi%max), quantifies the mechanical load on the respiratory muscles and relates closely to breathlessness. We tested the hypothesis that end-exercise EMGdi%max would be higher in patients stopping because of breathlessness than in those limited by leg fatigue. METHODS: EMGdi, ventilation, rate of oxygen consumption (VO2), and ventilatory reserve (ventilation/maximum ventilatory volume ratio [VE/MVV]) were measured continuously in patients with COPD during exhaustive cycle ergometry. EMGdi was measured with a multipair oesophageal catheter passed per-nasally. Differences in physiological variables between groups of patients stopping because of breathlessness, leg fatigue, or both were assessed with one-way ANOVA. FINDINGS: 23 patients were included (median FEV1, 39% of predicted, IQR 30·0-56·8). End-exercise EMGdi%max was significantly higher in patients stopping exercise because of breathlessness (n=12, median EMGdi%max 75·7% [IQR 69·5-77·1]) than in those stopping because of leg fatigue (n=8, 44·1 [39·4-63·3]) or both (n=3, 74·1 [63·6-81·2]) (p=0·02). There were no significant differences between the groups in end-exercise ventilation (breathlessness 25·7 L/min [16·3-32·0] vs leg fatigue 31·5 [20·9-39·6] vs both 22·0 [17·7-35·7]), VO2, (13·4 mL/min per kg [11·6-14·2] vs 12·1 [10·4-14·8] vs 9·4 [9·1-12·4]), or VE/MVV (80·4% [72·6-88·3] vs 57·8 [52·1-92·6] vs 63·9 [34·5-88·9]). INTERPRETATION: These results suggest that patients limited by breathlessness due to ventilatory constraints can be identified as those reaching near-maximum levels of neural respiratory drive during exercise. Measurement of EMGdi%max during exercise could prove useful in identifying patients whose functional performance would be best optimised by improvment in pulmonary mechanics rather than interventions to train peripheral muscle groups. FUNDING: None.
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UNLABELLED: There is little available evidence to demonstrate how cough strength mediates the risk of aspiration-related pneumonia in acute stroke. Our secondary analysis of trial data indicates that risk of pneumonia reduces with increasing peak cough flow (PCF) of voluntary cough (OR 0.994 for each 1â L/min increase in PCF, 95% CI 0.988 to 1.0, p=0.035); and to a lesser degree with increasing PCF of reflex cough (OR 0.998 for each 1â L/min increase in PCF, 95% CI 0.992 to 1.004, p=0.475). These data serve hypothesis generation. Further studies are needed to confirm these findings and validate their clinical utility. CLINICAL TRIAL REGISTRATION NUMBER: ISRCTN40298220 (post-results).
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Tosse/fisiopatologia , Pico do Fluxo Expiratório , Pneumonia Aspirativa/prevenção & controle , Acidente Vascular Cerebral/complicações , Tosse/complicações , Humanos , Pneumonia Aspirativa/etiologia , Pneumonia Aspirativa/fisiopatologia , Medição de Risco , Fatores de RiscoRESUMO
INTRODUCTION: Obstructive sleep apnoea (OSA) is characterised by a loss of neuromuscular tone of the upper airway dilator muscles while asleep. This study investigated the effectiveness of transcutaneous electrical stimulation in patients with OSA. PATIENTS AND METHODS: This was a randomised, sham-controlled crossover trial using transcutaneous electrical stimulation of the upper airway dilator muscles in patients with confirmed OSA. Patients were randomly assigned to one night of sham stimulation and one night of active treatment. The primary outcome was the 4% oxygen desaturation index, responders were defined as patients with a reduction >25% in the oxygen desaturation index when compared with sham stimulation and/or with an index <5/hour in the active treatment night. RESULTS: In 36 patients (age mean 50.8 (SD 11.2) years, male/female 30/6, body mass index median 29.6 (IQR 26.9-34.9) kg/m(2), Epworth Sleepiness Scale 10.5 (4.6) points, oxygen desaturation index median 25.7 (16.0-49.1)/hour, apnoea-hypopnoea index median 28.1 (19.0-57.0)/hour) the primary outcome measure improved when comparing sham stimulation (median 26.9 (17.5-39.5)/hour) with active treatment (median 19.5 (11.6-40.0)/hour; p=0.026), a modest reduction of the mean by 4.1 (95% CI -0.6 to 8.9)/hour. Secondary outcome parameters of patients' perception indicated that stimulation was well tolerated. Responders (47.2%) were predominantly from the mild-to-moderate OSA category. In this subgroup, the oxygen desaturation index was reduced by 10.0 (95% CI 3.9 to 16.0)/hour (p<0.001) and the apnoea-hypopnoea index was reduced by 9.1 (95% CI 2.0 to 16.2)/hour (p=0.004). CONCLUSION: Transcutaneous electrical stimulation of the pharyngeal dilators during a single night in patients with OSA improves upper airway obstruction and is well tolerated. TRIAL REGISTRATION NUMBER: NCT01661712.
Assuntos
Apneia Obstrutiva do Sono/terapia , Estimulação Elétrica Nervosa Transcutânea/métodos , Adulto , Antropometria/métodos , Estudos Cross-Over , Método Duplo-Cego , Feminino , Humanos , Nervo Hipoglosso/fisiopatologia , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Polissonografia/métodos , Músculos Respiratórios/fisiopatologia , Apneia Obstrutiva do Sono/sangue , Estimulação Elétrica Nervosa Transcutânea/efeitos adversos , Resultado do TratamentoRESUMO
Cough is a common symptom of pulmonary sarcoidosis. This study aimed to quantify cough frequency, and investigate its relationship with cough reflex sensitivity, pulmonary function and health status.32 patients with pulmonary sarcoidosis were compared with 40 healthy controls. Cough reflex sensitivity to capsaicin, objective 24-h cough counts, cough-specific health status, cough severity and cough triggers were measured. The predictors of cough frequency in sarcoidosis were determined in a multivariate analysis.Objective cough frequency was significantly raised in patients with sarcoidosis compared with healthy controls (p<0.001) and patients with cough had an impaired health status. Patients with pulmonary sarcoidosis had a heightened cough reflex sensitivity compared with healthy controls (p<0.001). Only cough reflex sensitivity was significantly associated with objective cough frequency in multivariate analysis, explaining 42% of the variance (p<0.001). There was no association between cough frequency, lung function, number of organs involved, chest radiograph stage or serum angiotensin-converting enzyme levels.Cough is a common and significant symptom in patients with sarcoidosis. Ambulatory objective cough monitoring provides novel insights into the determinants of cough in sarcoidosis, suggesting that cough reflex sensitivity may be more important than lung function and other measures of disease severity, and this should be investigated further.
Assuntos
Tosse/diagnóstico , Tosse/fisiopatologia , Sarcoidose Pulmonar/diagnóstico , Sarcoidose Pulmonar/fisiopatologia , Adulto , Capsaicina , Estudos de Casos e Controles , Feminino , Nível de Saúde , Humanos , Pulmão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Peptidil Dipeptidase A/sangue , Qualidade de Vida , Radiografia Torácica , Reflexo , Testes de Função Respiratória , Sarcoidose Pulmonar/psicologia , Fumar , Inquéritos e QuestionáriosRESUMO
The ventilatory response of infants of mothers who smoke and misuse substances and controls to carbon dioxide was assessed at 6-12 weeks and the perinatal period. Infants of mothers who smoke and misuse substances had a dampened response at the peak age of sudden infant death syndrome, greater than in the perinatal period.
Assuntos
Dióxido de Carbono/fisiologia , Comportamento Materno , Complicações na Gravidez , Efeitos Tardios da Exposição Pré-Natal/etiologia , Respiração , Fumar , Transtornos Relacionados ao Uso de Substâncias , Feminino , Seguimentos , Humanos , Hipercapnia/fisiopatologia , Lactente , Recém-Nascido , Masculino , Gravidez , Testes de Função Respiratória , Fatores de Risco , Morte Súbita do Lactente/etiologia , Poluição por Fumaça de Tabaco/efeitos adversosRESUMO
BACKGROUND: Parasternal intercostal muscle electromyography (EMGpara) represents a novel tool to assess respiratory load when volitional techniques are not possible. This study examined the application of EMGpara in healthy, wheezy, and critically ill children. METHODS: Surface EMGpara was measured during tidal breathing in 92 healthy children, 20 wheezy preschool children (with measurements repeated following bronchodilator), and 25 mechanically ventilated children during supported ventilation and on continuous positive airways pressure. RESULTS: EMGpara was related to age, height, and weight in the healthy group (r = -0.623, -0.625, -0.641 respectively, all P < 0.0001). An age-based equation for predicted EMGpara was developed and patient data expressed as z-scores. EMGpara was higher in wheezy children prebronchodilator than healthy controls (median interquartile range (IQR) z-score 0.53 (0.07-1.94), P = 0.0073), falling to levels not different to healthy children postbronchodilator (-0.08 (-0.50-1.00)). In the critically ill children, EMGpara was higher (P < 0.0001) than in healthy subjects during both mechanical ventilation (median (IQR) z-score 1.14 (0.33-1.93)) and continuous positive airways pressure (1.88 (0.91-3.03)). CONCLUSION: EMGpara is feasible in children and infants both healthy and diseased, is raised in those with elevated respiratory load, and is responsive to clinical interventions. EMGpara represents a potential method to assess respiratory status in patients conventionally challenging to assess.
Assuntos
Eletromiografia/métodos , Pneumologia/instrumentação , Respiração , Adolescente , Criança , Pré-Escolar , Estudos de Coortes , Estado Terminal , Estudos de Viabilidade , Feminino , Humanos , Unidades de Terapia Intensiva Pediátrica , Masculino , Pneumologia/métodos , Respiração Artificial/efeitos adversos , Sons RespiratóriosRESUMO
BACKGROUND: Children with sickle cell disease (SCD) often have obstructive lung function abnormalities which could be due to asthma or increased pulmonary blood volume; it is important to determine the underlying mechanism to direct appropriate treatment. In asthmatics, exhaled nitric oxide (FeNO) is elevated. FeNO, however, can also be raised due to increased alveolar production. Our aim, therefore, was to determine if airway or alveolar NO production differed between SCD children and ethnic and age-matched controls. METHODS: Lung function, airway NO flux and alveolar NO production, and effective pulmonary blood flow were assessed in 18 SCD children and 18 ethnic and age-matched controls. RESULTS: The SCD children compared to the controls had a higher respiratory system resistance (P = 0.0008), alveolar NO production (P = 0.0224), and pulmonary blood flow (P < 0.0001), but not airway NO flux. There was no significant correlation between FeNO and respiratory system resistance in either group, but in the SCD children, there were correlations between alveolar NO production (P = 0.0006) and concentration (P < 0.0001) and pulmonary blood flow. CONCLUSION: Airway NO flux was not elevated in the SCD children nor correlated with airways obstruction, suggesting that airways obstruction, at least in some SCD children, is not due to asthma.
Assuntos
Obstrução das Vias Respiratórias/etiologia , Resistência das Vias Respiratórias , Anemia Falciforme/complicações , Pulmão/metabolismo , Óxido Nítrico/metabolismo , Circulação Pulmonar , Adolescente , Obstrução das Vias Respiratórias/diagnóstico , Obstrução das Vias Respiratórias/metabolismo , Obstrução das Vias Respiratórias/fisiopatologia , Anemia Falciforme/diagnóstico , Biomarcadores/metabolismo , Velocidade do Fluxo Sanguíneo , Testes Respiratórios , Estudos de Casos e Controles , Criança , Feminino , Humanos , Pulmão/irrigação sanguínea , Pulmão/fisiopatologia , Masculino , Testes de Função Respiratória , Fatores de RiscoRESUMO
Our aims were to determine whether volume-targeted ventilation (VTV) or pressure-limited ventilation (PLV) reduced the time to successful extubation and if any difference was explained by a lower work of breathing (WOB), better respiratory muscle strength or less thoracoabdominal asynchrony (TAA) and associated with fewer hypocarbic episodes. Infants born at ≥34 weeks of gestational age were randomised to VTV or PLV. The WOB was assessed by the transdiaphragmatic pressure time product, respiratory muscle strength by the maximum inflation (Pimax) and expiratory (Pemax) pressures and TAA assessed using uncalibrated respiratory inductance plethysmography. Forty infants, median gestational age of 39 (range 34-42) weeks, were recruited. The time to successful extubation did not differ between the two groups (median 25, range 2.5-312 h (VTV) versus 33.5, 1.312 h (PLV)) (p = 0.461). There were no significant differences between the groups with regard to the WOB, respiratory muscle strength or the TAA results. The median number of hypocarbic episodes was 1.5 (range 0-8) in the VTV group versus 4 (range 1-13) in the PLV group (p = 0.005). CONCLUSION: In infants born at or near term, VTV compared to PLV did not reduce the time to successful extubation but was associated with significantly fewer hypocarbic episodes. WHAT IS KNOWN: In prematurely born infants, volume-targeted ventilation (VTV) compared to pressure-limited ventilation (PLV) reduces bronchopulmonary dysplasia or death. In addition, VTV is associated in prematurely born infants with lower incidences of pneumothorax, intraventricular haemorrhage and hypocarbic episodes. WHAT IS NEW: Despite a high morbidity, few studies have investigated optimum ventilation strategies for infants born at or near term. In a RCT, we have demonstrated VTV versus PLV in infants ≥34 weeks gestation was associated with significantly fewer hypocarbic episodes.