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2.
Crit Care ; 24(1): 494, 2020 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-32778136

RESUMO

Deterioration of lung function during the first week of COVID-19 has been observed when patients remain with insufficient respiratory support. Patient self-inflicted lung injury (P-SILI) is theorized as the responsible, but there is not robust experimental and clinical data to support it. Given the limited understanding of P-SILI, we describe the physiological basis of P-SILI and we show experimental data to comprehend the role of regional strain and heterogeneity in lung injury due to increased work of breathing.In addition, we discuss the current approach to respiratory support for COVID-19 under this point of view.


Assuntos
Infecções por Coronavirus/fisiopatologia , Progressão da Doença , Lesão Pulmonar/fisiopatologia , Pneumonia Viral/fisiopatologia , Trabalho Respiratório/fisiologia , Infecções por Coronavirus/terapia , Cuidados Críticos , Humanos , Lesão Pulmonar/etiologia , Pandemias , Pneumonia Viral/terapia , Ensaios Clínicos Controlados Aleatórios como Assunto , Respiração Artificial
4.
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
5.
Crit Care ; 24(1): 85, 2020 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-32164784

RESUMO

BACKGROUND: Diaphragm atrophy and dysfunction are consequences of mechanical ventilation and are determinants of clinical outcomes. We hypothesize that partial preservation of diaphragm function, such as during assisted modes of ventilation, will restore diaphragm thickness. We also aim to correlate the changes in diaphragm thickness and function to outcomes and clinical factors. METHODS: This is a prospective, multicentre, observational study. Patients mechanically ventilated for more than 48 h in controlled mode and eventually switched to assisted ventilation were enrolled. Diaphragm ultrasound and clinical data collection were performed every 48 h until discharge or death. A threshold of 10% was used to define thinning during controlled and recovery of thickness during assisted ventilation. Patients were also classified based on the level of diaphragm activity during assisted ventilation. We evaluated the association between changes in diaphragm thickness and activity and clinical outcomes and data, such as ventilation parameters. RESULTS: Sixty-two patients ventilated in controlled mode and then switched to the assisted mode of ventilation were enrolled. Diaphragm thickness significantly decreased during controlled ventilation (1.84 ± 0.44 to 1.49 ± 0.37 mm, p < 0.001) and was partially restored during assisted ventilation (1.49 ± 0.37 to 1.75 ± 0.43 mm, p < 0.001). A diaphragm thinning of more than 10% was associated with longer duration of controlled ventilation (10 [5, 15] versus 5 [4, 8.5] days, p = 0.004) and higher PEEP levels (12.6 ± 4 versus 10.4 ± 4 cmH2O, p = 0.034). An increase in diaphragm thickness of more than 10% during assisted ventilation was not associated with any clinical outcome but with lower respiratory rate (16.7 ± 3.2 versus 19.2 ± 4 bpm, p = 0.019) and Rapid Shallow Breathing Index (37 ± 11 versus 44 ± 13, p = 0.029) and with higher Pressure Muscle Index (2 [0.5, 3] versus 0.4 [0, 1.9], p = 0.024). Change in diaphragm thickness was not related to diaphragm function expressed as diaphragm thickening fraction. CONCLUSION: Mode of ventilation affects diaphragm thickness, and preservation of diaphragmatic contraction, as during assisted modes, can partially reverse the muscle atrophy process. Avoiding a strenuous inspiratory work, as measured by Rapid Shallow Breathing Index and Pressure Muscle Index, may help diaphragm thickness restoration.


Assuntos
Diafragma/diagnóstico por imagem , Respiração Artificial/efeitos adversos , Insuficiência Respiratória/terapia , Ultrassonografia/métodos , Trabalho Respiratório , Estado Terminal , Diafragma/patologia , Diafragma/fisiopatologia , Feminino , Humanos , Unidades de Terapia Intensiva , Masculino , Pessoa de Meia-Idade , Contração Muscular/fisiologia , Debilidade Muscular/diagnóstico por imagem , Estudos Prospectivos , Insuficiência Respiratória/patologia
6.
Arch Dis Child Fetal Neonatal Ed ; 105(5): 550-554, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32047029

RESUMO

BACKGROUND: The original bubble continuous positive airway pressure (bCPAP) design has wide-bore tubing and a low-resistance interface. This creates a stable airway pressure that is reflected by the submersion depth of the expiratory tubing. Several systems with alterations to the original bCPAP design are now available. Most of these are aimed for use in low-income and middle-income countries and have not been compared with the original design. OBJECTIVE: We identified three major alterations to the original bCPAP design: (1) resistance of nasal interface, (2) volume of dead space and (3) diameter of expiratory tubing. Our aim was to study the effect of these alterations on CPAP delivery and work of breathing in a mechanical lung model. Dead space should always be avoided and was not further tested. METHODS: The effect of nasal interface resistance and expiratory tubing diameter was evaluated with simulated breathing in a mechanical lung model without interface leakage. The main outcome was delivered CPAP and imposed work of breathing. RESULTS: High-resistance interfaces and narrow expiratory tubing increased the work of breathing. Additionally, narrow expiratory tubing resulted in higher CPAP levels than indicated by the submersion depth. CONCLUSION: Our study shows the significant effect on CPAP delivery and imposed work of breathing when using high-resistance interfaces and narrow expiratory tubing in bCPAP systems. New systems should include low-resistance interfaces and wide-bore tubing and be compared with the original bCPAP. Referring to all systems that bubble as bCPAP is misleading and potentially hazardous.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas/instrumentação , Pressão Positiva Contínua nas Vias Aéreas/métodos , Trabalho Respiratório/fisiologia , Resistência das Vias Respiratórias/fisiologia , Humanos , Recém-Nascido , Modelos Biológicos
7.
Am J Respir Crit Care Med ; 201(9): 1086-1098, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32097569

RESUMO

Rationale: Monitoring and controlling respiratory drive and effort may help to minimize lung and diaphragm injury. Airway occlusion pressure (P0.1) is a noninvasive measure of respiratory drive.Objectives: To determine 1) the validity of "ventilator" P0.1 (P0.1vent) displayed on the screen as a measure of drive, 2) the ability of P0.1 to detect potentially injurious levels of effort, and 3) how P0.1vent displayed by different ventilators compares to a "reference" P0.1 (P0.1ref) measured from airway pressure recording during an occlusion.Methods: Analysis of three studies in patients, one in healthy subjects, under assisted ventilation, and a bench study with six ventilators. P0.1vent was validated against measures of drive (electrical activity of the diaphragm and muscular pressure over time) and P0.1ref. Performance of P0.1ref and P0.1vent to detect predefined potentially injurious effort was tested using derivation and validation datasets using esophageal pressure-time product as the reference standard.Measurements and Main Results: P0.1vent correlated well with measures of drive and with the esophageal pressure-time product (within-subjects R2 = 0.8). P0.1ref >3.5 cm H2O was 80% sensitive and 77% specific for detecting high effort (≥200 cm H2O ⋅ s ⋅ min-1); P0.1ref ≤1.0 cm H2O was 100% sensitive and 92% specific for low effort (≤50 cm H2O ⋅ s ⋅ min-1). The area under the receiver operating characteristics curve for P0.1vent to detect potentially high and low effort were 0.81 and 0.92, respectively. Bench experiments showed a low mean bias for P0.1vent compared with P0.1ref for most ventilators but precision varied; in patients, precision was lower. Ventilators estimating P0.1vent without occlusions could underestimate P0.1ref.Conclusions: P0.1 is a reliable bedside tool to assess respiratory drive and detect potentially injurious inspiratory effort.


Assuntos
Pressão do Ar , Monitoramento Biológico/normas , Inalação/fisiologia , Respiração com Pressão Positiva/normas , Guias de Prática Clínica como Assunto , Respiração Artificial/normas , Trabalho Respiratório/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes
8.
PLoS One ; 15(1): e0226980, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923192

RESUMO

RATIONALE: Pulmonary function testing (PFT) provides diagnostic information regarding respiratory physiology. However, many forms of PFT are time-intensive and require patient cooperation. Respiratory inductance plethysmography (RIP) provides thoracoabdominal asynchrony (TAA) and work of breathing (WOB) data. pneuRIPTM is a noninvasive, wireless analyzer that provides real-time assessment of RIP via an iPad. In this study, we show that pneuRIPTM can be used in a hospital clinic setting to differentiate WOB indices and breathing patterns in children with DMD as compared to age-matched healthy subjects. METHODS: RIP using the pneuRIPTM was conducted on 9 healthy volunteers and 7 DMD participants (ages 5-18) recruited from the neuromuscular clinic, under normal resting conditions over 3-5 min during routine outpatient visits. The tests were completed in less than 10 minutes and did not add excessive time to the clinic visit. Variables recorded included labored-breathing index (LBI), phase angle (Φ) between abdomen and rib cage, respiratory rate (RR), percentage of rib cage input (RC%), and heart rate (HR). The data were displayed in histogram plots to identify distribution patterns within the normal ranges. The percentages of data within the ranges (0≤ Φ ≤30 deg.; median RC %±10%; median RR±5%; 1≤LBI≤1.1) were compared. Unpaired t-tests determined significance of the data between groups. RESULTS: 100% patient compliance demonstrates the feasibility of such testing in clinical settings. DMD patients showed a significant elevation in Φ, LBI, and HR averages (P<0.006, P<0.002, P<0.046, respectively). Healthy subjects and DMD patients had similar BPM and RC% averages. All DMD data distributions were statistically different from healthy subjects based on analysis of histograms. The DMD patients showed significantly less data within the normal ranges, with only 49.7% Φ, 48.0% RC%, 69.2% RR, and 50.7% LBI. CONCLUSION: In this study, noninvasive pneuRIPTM testing provided instantaneous PFT diagnostic results. As compared to healthy subjects, patients with DMD showed abnormal results with increased markers of TAA, WOB indices, and different breathing patterns. These results are similar to previous studies evaluating RIP in preterm infants. Further studies are needed to compare these results to other pulmonary testing methods. The pneuRIPTM testing approach provides immediate diagnostic information in outpatient settings.


Assuntos
Distrofia Muscular de Duchenne/fisiopatologia , Pletismografia/instrumentação , Mecânica Respiratória , Trabalho Respiratório , Adolescente , Estudos de Casos e Controles , Criança , Pré-Escolar , Frequência Cardíaca , Humanos , Masculino , Distrofia Muscular de Duchenne/diagnóstico , Pletismografia/métodos , Testes de Função Respiratória , Taxa Respiratória
9.
Pneumologie ; 74(3): 137-148, 2020 Mar.
Artigo em Alemão | MEDLINE | ID: mdl-31918445

RESUMO

Nasal high-flow provides a stable oxygenation in acute hypoxemic respiratory failure, modifies breathing patterns, reduces work of breathing and can decrease hypercapnia. Thereby NHF provides more features than low-flow oxygen and acts as a ventilatory support device. Different studies show benefits of NHF compared to NIV. For these reasons we will discuss the capabilities of NHF and NIV in selected settings.


Assuntos
Pulmão/fisiopatologia , Ventilação não Invasiva/métodos , Oxigenoterapia/métodos , Oxigênio/administração & dosagem , Respiração com Pressão Positiva/métodos , Insuficiência Respiratória/terapia , Trabalho Respiratório/fisiologia , Humanos , Hipercapnia/prevenção & controle , Resultado do Tratamento
10.
Crit Care ; 23(1): 346, 2019 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-31694692

RESUMO

BACKGROUND: Excessive respiratory muscle effort during mechanical ventilation may cause patient self-inflicted lung injury and load-induced diaphragm myotrauma, but there are no non-invasive methods to reliably detect elevated transpulmonary driving pressure and elevated respiratory muscle effort during assisted ventilation. We hypothesized that the swing in airway pressure generated by respiratory muscle effort under assisted ventilation when the airway is briefly occluded (ΔPocc) could be used as a highly feasible non-invasive technique to screen for these conditions. METHODS: Respiratory muscle pressure (Pmus), dynamic transpulmonary driving pressure (ΔPL,dyn, the difference between peak and end-expiratory transpulmonary pressure), and ΔPocc were measured daily in mechanically ventilated patients in two ICUs in Toronto, Canada. A conversion factor to predict ΔPL,dyn and Pmus from ΔPocc was derived and validated using cross-validation. External validity was assessed in an independent cohort (Nanjing, China). RESULTS: Fifty-two daily recordings were collected in 16 patients. In this sample, Pmus and ΔPL were frequently excessively high: Pmus exceeded 10 cm H2O on 84% of study days and ΔPL,dyn exceeded 15 cm H2O on 53% of study days. ΔPocc measurements accurately detected Pmus > 10 cm H2O (AUROC 0.92, 95% CI 0.83-0.97) and ΔPL,dyn > 15 cm H2O (AUROC 0.93, 95% CI 0.86-0.99). In the external validation cohort (n = 12), estimating Pmus and ΔPL,dyn from ΔPocc measurements detected excessively high Pmus and ΔPL,dyn with similar accuracy (AUROC ≥ 0.94). CONCLUSIONS: Measuring ΔPocc enables accurate non-invasive detection of elevated respiratory muscle pressure and transpulmonary driving pressure. Excessive respiratory effort and transpulmonary driving pressure may be frequent in spontaneously breathing ventilated patients.


Assuntos
Ventilação não Invasiva/métodos , Pressão , Pesos e Medidas/instrumentação , Trabalho Respiratório/fisiologia , Lesão Pulmonar Aguda/fisiopatologia , Lesão Pulmonar Aguda/prevenção & controle , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica/métodos , Respiração Artificial/métodos , Músculos Respiratórios/lesões , Músculos Respiratórios/fisiopatologia , Pesos e Medidas/normas
11.
Chron Respir Dis ; 16: 1479973119880892, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31635493

RESUMO

High-flow nasal cannula (HFNC) therapy has been increasingly applied to treat patients with severe hypoxemic respiratory failure. We investigated whether vital signs reflect the reduction of work of breathing in a simulator study and a clinical study. In the simulator study, a standard model high-fidelity human patient simulator (HPS) directly received 35 L/minute of 100% O2 via the HFNC. In the clinical study, the medical records of patients with hypoxemic respiratory failure who received HFNC therapy between January 2013 and May 2015 were retrospectively reviewed. Statistical analysis was performed using a one-way repeated analysis of variance followed by Bonferroni post-hoc testing. In the HPS, HFNC therapy significantly reduced the partial pressure of alveolar CO2, respiratory rate, and tidal volume (p < 0.001), and all values returned to baseline following HFNC therapy termination (p < 0.001). In the clinical study including 48 patients, the respiratory rate was significantly reduced from 27 ± 9 (baseline) to 24 ± 8 (3 hours), 24 ± 8 (5 hours), and 24 ± 8.0 (6 hours) (p < 0.05). The heart rate also decreased significantly (p < 0.05). Our results suggested that HFNC therapy reduced work of breathing and assessing vital signs can be important.


Assuntos
Hipóxia/terapia , Oxigenoterapia/métodos , Oxigênio/administração & dosagem , Insuficiência Respiratória/terapia , Trabalho Respiratório , Idoso , Idoso de 80 Anos ou mais , Cânula , Simulação por Computador , Feminino , Frequência Cardíaca , Humanos , Hipóxia/etiologia , Masculino , Pressão Parcial , Alvéolos Pulmonares/fisiopatologia , Insuficiência Respiratória/complicações , Taxa Respiratória , Estudos Retrospectivos , Volume de Ventilação Pulmonar
12.
Pulmonology ; 25(6): 348-354, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31591056

RESUMO

Chronic Obstructive Pulmonary Disease (COPD) history is characterized by episodes of exacerbation of varying severity, featured by acute worsening of respiratory symptoms, commonly precipitated by respiratory tract infection. The recent ERS/ATS clinical practice guidelines strongly recommend the application of non invasive ventilation (NIV) for patients with acute respiratory failure (ARF) leading to acute or acute-on-chronic respiratory acidosis (pH 7.35) and not for those patients with acute exacerbation of COPD (AECOPD) and hypercapnia who are not acidotic. In recent years, High-Flow through Nasal Cannula (HFNC) has been introduced in the clinical practice. We designed the present systematic review of the literature to assess all effects of HFNC use reported in exacerbated COPD patients. In this setting, HFNC is able to keep PaCO2 unmodified, while oxygenation slightly deteriorates as opposed to NIV. Furthermore, the work of breathing is reduced with HFNC by a similar extent to NIV, while it increases by 40-50% during conventional oxygen therapy (COT). HFNC is also reported to be more comfortable than COT and NIV. Despite these results, little and limited evidence for improved clinical outcomes is currently available.


Assuntos
Ventilação não Invasiva/métodos , Doença Pulmonar Obstrutiva Crônica/terapia , Terapia Respiratória/métodos , Acidose Respiratória/terapia , Gasometria , Progressão da Doença , Humanos , Hipercapnia/terapia , Ventilação não Invasiva/instrumentação , Respiração com Pressão Positiva/instrumentação , Respiração com Pressão Positiva/métodos , Doença Pulmonar Obstrutiva Crônica/sangue , Insuficiência Respiratória/complicações , Insuficiência Respiratória/terapia , Taxa Respiratória , Terapia Respiratória/instrumentação , Resultado do Tratamento , Trabalho Respiratório
13.
Ann Acad Med Singapore ; 48(7): 224-232, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31495868

RESUMO

INTRODUCTION: Evidence supporting non-invasive ventilation (NIV) in paediatric acute respiratory distress syndrome (PARDS) remains sparse. We aimed to describe characteristics of patients with PARDS supported with NIV and risk factors for NIV failure. MATERIALS AND METHODS: This is a multicentre retrospective study. Only patients supported on NIV with PARDS were included. Data on epidemiology and clinical outcomes were collected. Primary outcome was NIV failure which was defined as escalation to invasive mechanical ventilation within the first 7 days of PARDS. Patients in the NIV success and failure groups were compared. RESULTS: There were 303 patients with PARDS; 53/303 (17.5%) patients were supported with NIV. The median age was 50.7 (interquartile range: 15.7-111.9) months. The Paediatric Logistic Organ Dysfunction score and oxygen saturation/fraction of inspired oxygen (SF) ratio were 2.0 (1.0-10.0) and 155.0 (119.4- 187.3), respectively. Indications for NIV use were increased work of breathing (26/53 [49.1%]) and hypoxia (22/53 [41.5%]). Overall NIV failure rate was 77.4% (41/53). All patients with sepsis who developed PARDS experienced NIV failure. NIV failure was associated with an increased median paediatric intensive care unit stay (15.0 [9.5-26.5] vs 4.5 [3.0-6.8] days; P <0.001) and hospital length of stay (26.0 [17.0-39.0] days vs 10.5 [5.5-22.3] days; P = 0.004). Overall mortality rate was 32.1% (17/53). CONCLUSION: The use of NIV in children with PARDS was associated with high failure rate. As such, future studies should examine the optimal selection criteria for NIV use in these children.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas/métodos , Hipóxia/terapia , Ventilação não Invasiva/métodos , Síndrome do Desconforto Respiratório do Adulto/terapia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Hipóxia/metabolismo , Hipóxia/fisiopatologia , Lactente , Unidades de Terapia Intensiva Pediátrica , Intubação Intratraqueal , Tempo de Internação , Masculino , Mortalidade , Escores de Disfunção Orgânica , Oxigênio/metabolismo , Respiração Artificial , Síndrome do Desconforto Respiratório do Adulto/metabolismo , Síndrome do Desconforto Respiratório do Adulto/fisiopatologia , Estudos Retrospectivos , Fatores de Risco , Falha de Tratamento , Trabalho Respiratório
14.
J Sports Sci ; 37(23): 2653-2659, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31419921

RESUMO

This study assessed the intra-individual reliability of oxygen saturation in intercostal muscles (SmO2-m.intercostales) during an incremental maximal treadmill exercise by using portable NIRS devices in a test-retest study. Fifteen marathon runners (age, 24.9 ± 2.0 years; body mass index, 21.6 ± 2.3 kg·m-2; V̇O2-peak, 63.7 ± 5.9 mL·kg-1·min-1) were tested on two separate days, with a 7-day interval between the two measurements. Oxygen consumption (V̇O2) was assessed using the breath-by-breath method during the V̇O2-test, while SmO2 was determined using a portable commercial device, based in the near-infrared spectroscopy (NIRS) principle. The minute ventilation (VE), respiratory rate (RR), and tidal volume (Vt) were also monitored during the cardiopulmonary exercise test. For the SmO2-m.intercostales, the intraclass correlation coefficient (ICC) at rest, first (VT1) and second ventilatory (VT2) thresholds, and maximal stages were 0.90, 0.84, 0.92, and 0.93, respectively; the confidence intervals ranged from -10.8% - +9.5% to -15.3% - +12.5%. The reliability was good at low intensity (rest and VT1) and excellent at high intensity (VT2 and max). The Spearman correlation test revealed (p ≤ 0.001) an inverse association of SmO2-m.intercostales with V̇O2 (ρ = -0.64), VE (ρ = -0.73), RR (ρ = -0.70), and Vt (ρ = -0.63). The relationship with the ventilatory variables showed that increased breathing effort during exercise could be registered adequately using a NIRS portable device.


Assuntos
Exercício Físico/fisiologia , Músculos Intercostais/fisiologia , Consumo de Oxigênio/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/instrumentação , Trabalho Respiratório/fisiologia , Adulto , Desempenho Atlético/fisiologia , Teste de Esforço/métodos , Humanos , Masculino , Reprodutibilidade dos Testes , Taxa Respiratória/fisiologia , Corrida/fisiologia , Volume de Ventilação Pulmonar/fisiologia , Adulto Jovem
16.
Intensive Care Med ; 45(8): 1061-1071, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31236639

RESUMO

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.


Assuntos
Expiração/fisiologia , Doenças Musculares/fisiopatologia , Músculos Respiratórios/fisiopatologia , Estado Terminal , Humanos , Músculos Respiratórios/anormalidades , Músculos Respiratórios/efeitos dos fármacos , Trabalho Respiratório/fisiologia
17.
Eur J Pediatr ; 178(8): 1237-1242, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31187264

RESUMO

Heated, humidified, high-flow nasal cannula (HHHFNC) is increasingly being used, but there is a paucity of evidence as to the optimum flow rates in prematurely born infants. We have determined the impact of three flow rates on the work of breathing (WOB) assessed by transcutaneous diaphragm electromyography (EMG) amplitude in infants with respiratory distress or bronchopulmonary dysplasia (BPD). Flow rates of 4, 6 and 8 L/min were delivered in random order. The mean amplitude of the EMG trace and mean area under the EMG curve (AEMGC) were calculated and the occurrence of bradycardias and desaturations recorded. Eighteen infants were studied with a median gestational age of 27.8 (range 23.9-33.5) weeks and postnatal age of 54 (range 3-122) days. The median flow rate prior to the study was 5 (range 3-8) L/min and the fraction of inspired oxygen (FiO2) was 0.29 (range 0.21-0.50). There were no significant differences between the mean amplitude of the diaphragm EMG and the AEGMC and the number of bradycardias or desaturations between the three flow rates.Conclusions: In infants with respiratory distress or BPD, there was no advantage of using high (8 L/min) compared with lower flow rates (4 or 6 L/min) during support by HHHFNC. What is known: • Humidified high flow nasal cannulae (HHHFNC) is increasingly being used as a non-invasive form of respiratory support for prematurely born infants. • There is a paucity of evidence regarding the optimum flow rate with 1 to 8 L/min being used. What is new: • We have assessed the work of breathing using the amplitude of the electromyogram of the diaphragm at three HHHFNC flow rates in infants with respiratory distress or BPD. • No significant differences were found in the EMG amplitude results or the numbers of bradycardias or desaturations at 4, 6 and 8 L/min.


Assuntos
Displasia Broncopulmonar/terapia , Diafragma/fisiologia , Eletromiografia , Ventilação não Invasiva/métodos , Síndrome do Desconforto Respiratório do Recém-Nascido/terapia , Trabalho Respiratório/fisiologia , Displasia Broncopulmonar/fisiopatologia , Cânula , Estudos Cross-Over , Feminino , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Ventilação não Invasiva/instrumentação , Síndrome do Desconforto Respiratório do Recém-Nascido/fisiopatologia , Resultado do Tratamento
18.
Respir Care ; 64(6): 647-657, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31110034

RESUMO

Noninvasive ventilation is well established as the ventilatory modality of first choice to treat acute or acute-on-chronic hypercapnic respiratory failure in patients with COPD by improving dyspnea and gas exchange, avoiding the need for intubation, and reducing morbidity and mortality rates. Noninvasive ventilation also offers benefit for patients with COPD and with accompanying pneumonia or with hypercapnic respiratory failure in postextubation, postoperative, and do not intubate settings. Noninvasive ventilation, in addition, offers benefit in other forms of acute hypercapnic respiratory failure, including those caused by asthma, cystic fibrosis, and obesity hypoventilation. A newer form of noninvasive ventilatory assistance, high-flow nasal cannula, has emerged in recent years as a technique to not only oxygenate effectively but also to improve ventilatory efficiency and reduce the work of breathing in patients with severe COPD. Results of recent studies indicate that high-flow nasal cannula therapy can benefit some patients with acute hypercapnic respiratory failure, either instead of or in combination with noninvasive ventilation, but more study is needed.


Assuntos
Hipercapnia/terapia , Ventilação não Invasiva/métodos , Doença Pulmonar Obstrutiva Crônica/terapia , Insuficiência Respiratória/terapia , Humanos , Hipercapnia/fisiopatologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Insuficiência Respiratória/fisiopatologia , Trabalho Respiratório
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