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2.
Goiânia; SES-GO; 22 abr. 2021. 1-8 p. fig, ilus.
Não convencional em Português | LILACS, Coleciona SUS, CONASS, SES-GO | ID: biblio-1247557

RESUMO

Trata-se de síntese de evidências sobre as possibilidades terapêuticas para insuficiência respiratória grave no contexto da pandemia de Covid-19. O tratamento inclui as possibilidades terapêuticas de ventilação não invasiva (VNI), intubação e ventilação mecânica invasiva (VMI). Considera as características dos métodos, suas vantagens e limitações.


This is a synthesis of evidence on the therapeutic possibilities for severe respiratory failure in the context of the Covid-19 pandemic. Treatment includes the therapeutic possibilities of noninvasive ventilation (NIV), intubation, and invasive mechanical ventilation (IMV). It considers the characteristics of the methods, their advantages and limitations.


Assuntos
Humanos , Masculino , Feminino , Gravidez , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Adulto Jovem , Respiração Artificial/métodos , Suporte Ventilatório Interativo/estatística & dados numéricos , Ventilação não Invasiva/métodos
5.
Eur J Anaesthesiol ; 38(1): 32-40, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32657806

RESUMO

BACKGROUND: Variable assisted mechanical ventilation has been shown to improve lung function and reduce lung injury. However, differences between extrinsic and intrinsic variability are unknown. OBJECTIVE: To investigate the effects of neurally adjusted ventilatory assist (NAVA, intrinsic variability), variable pressure support ventilation (Noisy PSV, extrinsic variability) and conventional pressure-controlled ventilation (PCV) on lung and diaphragmatic function and damage in experimental acute respiratory distress syndrome (ARDS). DESIGN: Randomised controlled animal study. SETTING: University Hospital Research Facility. SUBJECTS: A total of 24 juvenile female pigs. INTERVENTIONS: ARDS was induced by repetitive lung lavage and injurious ventilation. Animals were randomly assigned to 24 h of either: 1) NAVA, 2) Noisy PSV or 3) PCV (n=8 per group). Mechanical ventilation settings followed the ARDS Network recommendations. MEASUREMENTS: The primary outcome was histological lung damage. Secondary outcomes were respiratory variables and patterns, subject-ventilator asynchrony (SVA), pulmonary and diaphragmatic biomarkers, as well as diaphragmatic muscle atrophy and myosin isotypes. RESULTS: Global alveolar damage did not differ between groups, but NAVA resulted in less interstitial oedema in dorsal lung regions than Noisy PSV. Gas exchange and SVA incidence did not differ between groups. Compared with Noisy PSV, NAVA generated higher coefficients of variation of tidal volume and respiratory rate. During NAVA, only 40.4% of breaths were triggered by the electrical diaphragm signal. The IL-8 concentration in lung tissue was lower after NAVA compared with PCV and Noisy PSV, whereas Noisy PSV yielded lower type III procollagen mRNA expression than NAVA and PCV. Diaphragmatic muscle fibre diameters were smaller after PCV compared with assisted modes, whereas expression of myosin isotypes did not differ between groups. CONCLUSION: Noisy PSV and NAVA did not reduce global lung injury compared with PCV but affected different biomarkers and attenuated diaphragmatic atrophy. NAVA increased the respiratory variability; however, NAVA yielded a similar SVA incidence as Noisy PSV. TRIAL REGISTRATION: This trial was registered and approved by the Landesdirektion Dresden, Germany (AZ 24-9168.11-1/2012-2).


Assuntos
Suporte Ventilatório Interativo , Síndrome do Desconforto Respiratório , Animais , Diafragma , Feminino , Alemanha , Pulmão , Respiração Artificial/efeitos adversos , Síndrome do Desconforto Respiratório/terapia , Suínos
6.
Curr Opin Crit Care ; 27(1): 29-36, 2021 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33337620

RESUMO

PURPOSE OF REVIEW: Ventilator weaning forms an integral part in critical care medicine and strategies to shorten duration are rapidly evolving alongside our knowledge of the relevant physiological processes. The purpose of the current review is to discuss new physiological and clinical insights in ventilator weaning that help us to fasten liberation from mechanical ventilation. RECENT FINDINGS: Several new concepts have been introduced in the field of ventilator weaning in the past 2 years. Approaches to shorten the time until ventilator liberation include frequent spontaneous breathing trials, early noninvasive mechanical ventilation to shorten invasive ventilation time, novel ventilatory modes, such as neurally adjusted ventilatory assist and drugs to enhance the contractile efficiency of respiratory muscles. Equally important, ultrasound has been shown to be a versatile tool to monitor physiological changes of the cardiorespiratory system during weaning and steer targeted interventions to improve extubation outcome. SUMMARY: A thorough understanding of the physiological adaptations during withdrawal of positive pressure ventilation is extremely important for clinicians in the ICU. We summarize and discuss novel insights in this field.


Assuntos
Suporte Ventilatório Interativo , Desmame do Respirador , Extubação , Humanos , Respiração com Pressão Positiva , Respiração Artificial , Literatura de Revisão como Assunto
8.
Recurso educacional aberto em Português | CVSP - Regional | ID: oer-3924

RESUMO

O conteúdo da aula é baseado em treinamento prático a partir de um simulador como proceder na monitoração de um aparelho de ventilação pulmonar. No conteúdo são avaliados a pressão de Platô e Complacência.


Assuntos
Respiração Artificial , Treinamento com Simulação de Alta Fidelidade , Suporte Ventilatório Interativo , Coronavirus , Aprendizagem Baseada em Problemas
10.
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue ; 32(5): 575-580, 2020 May.
Artigo em Chinês | MEDLINE | ID: mdl-32576350

RESUMO

OBJECTIVE: To explore the patient-ventilator interaction of neurally adjusted ventilatory assist (NAVA) in patients with severe neurological diseases. METHODS: A prospective study was conducted. Sixteen severe neurological patients with tracheotomy admitted to neurosurgery intensive care unit (NSICU) of Yijishan Hospital of the First Affiliated Hospital of Wannan Medical College from September 2019 to February 2020 were enrolled. According to the random number table method, they were treated with pressure support ventilation (PSV) mode followed by NAVA mode or NAVA mode followed by PSV mode mechanical ventilation. Each mode was ventilated for 24 hours. The number of auto-triggering, ineffective trigger, double trigger, inspiratory trigger delay, premature cycling, late cycling, and patient-ventilator asynchronous time (inspiratory trigger delay time, premature cycling time, and late cycling time) within 1 minute were recorded every 8 hours for 3 minutes. The average number of asynchronies per minute, asynchrony index (AI), total AI, asynchrony time, arterial blood gas analysis, and coefficient variation (CV%) of respiratory mechanics parameters of each asynchrony type between the two modes were compared. RESULTS: There were significant decrease in the number or AI of auto-triggering, ineffective trigger, inspiratory trigger delay, premature cycling, and late cycling with NAVA mode ventilation compared with PSV mode ventilation [auto-triggering times (times/min): 0.00 (0.00, 0.00) vs. 0.00 (0.00, 0.58), auto-triggering AI: 0.00 (0.00, 0.00) vs. 0.00 (0.00, 0.02), ineffective trigger times (times/min): 0.00 (0.00, 0.33) vs. 1.00 (0.33, 2.17), ineffective trigger AI: 0.00 (0.00, 0.02) vs. 0.05 (0.02, 0.09), inspiratory trigger delay times (times/min): 0.00 (0.00, 0.58) vs. 0.67 (0.33, 1.58), inspiratory trigger delay AI: 0.00 (0.00, 0.02) vs. 0.05 (0.02, 0.09), premature cycling times (times/min): 0.00 (0.00, 0.33) vs. 0.33 (0.08, 1.00), premature cycling AI: 0.00 (0.00, 0.01) vs. 0.02 (0.00, 0.05), late cycling times (times/min): 0.00 (0.00, 0.00) vs. 1.17 (0.00, 4.83), late cycling AI: 0.00 (0.00, 0.00) vs. 0.07 (0.00, 0.25), all P < 0.05]. But there was significant increase in the number or AI of double trigger with NAVA mode ventilation as compared with PSV mode ventilation [times (times/min): 1.00 (0.33, 2.00) vs. 0.00 (0.00, 0.00), AI: 0.04 (0.02, 0.11) vs. 0.00 (0.00, 0.00), both P < 0.05]. Total AI and incidence of total AI > 0.1 showed significant decrease during NAVA mode ventilation as compared with PSV mode ventilation [total AI: 0.08 (0.04, 0.14) vs. 0.22 (0.18, 0.46), incidence of total AI > 0.1: 37.50% (6/16) vs. 93.75% (15/16), both P < 0.01]. There was no significant difference in asynchronous time or arterial blood gas analysis between the two modes. There were significant increases in variances of peak airway pressure (Ppeak) and expiratory tidal volume (VTe) during NAVA mode ventilation as compared with PSV mode ventilation [Ppeak coefficient of variation (CV%): 11.25 (7.12, 15.17)% vs. 0.00 (0.00, 2.82)%, VTe CV%: (8.93±5.53)% vs. (4.71±2.61)%, both P < 0.05]. CONCLUSIONS: Compared with PSV mode, NAVA mode can reduce the occurrence of patient-ventilator asynchronous events, reduce the AI and the occurrence of serious patient-ventilator asynchronous events, so as to improve the patient-ventilator interaction. NAVA and PSV modes can achieve the same gas exchange effect. At the same time, NAVA mode has potential advantages in avoiding insufficient or excessive ventilation support, diaphragm protection and prevention of ventilator-induced lung injury.


Assuntos
Suporte Ventilatório Interativo , Humanos , Respiração com Pressão Positiva , Estudos Prospectivos , Respiração Artificial , Traqueotomia , Ventiladores Mecânicos
11.
The Academic Society ; 4(2): 131-143, Jun. 2020. ilustração, imagem, gráfico, tabela
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IDPCPROD, Sec. Est. Saúde SP | ID: biblio-1103679

RESUMO

Abstract. In the face of the coronavirus pandemic (COVID-19), in hospital and emergency units, there is low availability of mechanical respirator for patients in need of this support, greatly improving the survival rate. In these situations, there is a need for simpler equipment, easy access, low cost, and fast manufacturing. In this study, a 3D prototype transport respirator was developed using as a model the Takaoka 600 Mini Respirator, national technology from the 1950s. The influence of adjustable parameters of the respirator was evaluated to understand it is functioning: maximum and minimum lung pressure; respirator intake pressure; respiratory rate; inspiratory and expiratory time according to the sensitivity of the mini respirator; and pressure and flow of O2 line intake. The increase in sensitivity led to an increase in maximum and minimum pulmonary pressure, decreased inspiratory and expiratory time, with margins of 1/1, 1/2, 1/3 inspiratory/expiratory time ratio (I/E ratio). The intake flow of O2 varied proportionally with the pressure of air intake into the respirator, with its increase leading to an increase in respiratory rate, without major influences on lung pressure and the I/E ratio. The O2 line intake pressure without major influences on lung pressure, showing and I/E ratio >1 in values below 3.5 kPa x 100. In conclusion, it was possible to obtain a pulmonary ventilator-dependent only on positive O2 flow, compact and effective for patient transport, and in cases of emergencies with control of maximum pressure and respiratory rate offered to the patient. Among the parameters evaluated for this respirator, an line pressure of O2 from 3.5 kPa x 100, sensitivity between 3 and 5, a flow of 5 to 15 L/min is recommended.


Assuntos
Ventiladores Mecânicos , Infecções por Coronavirus , Suporte Ventilatório Interativo , Unidades de Terapia Intensiva
13.
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
15.
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
16.
Anesthesiology ; 132(6): 1482-1493, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32217876

RESUMO

BACKGROUND: Difficult weaning frequently develops in ventilated patients and is associated with poor outcome. In neurally adjusted ventilatory assist, the ventilator is controlled by diaphragm electrical activity, which has been shown to improve patient-ventilator interaction. The objective of this study was to compare neurally adjusted ventilatory assist and pressure support ventilation in patients difficult to wean from mechanical ventilation. METHODS: In this nonblinded randomized clinical trial, difficult-to-wean patients (n = 99) were randomly assigned to neurally adjusted ventilatory assist or pressure support ventilation mode. The primary outcome was the duration of weaning. Secondary outcomes included the proportion of successful weaning, patient-ventilator asynchrony, ventilator-free days, and mortality. Weaning duration was calculated as 28 days for patients under mechanical ventilation at day 28 or deceased before day 28 without successful weaning. RESULTS: Weaning duration in all patients was statistically significant shorter in the neurally adjusted ventilatory assist group (n = 47) compared with the pressure support ventilation group (n = 52; 3.0 [1.2 to 8.0] days vs. 7.4 [2.0 to 28.0], mean difference: -5.5 [95% CI, -9.2 to -1.4], P = 0.039). Post hoc sensitivity analysis also showed that the neurally adjusted ventilatory assist group had shorter weaning duration (hazard ratio, 0.58; 95% CI, 0.34 to 0.98). The proportion of patients with successful weaning from invasive mechanical ventilation was higher in neurally adjusted ventilatory assist (33 of 47 patients, 70%) compared with pressure support ventilation (25 of 52 patients, 48%; respiratory rate for neurally adjusted ventilatory assist: 1.46 [95% CI, 1.04 to 2.05], P = 0.026). The number of ventilator-free days at days 14 and 28 was statistically significantly higher in neurally adjusted ventilatory assist compared with pressure support ventilation. Neurally adjusted ventilatory assist improved patient ventilator interaction. Mortality and length of stay in the intensive care unit and in the hospital were similar among groups. CONCLUSIONS: In patients difficult to wean, neurally adjusted ventilatory assist decreased the duration of weaning and increased ventilator-free days.


Assuntos
Suporte Ventilatório Interativo/estatística & dados numéricos , Respiração com Pressão Positiva/estatística & dados numéricos , Desmame do Respirador/estatística & dados numéricos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Suporte Ventilatório Interativo/métodos , Masculino , Respiração com Pressão Positiva/métodos , Taxa Respiratória , Desmame do Respirador/métodos
17.
Curr Opin Crit Care ; 26(1): 41-46, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31738231

RESUMO

PURPOSE OF REVIEW: Complications of mechanical ventilation, such as ventilator-induced lung injury (VILI) and ventilator-induced diaphragmatic dysfunction (VIDD), adversely affect the outcome of critically ill patients. Although mostly studied during control ventilation, it is increasingly appreciated that VILI and VIDD also occur during assisted ventilation. Hence, current research focuses on identifying ways to monitor and deliver protective ventilation in assisted modes. This review describes the operating principles of proportional modes of assist, their implications for lung and diaphragm protective ventilation, and the supporting clinical data. RECENT FINDINGS: Proportional modes of assist, proportional assist ventilation, PAV, and neurally adjusted ventilatory assist, NAVA, deliver a pressure assist that is proportional to the patient's effort, enabling ventilation to be better controlled by the patient's brain. This control underlies the potential of proportional modes to avoid over-assist and under-assist, improve patient--ventilator interaction, and provide protective ventilation. Indeed, in clinical studies, proportional modes have been associated with reduced asynchronies, enhanced diaphragmatic recovery, and limitation of excessive tidal volume. Additionally, proportional modes facilitate better monitoring of the delivery of protective assisted ventilation. SUMMARY: Physiological rationale and clinical data suggest a potential role for proportional modes of assist in providing and monitoring lung and diaphragm protective ventilation.


Assuntos
Diafragma , Suporte Ventilatório Interativo , Diafragma/fisiopatologia , Humanos , Respiração Artificial/efeitos adversos , Volume de Ventilação Pulmonar , Ventiladores Mecânicos/efeitos adversos
18.
Respir Care ; 65(1): 53-61, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31641071

RESUMO

BACKGROUND: This study was conducted to compare the effectiveness of noninvasive ventilation (NIV) with pressure support (NIV-PSV) to noninvasive neurally-adjusted ventilatory assist (NIV-NAVA) during COPD exacerbation. METHODS: In this study, 40 subjects with COPD and acute hypercapnic respiratory failure were randomized to receive either NIV-NAVA (n = 20) or NIV-PSV (n = 20) via a critical care ventilator. Subjects' vital parameters, arterial blood gas values, patient-ventilator asynchrony events, and asynchrony index were noted at specific time intervals in both groups. The duration of NIV, rate of NIV failure, and length hospital stay were also recorded for these 2 modes of NIV. RESULTS: NIV-NAVA significantly reduced the total number (median [interquartile range]) of asynchrony events compared to NIV-PSV: 22 (15-32.5) versus 65 (50.75-104.25), respectively, P = .002. Severe asynchrony defined as asynchrony index > 10% was also significantly lower in NIV-NAVA than in NIV-PSV (P < .001). There was no significant difference between the 2 groups regarding improvement in gas exchange and vital parameters. Rate of failure of NIV (P = .73), duration of the requirement of ventilatory support (P = .40), and hospital length of stay (P = .46) were also comparable between the 2 modes of ventilation. CONCLUSIONS: Compared to NIV-PSV, NIV-NAVA was associated with better patient-ventilator synchrony and a reduction in the number of asynchrony events in subjects with an exacerbation of COPD, with similar effects on improvement in gas exchange, duration of NIV, hospital lenght of stay, and rate of NIV failure. (Clinicaltrials.gov registration NCT02912689.).


Assuntos
Suporte Ventilatório Interativo/estatística & dados numéricos , Ventilação não Invasiva , Respiração com Pressão Positiva/estatística & dados numéricos , Doença Pulmonar Obstrutiva Crônica/terapia , Gasometria , Humanos , Tempo de Internação , Insuficiência Respiratória/terapia , Desmame do Respirador
19.
Respir Care ; 65(1): 36-44, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31530626

RESUMO

BACKGROUND: The present study aimed to validate a recently proposed algorithm for assistance titration during proportional assist ventilation with load-adjustable gain factors, based on a noninvasive estimation of maximum inspiratory pressure (peak Pmus) and inspiratory effort (pressure-time product [PTP] peak Pmus). METHODS: Retrospective analysis of the recordings obtained from 26 subjects ventilated on proportional assist ventilation with load-adjustable gain factors under different conditions, each considered as an experimental case. The estimated inspiratory output (peak Pmus) and effort (PTP-peak Pmus) were compared with the actual-determined by the measurement of transdiaphragmatic pressure- and the derived PTP. Validation of the algorithm was performed by assessing the accuracy of peak Pmus in predicting the actual inspiratory muscle effort and indicating the appropriate level of assist. RESULTS: In the 63 experimental cases analyzed, a limited agreement was observed between the estimated and the actual inspiratory muscle pressure (-11 to 10 cm H2O) and effort (-82 to 125 cm H2O × s/min). The sensitivity and specificity of peak Pmus to predict the range of the actual inspiratory effort was 81.2% and 58.1%, respectively. In 49% of experimental cases, the level of assist indicated by the algorithm differed from that indicated by the transdiaphragmatic pressure and PTP. CONCLUSIONS: The proposed algorithm had limited accuracy in estimating inspiratory muscle effort and with indicating the appropriate level of assist.


Assuntos
Suporte Ventilatório Interativo/métodos , Insuficiência Respiratória/terapia , Algoritmos , Humanos , Respiração Artificial , Músculos Respiratórios , Estudos Retrospectivos , Volume de Ventilação Pulmonar
20.
Respir Care ; 65(1): 45-52, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31551283

RESUMO

BACKGROUND: To investigate patient-ventilator interaction during different levels of noninvasive proportional assist ventilation (PAV) compared with noninvasive pressure support ventilation (PSV). METHODS: Fifteen subjects with severe COPD and hypercapnia were consecutively recruited. After the baseline assessment of unassisted spontaneous breathing, 3 levels of ventilatory support were applied. The proportional assist (PA) and pressure support (PS) levels were set by subject comfort. PA-, PS- or PA+, PS+ were set at 25% more or less of PA or PS (PA- = 75% PA, PA+ = 125% PA, PS- = 75% PS, PS+ = 125% PS). Each level lasted at least 20 min. To demonstrate the patient-ventilator interaction, the neural respiratory drive, respiratory muscle effort, flow signal, and airway pressure were simultaneously monitored. RESULTS: The expiratory cycle delay (time between the termination of the diaphragm electromyogram [EMGdi] signal and the end of the inspiratory flow) progressively increased with increasing assist level in both modes. However, compared with PSV, the expiratory cycle delay was significantly longer in each assist level during noninvasive PAV. The runaway phenomenon was observed in PA+. The time between the peak EMGdi signal and the maximum value of the flow signal and the time difference between the peak EMGdi signal and the maximum value of inspiratory pressure were significantly increased with the increasing assist level of PAV. CONCLUSIONS: The expiratory cycle delay of noninvasive PAV was significantly longer than that of noninvasive PSV in the subjects with COPD with respiratory failure. During the levels of PAV, the lag time between neural respiratory drive and airway pressurization was significantly increased and the "runaway" phenomenon may be observed. (ClinicalTrials.gov registration NCT01782768.).


Assuntos
Suporte Ventilatório Interativo , Ventilação não Invasiva , Respiração com Pressão Positiva , Doença Pulmonar Obstrutiva Crônica/terapia , Idoso , Humanos , Hipercapnia/terapia , Pessoa de Meia-Idade , Mecânica Respiratória/fisiologia , Músculos Respiratórios/fisiologia , Volume de Ventilação Pulmonar/fisiologia , Trabalho Respiratório
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