Noninvasive high-frequency oscillatory ventilation as respiratory support in preterm infants: a meta-analysis of randomized controlled trials.

BACKGROUND: Noninvasive high-frequency oscillatory ventilation (nHFOV), a relatively new modality, is gaining popularity despite scarce evidence. This meta-analysis was designed to evaluate the efficacy and safety of nHFOV as respiratory support in premature infants. METHODS: We searched MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL from inception of the database to January 2019. All published randomized controlled trials (RCTs) evaluating the effect of nHFOV therapy with nasal continuous positive airway pressure (nCPAP) or biphasic nCPAP (BP-CPAP) in newborns for respiratory support were included. All meta-analyses were performed using Review Manager 5.3. RESULTS: A total of 8 RCTs involving 463 patients were included. The meta-analysis estimated a lower risk of intubation (relative risk = 0.50, 95% confidence interval of 0.36 to 0.70) and more effective clearance of carbon dioxide (weighted mean difference = - 4.61, 95% confidence interval of - 7.94 to - 1.28) in the nHFOV group than in the nCPAP/BP-CPAP group. CONCLUSIONS: Our meta-analysis of RCTs suggests that nHFOV, as respiratory support in preterm infants, significantly remove carbon dioxide and reduce the risk of intubation compared with nCPAP/BP-CPAP. The appropriate parameter settings for different types of noninvasive high-frequency ventilators, the effect of nHFOV in extremely preterm infants, and the long-term safety of nHFOV need to be assessed in large trials.

High-Frequency Oscillatory Ventilation in Adults With ARDS: Past, Present, and Future.

High-frequency oscillatory ventilation (HFOV) is a unique mode of mechanical ventilation that uses nonconventional gas exchange mechanisms to deliver ventilation at very low tidal volumes and high frequencies. The properties of HFOV make it a potentially ideal mode to prevent ventilator-induced lung injury in patients with ARDS. Despite a compelling physiological basis and promising experimental data, large randomized controlled trials have not detected an improvement in survival with the use of HFOV, and its use as an early lung-protective strategy in patients with ARDS may be harmful. Nevertheless, HFOV still has an important potential role in the management of refractory hypoxemia. Careful attention should be paid to right ventricular function and lung stress when applying HFOV. This review discusses the physiological principles, clinical evidence, practical applications, and future prospects for the use of HFOV in patients with ARDS.

Síndrome de apnea-hipopnea del sueño / Sleep apnoea-hypopnoea syndrome

El síndrome de apnea-hipopnea del sueño es un trastorno médico infradiagnosticado con una importancia creciente. Se asocia a enfermedades cardiovasculares, cerebrovasculares, hipertensión arterial, resistencia a insulina y accidentes de tráfico, con el consiguiente deterioro de calidad de vida y aumento de mortalidad. Los síntomas más característicos son ronquido, apneas presenciadas y excesiva somnolencia diurna. La polisomnografía es la prueba de referencia para el diagnóstico, aunque en los pacientes con una alta probabilidad pretest se debería optar por la poligrafía respiratoria, una prueba más accesible y menos costosa. Aparte de la realización de medidas higiénico-dietéticas, el tratamiento de elección es la presión positiva continua de la vía aérea. Algunas técnicas quirúrgicas pueden tener utilidad en el tratamiento del síndrome de apnea-hipopnea del sueño. En pacientes que no toleran la presión positiva continua de la vía aérea, no son candidatos a cirugía o tienen un riesgo quirúrgico elevado, se podrían utilizar dispositivos intraorales (AU)

Sleep apnea-hypopnea syndrome is an underdiagnosed medical condition which is gainingin importance. It is associated with cardiovascular disease, stroke, hypertension, insulin resistance and traffic accidents, resulting in deterioration of quality of life and increased mortality in these patients. The most characteristic symptoms of the disease are snoring, documented apnoeas and excessive daytime sleepiness. Polysomnography is the gold standard for diagnosis, but in patients with high pre-test probability, we should opt for respiratory polygraphy, a more accessible and less expensive test. Besides making lifestyle changes, the treatment of choice is continuous positive airway pressure. Some surgical techniques may be useful in the treatment of sleep apnoea-hypopnoea syndrome. In patients who cannot tolerate continuous positive airway pressure, are not candidates for surgery or have a high surgical risk intraoral devices might be used (AU)

High-frequency ventilation does not provide mortality benefit in comparison with conventional lung-protective ventilation in acute respiratory distress syndrome: a meta-analysis of the randomized controlled trials.

BACKGROUND: Despite implementation of lung-protective ventilation strategy, acute respiratory distress syndrome is associated with significant mortality, which necessitates the evaluation of ventilatory modes other than conventional lung-protective strategy. This meta-analysis of the randomized controlled trials has been undertaken to know whether high-frequency oscillatory ventilation (HFOV) provides any mortality benefit over conventional ventilation in adult patients with acute respiratory distress syndrome. METHODS: Published randomized controlled trials comparing HFOV with conventional lung-protective ventilation in adult patients with acute respiratory distress syndrome were included in this meta-analysis. RESULTS: A total 1,759 patient data from seven randomized controlled trials have been analyzed here. Primary outcome of the review is in-hospital/30-day mortality and secondary outcomes are duration of intensive care unit stay, duration of mechanical ventilation, requirement of additional treatment, and complications associated with the interventions. HFOV does not offer any in-hospital/30-day mortality benefit (386 of 886 in HFOV vs. 368 of 873 in conventional ventilation; risk ratio, 0.96; 95% CI, 0.77 to 1.19; P = 0.70) over conventional ventilation. It may also prolong the duration of mechanical ventilation (mean difference, 1.18 days; 95% CI, 0.00 to 2.35 days; P = 0.05). Duration of intensive care unit stay (mean difference, 1.24 days; 95% CI, -0.08 to 2.56 days; P = 0.06) and requirement of neuromuscular blocker is similar between two treatment arm. Incidence of refractory hypoxemia is significantly less (risk ratio, 0.60; 95% CI, 0.39 to 0.93; P = 0.02) with the use of HFOV. HFOV is not associated with increased incidence of barotrauma and refractory hypotension. CONCLUSION: HFOV should not be used routinely in all adult patients with acute respiratory distress syndrome as primary ventilation strategy in place of conventional lung-protective ventilation.

Re-evaluating high-frequency oscillation for ARDS: Would a targeted approach be successful?

High-frequency oscillatory ventilation (HFOV) seems ideal for lung protection in acute respiratory distress syndrome, but randomized trials have not shown a mortality reduction. The initial oxygenation response to HFOV appears to be associated with survival. Here, we discuss the mechanisms of oxygenation response to increases in airway pressure and the interpretation of the oxygenation response observed in the present study.

Physiological predictors of survival during high-frequency oscillatory ventilation in adults with acute respiratory distress syndrome.

INTRODUCTION: Data that provide clinical criteria for the identification of patients likely to respond to high-frequency oscillatory ventilation (HFOV) are scarce. Our aim was to describe physiological predictors of survival during HFOV in adults with severe acute respiratory distress syndrome (ARDS) admitted to a respiratory failure center in the United Kingdom. METHODS: Electronic records of 102 adults treated with HFOV were reviewed retrospectively. We used logistic regression and receiving-operator characteristics curve to test associations with oxygenation and mortality. RESULTS: Patients had severe ARDS with a mean (SD) Murray's score of 2.98 (0.7). Partial pressure of oxygen in arterial blood to fraction of inspired oxygen (PaO2/FiO2) ratio and oxygenation index improved only in survivors. The earliest time point at which the two groups differed was at three hours after commencing HFOV. An improvement of >38% in PaO2/FiO2 occurring at any time within the first 72 hours, was the best predictor of survival at 30 days (area under the curve (AUC) of 0.83, sensitivity 93%, specificity 78% and a positive likelihood ratio (LR) of 4.3). These patients also had a 3.5 fold greater reduction in partial pressure of carbon dioxide in arterial blood (PaCO2). Multivariate analysis showed that HFOV was more effective in younger patients, when instituted early, and in patients with milder respiratory acidosis. CONCLUSIONS: HFOV is effective in improving oxygenation in adults with ARDS, particularly when instituted early. Changes in PaO2/FiO2 during the first three hours of HFOV can identify those patients more likely to survive.

Extracción de oxígeno como predictor de mortalidad en pacientes con ventilación con alta frecuencia / Oxygen extraction as a predictor of mortality in patients on high frequency ventilation

Introducción: La ventilación con alta frecuencia (VAFO) puede reducir el gasto cardíaco. Analizamos su repercusión hemodinámica e identificamos factores pronósticos de mortalidad. Pacientes y métodos: Entre enero del 2003 y diciembre del 2010, incluimos a 48 niños con fallo respiratorio sometidos a VAFO. El diseño del estudio fue prospectivo, observacional y descriptivo. Los criterios de inclusión se basaron en la existencia de hipoxemia. Las variables estudiadas fueron: presiones arterial y venosa central, pH arterial, saturación venosa e índice de extracción de oxígeno; haciéndose determinaciones previas a la VAFO, durante y antes de pasar a convencional. Se identificaron factores pronósticos mediante un análisis bivariante y determinamos un modelo predictivo de mortalidad. Resultados: La edad fue de 21 (4-72) meses. Al ingreso, las escalas de PRISM y Murray fueron de 33 y de 2,8, la PaO2/FiO2 de 61 y el índice de oxigenación de 35. Tras la VAFO, se obtuvo un aumento del pH (p>0,001), de la presión arterial media (p<0,001) y de la saturación venosa, y un descenso de la presión venosa y de la extracción de O2 (p < 0,001). Los factores pronósticos de mortalidad a las 24 h de iniciar la VAFO fueron: FiO2, PaO2/FiO2, índice de oxigenación, shunt, pH, presiones venosa central y arterial media, saturación venosa y extracción de O2. El modelo creado a las 12 h, compuesto por la SvcO2 y el ETO2, fue capaz de pronosticar la muerte con una probabilidad del 92,3%. Conclusiones: La VAFO mejora la hemodinámica. El modelo a las 12 h es el que mejor nos predice la muerte(AU)

Introduction: The high frequency oscillatory ventilation (HFOV) may reduce cardiac output. The haemodynamics were analysed and predictors of mortality identified. Patients and methods: A total of 48 children with respiratory failure undergoing HFOV between January 2003 and December 2010 were included. The study design was prospective, observational, and descriptive. Inclusion criteria were based on the existence of hypoxemia. The variables studied were: arterial and central venous pressure, arterial pH, venous saturation and oxygen extraction ratio, with determinations performed prior to HFOV, during, and before turning to conventional ventilation. Prognostic factors were identified by bivariate analysis and a predictive model of mortality was developed. Results: The mean age was 21 [4 to 72] months. On admission, PRISM scales and Murray were 33 and 2.8, PaO2/FiO2 of 61 and oxygenation index of 35. After HFOV an increase in pH (P<0.001), mean arterial pressure (P<0.001) and venous saturation, and decreased venous pressure and O2 extraction (P<0.001), was obtained. The prognostic factors of mortality at 24hours after starting HFOV were: FiO2, PaO2/FiO2, oxygenation index, shunt, pH, central venous pressure and mean arterial pressure, venous saturation, and O2 extraction. The model developed at 12hours, consisting of EtO2 and SvcO2 was able to predict death with a probability of 92.3%. Conclusions: HFOV improves haemodynamics. The model at 12hours is the best predictor of death(AU)

[Oscillating physiotherapy for secretolysis]. / Oszillierende Physiotherapie zur Sekretolyse.

Assisted coughing and mechanical cough aids compensate for the weak cough flow in patients with neuromuscular diseases (NMD). In cases with preserved respiratory muscles also breathing techniques and special devices, e. g., flutter or acapella can be used for secretion mobilisation during infections of the airways. These means are summarised as oscillating physiotherapy. Their mechanisms are believed to depend on separation of the mucus from the bronchial wall by vibration, thus facilitating mucus transport from the peripheral to the central airways. In mucoviscidosis and chronic obstructive pulmonary disease their application is established, but there is a paucity of data regarding the commitment in patients with neuromuscular diseases. The effective adoption of simple oscillation physiotherapeutic interventions demands usually a sufficient force of the respiratory muscles--exceptions are the application of the percussionaire (intrapulmonary percussive ventilator, IPV) or high frequency chest wall oscillation (HFCWO). In daily practice there is evidence that patients with weak respiratory muscles are overstrained with the use of these physiotherapeutic means, or get exhausted. A general recommendation for the adoption of simple oscillating physiotherapeutic interventions cannot be made in patients with NMDs. Perhaps in the future devices such as IPV or HFCWO will prove to be more effective in NMD patients.

Trends in use and outcome of newborn infants treated with high frequency ventilation in Australia and New Zealand, 1996-2003.

AIM: To examine the use of high frequency ventilation (HFV) to treat newborn infants in Australia and New Zealand and the associated complications and outcomes. METHODS: Data for all infants receiving HFV were collected from the 28 neonatal intensive care units contributing to the Australian and New Zealand Neonatal Network database between 1996 and 2003, inclusive. For comparison, the same data were gathered on all infants who received conventional mechanical ventilation (CMV) and nasal continuous positive airway pressure. RESULTS: HFV was used to treat 3270 infants (10.1% of all ventilated infants) between 1996 and 2003; uptake doubled during this period from 5.9% to 12.6% of ventilated infants per year. HFV was most frequently applied in the context of extreme prematurity (29.9% of ventilated infants <26 weeks gestation). HFV is being increasingly used to treat complex diseases such as meconium aspiration syndrome and congenital diaphragmatic hernia (12.2% and 10.6% in 1996 to 25.2% and 48.4% in 2003, respectively, chi2 -test for trend, P<0.001). Infants receiving HFV spent longer on respiratory support than infants treated with CMV (median 21 days compared with 7 days, Mann-Whitney test P<0.001) and required a higher initial FiO2 (median 0.8 compared to 0.5, Mann-Whitney test, P<0.001). The use of HFV was associated with a higher mortality than CMV and nasal continuous positive airway pressure (39.7%, 10.1% and 0.4%, chi2 -test, P<0.001). The incidence of death and intraventricular haemorrhage decreased over time in the HFV group (chi2 -test for trend, P<0.001 and P=0.02 respectively). CONCLUSION: HFV is an established mode of neonatal ventilation in Australia and New Zealand. HFV is being applied to infants at the greatest risk of serious adverse outcomes, most likely as a rescue therapy.

Resultados en el tratamiento de la hernia diafragmática con terapias convencionales / Results of the treatment of congenital diaphragmatic hernia with conventional terapeutics modalities

Objetivo. Este estudio analiza nuestros resultados en el tratamiento de la hernia diafragmática congénita con terapia convencional óptima sin el empleo de oxigenación de membrana extracorpórea (ECMO). Material y métodos. Revisamos 51 casos de HDC (27 varones y 24 mujeres) tratados en nuestro hospital entre 1997 y 2004 y estudiamos datos obstétricos, perinatales y neonatales, localización de la HDC y tipo de tratamiento quirúrgico. Tabulamos parámetros ventilatorios y modalidades de asistencia ventilatoria así como datos de morbimortalidad. Comparamos la supervivencia de nuestros pacientes con la esperable según la ecuación propuesta por el CDH Study Group en el año 2001. En los niños que presentaron clínica respiratoria en las primeras 24 horas analizamos separadamente aquellos con criterios de inclusión en ECMO para comparar su mortalidad con la de los (..) (AU)

Aim. In this study, we analyze our results in the treatment of congenital diaphragmatic hernia (CDH) using conventional ventilatory therapy without ECMO. Patients and methods. fifty one CDH patients (27 males and 24 females) treated at our institution between 1997 and 2004 were reviewed. Data referred to obstetrics, prenatal diagnosis, newborn care, type of hernia and surgical treatment were analyzed. We recorded ventilatory treatment modalities and the outcome of the patients. We also compared the survival of our series with those expected using the formula proposed by the CDH study group in 2001. We finally analized separately those patients with early clinical presentation and who fulfilled ECMO criteria. Data from necropsies were also recovered when available. Results. Prenatal diagnosis was made in 58% of the patients. Fifty nine percent were born by c-section. The diaphragmatic defect was left-sided in 42 patients, right in 8 and bilateral in 1. Ten patients needed a prosthetic patch to close the defect. Eighteen out of the 51 patients (35%) died, 11 of them without surgical treatment. Early presentation of clinical picture was evident in 44 patients; among them 46% required high frequency ventilation and 53% nitric oxide therapy. Medium age at operation was 56±49 hours. The 7 children with late clinical presentation are alive. Among the 44 remaining patients, 26 are also alive (59,09%), data similar to those expected by the formula (..) (AU)

New methods advance treatment for respiratory distress syndrome.

The past 20 years of hard labor in neonatal respiratory distress have resulted in several important advances arising from our understanding of lung chemistry and physiology. Our knowledge of surfactant chemistry has enabled us to identify infants at high risk for developing neonatal distress due to surfactant deficiency, reducing this risk with antenatal corticosteroid treatment, and improving the neonatal outcome by means of administration of effective surfactant replacement. Recognition of the roles of oxygen toxicity and barotrauma in promoting lung injury has premitted the development of more effective means of assisted ventilation less likely to injure the lungs of severely ill infants with pulmonary failure. Nitric oxide has proven to be an effective pulmonary vasodilator and permits the successful treatment of patients with pulmonary hypertension who might previously have required an invasive surgical treatment to achieve a desirable clinical outcome.

Use of high-frequency and nonconventional ventilation for respiratory failure.

Over the past several years, many new strategies have evolved for improving the care of patients with acute lung injury and respiratory failure. Although many of these new modalities remain unproven, some show much promise for decreasing the morbidity and mortality seen in critically ill patients who need assisted ventilation. In this review, we discuss recent data concerning four of these modalities: high frequency ventilation, prone positioning, tracheal gas insufflation, and partial liquid ventilation.

High frequency ventilation.

The 1990s have seen a dramatic resurgence of interest in high frequency ventilation (HFV). The role of HFV in the rescue of infants failing conventional mechanical ventilation (CMV) is now relatively well established. However, the wider role of HFV in the routine management of respiratory failure in the newborn is more contentious. Recent trials in small numbers of infants suggest that HFV may be associated with significantly less chronic lung disease than CMV when used under optimal conditions (i.e. with a 'high-volume' strategy, from early in the disease and continued to the point of weaning). Further, clinical trials are now required to define the role of HFV more clearly.