Use Of High-frequency Oscillatory Ventilation Research Articles

Nasal High-Frequency Oscillatory Ventilation Use in Romanian Neonatal Intensive Care Units-The Results of a Recent Survey.

Nasal high-frequency oscillatory ventilation (nHFOV) has emerged as an effective initial and rescue noninvasive respiratory support mode for preterm infants with respiratory distress syndrome (RDS); however, little is known about nHFOV use in Romanian neonatal intensive care units (NICUs). We aimed to identify the usage extent and clinical application of nHFOV in Romania. A structured web-based questionnaire was designed to find the rate of nHFOV use and knowledge of this new method of noninvasive respiratory support in Romanian level III NICUs. Using multiple-choice, open-ended, and yes/no questions, we collected information on the NICU's size, noninvasive respiratory support modes used, nHFOV use, indications, settings, nasal interfaces, secondary effects, and equipment used. Descriptive statistics and comparisons were performed using IBM SPSS Statistics 26.0. A total of 21/23 (91.3%) leaders from level III NICUs (median [IQR] number of beds of 10 [10-17.5]) responded to the survey. The most frequently used noninvasive ventilation modes were CPAP mode on mechanical ventilators (76.2%), followed by NIPPV (76.2%); heated, humidified high-flow nasal cannula (HHHFNC) (61.9%); and nHFOV (11/21 units; 52.4%). A total of 5/11 units reported frequent nHFOV use (in two or more newborns/month) in both term and preterm infants. The main indications reported for nHFOV use were CPAP failure (90.9%), hypercapnia (81.8%), and bronchopulmonary dysplasia (72.7%). Face/nasal masks and short binasal prongs are the most commonly used nasal interfaces (90.9% and 72.7%, respectively). Air leaks at the interface level (90.9%), thick secretions (81.8%), and airway obstruction (63.6%) were the most frequently mentioned adverse effects of nHFOV. Only three of the NICUs had a written protocol for nHFOV use. Most units not yet using nHFOV cited lack of equipment, experience, training, or insufficient information and evidence for the clinical use and outcome of nHFOV use in neonates as the main reasons for not implementing this noninvasive respiratory mode. Our survey showed that nHFOV is already used in more than half of the Romanian level III NICUs to support term and preterm infants with respiratory distress despite a lack of consensus regarding indications and settings during nHFOV.

The outcome of high-frequency oscillatory ventilation in pediatric patients with acute respiratory distress syndrome in an intensive care unit.

In adults with acute respiratory distress syndrome (ARDS), high-frequency oscillatory ventilation (HFOV) has been associated with higher mortality rates. Therefore, its use in children with ARDS is still controversial. Evaluate the overall mortality of HFOV in children with ARDS and explore mortality-related risk factors; compare the outcome of using HFOV post-endotracheal intubation early (≤24 hours) versus late (≤24 hours). Retrospective (medical record review) SETTING: Pediatric intensive care unit in a tertiary care center in Saudi Arabia. Data were collected from medical records of all pediatric patients with ARDS aged one week to 14 years, who were admitted to the pediatric intensive care unit (PICU) from January 2016-June 2019 and who required HFOV. PICU mortality. 135 ARDS patients including 74 females (54.8%), and 61 males (45.2%), with a median age (interquar-tile range) of 35 (72) months. The overall mortality rate was 60.0% (81/135), and most died in the first 28 days in the PICU (91.3%, 74/8). Of non-survivors, 75.3% (61/81) were immunocompromised, and 24.7% (20/81) were immuno-competent patients, 52 (64.2%) received inotropic support, 40 (49.4%) had a bone-marrow transplant (BMT) before HFOV initiation. Although the prone position was used in 20.7% (28/135) to improve the survival rate post-HFOV ventilation, only 28.6% (8/28) survived. In addition, altered code status or chemotherapy reported a significant association with mortality (P<.05). Interestingly, early HFOV initiation (≤24 hours) did not seem to have a high impact on survival compared to late initiation (>24 hours); (57.4% vs. 42.6%, P=.721). Immunocompromised and oncology patients, including post-BMT, reported poorer outcomes, and neither the prone position nor early use of HFOV improved outcomes. However, it is recommended to replicate the study in a larger cohort to generalize the results. Retrospective single-center study.

The Physiological Basis of High-Frequency Oscillatory Ventilation and Current Evidence in Adults and Children: A Narrative Review.

High-frequency oscillatory ventilation (HFOV) is a type of invasive mechanical ventilation that employs supra-physiologic respiratory rates and low tidal volumes (VT) that approximate the anatomic deadspace. During HFOV, mean airway pressure is set and gas is then displaced towards and away from the patient through a piston. Carbon dioxide (CO2) is cleared based on the power (amplitude) setting and frequency, with lower frequencies resulting in higher VT and CO2 clearance. Airway pressure amplitude is significantly attenuated throughout the respiratory system and mechanical strain and stress on the alveoli are theoretically minimized. HFOV has been purported as a form of lung protective ventilation that minimizes volutrauma, atelectrauma, and biotrauma. Following two large randomized controlled trials showing no benefit and harm, respectively, HFOV has largely been abandoned in adults with ARDS. A multi-center clinical trial in children is ongoing. This article aims to review the physiologic rationale for the use of HFOV in patients with acute respiratory failure, summarize relevant bench and animal models, and discuss the potential use of HFOV as a primary and rescue mode in adults and children with severe respiratory failure.

Congenital Diaphragmatic Hernia Repair at the Bedside or Operating Theater.

For critically ill congenital diaphragmatic hernia (CDH) patients on high frequency oscillatory ventilation (HFOV), extracorporeal membrane oxygenation (ECMO), and/or inhaled nitric oxide (iNO), operative repair in the neonatal intensive care unit (NICU) has been proposed to avoid complications during transport to an operating room (OR). This study compared neonates with CDH who received herniorrhaphy in the NICU or OR, with a subgroup analysis considering only patients supported with ECMO. Patients admitted to the NICU in the first 2weeks of life at a free-standing children's hospital between July 2004 and September 2021 were examined. Patients were categorized according to location of CDH repair, and impact on operative complications and survival was compared. 185 patients were admitted to the NICU with posterolateral CDH and received operative repair. 48 cases were operated on at the bedside in the NICU and 137 in the OR. Patients repaired in the NICU had higher use of HFOV, pulmonary vasodilators, and ECMO (all P < .001). Children repaired in the NICU experienced significantly higher in-hospital death and overall mortality (P < .001). However, in multivariate analysis, repair location was not a significant predictor of survival to discharge in patients receiving ECMO. No significant difference in surgical site infection was detected for operative location (P = .773). Congenital diaphragmatic hernia repair in the NICU occurred more frequently among higher risk patients who experienced worse survival. The rate of surgical site infection appeared similar overall and across subgroups suggesting adequate sterility and technique for bedside procedures, when necessary, despite restricted access to advanced operative equipment.

Evaluation of High-Frequency Oscillatory Ventilation as a Rescue Strategy in Respiratory Failure.

The use of high-frequency oscillatory ventilation (HFOV) is backed by sound physiologic rationale, but clinical data on the elective use of HFOV have been largely disappointing. Nonetheless, HFOV is still occasionally used as a rescue mode in patients with severe hypoxemia. The evidence that supports this practice is sparse. This was a retrospective single-center analysis that involved subjects admitted to the medical ICU at Cleveland Clinic, Cleveland, Ohio. We included all adult patients (ages > 18 y) who received rescue HFOV between January 1, 2010, and December 31, 2018, and analyzed their clinical outcomes. A total of 48 subjects were included in the analysis. The most common primary diagnosis was pneumonia (n = 33 [68.8%]), followed by aspiration (n = 6 [12.5%]) and diffuse alveolar hemorrhage (n = 2 [4.2%]). Switching to HFOV improved oxygenation but also increased vasopressor requirements at 3 h. The mortality rate of the study population was 92% (44/48). Our study did not support utilization of HFOV as a "last-ditch" rescue measure in subjects with respiratory failure. The delayed timing of HFOV initiation and its detrimental hemodynamic effects are among the potential reasons for the high mortality rate.

High-frequency oscillatory ventilation in children: A systematic review and meta-analysis.

High-frequency oscillatory ventilation (HFOV) is an alternative mechanical ventilation mode proposed to reduce ventilator-induced lung injuries and improve clinical outcomes. The aim of this study was to determine the effects of HFOV compared to conventional mechanical ventilation (CMV) when used in children with hypoxemic respiratory failure. The literature search was conducted to identify all studies published before December 2020. Eligible studies included a population aged between 28 days and 18 years old, presented original data from randomized controlled trials (RCTs) or observational studies, compared the use of HFOV with CMV. Meta-analyses of the pooled data were performed by using random-effects models with inverse-variance weighting. A total of 11 studies (2605 cases) were included, most of them evaluating patients with acute respiratory distress syndrome. The mean age of participants was 8.2 months and the mean oxygenation index of those included in the RCTs was 24.4. The effect of HFOV on mortality was not significant, and clinically significant harm or benefit could not be excluded (risk ratio [RR], 0.93; 95% confidence interval [CI], 0.72 to 1.20). No significant difference between groups was found in duration of mechanical ventilation (-2.23; 95% CI, -5.07 to 0.61), treatment failure (RR, 0.28; 95% CI, 0.08 to 1.02), and occurrence of barotrauma (RR, 0.88; 95% CI, 0.39 to 1.99). The scarce evidence currently available does not allow us to conclude that HFOV has advantages over CMV and further studies are needed to clarify its role in the treatment of acute hypoxemic respiratory failure in children.

Therapeutic effects and outcomes of rescue high-frequency oscillatory ventilation for premature infants with severe refractory respiratory failure

Despite wide application of high frequency oscillatory ventilation (HFOV) in neonates with respiratory distress, little has been reported about its rescue use in preterm infants. We aimed to evaluate the therapeutic effects of HFOV in preterm neonates with refractory respiratory failure and investigate the independent risk factors of in-hospital mortality. We retrospectively analyzed data collected prospectively (January 2011–December 2018) in four neonatal intensive care units of two tertiary-level medical centers in Taiwan. All premature infants (gestational age 24–34 weeks) receiving HFOV as rescue therapy for refractory respiratory failure were included. A total of 668 preterm neonates with refractory respiratory failure were enrolled. The median (IQR) gestational age and birth weight were 27.3 (25.3–31.0) weeks and 915.0 (710.0–1380.0) g, respectively. Pre-HFOV use of cardiac inotropic agents and inhaled nitric oxide were 70.5% and 23.4%, respectively. The oxygenation index (OI), FiO2, and AaDO2 were markedly increased after HFOV initiation (all p < 0.001), and can be decreased within 24–48 h (all p < 0.001) after use of HFOV. 375 (56.1%) patients had a good response to HFOV within 3 days. The final in-hospital mortality rate was 34.7%. No association was found between specific primary pulmonary disease and survival in multivariate analysis. We found preterm neonates with gestational age < 28 weeks, occurrences of sepsis, severe hypotension, multiple organ dysfunctions, initial higher severity of respiratory failure and response to HFOV within the first 72 h were independently associated with final in-hospital mortality. The mortality rate of preterm neonates with severe respiratory failure remains high after rescue HFOV treatment. Aggressive therapeutic interventions to treat sepsis and prevent organ dysfunctions are the suggested strategies to optimize outcomes.

Hemodynamic effects of high-frequency oscillatory ventilation in preterm neonates with respiratory distress syndrome.

High-frequency oscillatory ventilation (HFOV) can have negative hemodynamic effects in neonates. We aimed to assess systemic, cerebral, and cardiac hemodynamic changes in preterm neonates with respiratory distress syndrome (RDS) on HFOV. This observational study was conducted from June 2017 until May 2019 on 100 preterm neonates with RDS that needed switching from conventional mechanical ventilation to HFOV. Initial and Follow up capillary blood gas, echocardiographic examination, cranial ultrasound, and Doppler study of cerebral, celiac, superior mesenteric, and renal arteries using resistive index (RI) were performed before, 24 h, and 72 h after the use of HFOV. There was no statistically significant difference as regards cardiac function, heart rate, or intraventricular hemorrhage on follow up measurements. However blood pressure, left ventricular dimensions, and volumes statistically increased after HFOV. There was a statistically significant decrease in the pulmonary artery systolic pressure after the use of HFOV. After the use of HFOV, there was a statistically significant increase in the superior vena cava flow and left ventricular output while right ventricular output values initially increased then slightly decreased but still higher than the initial values. RI of cerebral, superior mesenteric, celiac, and renal arteries significantly decreased on follow up measurements which reflected increased blood flow in these arteries. HFOV had no negative effect on the cerebral, systemic, or cardiac hemodynamics when applied at optimum MAP. Therefore, concerns about negative hemodynamic effects of HFOV should not discourage the use of HFOV when deemed clinically indicated provided the use of optimum MAP.

Effect of a new respiratory care bundle on bronchopulmonary dysplasia in preterm neonates.

The development of devices that can fix the tidal volume in high-frequency oscillatory ventilation (HFOV) has allowed for a significant improvement in the management of HFOV. At our institution, this had led to the earlier use of HFOV and promoted a change in the treatment strategy involving the use of higher frequencies (above 15 Hz) and lower high-frequency tidal volumes (VThf). The purpose of this observational study was to assess how survival without bronchopulmonary dysplasia grades 2 and 3 (SF-BPD) is influenced by these modifications in the respiratory strategy applied to preterm infants (gestational age < 32 weeks at birth) who required mechanical ventilation (MV) in the first 3 days of life. We compared a baseline period (2012–2013) against a period in which this strategy had been fully implemented (2016–2017). A total of 182 patients were exposed to MV in the first 3 days of life being a higher proportion on HFOV at day 3 in the second period 79.5% (n 35) in 2016–2017 vs 55.4% (n 31) in 2012–2013. After adjusting for perinatal risk factors, the second period is associated with an increased rate of SF-BPD (OR 2.28; CI 95% 1.072–4.878); this effect is more evident in neonates born at a gestational age of less than 29 weeks (OR 4.87; 95% CI 1.9–12.48).Conclusions : The early use of HFOV combined with the use of higher frequencies and very low VT was associated with an increase in the study population’s SF-BPD.What is Known:• High-frequency ventilation with volume guarantee improve ventilation stability and has been shown to reduce lung damage in animal models.What is New:• The strategy of an earlier use of high-frequency oscillatory ventilation combined with the use of higher frequencies and lower tidal volume is associated to an increase in survival without bronchopulmonary dysplasia in our population of preterm infants.

Use of high frequency oscillatory ventilator in neonates with respiratory failure: the clinical practice in Taiwan and early multimodal outcome prediction

High-frequency oscillatory ventilation (HFOV) can be a rescue for neonates with refractory respiratory failure or an early elective therapy for preterm infants with severe respiratory distress syndrome (RDS). However, little is known about the current evolution and therapeutic limitations of HFOV. We therefore aimed to describe its use in clinical practice and predict the risk of mortality for neonates receiving HFOV. A retrospective observational study of all neonates treated with HFOV in a quaternary referral NICU between January 2007 and December 2016 was conducted. We classified these patients into five subgroups based on primary respiratory diagnoses. We performed the logistic regression and decision tree regression analyses to identify independent factors of 30-day mortality following HFOV. A total of 1125 patients who were ever supported on HFOV were enrolled, of whom 64.1% received HFOV as a rescue therapy, 27.2% received it as an elective therapy, and 8.7% received it for air leak. An average oxygenation index (OI) greater than 25 in the first 24 hours after the initiation of HFOV and patients with secondary pulmonary hypertension were found to have the greatest risk of in-hospital mortality (p < 0.0001). The overall in-hospital mortality rate was 25.8% (290/1125). Decision tree regression analysis revealed that neonates with refractory respiratory failure who had a pre-HFOV OI value higher than 20.5 and OI values higher than 21.5, 23.5 and 34 at 2 hours, 6 hours, and 12 hours after the use of HFOV, respectively, had a significantly increased risk of 30-day mortality. We identified the predictors and cutoff points of OI before and after the initiation of HFOV in neonates with respiratory failure, which can be clinically used as a reference for 30-day mortality. Further efforts are still needed to optimize the outcomes.

Neonatal high-frequency oscillatory ventilation

Abstract High frequency oscillatory ventilation (HFOV) is often used as a rescue strategy for neonatal lung disease. In this article we discuss our experience of using HFOV including basic ventilator settings, optimising HFOV with monitoring and how specific diseases alter management. The article is focussed on ensuring understanding and safe use of HFOV by all neonatal staff.

High-frequency oscillatory ventilation in a tertiary paediatric intensive care unit in an academic hospital in Johannesburg, South Africa.

High-frequency oscillatory ventilation (HFOV) remains an option for the management of critically ill children when conventional mechanical ventilation fails. However, its use is not widespread, and there is wide variability reported with respect to how it is used. To describe the frequency, indications, settings and outcomes of HFOV use among paediatric patients with a primary respiratory disorder admitted to a tertiary paediatric intensive care unit (PICU). The study was a 2-year, single-centre, retrospective chart review. Thirty-four (32.7%) patients were managed with HFOV in the PICU during the study period. Thirty-three of the 34 patients had paediatric acute respiratory distress syndrome. Indications for HFOV were inadequate oxygenation in 17 patients (50%), and refractory respiratory acidosis in 15 patients (44.1%) (2 patients did not fit into either category). Approaches to the setting of HFOV varied considerably, particularly with respect to initial pressure around the airways. HFOV was effective at improving both oxygenation, with a median (interquartile range (IQR)) decrease in oxygenation index of 6.34 (5.0 - 9.5), and ventilation with a the median decrease in PaCO2 of 67.6 (46.2 - 105.7) mmHg after 24 hours. Overall mortality was 29.4% in the HFOV group, which is consistent with other studies. HFOV remains an effective rescue ventilatory strategy, which resulted in rapid and sustained improvement in gas exchange in patients with severe hypoxaemia and/or severe respiratory acidosis, particularly in the absence of extracorporeal support. However, the variability in practice and the adverse effects described highlight the need for future high-quality randomised controlled trials to allow for development of meaningful guidelines to optimise HFOV use. This study describes the use and outcomes of high-frequency oscillatory ventilation (HFOV) in a South African paediatric intensive care unit, thus addressing a local knowledge gap and providing evidence of the continued efficacy of HFOV for severe hypoxaemia and refractory respiratory acidosis in settings without access to extracorporeal technologies.

High-Frequency Oscillation for Adult Patients with Acute Respiratory Distress Syndrome. A Systematic Review and Meta-Analysis.

By minimizing tidal lung strain and maintaining alveolar recruitment, high-frequency oscillatory ventilation (HFOV) may protect against ventilator-induced lung injury. To summarize the current evidence in support of the use of HFOV in adult patients with acute respiratory distress syndrome. We conducted a systematic review and meta-analysis of randomized trials comparing mortality rates with the use of HFOV versus conventional mechanical ventilation for adult patients with acute respiratory distress syndrome. Eligible trials were identified from previously published systematic reviews and an updated literature search. Data on 28-day mortality, oxygenation, adverse events, and use of rescue therapies were collected; effects were pooled using random effects models weighted by inverse variance. Strength of evidence was assessed using Grading of Recommendations Assessment, Development, and Evaluation methodology. Six trials were eligible for inclusion (total n = 1,715 patients). Four trials mandated lung-protective ventilation in the control group and one trial applied a higher positive end-expiratory pressure (PEEP) ventilation strategy in the control group. None of the trials were judged to be at high risk of bias, though all were unblinded. In trials that did not systematically employ any cointerventions with HFOV and that targeted low tidal volumes in the patients randomized to conventional ventilation (primary analysis), HFOV had no significant effect on mortality (three trials; risk ratio [RR], 1.14; 95% confidence interval [CI], 0.88 to 1.48; evidence grade = high). Pooled analysis of all six trials also did not suggest a significant mortality reduction (RR, 0.94; 95% CI, 0.71 to 1.24; evidence grade = low). The single trial that employed a conventional ventilation strategy with both lower tidal volumes and higher PEEP as control reported higher mortality in patients receiving HFOV (RR, 1.41; 95% CI, 1.12 to 1.79). HFOV was not associated with improved oxygenation after 24 hours (five trials; mean increase of 10 mm Hg; 95% CI, -16 to 37 mm Hg). Rates of barotrauma were not different between HFOV and conventional ventilation, although significant benefit or harm could not be excluded (RR, 1.15; 95% CI, 0.61 to 2.17). Published randomized trials suggest that HFOV is not associated with a mortality benefit, and may even be harmful in comparison to ventilation with low tidal volumes and higher levels of PEEP.

Early High-Frequency Oscillatory Ventilation in Pediatric Acute Respiratory Failure. A Propensity Score Analysis.

The use of high-frequency oscillatory ventilation (HFOV) for acute respiratory failure in children is prevalent despite the lack of efficacy data. To compare the outcomes of patients with acute respiratory failure managed with HFOV within 24-48 hours of endotracheal intubation with those receiving conventional mechanical ventilation (CMV) and/or late HFOV. This is a secondary analysis of data from the RESTORE (Randomized Evaluation of Sedation Titration for Respiratory Failure) study, a prospective cluster randomized clinical trial conducted between 2009 and 2013 in 31 U.S. pediatric intensive care units. Propensity score analysis, including degree of hypoxia in the model, compared the duration of mechanical ventilation and mortality of patients treated with early HFOV matched with those treated with CMV/late HFOV. Among 2,449 subjects enrolled in RESTORE, 353 patients (14%) were ever supported on HFOV, of which 210 (59%) had HFOV initiated within 24-48 hours of intubation. The propensity score model predicting the probability of receiving early HFOV included 1,064 patients (181 early HFOV vs. 883 CMV/late HFOV) with significant hypoxia (oxygenation index ≥ 8). The degree of hypoxia was the most significant contributor to the propensity score model. After adjusting for risk category, early HFOV use was associated with a longer duration of mechanical ventilation (hazard ratio, 0.75; 95% confidence interval, 0.64-0.89; P = 0.001) but not with mortality (odds ratio, 1.28; 95% confidence interval, 0.92-1.79; P = 0.15) compared with CMV/late HFOV. In adjusted models including important oxygenation variables, early HFOV was associated with a longer duration of mechanical ventilation. These analyses make supporting the current approach to HFOV less convincing.

Right over left ventricular end-diastolic area relevance to predict hemodynamic intolerance of high-frequency oscillatory ventilation in patients with severe ARDS.

BackgroundHigh-frequency oscillatory ventilation (HFOV) does not improve the prognosis of ARDS patients despite an improvement in oxygenation. This paradox may partly be explained by HFOV hemodynamic side-effects on right ventricular function. Our goal was to study the link between HFOV and hemodynamic effects and to test if the pre-HFOV right over left ventricular end-diastolic area (RVEDA/LVEDA) ratio, as a simple parameter of afterload-related RV dysfunction, could be used to predict HFOV hemodynamic intolerance in patients with severe ARDS.MethodsTwenty-four patients were studied just before and within 3 h of HFOV using transthoracic echocardiography and transpulmonary thermodilution.ResultsBefore HFOV, the mean PaO2/FiO2 ratio was 89 ± 23. The number of patients with a RVEDA/LVEDA ratio >0.6 significantly increased after HFOV [11 (46 %) vs. 17 (71 %)]. Although HFOV did not significantly decrease the arterial pressure (systolic, diastolic, mean and pulse pressure), it significantly decreased the cardiac index (CI) by 13 ± 18 % and significantly increased the RVEDA/LVEDA ratio by 14 ± 11 %. A significant correlation was observed between pre-HFOV RVEDA/LVEDA ratio and CI diminution after HFOV (r = 0.78; p < 0.0001). A RVEDA/LVEDA ratio superior to 0.6 resulted in a CI decrease >15 % during HFOV with a sensitivity of 80 % (95 % confidence interval 44–98 %) and a specificity of 79 % (confidence interval 49–95 %).ConclusionThe RVEDA/LVEDA ratio measured just before HFOV predicts the hemodynamic intolerance of this technique in patients with severe ARDS. A high ratio under CMV raises questions about the use of HFOV in such patients.Trial registration: ClinicalTrials.gov: NCT01167621

High-frequency Ventilation Does Not Provide Mortality Benefit in Comparison with Conventional Lung-protective Ventilation in Acute Respiratory Distress Syndrome

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. 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. 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. 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.

A randomised controlled trial and cost-effectiveness analysis of high-frequency oscillatory ventilation against conventional artificial ventilation for adults with acute respiratory distress syndrome. The OSCAR (OSCillation in ARDS) study.

Patients with the acute respiratory distress syndrome (ARDS) require artificial ventilation but this treatment may produce secondary lung damage. High-frequency oscillatory ventilation (HFOV) may reduce this damage. To determine the clinical benefit and cost-effectiveness of HFOV in patients with ARDS compared with standard mechanical ventilation. A parallel, randomised, unblinded clinical trial. UK intensive care units. Mechanically ventilated patients with a partial pressure of oxygen in arterial blood/fractional concentration of inspired oxygen (P : F) ratio of 26.7 kPa (200 mmHg) or less and an expected duration of ventilation of at least 2 days at recruitment. Treatment arm HFOV using a Novalung R100(®) ventilator (Metran Co. Ltd, Saitama, Japan) ventilator until the start of weaning. Control arm Conventional mechanical ventilation using the devices available in the participating centres. The primary clinical outcome was all-cause mortality at 30 days after randomisation. The primary health economic outcome was the cost per quality-adjusted life-year (QALY) gained. One hundred and sixty-six of 398 patients (41.7%) randomised to the HFOV group and 163 of 397 patients (41.1%) randomised to the conventional mechanical ventilation group died within 30 days of randomisation (p = 0.85), for an absolute difference of 0.6% [95% confidence interval (CI) -6.1% to 7.5%]. After adjustment for study centre, sex, Acute Physiology and Chronic Health Evaluation II score, and the initial P : F ratio, the odds ratio for survival in the conventional ventilation group was 1.03 (95% CI 0.75 to 1.40; p = 0.87 logistic regression). Survival analysis showed no difference in the probability of survival up to 12 months after randomisation. The average QALY at 1 year in the HFOV group was 0.302 compared to 0.246. This gives an incremental cost-effectiveness ratio (ICER) for the cost to society per QALY of £88,790 and an ICER for the cost to the NHS per QALY of £ 78,260. The use of HFOV had no effect on 30-day mortality in adult patients undergoing mechanical ventilation for ARDS and no economic advantage. We suggest that further research into avoiding ventilator-induced lung injury should concentrate on ventilatory strategies other than HFOV. Current Controlled Trials ISRCTN10416500.

Repair of congenital diaphragmatic hernia under high-frequency oscillatory ventilation in high-risk patients: an opportunity for earlier repair while minimizing lung injury.

BACKGROUNDRepair of congenital diaphragmatic hernia (CDH) is ideally delayed until ventilatory parameters are stabilized and patients are switched to conventional ventilation. However, in selected high-risk patients, repair can be performed earlier while they are still on high-frequency oscillatory ventilation (HFOV).DESIGN AND SETTINGSA retrospective review of all CDH cases treated in our tertiary referral center between 1997 and 2013.METHODSIn 1997, we started repairing selected high-risk CDH cases under HFOV with or without inhaled nitric oxide (iNO). All repairs were performed once the infants’ blood gas levels were acceptable. The infants were gradually weaned to conventional ventilation followed by extubation as their ventilatory parameters improved. Their records were reviewed to determine the group-wide outcomes.RESULTSBetween 1997 and 2013, 55 infants with CDH were treated in our institute; of these 12 high-risk cases were repaired under HFOV/iNO combinations and 1 was repaired without iNO. All patients had significant pulmonary hypertension and 8 had herniated livers. The mean age at repair was 9.1 (6.3) days. Two mortalities occurred at the first and tenth postoperative days. Among the remaining 11 survivors, the median ventilation and hospitalization days were 29.5 (11–84) and 45.5 (25–107), respectively, and the median duration under HFOV and conventional ventilation days were 15 (9–40) and 12 (3–47), respectively.CONCLUSIONCDH repair can be performed earlier under HFOV and iNO. The possible advantages are earlier restoration of normal anatomy and earlier start of enteral feeding while minimizing the risk of lung injury.

High-frequency oscillatory ventilation use in patients with H1N1: a single-centre review

Limited evidence exists as to the value of high-frequency oscillatory ventilation (HFOV) for patients with H1N1 [1][2]. We describe a subgroup of patients, from a single UK centre, who received HFOV and had H1N1-positive virology.

Higher Frequency Ventilation Attenuates Lung Injury during High-frequency Oscillatory Ventilation in Sheep Models of Acute Respiratory Distress Syndrome

High-frequency oscillatory ventilation (HFOV) at higher frequencies minimizes the tidal volume. However, whether increased frequencies during HFOV can reduce ventilator-induced lung injury remains unknown. After the induction of acute respiratory distress syndrome in the model by repeated lavages, 24 adult sheep were randomly divided into four groups (n = 6): three HFOV groups (3, 6, and 9 Hz) and one conventional mechanical ventilation (CMV) group. Standard lung recruitments were performed in all groups until optimal alveolar recruitment was reached. After lung recruitment, the optimal mean airway pressure or positive end-expiratory pressure was determined with decremental pressure titration, 2 cm H2O every 10 min. Animals were ventilated for 4 h. After lung recruitment, sustained improvements in gas exchange and compliance were observed in all groups. Compared with the HFOV-3 Hz and CMV groups, the transpulmonary pressure and tidal volumes were statistically significantly lower in the HFOV-9 Hz group. The lung injury scores and wet/dry weight ratios were significantly reduced in the HFOV-9 Hz group compared with the HFOV-3 Hz and CMV groups. Expression of interleukin-1β and interleukin-6 in the lung tissue, decreased significantly in the HFOV-9 Hz group compared with the HFOV-3 Hz and CMV groups. Malondialdehyde expression and myeloperoxidase activity in lung tissues in the HFOV-9 Hz group decreased significantly, compared with the HFOV-3 Hz and CMV groups. The use of HFOV at 9 Hz minimizes lung stress and tidal volumes, resulting in less lung injury and reduced levels of inflammatory mediators compared with the HFOV-3 Hz and CMV conditions.