The impact of high frequency oscillatory ventilation on mortality in paediatric acute respiratory distress syndrome.

BACKGROUND: High-frequency oscillatory ventilation (HFOV) use was associated with greater mortality in adult acute respiratory distress syndrome (ARDS). Nevertheless, HFOV is still frequently used as rescue therapy in paediatric acute respiratory distress syndrome (PARDS). In view of the limited evidence for HFOV in PARDS and evidence demonstrating harm in adult patients with ARDS, we hypothesized that HFOV use compared to other modes of mechanical ventilation is associated with increased mortality in PARDS. METHODS: Patients with PARDS from 10 paediatric intensive care units across Asia from 2009 to 2015 were identified. Data on epidemiology and clinical outcomes were collected. Patients on HFOV were compared to patients on other modes of ventilation. The primary outcome was 28-day mortality and secondary outcomes were 28-day ventilator- (VFD) and intensive care unit- (IFD) free days. Genetic matching (GM) method was used to analyse the association between HFOV treatment with the primary outcome. Additionally, we performed a sensitivity analysis, including propensity score (PS) matching, inverse probability of treatment weighting (IPTW) and marginal structural modelling (MSM) to estimate the treatment effect. RESULTS: A total of 328 patients were included. In the first 7 days of PARDS, 122/328 (37.2%) patients were supported with HFOV. There were significant differences in baseline oxygenation index (OI) between the HFOV and non-HFOV groups (18.8 [12.0, 30.2] vs. 7.7 [5.1, 13.1] respectively; p < 0.001). A total of 118 pairs were matched in the GM method which found a significant association between HFOV with 28-day mortality in PARDS [odds ratio 2.3, 95% confidence interval (CI) 1.3, 4.4, p value 0.01]. VFD was indifferent between the HFOV and non-HFOV group [mean difference - 1.3 (95%CI - 3.4, 0.9); p = 0.29] but IFD was significantly lower in the HFOV group [- 2.5 (95%CI - 4.9, - 0.5); p = 0.03]. From the sensitivity analysis, PS matching, IPTW and MSM all showed consistent direction of HFOV treatment effect in PARDS. CONCLUSION: The use of HFOV was associated with increased 28-day mortality in PARDS. This study suggests caution but does not eliminate equivocality and a randomized controlled trial is justified to examine the true association.

High-Frequency Percussive Ventilation Rescue Therapy in Morbidly Obese Patients Failing Conventional Mechanical Ventilation.

BACKGROUND: Morbidly obese patients with respiratory failure who do not improve on conventional mechanical ventilation (CMV) often undergo rescue therapy with extracorporeal membrane oxygenation (ECMO). We describe our experience with high-frequency percussive ventilation (HFPV) as a rescue modality. METHODS: In a retrospective analysis from 2009 to 2016, 12 morbidly obese patients underwent HFPV after failing to wean from CMV. Data were collected regarding demographics, cause of respiratory failure, ventilation settings, and hospital course outcomes. Our end point data were pre- and post-HFPV partial pressure of arterial oxygen and PaO2 to fraction of inspired oxygen (PF) ratios measured at initiation, 2, and 24 hours. RESULTS: Twelve morbidly obese patients required HFPV for respiratory failure. Causes of respiratory failure overlapped and included cardiogenic pulmonary edema (n = 8), pneumonia (n = 5), septic shock (n = 5), and asthma (n = 1). After HFPV initiation, mean fraction of inspired oxygen FiO2 was tapered from 98% to 82% and 66% at 2 and 24 hours, respectively. Mean PaO2 increased from 60.9 mm Hg before HFPV to 175.1 mm Hg (P < .05) at initiation of HFPV, then sustained at 129.5 mm Hg (P < .05) and 88.1 mm Hg (P < .005) at 2 and 24 hours, respectively. Mean PF ratio improved from 66.1 before HFPV to 180.3 (P < .05), 181.0 (P < .05) and 148.9 (P < .0005) at initiation, 2, and 24 hours, respectively. The improvement in mean PaO2 and PF ratios was durable at 24 hours whether or not the patient was returned to CMV (n = 10) or remained on HFPV (n = 2). Survival to discharge was 66.7%. CONCLUSION: In our cohort of morbidly obese patients, HFPV was successfully utilized as a rescue therapy precluding the need for ECMO. Despite our small sample size, HFPV should be considered as a rescue therapy in morbidly obese patients failing CMV prior to the initiation of ECMO. Our retrospective analysis supports consideration for HFPV as another form of rescue therapy for obese patients with refractory hypoxemia and respiratory failure who are not improving with CMV.

An observational, prospective, multicenter study on rescue high-frequency oscillatory ventilation in neonates failing with conventional ventilation.

BACKGROUND: To achieve gas exchange goals and mitigate lung injury, infants who fail with conventional ventilation (CV) are generally switched to high-frequency oscillatory ventilation (HFOV). Although preferred in many neonatal intensive care units (NICUs), research on this type of rescue HFOV has not been reported recently. METHODS: An online registry database for a multicenter, prospective study was set to evaluate factors affecting the response of newborn infants to rescue HFOV treatment. The study population consisted of 372 infants with CV failure after at least 4 hours of treatment in 23 participating NICUs. Patients were grouped according to their final outcome as survived (Group S) or as died or received extracorporeal membrane oxygenation (ECMO) (Group D/E). Patients' demographic characteristics and underlying diseases in addition to their ventilator settings, arterial blood gas (ABG) analysis results at 0, 1, 4, and 24 hours, type of device, ventilation duration, and complications were compared between groups. RESULTS: HFOV as rescue treatment was successful in 58.1% of patients. Demographic and treatment parameters were not different between groups, except that infants in Group D/E had lower birthweight (BW) (1655 ± 1091 vs. 1858 ± 1027 g, p = 0.006), a higher initial FiO2 setting (83% vs. 72%, p < 0.001), and a higher rate of nitric oxide exposure (21.8% vs. 11.1%, p = 0.004) in comparison to infants who survived (Group S). The initial cut-offs for a successful response on ABG were defined as pH >7.065 (OR: 19.74, 95% CI 4.83-80.6, p < 0.001), HCO3 >16.35 mmol/L (OR: 1.06, 95% CI 1.01-1.1, p = 0.006), and lactate level <3.75 mmol/L (OR: 1.09%95 CI 1.01-1.16, p = 0.006). Rescue HFOV duration was associated with retinopathy of prematurity (p = 0.005) and moderate or severe chronic lung disease (p < 0.001), but not with patent ductus arteriosus or intraventricular hemorrhage, in survivors (p > 0.05). CONCLUSION: Rescue HFOV as defined for this population was successful in more than half of the patients with CV failure. Although the response was not associated with gestational age, underlying disease, device used, or initial MV settings, it seemed to be more effective in patients with higher BW and those not requiring nitric oxide. Initial pH, HCO3, and lactate levels on ABG may be used as predictors of a response to rescue HFOV.

Body Mass Index and Mortality in Subjects With ARDS: Post-hoc Analysis of the OSCILLATE Trial.

BACKGROUND: Studies on the association of obesity with mortality in subjects with ARDS have yielded inconsistent results. METHODS: In a sub-analysis of the Oscillation for ARDS Treated Early (OSCILLATE) randomized controlled trial, 451 subjects were divided into 5 strata based on their body mass index (BMI) using the World Health Organization definitions: underweight < 18.5 kg/m2; normal weight 18.5-24.99 kg/m2; overweight 25-29.99 kg/m2; obese 30-39.99 kg/m2; severely obese > 40 kg/m2. The primary outcome was all-cause hospital mortality across BMI strata for all subjects and for the 2 study arms (high-frequency oscillatory ventilation [HFOV] vs conventional ventilation) separately using multivariable logistic regression adjusting for potential confounding variables. RESULTS: Hospital mortality was not different across the BMI strata for all subjects (P = .86), for the HFOV arm (P = .94) or for the conventional ventilation arm (P = .59). After risk adjustment, BMI was not associated with increased risk for hospital mortality (odds ratio 1.01, 95% CI 0.97-1.04, P = .67), whereas HFOV was independently associated with increased mortality (odds ratio 1.74, 95% CI 1.11-2.72, P = .02) with no effect modification by BMI strata (for this interaction, P = .56). Although there was no difference in the use of rescue therapies or in the number of days on sedation or analgesia, higher daily doses of fentanyl and midazolam were administered as BMI increased. CONCLUSION: There was no difference in adjusted hospital mortality across BMI strata in subjects with moderate to severe ARDS. Processes of care were not different across BMI strata except for higher daily doses of fentanyl as BMI increased. (ClinicalTrials.gov registration NCT0150640).

High-Frequency Percussive Ventilation Facilitates Weaning from Extracorporeal Membrane Oxygenation in Adults.

Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an invaluable rescue therapy for patients suffering from cardiopulmonary arrest, but it is not without its drawbacks. There are cases where patients recover their cardiac function, yet they fail to wean to mechanical conventional ventilation (MCV). The use of high-frequency percussive ventilation (HFPV) has been described in patients with acute respiratory failure (RF) who fail MCV. We describe our experience with five patients who underwent VA-ECMO for cardiopulmonary arrest who were successfully weaned from VA-ECMO with HFPV after failure to wean with MCV. Weaning trials of HFPV a day before decannulation or at the time of separation from VA-ECMO were conducted. Primary endpoint data collected include pre- and post-HFPV partial pressures of oxygen (PaO2) and PaO2/FIO2 (P/F) ratios measured at 2 and 24 hours after institution of HFPV. Additional periprocedural data points were collected including length of time on ECMO, hospital stay, and survival to discharge. Four of five patients were placed on VA-ECMO subsequent to percutaneous coronary intervention. One patient had cardiac arrest secondary to RF. Mean PaO2 (44 ± 15.9 mmHg vs. 354 ± 149 mmHg, p < .01) and mean P/F ratio (44 ± 15.9 vs. 354 ± 149, p < .01) increased dramatically at 2 hours after the initiation of HFPV. The improvement in mean PaO2 and P/F ratio was durable at 24 hours whether or not the patient was returned to MCV (n = 3) or remained on HFPV (n = 2) (44 ± 15.9 mmHg vs. 131 ± 68.7 mmHg, p = .036 and 44 ± 15.9 vs. 169 ± 69.9, p < .01, respectively). Survival to discharge was 80%. The data presented suggest that HFPV may be used as a strategy to shorten time on ECMO, thereby reducing the negative effects of the ECMO circuit and improving its cost efficacy.

High-Frequency Ventilation Modalities as Salvage Therapy for Smoke Inhalation-Associated Acute Lung Injury: A Systematic Review.

BACKGROUND: Smoke inhalation-associated acute lung injury (SI-ALI) is a major cause of morbidity and mortality in victims of fire tragedies. To date, there are no evidence-based guidelines on ventilation strategies in acute respiratory distress syndrome (ARDS) after smoke inhalation. We reviewed the existing literature for clinical studies of salvage mechanical ventilation (MV) strategies in patients with SI-ALI, focusing on mortality and pneumonia as outcomes. METHODS: A systematic search was designed in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Risk of bias assessment was performed using the Newcastle-Ottawa Quality Assessment Scale (NOS; 0 to 9 stars), with a score ≥7 being the threshold for inclusion in the meta-analysis. A systematic search strategy was used to search 10 databases. Clinical studies were included in which patients: (1) experienced smoke inhalation, (2) treated with MV, and (3) described a concurrent or historical control group. RESULTS: A total of 226 potentially relevant studies were identified, of which 7 studies on high-frequency percussive ventilation (HFPV) met inclusion criteria. No studies met inclusion for meta-analysis (NOS ≥ 7). In studies comparing HFPV to conventional mechanical ventilation (CMV), mortality and pneumonia incidence improved in 3 studies and remained unchanged in 3 others. No change in ventilator days or ICU length of stay was observed; however, oxygenation and work of breathing improved with HFPV. CONCLUSIONS: Mechanical ventilation in patients with SI-ALI has not been well studied. High-frequency percussive ventilation may decrease in-hospital mortality and pneumonia incidence when compared to CMV. The absence of "good" quality evidence precluded meta-analysis. Based upon low-quality evidence, there was a very weak recommendation that HFPV use may be associated with lower mortality and pneumonia rates in patients with SI-ALI. Given SI-ALI's unique underlying pathophysiology, and its potential implications on therapy, randomized controlled studies are required to ensure that patients receive the safest and most effective care. TRIAL REGISTRATION: The study was registered with PROSPERO International prospective register of systematic reviews (#47015).

Neurally adjusted ventilatory assist as an alternative to pressure support ventilation in adults: a French multicentre randomized trial.

PURPOSE: Neurally adjusted ventilatory assist (NAVA) is a ventilatory mode that tailors the level of assistance delivered by the ventilator to the electromyographic activity of the diaphragm. The objective of this study was to compare NAVA and pressure support ventilation (PSV) in the early phase of weaning from mechanical ventilation. METHODS: A multicentre randomized controlled trial of 128 intubated adults recovering from acute respiratory failure was conducted in 11 intensive care units. Patients were randomly assigned to NAVA or PSV. The primary outcome was the probability of remaining in a partial ventilatory mode (either NAVA or PSV) throughout the first 48 h without any return to assist-control ventilation. Secondary outcomes included asynchrony index, ventilator-free days and mortality. RESULTS: In the NAVA and PSV groups respectively, the proportion of patients remaining in partial ventilatory mode throughout the first 48 h was 67.2 vs. 63.3 % (P = 0.66), the asynchrony index was 14.7 vs. 26.7 % (P < 0.001), the ventilator-free days at day 7 were 1.0 day [1.0-4.0] vs. 0.0 days [0.0-1.0] (P < 0.01), the ventilator-free days at day 28 were 21 days [4-25] vs. 17 days [0-23] (P = 0.12), the day-28 mortality rate was 15.0 vs. 22.7 % (P = 0.21) and the rate of use of post-extubation noninvasive mechanical ventilation was 43.5 vs. 66.6 % (P < 0.01). CONCLUSIONS: NAVA is safe and feasible over a prolonged period of time but does not increase the probability of remaining in a partial ventilatory mode. However, NAVA decreases patient-ventilator asynchrony and is associated with less frequent application of post-extubation noninvasive mechanical ventilation. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT02018666.

High-frequency oscillatory ventilation versus conventional ventilation for acute respiratory distress syndrome.

BACKGROUND: High-frequency oscillation (HFO) is an alternative to conventional mechanical ventilation that is sometimes used to treat people with acute respiratory distress syndrome, but effects on oxygenation, mortality and adverse clinical outcomes are uncertain. This review was originally published in 2004 and was updated in 2013 and again in 2015. OBJECTIVES: To determine the effects of HFO compared to conventional mechanical ventilation on physiological outcomes, clinical outcomes, and mortality when used for the treatment of acute respiratory distress syndrome (ARDS). SEARCH METHODS: We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Ovid), MEDLINE (Ovid), EMBASE (Ovid), and ISI, from inception to December 2015. We conducted the original search in 2002. We manually searched reference lists from included studies and review articles; searched conference proceedings of the American Thoracic Society (1994 to 2015), Society of Critical Care Medicine (1994 to 2015), European Society of Intensive Care Medicine (1994 to 2015), and American College of Chest Physicians (1994 to 2015); contacted clinical experts in the field; and searched for unpublished and ongoing trials in clinicaltrials.gov and controlled-trials.com. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing treatment using HFO with conventional mechanical ventilation for children and adults diagnosed with ARDS. DATA COLLECTION AND ANALYSIS: Three review authors independently extracted data on clinical, physiological, and safety outcomes according to a predefined protocol. We contacted investigators of all included studies to clarify methods and obtain additional data. We used random-effects models in the analyses. MAIN RESULTS: We include 10 RCTs (n = 1850); almost all participants had moderate or severe ARDS. For the primary analysis, the risk of bias was low in three studies and unclear in five studies; the overall quality of evidence was very low due to imprecision, inconsistency, indirectness and methodologic limitations. In participants randomized to HFO, there was no significant difference in hospital or 30-day mortality (risk ratio (RR) 0.92, 95% confidence interval (CI) 0.72 to 1.16; P = 0.46, I² = 66%; 8 trials, 1779 participants, 807 deaths) compared with conventional ventilation. One large multicentre RCT was terminated early because of increased mortality in participants randomized to HFO compared to mechanical ventilation with low tidal volume and high positive end expiratory pressure, with HFO reserved only as a rescue therapy. We found substantial between-trial statistical heterogeneity (I² = 0% to 66%) for clinical outcomes, including mortality.  AUTHORS' CONCLUSIONS: The findings of this systematic review suggest that HFO does not reduce hospital and 30-day mortality due to ARDS; the quality of evidence was very low. Our findings do not support the use of HFO as a first-line strategy in people undergoing mechanical ventilation for ARDS.

High-Frequency Oscillatory Ventilation in Pediatric Acute Lung Injury: A Multicenter International Experience.

OBJECTIVE: We aim to describe current clinical practice, the past decade of experience and factors related to improved outcomes for pediatric patients receiving high-frequency oscillatory ventilation. We have also modeled predictive factors that could help stratify mortality risk and guide future high-frequency oscillatory ventilation practice. DESIGN: Multicenter retrospective, observational questionnaire study. SETTING: Seven PICUs. PATIENTS: Demographic, disease factor, and ventilatory and outcome data were collected, and 328 patients from 2009 to 2010 were included in this analysis. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Patients were classified into six cohorts based on underlying diagnosis. We used univariate analysis to identify factors associated with mortality risk and multivariate logistic regression to identify independent predictors of mortality risk. An oxygenation index greater than 35 and immunocompromise exhibited the greatest predictive power (p < 0.0001) for increased mortality risk, and respiratory syncytial virus was associated with lowest mortality risk (p = 0.003). Differences in mortality risk as a function of oxygenation index were highly dependent on primary underlying condition. A trend toward an increase in oscillator amplitude and frequency was observed when compared with historical data. CONCLUSIONS: Given the number of centers and subjects included in the database, these findings provide a robust description of current practice regarding the use of high-frequency oscillatory ventilation for pediatric hypoxic respiratory failure. Patients with severe hypoxic respiratory failure and immunocompromise had the highest mortality risk, and those with respiratory syncytial virus had the lowest. A means of identifying the risk of 30-day mortality for subjects can be obtained by identifying the underlying disease and oxygenation index on conventional ventilation preceding the initiation of high-frequency oscillatory 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.

BACKGROUND: 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. OBJECTIVES: To determine the clinical benefit and cost-effectiveness of HFOV in patients with ARDS compared with standard mechanical ventilation. DESIGN: A parallel, randomised, unblinded clinical trial. SETTING: UK intensive care units. PARTICIPANTS: 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. INTERVENTIONS: 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. MAIN OUTCOME MEASURES: 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. RESULTS: 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. CONCLUSIONS: 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. TRIAL REGISTRATION: Current Controlled Trials ISRCTN10416500.

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.

Ventilação oscilatória de alta frequência em crianças com síndrome da angústia respiratória aguda: experiência de um centro de tratamento intensivo pediátrico / High-frequency oscillatory ventilation in children with acute respiratory distress syndrome: experience of a pediatric intensive care unit

OBJETIVO: Descrever os efeitos da aplicação da ventilação de alta frequência oscilatória como suporte ventilatório de resgate em uma série de pacientes pediátricos com síndrome da angústia respiratória aguda (SARA). MÉTODOS: Participaram do estudo 25 crianças(> 1mês e < 17 anos) internadas em uma UTI pediátrica universitária com SARA e submetidas à ventilação de alta frequência oscilatória (VAFO) por um mínimo de 48 horas, após falha da ventilação mecânica convencional. RESULTADOS: A taxa de mortalidade foi de 52% (13/25) 28 dias após o início da SARA. Ao longo de 48 horas, a aplicação da VAFO reduziu o índice de oxigenação [38 (31-50) vs. 17 (10-27)] e aumentou a relação pressão arterial parcial de O2/fração inspirada de O2 [65 (44-80) vs. 152 (106-213)]. A pressão arterial parcial de CO2 [54 (45-74) vs. 48 (39-58) mmHg] manteve-se inalterada. A pressão média de vias aéreas oscilou entre 23 e 29 cmH2O. A VAFO não comprometeu a hemodinâmica e observou-se uma redução da frequência cardíaca (141 ± 32 vs. 119 ± 22 bat/min), a pressão arterial média (66 ± 20 vs. 71 ± 17 mmHg) e o escore inotrópico [44 (17-130) vs. 20 (16-75)] mantiveram-se estáveis nesse período. Nenhum sobrevivente ficou dependente de oxigênio. CONCLUSÃO: VAFO melhora a oxigenação de pacientes pediátricos com SARA grave e hipoxemia refratária ao suporte ventilatório convencional.

OBJECTIVE: To describe the effects of high-frequency oscillatory ventilation (HFOV) as a rescue Acute respiratory distress syndrome ventilatory support in pediatric patients with acute respiratory distress syndrome (ARDS). METHODS: Twenty-five children (1 month < age < 17 years) admitted to a university hospital pediatric intensive care unit (ICU) with ARDS and submitted to HFOV for a minimum of 48 hours after failure of conventional mechanical ventilation were assessed. RESULTS: Twenty eight days after the onset of ARDS, the mortality rate was 52% (13/25). Over the course of 48 hours, the use of HFOV reduced the oxygenation index [38 (31-50) vs. 17 (10-27)] and increased the ratio of partial arterial pressure O2 and fraction of inspired O2 [65 [44-80) vs. 152 (106-213)]. Arterial CO2 partial pressure [54 (45-74) vs. 48 (39-58) mmHg] remained unchanged. The mean airway pressure ranged between 23 and 29 cmH2O. HFOV did not compromise hemodynamics, and a reduction in heart rate was observed (141±32 vs. 119±22 beats/min), whereas mean arterial pressure (66±20 vs. 71±17mmHg) and inotropic score [44 (17-130) vs. 20 (16-75)] remained stable during this period. No survivors were dependent on oxygen. CONCLUSION: HFOV improves oxygenation in pediatric patients with ARDS and severe hypoxemia refractory to conventional ventilatory support.

High-frequency oscillatory ventilation in children with acute respiratory distress syndrome: experience of a pediatric intensive care unit.

OBJECTIVE: To describe the effects of high-frequency oscillatory ventilation (HFOV) as a rescue ventilatory support in pediatric patients with acute respiratory distress syndrome (ARDS). METHODS: Twenty-five children (1 month < age < 17 years) admitted to a university hospital pediatric intensive care unit (ICU) with ARDS and submitted to HFOV for a minimum of 48 hours after failure of conventional mechanical ventilation were assessed. RESULTS: Twenty eight days after the onset of ARDS, the mortality rate was 52% (13/25). Over the course of 48 hours, the use of HFOV reduced the oxygenation index [38 (31-50) vs. 17 (10-27)] and increased the ratio of partial arterial pressure O2 and fraction of inspired O2 [65 [44-80) vs. 152 (106-213)]. Arterial CO2 partial pressure [54 (45-74) vs. 48 (39-58) mmHg] remained unchanged. The mean airway pressure ranged between 23 and 29 cmH2O. HFOV did not compromise hemodynamics, and a reduction in heart rate was observed (141±32 vs. 119±22 beats/min), whereas mean arterial pressure (66±20 vs. 71±17 mmHg) and inotropic score [44 (17-130) vs. 20 (16-75)] remained stable during this period. No survivors were dependent on oxygen. CONCLUSION: HFOV improves oxygenation in pediatric patients with ARDS and severe hypoxemia refractory to conventional ventilatory support.

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.

High-frequency ventilation versus conventional ventilation for treatment of acute lung injury and acute respiratory distress syndrome.

BACKGROUND: High frequency oscillation is an alternative to conventional mechanical ventilation that is sometimes used to treat patients with acute respiratory distress syndrome, but effects on oxygenation, mortality and adverse clinical outcomes are uncertain. This review was originally published in 2004 and was updated in 2011. OBJECTIVES: To determine clinical and physiological effects of high frequency oscillation (HFO) in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) compared to conventional ventilation. SEARCH METHODS: We electronically searched CENTRAL (Ovid), MEDLINE (Ovid), EMBASE (Ovid), and ISI (from inception to March 2011). The original search was performed in 2002. We manually searched reference lists from included studies and review articles; searched conference proceedings of the American Thoracic Society (1994 to 2010), Society of Critical Care Medicine (1994 to 2010), European Society of Intensive Care Medicine (1994 to 2010), and American College of Chest Physicians (1994 to 2010); contacted clinical experts in the field; and searched for unpublished and ongoing trials in clinicaltrials.gov and controlled-trials.com. SELECTION CRITERIA: Randomized controlled clinical trials comparing treatment using HFO with conventional mechanical ventilation for children and adults diagnosed with ALI or ARDS. DATA COLLECTION AND ANALYSIS: Three authors independently extracted data on clinical, physiological, and safety outcomes according to a predefined protocol. We contacted investigators of all included studies to clarify methods and obtain additional data. We used random-effects models in the analyses. MAIN RESULTS: Eight RCTs (n = 419) were included; almost all patients had ARDS. The risk of bias was low in six studies and unclear in two studies. The quality of evidence for hospital and six-month mortality was moderate and low, respectively. The ratio of partial pressure of oxygen to inspired fraction of oxygen at 24, 48, and 72 hours was 16% to 24% higher in patients receiving HFO. There were no significant differences in oxygenation index because mean airway pressure rose by 22% to 33% in patients receiving HFO (P < 0.01).  In patients randomized to HFO, mortality was significantly reduced (RR 0.77, 95% CI 0.61 to 0.98; P = 0.03; 6 trials, 365 patients, 160 deaths) and treatment failure (refractory hypoxaemia, hypercapnoea, hypotension, or barotrauma) was less likely (RR 0.67, 95% CI 0.46 to 0.99; P = 0.04; 5 trials, 337 patients, 73 events). Other risks, including adverse events, were similar. We found substantial between-trial statistical heterogeneity for physiological (I(2) = 21% to 95%) but not clinical (I(2) = 0%) outcomes.  Pooled results were based on few events for most clinical outcomes. AUTHORS' CONCLUSIONS: The findings of this systematic review suggest that HFO was a promising treatment for ALI and ARDS prior to the uptake of current lung protective ventilation strategies. These findings may not be applicable with current conventional care, pending the results of large multi-centre trials currently underway.