BACKGROUND: The role of high-frequency oscillatory ventilation (HFOV) has long been debated. Numerous studies documented its benefits, whereas several more recent studies did not prove superiority of HFOV over protective conventional mechanical ventilation (CV). One of the accepted explanations is that CV and HFOV act differently, including gas exchange. METHODS: To investigate a different level of coupling or decoupling between oxygenation and carbon dioxide elimination during CV and HFOV, we conducted a prospective crossover animal study in 11 healthy pigs. In each animal, we found a normocapnic tidal volume (VT) after the lung recruitment maneuver. Then, VT was repeatedly changed over a wide range while keeping constant the levels of PEEP during CV and mean airway pressure during HFOV. Arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were recorded. The same procedure was repeated for CV and HFOV in random order. RESULTS: Changes in PaCO2 intentionally induced by adjustment of VT affected oxygenation more significantly during HFOV than during CV. Increasing VT above its normocapnic value during HFOV caused a significant improvement in oxygenation, whereas improvement in oxygenation during CV hyperventilation was limited. Any decrease in VT during HFOV caused a rapid worsening of oxygenation compared to CV. CONCLUSION: A change in PaCO2 induced by the manipulation of tidal volume inevitably brings with it a change in oxygenation, while this effect on oxygenation is significantly greater in HFOV compared to CV.

• Klíčová slova
• High-frequency oscillatory ventilation, Mechanical ventilation, Oxygenation, Tidal volume,
• MeSH
• dechový objem MeSH
• plíce MeSH
• prasata MeSH
• prospektivní studie MeSH
• výměna plynů v plicích * MeSH
• vysokofrekvenční ventilace * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

RATIONALE: High-frequency oscillatory ventilation (HFOV) is theoretically beneficial for lung protection, but the results of clinical trials are inconsistent, with study-level meta-analyses suggesting no significant effect on mortality. OBJECTIVES: The aim of this individual patient data meta-analysis was to identify acute respiratory distress syndrome (ARDS) patient subgroups with differential outcomes from HFOV. METHODS: After a comprehensive search for trials, two reviewers independently identified randomized trials comparing HFOV with conventional ventilation for adults with ARDS. Prespecified effect modifiers were tested using multivariable hierarchical logistic regression models, adjusting for important prognostic factors and clustering effects. MEASUREMENTS AND MAIN RESULTS: Data from 1,552 patients in four trials were analyzed, applying uniform definitions for study variables and outcomes. Patients had a mean baseline PaO2/FiO2 of 114 ± 39 mm Hg; 40% had severe ARDS (PaO2/FiO2 <100 mm Hg). Mortality at 30 days was 321 of 785 (40.9%) for HFOV patients versus 288 of 767 (37.6%) for control subjects (adjusted odds ratio, 1.17; 95% confidence interval, 0.94-1.46; P = 0.16). This treatment effect varied, however, depending on baseline severity of hypoxemia (P = 0.0003), with harm increasing with PaO2/FiO2 among patients with mild-moderate ARDS, and the possibility of decreased mortality in patients with very severe ARDS. Compliance and body mass index did not modify the treatment effect. HFOV increased barotrauma risk compared with conventional ventilation (adjusted odds ratio, 1.75; 95% confidence interval, 1.04-2.96; P = 0.04). CONCLUSIONS: HFOV increases mortality for most patients with ARDS but may improve survival among patients with severe hypoxemia on conventional mechanical ventilation.

• Klíčová slova
• acute respiratory distress syndrome, high-frequency oscillatory ventilation, mechanical ventilation,
• MeSH
• dospělí MeSH
• hypoxie terapie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• syndrom dechové tísně terapie   MeSH
• umělé dýchání metody   MeSH
• výsledek terapie MeSH
• vysokofrekvenční ventilace metody   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• metaanalýza MeSH
• srovnávací studie MeSH

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.

• MeSH
• analýza krevních plynů MeSH
• chronická nemoc MeSH
• dítě MeSH
• imunokompromitovaný pacient MeSH
• jednotky intenzivní péče pediatrické statistika a číselné údaje   MeSH
• kojenec MeSH
• lidé MeSH
• novorozenec MeSH
• prediktivní hodnota testů MeSH
• předškolní dítě MeSH
• respirační insuficience etiologie   mortalita   terapie   MeSH
• retrospektivní studie MeSH
• socioekonomické faktory MeSH
• vysokofrekvenční ventilace škodlivé účinky   metody   mortalita   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• pozorovací studie MeSH
• práce podpořená grantem MeSH

High frequency oscillatory ventilation (HFOV), contrary to conventional ventilation, enables a safe increase in tidal volume (V(T)) without endangering alveoli by volutrauma or barotrauma. The aim of the study is to introduce the concept of normocapnic high frequency oscillatory hyperventilation and to assess its effect upon oxygen gain under experimental conditions. Laboratory pigs (n = 9) were investigated under total intravenous anesthesia in three phases. Phase 1: Initial volume controlled HFOV period. Phase 2: Hyperventilation--V(T) was increased by (46 +/- 12) % when compared to normocapnic V(T) during phase 1. All other ventilatory parameters were unchanged. A significant increase in PaO(2) (by 3.75 +/- 0.52 kPa, p < 0.001) and decrease in PaCO(2) (by -2.05 +/- 0.31 kPa, p < 0.001) were obtained. Phase 3: Normocapnia during hyperventilation was achieved by an iterative increase in the CO(2) fraction in the inspiratory gas by a CO(2) admixture. All ventilatory parameters were unchanged. A significant increase in PaO(2) (by 3.79 +/- 0.73 kPa, p < 0.001), similar to that which was observed in phase 2, was preserved in phase 3 whereas normocapnia was fully re-established. The concept of high frequency normocapnic hyperventilation offers a lung protective strategy that significantly improves oxygenation whilst preserving normocapnia.

• MeSH
• kyslík krev   MeSH
• oxid uhličitý krev   MeSH
• prasata MeSH
• spotřeba kyslíku fyziologie   MeSH
• výměna plynů v plicích fyziologie   MeSH
• vysokofrekvenční ventilace * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyslík MeSH
• oxid uhličitý MeSH

BACKGROUND: Acute respiratory failure in both pediatric and adult patient populations has been extensively studied with recent emphasis on ventilation strategies that can effect mortality outcome. This research in adults has focused on definitive trials of lung protective strategies that have been proposed following preliminary reports of their potential benefits. High frequency oscillatory ventilation has also been described as a lung protective strategy. For many institutions HFOV is today considered a routine therapy as a "rescue" method in acute pediatric respiratory failure. Because HFOV is considered to be a "rescue" therapy, intervention with HFOV is usually in the later stages of acute respiratory failure and consideration of the time to intervention has not been previously examined. OBJECTIVE: To evaluate the effect of time to intervention with high-frequency oscillatory ventilation (HFOV) on the survival of children with severe acute hypoxemic respiratory failure who were managed with lung protective strategies on conventional mechanical ventilation (CMV). METHODS: Twenty-six consecutive patients older 1 month of age with severe hypoxemic respiratory failure and ARDS who at some point in their management were treated with HFOV were evaluated. The mean age was 3.7 years and included three patients treated in the Pediatric Intensive Care Unit (17, 19 and 24 years). Mean weight was 13.8 kg and there were 17 males and 9 females. Nine patients met Extracorporeal Membrane Oxygenation (ECMO) criteria, although only two patients were cannulated. Upon admission to the PICU, patients were initially managed with lung protective strategies using Pressure Controlled Ventilation (PCV) or Pressure Regulated Volume Control (PRVC) modes with limited peak inspiratory pressure, high positive end-expiratory pressure, and permissive hypercapnia. If a Pa-CO2 reached > 75 torr (10.0 kPa) and/or pH < 7.20, tracheal gas insufflation (TGI) was instituted. If FiO2 remained above 0.6 and mean airway pressure (Paw) exceeded 15 cmH2O in order to maintain arterial saturation above 89% or if hypercapnia and/or acidosis on CMV with TGI persisted, the patients were switched to HFOV. An "Optimal Volume Strategy" with HFOV was utilized to recruit alveoli and optimize lung volume. Patients were returned to CMV when their mean airway pressure were between 15 and 20 cmH2O, FiO2 < 0.6, had no evidence of air-leak and/or improved chest X-rays, and did not desaturated during airway suctioning. Patients were offered ECMO if the hypoxemia persisted on HFOV and there were no contraindications to its use. The patients were stratified for analysis by the time to intervention with HFOV. Early intervention was defined as within the first 24 hours of mechanical ventilation (17 patients) and late intervention defined patients beyond 24 hours (9 patients). Demographic data (gender, age, weight, admission PRISM score), time of each mode of ventilation, oxygenation indices and outcomes were recorded for both groups of patients. MAIN RESULTS: The severity of respiratory failure at the time of HFOV intervention was comparable in both early and late groups (PaCO2/FiO2 83 vs. 79 torr, oxygenation index 27 vs. 33, AaDO2 421 torr (56 kPa) vs. 413 torr (55 kPa)). There were no differences in mean age, weight, admission PRISM score length of HFOV, length of CMV after HFOV (CMV post-HFOV) and the total duration of mechanical ventilation between the groups. We found a statistically significant difference in mortality with 58.8% of the early intervention patients surviving while only 12.5% of the late intervention patients survived. The overall survival rate was 42% (11/26 patients). CONCLUSION: Early use of HFOV within the first 24 hours of acute hypoxic respiratory failure in pediatric patients is associated with better survival. Use of this therapy should be considered early in the course of treatment of any pediatric patient meeting this definition. (Tab. 2, Fig. 1, Ref. 28.)

• MeSH
• časové faktory MeSH
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• retrospektivní studie MeSH
• syndrom dechové tísně terapie   MeSH
• vysokofrekvenční ventilace * MeSH
• Check Tag
• dítě MeSH
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

The recently reported differences between pulmonary and extrapulmonary acute respiratory distress syndromes (ARDS(p), ARDS(exp)) are the main reasons of scientific discussion on potential differences in the effects of current ventilatory strategies. The aim of this study is to assess whether the presence of ARDS(p) or ARDS(exp) can differently affect the beneficial effects of high-frequency oscillatory ventilation (HFOV) upon physiological and clinical parameters. Thirty adults fulfilling the ARDS criteria were indicated for HFOV in case of failure of conventional ventilation strategy. According to the ARDS type, each patient was included either in the group of patients with ARDS(p) or ARDS(exp). Six hours after normocapnic HFOV introduction, there was no significant increase in PaO2/F(I)O2 in ARDS(p) group (from 129+/-47 to 133+/-50 Torr), but a significant improvement was found in ARDS(exp) (from 114+/-54 to 200+/-65 Torr, p<0.01). Despite the insignificant difference in the latest mean airway pressure (MAP) on conventional mechanical ventilation (CMV) between both groups, initial optimal continuous distension pressure (CDP) for the best PaO2/F(I)O2 during HFOV was 2.0+/-0.6 kPa in ARDS(p) and 2.8+/-0.6 kPa in ARDS(exp) (p<0.01). HFOV recruits and thus it is more effective in ARDS(exp). ARDS(exp) patients require higher CDP levels than ARDS(p) patients. The testing period for positive effect of HFOV is recommended not to be longer than 24 hours.

• MeSH
• časové faktory MeSH
• lidé středního věku MeSH
• lidé MeSH
• respirační funkční testy MeSH
• syndrom dechové tísně klasifikace   terapie   MeSH
• vysokofrekvenční ventilace * MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

OBJECTIVE: To determine whether early surfactant administration is superior to selective delayed treatment in terms of improving survival and/or reducing chronic lung disease in extremely premature neonates with respiratory distress syndrome (RDS) treated by high-frequency oscillatory ventilation (HFOV). DESIGN: Prospective randomized clinical trial. SETTING: Tertiary neonatal intensive care unit (NICU) in the Perinatology Center of Prague. PATIENTS: Forty-three extremely premature infants who needed artificial ventilation within 3 h after delivery. INTERVENTIONS: Patients were randomly assigned to either early ( n=21) or delayed (n=22) administration of surfactant. All were ventilated by HFOV as the primary mode of ventilation using the high volume strategy aimed at optimizing lung volume. Curosurf at a dose of 100 mg/kg was given as a single bolus via the endotracheal tube within 1 min immediately after intubation in the early group (EARL), or during HFOV only when defined criteria were reached in the delayed (DEL) group. MEASUREMENTS AND RESULTS: No differences were noted in demographic data between the two groups. Fewer infants randomized to the EARL group required oxygen use or died at 36 weeks (combined outcome 29% vs 64%, p=0.021), and there was a lower incidence of any intraventricular hemorrhage in this group (43 vs 82%, p=0.008). CONCLUSIONS: When compared to delayed dosing, early administration of surfactant followed by HFOV facilitates and accelerates respiratory stabilization during the acute phase of severe RDS, may reduce the incidence of chronic lung disease or death and may positively influence the incidence of severe intracranial pathology in extremely premature infants with primary surfactant insufficiency.

• MeSH
• chronická nemoc MeSH
• jednotky intenzivní péče o novorozence MeSH
• lidé MeSH
• novorozenec nedonošený MeSH
• novorozenec MeSH
• plicní surfaktanty aplikace a dávkování   terapeutické užití   MeSH
• premedikace MeSH
• prospektivní studie MeSH
• regresní analýza MeSH
• syndrom respirační tísně novorozenců farmakoterapie   prevence a kontrola   MeSH
• výsledek terapie MeSH
• vysokofrekvenční ventilace * MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• randomizované kontrolované studie MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• plicní surfaktanty MeSH

OBJECTIVE: To compare the effectiveness and safety of very early high-frequency oscillatory ventilation (HFOV) with conventional mechanical ventilation (CMV) in treatment of the respiratory distress syndrome (RDS) and to evaluate their impact on the incidence of chronic pulmonary disease and early and late morbidity of very low-birthweight neonates. DESIGN: A prospective randomized clinical trial. SETTING: Tertiary neonatal intensive care unit in the Perinatology Center in Prague. PATIENTS: 43 premature newborns, delivered in the Department of Obstetrics in the Perinatology Center, were randomly divided into two groups (HFOV and CMV) immediately after delivery; 2 patients in each group died, 2 fulfilled crossover criteria from CMV to HFOV, and 2 were excluded because of congenital malformations. Nineteen patients treated with HFOV were therefore compared with 18 infants in the CMV group. METHODS: The two contrasting modes of ventilation were introduced immediately after intubation. Maintenance of optimal lung volume in HFOV to optimize oxygenation and the therapeutic administration of surfactant after fulfilling defined criteria are important points of the strategy and design of the study. MEASUREMENTS AND MAIN RESULTS: Except for a higher proportion of males in the HFOV group (p<0.02), the basic clinical characteristics (gestational age, birthweight, Apgar score at 5 min, umbilical arterial pH), the two groups were similar. In the acute stage of RDS, infants treated with HFOV had higher proximal airway distending pressure with HFOV for 6 h after delivery (p<0.05). For a period of 12 h after delivery lower values for the alveolar-arterial oxygen difference (p<0.03) were noted. The number of patients who did not require surfactant treatment was higher in the HFOV group (11 vs. 1, p<0.001). In the HFOV group the authors found a lower roentgenographic score at 30 days of age (p<0.03) and a lower clinical score in the 36th postconceptional week (p<0.05), using these two scoring systems for assessing chronic lung disease according to Toce scale. The incidence of pneumothorax, pulmonary interstitial emphysema, intraventricular hemorrhage and retinopathy of prematurity in both groups was the same. CONCLUSIONS: HFOV, when applied early and when the clinical strategy of maintenance of optimal lung volume is used, improves oxygenation in the acute stage of RDS, reduces the need of surfactant administration, and can decrease the injury to lung tissue even in extremely immature newborns to whom surfactant is administered therapeutically.

• MeSH
• gestační stáří MeSH
• lidé MeSH
• novorozenec nedonošený MeSH
• novorozenec MeSH
• plicní surfaktanty MeSH
• prospektivní studie MeSH
• syndrom respirační tísně novorozenců terapie   MeSH
• umělé dýchání * MeSH
• výsledek terapie MeSH
• vysokofrekvenční ventilace * MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• novorozenec MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• randomizované kontrolované studie MeSH
• srovnávací studie MeSH
• Názvy látek
• plicní surfaktanty MeSH

UNLABELLED: Purpose/Aim : High-frequency oscillatory ventilation (HFOV) is a method of ventilation that theoretically achieves the goals of lung protective ventilation in acute respiratory distress syndrome (ARDS) patients. It is characterized by a rapid delivery of small tidal volumes at high frequencies oscillating around a continuous distending pressure (CDP). Optimization of CDP is not an easy task and it is titrated empirically in the clinical practice. The aim of this study is to investigate whether the level of CDP consistently affects the shape of the partial pressure of oxygen (PaO2) response to stepwise changes in CDP during HFOV of healthy and ARDS-induced pigs. MATERIALS AND METHODS: We performed two stepwise maneuvers of CDP in 14 pigs: one before and one after the lung lavage, inducing ARDS. For each CDP step performed, we fitted a segment of PaO2 curve with a one-term power model. RESULTS: PaO2 course follows shapes modeled by root, linear, quadratic, and cubic functions for values of PaO2 ≤ 110 mmHg and PaO2 ≤ 200 mmHg, before and after the lung lavage, respectively. PaO2 course follows a shape modeled exclusively by a root function for values of PaO2 > 110 mmHg and PaO2 > 200 mmHg, before and after the lung lavage, respectively. It is not possible to describe a relationship between the shape of the PaO2 course and the values of CDP. CONCLUSIONS: The PaO2 curve may give information about the level of recruitment of alveoli, but cannot be used for optimization of CDP level during HFOV in healthy and ARDS lung model pigs.

• Klíčová slova
• ARDS, HFOV, continuous distending pressure, lung lavage, oxygenation, power model,
• MeSH
• analýza krevních plynů metody   MeSH
• bronchoalveolární laváž metody   MeSH
• dechový objem fyziologie   MeSH
• kyslík metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• prasata MeSH
• syndrom dechové tísně metabolismus   patofyziologie   MeSH
• tlak MeSH
• umělé dýchání metody   MeSH
• výměna plynů v plicích fyziologie   MeSH
• vysokofrekvenční ventilace metody   MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kyslík MeSH

• MeSH
• cor pulmonale etiologie   patofyziologie   MeSH
• hemodynamika fyziologie   MeSH
• lidé MeSH
• syndrom dechové tísně patofyziologie   terapie   MeSH
• vysokofrekvenční ventilace škodlivé účinky   metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH