High-frequency Oscillatory Ventilation Research Articles

Utilization and effect of neuromuscular blockade in a randomized trial of high-frequency oscillation.

We evaluated characteristics associated with neuromuscular blockade (NMB) use, center-level variation, and whether NMB mediated excess mortality among patients assigned to high-frequency oscillatory ventilation (HFOV) in the OSCILLATE trial. NMB exposure was defined as receipt after randomization; the primary outcome was hospital mortality. Descriptive analyses compared NMB-exposed vs unexposed patients. Multivariable analyses included patients not on baseline NMB. Cox regression evaluated associations of patient- and center-level variables with NMB use. A log-normal frailty model evaluated center effects. Mediation analysis examined the effect of NMB in HFOV-assigned patients. 376/548 patients (39 centers) received post-randomization NMB, of whom 165 received baseline NMB. Patients receiving post-randomization NMB (vs. not) had worse lung mechanics and gas exchange, received more sedation and vasopressors (p<0.05), and had higher hospital mortality (44% vs. 34%, p=0.03). Mean airway pressure≥24 cmH2O, randomization to HFOV, and intensive care unit size ≥ 31 beds were associated with post-randomization NMB. After adjustment, center had a negligible effect on post-randomization NMB (median hazard ratio 1.01, p=0.047). NMB use did not mediate excess mortality among HFOV-allocated patients (p=0.80). In OSCILLATE, receipt of post-randomization NMB was associated with worse outcomes, but NMB use did not mediate HFOV-associated higher mortality.

Assessment of Respiratory System Resistance during High-Frequency Oscillatory Ventilation Based on In Vitro Experiment

High-frequency oscillatory ventilation (HFOV) is a type of mechanical ventilation with a protective potential characterized by a small tidal volume. Unfortunately, HFOV has limited monitoring of ventilation parameters and mechanical parameters of the respiratory system, which makes it difficult to adjust the continuous distension pressure (CDP) according to the individual patient’s airway status. Airway resistance Raw is one of the important parameters describing the mechanics of the respiratory system. The aim of the presented study was to verify in vitro whether the resistance of the respiratory system Rrs can be reliably determined during HFOV to evaluate Raw in pediatric and adult patients. An experiment was performed with a 3100B high-frequency oscillator, a physical model of the respiratory system, and a pressure and flow measurement system. The physical model with different combinations of resistance and compliance was ventilated during the experiment. The resistance Rrs was calculated from the impedance of the physical model, which was determined from the spectral density of the pressure at airway opening and the spectral cross-density of the gas flow and pressure at airway opening. Rrs of the model increased with an added resistor and did not change significantly with a change in compliance. The method is feasible for monitoring respiratory system resistance during HFOV and has the potential to optimize CDP settings during HFOV in clinical practice.

Improving respiratory outcomes after pediatric cardiac surgery: New uses for nitric oxide

This month's issue of Journal of Cardiac Surgery features a retrospective study on the effect of combining inhaled nitric oxide with high frequency oscillator ventilation to rescue infants who have failed conventional ventilation after congenital heart surgery. This commentary aims to place that study within the context of available published literature on the topic. The PubMed database was queried for all English-language entries between 1995 and 2021 with the terms nitric oxide, congenital heart disease, oscillator, and respiratory failure. The results were then assessed for relevance and impact by the author. From these results, 15 articles were selected for use in this review. The cost of prolonged mechanical ventilation is described. The use of nitric oxide has been used to improve outcomes in hypoxic respiratory failure. High-frequency oscillator ventilation has also been studied in pediatric patients with ARDS. To date, no studies have been published showing the benefit of combining these two modalities in pediatric cardiac surgical patients. The results of this month's study on nitric oxide and high frequency oscillator ventilation are placed in the context of current literature and suggestions for further study are presented. Pediatric patients with hypoxic respiratory failure following congenital heart surgery have a new treatment strategy that appears effective. Further studies to confirm this should be undertaken.

Effect of postoperative administration of inhaled nitric oxide combined with high-frequency oscillatory ventilation in infants with acute hypoxemic respiratory failure and pulmonary hypertension after congenital heart surgery: A retrospective cohort study.

To evaluate the effect of inhaled nitric oxide (iNO) combined with high-frequency oscillatory ventilation (HFOV) in the treatment of infants with acute hypoxemic respiratory failure (AHRF) and pulmonary hypertension (PH) after congenital heart surgery. A retrospective study was conducted on 63 infants with AHRF and PH after congenital heart surgery in our cardiac intensive care unit (CICU) from January 2020 to March 2021. A total of 24 infants in the A group were treated with HFOV combined with iNO, and 39 infants in the B group were treated with HFOV. Relevant clinical data were collected. Comparing the two groups, the improvement of the oxygenation index, PaO2 and PaO2 /FiO2 was more obvious for patients in the A group than for those in the B group after intervention (p < .05). Reexamination on the third day after the initiation of HFOV treatment indicated that the systolic pulmonary artery pressure in the A group was significantly lower than that in the B group (p < .05). In addition, the duration of mechanical ventilation and the length of CICU stay in the A group were shorter than those in the B group (p < .05). However, complications between the two groups were not statistically significant. No important adverse effects arose. For infants with AHRF and PH after congenital heart surgery, iNO combined with HFOV is superior to HFOV alone to improve oxygenation, decrease pulmonary pressure, and shorten the duration of mechanical ventilation and the length of CICU stay, with no adverse effects.

Extremely low birth weight infant surviving left congenital diaphragmatic hernia: a case report

In this study, we present the case of a 900 g, male infant born at 27+5 weeks, who was placed on high frequency oscillatory ventilation (HFOV) until repair of a left congenital diaphragmatic hernia (CDH) at 39 days of life (DOL). To date, this is the smallest infant with repair of the left CDH reported in the literature. After birth, he passed the cardiopulmonary stabilization phase and successfully underwent delayed surgery; in the process, he received ventilator assistance through HFOV. He weighed 1,660 gm at the time of surgery. We performed the thoracoscopic primary closure of the diaphragmatic defect. He was extubated on post-operation day (POD) 7 and discharged from hospital on POD 36 with 0.1 L/min supplemental oxygen via nasal cannula. He is being followed for growth and development and there has been no recurrence at the surgical site at 24 months of corrected age. In this case, high mean airway pressure (MAP) was required based on the patient’s weight to achieve adequate recruitment of the left lung, and the patient was diagnosed with mental developmental delay on Bayley Scales of Infant Development-II. Thus, we suggest that the postnatal course and long-term outcomes for extremely low birth weight (ELBW) and preterm infants with left CDH is different from that for full-term babies. Therefore, future research should focus on preterm infants with left CDH.

Pulmonary haemorrhage in neonates: Systematic review of management.

Pulmonary haemorrhage (PH) is an acute catastrophic event with low incidence yet high mortality among neonates. We aimed to systematically review the management of PH. A search was carried out of the PubMed, EMBASE and Cochrane databases according to the PRISMA guidelines. Data were extracted on study design and size, patient demographics, primary and adjunctive treatment methods, and treatment outcomes. Sixteen studies with 385 newborn infants were included and were significantly heterogeneous regarding treatment methods. Primary treatments included surfactant, high-frequency oscillatory ventilation (HFOV), epinephrine, coagulopathy management, intermittent positive pressure ventilation, cocaine and tolazoline. Adjunctive treatment methods included blood products, HFOV, increased positive end-expiratory pressure, vitamin K, surfactant, adrenaline, vasopressors and inotropes. All five studies using surfactant as primary treatment were effective in improving oxygenation index measures and preventing recurrence of PH, and three studies found no association between surfactant and death or long-term disability. Ventilatory support, epinephrine, management of coagulopathy and tolazoline were all found to be effective primary treatments for PH. There are several effective methods of managing PH in neonates. Further understanding of the aetiology of PH and ongoing research will allow future prevention and improvements in management of PH.

Impact of High-Frequency Oscillatory Ventilation Combined With Volume Guarantee on Lung Inflammatory Response in Infants With Acute Respiratory Distress Syndrome After Congenital Heart Surgery: A Randomized Controlled Trial

Congenital heart disease (CHD) after cardiopulmonary bypass can cause systemic inflammation, and its degree is closely related to the incidence of acute respiratory distress syndrome (ARDS). The purpose of this study was to determine the effectiveness of high-frequency oscillatory ventilation (HFOV) combined with volume guarantee (VG) in reducing systemic inflammation in infants with ARDS after cardiopulmonary bypass for congenital heart surgery. A randomized controlled trial. Single-center study in a tertiary teaching hospital. A total of 58 infants with ARDS after congenital heart surgery were eligible and were randomized to the HFOV (n = 29) or the HFOV-VG (n = 29) between January 2020 and January 2021. Tracheal aspirate samples for the measurement of interleukin (IL)-6, IL-8, and tumor necrosis factor-α (TNF-α) were obtained on days one, two, and three of HFOV or HFOV-VG ventilation. The authors found a significantly increasing trend in the HFOV group mean values of IL-6, IL-8, and TNF-α (p < 0.05 on days two and three v day one), and IL-6, IL-8, and TNF-α levels were significantly higher on day three in the HFOV group versus the HFOV+VG group (p < 0.05). In addition, the incidences of hypocapnia and hypercapnia in infants supported with HFOV-VG were significantly lower (p < 0.05). Furthermore, the postoperative mechanical ventilation duration in the HFOV-VG group also was shorter than that in the HFOV group (p < 0.05). Compared with HFOV alone, HFOV-VG reduced proinflammatory systemic reactions after congenital cardiac surgery, decreased the incidences of hypercapnia and hypocapnia, and shortened the postoperative mechanical ventilation duration.

A narrative review of advanced ventilator modes in the pediatric intensive care unit.

Respiratory failure is a common reason for pediatric intensive care unit admission. The vast majority of children requiring mechanical ventilation can be supported with conventional mechanical ventilation (CMV) but certain cases with refractory hypoxemia or hypercapnia may require more advanced modes of ventilation. This paper discusses what we have learned about the use of advanced ventilator modes [e.g., high-frequency oscillatory ventilation (HFOV), high-frequency percussive ventilation (HFPV), high-frequency jet ventilation (HFJV) airway pressure release ventilation (APRV), and neurally adjusted ventilatory assist (NAVA)] from clinical, animal, and bench studies. The evidence supporting advanced ventilator modes is weak and consists of largely of single center case series, although a few RCTs have been performed. Animal and bench models illustrate the complexities of different modes and the challenges of applying these clinically. Some modes are proprietary to certain ventilators, are expensive, or may only be available at well-resourced centers. Future efforts should include large, multicenter observational, interventional, or adaptive design trials of different rescue modes (e.g., PROSpect trial), evaluate their use during ECMO, and should incorporate assessments through volumetric capnography, electric impedance tomography, and transpulmonary pressure measurements, along with precise reporting of ventilator parameters and physiologic variables.

Performance of acute respiratory distress syndrome definitions in a high acuity paediatric intensive care unit

BackgroundFor years, paediatric critical care practitioners used the adult American European Consensus Conference (AECC) and revised Berlin Definition (BD) for acute respiratory distress syndrome (ARDS) to study the epidemiology of paediatric ARDS (PARDS). In 2015, the paediatric specific definition, Paediatric Acute Lung Injury Consensus Conference (PALICC) was developed. The use of non-invasive metrics of oxygenation to stratify disease severity were introduced in this definition, although this potentially may lead to a confounding effect of disease severity since it is more common to place indwelling arterial lines in sicker patients. We tested the hypothesis that PALICC outperforms AECC/BD in our high acuity PICU, which employs a liberal use of indwelling arterial lines and high-frequency oscillatory ventilation (HFOV).MethodsWe retrospectively collected data from children < 18 years mechanically ventilated for at least 24 h in our tertiary care, university-affiliated paediatric intensive care unit. The primary endpoint was the difference in the number of PARDS cases between AECC/BD and PALICC. Secondary endpoints included mortality and ventilator free days. Performance was assessed by the area under the receiver operating characteristics curve (AUC-ROC).ResultsData from 909 out of 2433 patients was eligible for analysis. AECC/BD identified 35 (1.4%) patients (mortality 25.7%), whereas PALICC identified 135 (5.5%) patients (mortality 14.1%). All but two patients meeting AECC/Berlin criteria were also identified by PALICC. Almost half of the cohort (45.2%) had mild, 33.3% moderate and 21.5% severe PALICC PARDS at onset. Highest mortality rates were seen in patients with AECC acute lung injury (ALI)/mild Berlin and severe PALICC PARDS. The AUC-ROC for Berlin was the highest 24 h (0.392 [0.124–0.659]) after onset. PALICC showed the highest AUC-ROC at the same moment however higher than Berlin (0.531 [0.345–0.716]). Mortality rates were significantly increased in patients with bilateral consolidations (9.3% unilateral vs 26.3% bilateral, p = 0.025).ConclusionsPALICC identified more new cases PARDS than the AECC/Berlin definition. However, both PALICC and Berlin performed poorly in terms of mortality risk stratification. The presence of bilateral consolidations was associated with a higher mortality rate. Our findings may be considered in future modifications of the PALICC criteria.

A rare case of persistent fetal intestinal hyperechogenicity – Question

A 24-year-old pregnant woman with an in vitro fertilization (IVF)-assisted pregnancy was examined at 12 weeks of gestation with a fetal ultrasound showing intestinal hyperechogenicity. The maternal anamnesis revealed 3 previous miscarriages, 2 due to ectopic pregnancies. Fetal karyotype and screening for cystic fibrosis performed on both parents were normal. Another ultrasound examination at 27 weeks showed fetal intestinal and gastric dilation and moderate polyhydramnios. The day before delivery, an ascitic effusion was found, not associated with pleural or pericardial effusion. At 29 weeks and 6 days of gestation, an emergency cesarean section was performed for absent variability of the cardiotocographic tracing. The female newborn birth weight was 1,390 g. Apgar scores were 5 at 1 minute and 7 at 5 minutes. The patient was intubated in the Delivery Room and remained on mechanical ventilation until she was transferred to the Neonatal Intensive Care Unit (NICU), then she was ventilated in high-frequency oscillatory ventilation (HFOV). At the time of admission to the NICU, in addition to severe respiratory insufficiency (the saturation was at the lower limits, with FiO2 = 1), at the clinical examination she had moderate pale skin and globose abdomen with generalized tenderness. The nasogastric tube was positioned correctly, and 6 ml of gastric fluid mixed with blood were aspirated. It was possible to insert the rectal tube only for 1.5 cm. To better understand the case, anteroposterior (AP) and translateral chest-abdomen X-rays were performed. 1. What do you see in these X-rays? 2. Which further investigations would you suggest? 3. What is your diagnosis?

In silico numerical simulation of ventilator settings during high-frequency ventilation in preterm infants.

Despite the routine use of antenatal steroids, exogenous surfactants, and different noninvasive ventilation methods, many extremely low gestational age neonates, preterm, and term infants eventually require invasive ventilation. In addition to prematurity, mechanical ventilation itself can induce ventilator-induced lung injury leading to lifelong pulmonary sequelae. Besides conventional mechanical ventilation, high-frequency oscillatory ventilation (HFOV) with tidal volumes below dead space and high ventilation frequencies is used either as a primary or rescue therapy in severe neonatal respiratory failure. Applying a high-resolution computational lung modeling technique in a preterm infant, we studied three different high-frequency ventilation settings as well as conventional ventilation (CV) settings. Evaluating the computed oxygen delivery (OD) and lung mechanics (LM) we outline for the first time how changing ventilator settings from CV to HFOV lead to significant improvements in OD and LM. This personalized "digital twin" strategy advances our general knowledge of protective ventilation strategies in neonatal care and can support decisions on various modes of ventilatory therapy at high frequencies.

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.

Nasal High-Frequency Oscillatory Ventilation vs. Nasal Continuous Positive Airway Pressure as Therapy for Postextubation Respiratory Failure in Infants After Congenital Heart Surgery.

Objective: This study aimed to evaluate the effects of nasal high-frequency oscillatory ventilation (NHFOV) vs. nasal continuous positive airway pressure (NCPAP) on postextubation respiratory failure (PRF) in infants after congenital heart surgery (CHS).Method: Eighty infants underwent postoperative invasive mechanical ventilation for more than 12 h and planned extubation. The infants were randomized to undergo either NHFOV or NCPAP after extubation. Primary outcomes were the incidence of PRF and reintubation, the average PaCO2 level, the average oxygenation index (OI), and pulmonary recruitment in the early extubation phase. Secondary outcomes included the NCPAP/NHFOV time, length of hospital stay, treatment intolerance, signs of discomfort, pneumothorax, adverse hemodynamic effects, nasal trauma, and mortality.Results: Except for PaCO2 within 12 after extubation (39.3 ± 5.8 vs. 43.6 ± 7.3 mmHg, p = 0.05), there was no statistically significant difference for any of the primary outcome measure (PRF, reintubation within 12 h after extubation, oxygenation index within 12 h after extubation, or lung volumes on X-ray after extubation) or secondary outcome measures (duration of non-invasive ventilation, duration of hospital stay, ventilation intolerance, signs of discomfort, pneumothorax, nasal trauma, adverse hemodynamic effects, or death prior to discharge), p > 0.1 for each comparison.Conclusion: NHFOV therapy after extubation in infants after CHS was more efficient in improving CO2 cleaning than NCPAP therapy, but there was no difference in other outcomes (PRF, reintubation, oxygenation index, and pulmonary recruitment).

Comparison Between Nasal High-Frequency Oscillatory Ventilation And Nasal Continuous Positive Airway Pressure In The Management Of Respiratory Distress Syndrome

Context: A neonatal respiratory distress syndrome occurs at or soon after delivery (<24 hours). Premature newborns with respiratory distress syndrome (RDS) often need breathing assistance. There has been a tendency to reduce in the previous decade the use of non-invasive ventilation modes (NIV) in neonatal intensive care units to prevent ventilator-induced lung damage, in particular after recent data showing NIV in preterm babies has equivalent efficiency compared to EMV. In practical practise, different forms of NIV may be employed include nasal continuing positive airway pressure and noninvasive intermittent positive airway pressure. Nasal continuous positive airway pressure is one of the most often utilised non-invasive techniques (NCPAP). Although HFV has been used in several neonatal critical care units, a relatively novel modality of nasal high frequency oscillatory ventilation (nHFOV) is limited in evidence of its utility. The objective of this research has been to examine the effectiveness and safety of nasal oscillatory ventilation with nasal airway continuous pressure in preterm baby respiratory distress syndrome therapy. Methods: This research is a (60 instances) clinical experiment conducted with respiratory distress syndrome (admitted to the Benha University Hospital Neonatal Intensive Care Unit and Benha Kids Hospital) between the 1–28 day age range. Cases were randomly picked in two groups: Group I: 30 instances of high-frequency oscillatory nasal ventilation were treated (nHFOV). Group II: 30 individuals with constant nasal airway pressure were treated (NCPAP). Methods: Detailed history of medicine. Total usage time NHFV and NCPAP usage time and oxygenation time required for each instance. Complication detection occurs during non-invasive breathing (pulmonary air leak syndrome, IVH, nasal injury and other.) Studies of imagery. Outcomes: There was no statistically significant difference in demographic data between the two groups. There was a statistically significant difference in IVH complication between Group I and Group II. The percentage of nasal septal injuries in Group I was significantly lower than in Group II. The rate of intervention failure (intubing and ventilator demand) in Group I was significantly lower than in Group II (3.3 percent, (26.6 percent) p value=0.030. Conclusion: High frequency nasal ventilation has a greater impact than continuous airway pressure on infants and is less complicated. This research revealed that the length of non-invasive respiratory support was greatly shortened by high frequency nasal ventilation and the necessity for intubation was minimised compared to the continuous positive airway pressure of RDS infants.

Effect of High-Frequency Oscillatory Ventilation Combined With Pulmonary Surfactant in the Treatment of Acute Respiratory Distress Syndrome After Cardiac Surgery: A Prospective Randomised Controlled Trial.

Background: This study aimed to evaluate the effects of pulmonary surfactant (PS) combined with high-frequency oscillatory ventilation (HFOV) or conventional mechanical ventilation (CMV) in infants with acute respiratory distress syndrome (ARDS) after congenital cardiac surgery.Methods: A total of 61 infants with ARDS were eligible and were randomised to the CMV + PS group (n = 30) or the HFOV + PS group (n = 31) between January 2020 and December 2020. The primary outcomes were the changes in arterial blood gas parameters. The duration of mechanical ventilation, length of hospitalisation and the incidence of complications were considered secondary outcomes.Results: A total of 61 infants completed the study. In the HFOV + PS group, the blood gas analysis results were significantly improved (P < 0.05), while the duration of mechanical ventilation and length of hospitalisation were shorter than the CMV + PS group (P < 0.05). However, the incidence of complications was not different between the two groups (P > 0.05).Conclusions: Compared with the CMV + PS group, the HFOV + PS group showed significantly improved ABG variables and had a shortened length of hospitalisation and mechanical ventilation in infants with ARDS after cardiac surgery.Clinical Trial Registration: Chinese Clinical Trial Registry; Number: ChiCTR2000039457.

Operating Within the Neonatal Intensive Care Unit: A Retrospective Analysis From a Tertiary Care Center.

BackgroundDespite ongoing advances in the field of neonatology, the survival outcomes among critically ill preterm surgical neonates remain unfavorable. Intrahospital transport is one of the major risk factors associated with early mortality (within 30 days) in these newborns. To overcome this, the approach of performing bedside surgeries is being followed. We aim to assess the safety and feasibility of performing bedside neonatal surgeries by analyzing our archives.MethodsThe study focused on retrospective evaluation of all the newborns who have undergone surgical procedures in the neonatal intensive care unit (NICU) at our center from August 2015 through February 2021. Newborns were operated within the NICU if they had very low birth weight or other risk factors making their transport to the operation room risky. The outcomes of surgeries were assessed in terms of postoperative complications, one-month survival, and overall survival.ResultsThirteen children (M:F=9:4) underwent twenty-two surgical procedures. The median (range) gestational age and birth weight of our cohort were 30 (26-36) weeks and 1200 (500-2860) grams, respectively. One-month and overall survival rates in our cohort were 84% (11/13) and 77% (10/13), respectively. No major postoperative complications were observed. The requirement of multiple inotropes and/or high-frequency oscillatory ventilation (HFOV) was the only factor having a significant association with unfavorable survival outcomes.ConclusionsBedside surgery is a safe and feasible alternative to surgeries within the operation room for at-risk newborns. In the present study, the requirement of multiple inotropes and/or HFOV was the only factor significantly associated with early mortality.

Çocuk yoğun bakım ünitesindeki akut solunum sıkıntısı sendromu vakalarının değerlendirilmesi

Purpose: The aim of this study was to evaluate the lung-protective mechanical ventilation strategy, early enteral nutrition, negative fluid balance, and adequacy of hospital resources in our pediatric intensive care unit.&#x0D; Materials and Methods: This study included 32 patients who developed acute respiratory distress syndrome (ARDS) during their monitoring in the pediatric intensive care unit.&#x0D; Results: According to their oxygenation status, 14 patients (43.8%) had mild ARDS, nine patients (28.1%) had moderate ARDS, and nine patients (28.1%) had severe ARDS. High-frequency oscillatory ventilation was applied to three patients (9.3%), and four patients (12.5%) received extracorporeal membrane oxygenation (ECMO) support. The most common complications were nosocomial infection (31.3%) and pneumothorax (12.5%). The mortality rate was 6.3%. The survival rate was 75.0% in patients with ECMO support. The patients with a higher Pediatric Index of Mortality (PIM-2) score confronted more severe ARDS, and non-pulmonary ARDS also progressed in advanced stages.&#x0D; Conclusion: In patients with high PIM-2 and PELOD scores, attention must be given to the development of severe ARDS. The lung-protective mechanical ventilation support, early enteral nutrition, negative fluid balance practices, and the adequacy of hospital resources led to a successful survival rate in our study. However, multicenter randomized controlled trials are needed on this subject.

Time to Lung Volume Stability After Pressure Change During High-Frequency Oscillatory Ventilation.

Prospective observational study. Regional quaternary teaching hospital neonatal ICU. Thirteen term or near-term infants receiving high-frequency oscillatory ventilation and muscle relaxants. One to two cm H2O mean airway pressure changes every 10 minutes as part of an open lung strategy based on oxygen response. Continuous lung volume measurements (respiratory inductive plethysmography) were made during the mean airway pressure changes. Volume signals were analyzed with a biexponential model to calculate the time to stable lung volume if the model R 2 was greater than 0.6. If volume stability did not occur within 10 minutes, the model was extrapolated to maximum 3,600 s. One-hundred ninety-six mean airway pressure changes were made, with no volume change in 33 occurrences (17%). One-hundred twenty-five volume signals met modeling criteria for inclusion; median (interquartile range) R 2, 0.96 (0.91-0.98). The time to stable lung volume was 1,131 seconds (718-1,959 s) (mean airway pressure increases) and 647 seconds (439-1,309 s) (mean airway pressure decreases), with only 17 (14%) occurring within 10 minutes and time to stability being longer when the lung was atelectatic. During high-frequency oscillatory ventilation, the time to stable lung volume after a mean airway pressure change is variable, often requires more than 10 minutes, and is dependent on the preceding volume state.

Target volume-guarantee in high-frequency oscillatory ventilation for preterm respiratory distress syndrome: Low volumes and high frequencies lead to adequate ventilation.

Respiratory distress syndrome (RDS) and ventilation-induced lung injury lead to significant morbidity in preterm infants. High-frequency oscillatory ventilation with volume-guarantee (HFOV-VG) has been used as a rescue therapy and might lead to lower rates of death and bronchopulmonary dysplasia, especially when using low tidal volumes and high frequencies. The aim of the study was to define HFOV-VG parameters leading to adequate ventilation in the first 72 h of preterm RDS using a low volume and high-frequency strategy. Retrospective cohort study in a tertiary-level neonatology unit. Infants <32 weeks with severe respiratory insufficiency needing HFOV-VG were included. Patients were ventilated following a standard mechanical ventilation aiming for low tidal volumes and high frequencies. Clinical data, perinatal characteristics and high-frequency parameters corresponding with adequate ventilation were recorded. 116 patients were included. Median gestational age was 25 weeks (interquartile range [IQR] = 24-27), median birth weight 724 g(IQR = 600-900 g). HFOV-VG was started at 2 h, median high-frequency tidal volume was 1.63 ml/kg (IQR = 1.44-1.84) and median frequency was 16 Hz (IQR = 15-18). Weight-adjusted tidal volumes did not depend on gestational age, antenatal corticosteroids nor chorioamnionitis, and were inversely correlated with frequencies (R 2 = -0.10, p = .001). HFOV-VG can reach adequate ventilation at high frequencies when using adequate volumes, providing a feasible ventilation strategy that might be of help in preterm infants with RDS.

Paediatrics: how to manage acute respiratory distress syndrome.

BackgroundAcute respiratory distress syndrome (ARDS) is a significant cause of mortality and morbidity amongst critically ill children. The purpose of this narrative review is to provide an up-to-date review on the evaluation and management of paediatric ARDS (PARDS).MethodsA PubMed search was performed with Clinical Queries using the key term “acute respiratory distress syndrome”. The search strategy included clinical trials, meta-analyses, randomized controlled trials, observational studies and reviews. Google, Wikipedia and UpToDate were also searched to enrich the review. The search was restricted to the English literature and children.DiscussionNon-invasive positive pressure ventilation, lung-protective ventilation strategies, conservative fluid management and adequate nutritional support all have proven efficacy in the management of PARDS. The Pediatric Acute Lung Injury Consensus Conference recommends the use of corticosteroids, high-frequency oscillation ventilation and inhaled nitric oxide in selected scenarios. Partial liquid ventilation and surfactant are not considered efficacious based on evidence from clinical trials.ConclusionPARDS is a serious but relatively rare cause of admission into the paediatric intensive care unit and is associated with high mortality. Non-invasive positive pressure ventilation, lung-protective ventilation strategies, conservative fluid management and adequate nutrition are advocated. As there has been a lack of progress in the management of PARDS in recent years, further well-designed, large-scale, randomized controlled trials in this field are urgently needed.