High-frequency Oscillatory Ventilation Research Articles

Reevaluation of the high frequency oscillatory ventilation strategy

Reevaluation of the high frequency oscillatory ventilation strategy

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.

Noninvasive High-Frequency Oscillatory Ventilation vs Nasal Continuous Positive Airway Pressure vs Nasal Intermittent Positive Pressure Ventilation as Postextubation Support for Preterm Neonates in China

Several respiratory support techniques are available to minimize the use of invasive mechanical ventilation (IMV) in preterm neonates. It is unknown whether noninvasive high-frequency oscillatory ventilation (NHFOV) is more efficacious than nasal continuous positive airway pressure (NCPAP) or nasal intermittent positive pressure ventilation (NIPPV) in preterm neonates after their first extubation. To test the hypothesis that NHFOV is more efficacious than NCPAP or NIPPV in reducing IMV after extubation and until neonatal intensive care unit discharge among preterm neonates. This multicenter, pathophysiology-based, assessor-blinded, 3-group, randomized clinical trial was conducted in 69 tertiary referral neonatal intensive care units in China, recruiting participants from December 1, 2017, to May 31, 2021. Preterm neonates who were between the gestational age of 25 weeks plus 0 days and 32 weeks plus 6 days and were ready to be extubated were randomized to receive NCPAP, NIPPV or NHFOV. Data were analyzed on an intention-to-treat basis. The NCPAP, NIPPV, or NHFOV treatment was initiated after the first extubation and lasted until discharge. Primary outcomes were total duration of IMV, need for reintubation, and ventilator-free days. These outcomes were chosen to describe the effect of noninvasive ventilation strategy on the general need for IMV. A total of 1440 neonates (mean [SD] age at birth, 29.4 [1.8] weeks; 860 boys [59.7%]) were included in the trial. Duration of IMV was longer in NIPPV (mean difference, 1.2; 95% CI, 0.01-2.3 days; P = .04) and NCPAP (mean difference, 1.5 days; 95% CI, 0.3-2.7 days; P = .01) compared with NHFOV. Neonates who were treated with NCPAP needed reintubations more often than those who were treated with NIPPV (risk difference: 8.1%; 95% CI, 2.9%-13.3%; P = .003) and NHFOV (risk difference, 12.5%; 95% CI, 7.5%-17.4%; P < .001). There were fewer ventilator-free days in neonates treated with NCPAP than in those treated with NIPPV (median [25th-75th percentile] difference, -3 [-6 to -1] days; P = .01). There were no differences between secondary efficacy or safety outcomes, except for the use of postnatal corticosteroids (lower in NHFOV than in NCPAP group; risk difference, 7.3%; 95% CI, 2.6%-12%; P = .002), weekly weight gain (higher in NHFOV than in NCPAP group; mean difference, -0.9 g/d; 95% CI, -1.8 to 0 g/d; P = .04), and duration of study intervention (shorter in NHFOV than in NIPPV group; median [25th-75th percentile] difference, -1 [-3 to 0] days; P = .01). Results of this trial indicated that NHFOV, if used after extubation and until discharge, slightly reduced the duration of IMV in preterm neonates, and both NHFOV and NIPPV resulted in a lower risk of reintubation than NCPAP. All 3 respiratory support techniques were equally safe for this patient population. ClinicalTrials.gov Identifier: NCT03181958.

Ventilating the blast lung: Exploring ventilation strategies in primary blast lung injury

Introduction Primary blast lung injury (PBLI) is the most common and fatal of all primary blast injuries. The majority of those with PBLI will require early intubation and mechanical ventilation, and thus, ventilation strategy forms a crucial part of any management plan. Methods: A comprehensive, but not systematic, PubMed and Google Scholar database search identified articles that contribute to our current understanding of ventilation strategies in PBLI for a narrative educational review. Results A PBLI ventilation strategy must strive to minimise all four of ventilator-associated lung injury (VALI), volutrauma, barotrauma and biotrauma. The three main ventilation strategies available are conventional low tidal volume (LTV) ventilation, airway pressure release ventilation (APRV) and high frequency oscillatory ventilation (HFOV). Conventional LTV ventilation together with a variable positive end-expiratory pressure (PEEP) and permissive hypercapnia has demonstrated reduced inflammation and mortality with a greater number of ventilator-free days. APRV has the potential to reduce dynamic strain, PaO2/FiO2 ratios, levels of applied mechanical power and extravascular lung water while encouraging spontaneous breathing. HFOV is able to effectively avoid VALI while curbing inflammation and histological lung injury, though not necessarily mortality. Conclusions: Presently, PBLI should largely be managed with conventional LTV ventilation alongside a variable PEEP and permissive hypercapnia with APRV and HFOV reserved as rescue strategies for where conventional LTV ventilation fails. Clinicians should additionally consider supplementing their strategy with adjunctive therapies such as prone positioning, inhaled nitric oxide and extracorporeal membrane oxygenation that may further reduce mortality and combat severe respiratory and/or cardiac 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.

Effects of High-Frequency Oscillatory Ventilation With Volume Guarantee During Surfactant Treatment in Extremely Low Gestational Age Newborns With Respiratory Distress Syndrome: An Observational Study.

ObjectiveTo evaluate the effect of volume guarantee (VG) combined with high-frequency oscillatory ventilation (HFOV) on respiratory and other physiological parameters immediately after lung recruitment and surfactant administration in HFOV elective ventilated extremely low gestational age newborns (ELGAN) with respiratory distress syndrome (RDS).DesignObservational study.SettingTertiary neonatal intensive care unit.PatientsTwenty-two ELGANs of 25.5 ± 1.1 weeks of gestational age requiring invasive mechanical ventilation and surfactant administration for RDS during the first 6 h of life.InterventionsAll infants intubated in delivery room, were managed with elective HFOV and received surfactant after a lung recruitment manoeuver. Eleven infants received HFOV + VG and were compared with a control group of 11 infants receiving HFOV alone. HFOV was delivered in both groups by Dräger Babylog VN500 ventilator (Dräger, Lubeck, Germany).Main Outcome MeasuresVariations and fluctuations of delivered high-frequency tidal volume (VThf), fluctuation of pressure amplitude (ΔP) and partial pressure of CO2 (pCO2) levels after recruitment manoeuver and immediately after surfactant administration, in HFOV + VG vs. HFOV ventilated infants.ResultsThere were no significant differences in the two groups at starting ventilation with or without VG. The mean applied VThf per kg was 1.7 ± 0.3 ml/kg in the HFOV group and 1.7 ± 0.1 ml/kg in the HFOV + VG group. Thirty minutes after surfactant administration, HFOV group had a significant higher VThf/Kg than HFOV + VG (2.1 ± 0.3 vs. 1.6 ± 0.1 ml/kg, p < 0.0001) with significantly lower pCO2 levels (43.1 ± 3.8 vs. 46.8 ± 1.5 mmHg, p = 0.01), 54.4% of patients having pCO2 below 45 mmHg. Measured post-surfactant ΔP values were higher in HFOV group (17 ± 3 cmH2O) than in HFOV + VG group (13 ± 3 cmH2O, p = 0.01).ConclusionHFOV + VG maintains pCO2 levels within target range and reduces VThf delivered variations more consistently than HFOV alone after surfactant administration.

Tidal volume significantly affects oxygenation in healthy pigs during high-frequency oscillatory ventilation compared to conventional ventilation

BackgroundThe 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.MethodsTo 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.ResultsChanges 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.ConclusionA 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.

Conventional mechanical ventilation versus high-frequency oscillatory ventilation in congenital diaphragmatic hernia of neonates: a systematic review

Background: Neonates with congenital diaphragmatic hernia (CDH) present with respiratory distress and circulatory insufficiency, requiring immediate intubation and mechanical ventilation. Studies in the literature present contradictory results regarding the optimal ventilation mode for neonates with congenital diaphragmatic hernia. We present a systematic review of the selected literature regarding high-frequency oscillatory ventilation (HFOV) compared to conventional mechanical ventilation (CMV) in congenital diaphragmatic hernia.&#x0D; Methodology: PubMed, SCOPUS, EBSCOhost, and ProQuest databases were used to identify literature regarding HFOV compared to CMV in a CDH. The methodological quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS) for cohort studies and the Joanna Briggs Institute critical appraisal tool for randomized clinical trials.&#x0D; Results: Four studies were identified and considered eligible for the study. One study was a randomized clinical trial, and the other three cohort studies. Patients in the high-frequency oscillatory (HFO) group presented with a higher length of ventilation and hospital stay. There was a lack of evidence regarding any significant difference in the mortality rate.&#x0D; Conclusion: We cannot make an evidence-based recommendation regarding the superiority of either CMV or HFOV as the optimal ventilation method in neonates with CDH. However, almost all studies observed a lengthened period of ventilation and time required before surgical repair in the HFOV group.&#x0D; Abbreviations: CDH: congenital diaphragmatic hernia; CLD: chronic lung disease; CMV: conventional mechanical ventilation; GER: gastroesophageal reflux; HFOV: high-frequency oscillatory ventilation; NOS: Newcastle-Ottawa Scale; RDS: respiratory distress syndrome&#x0D; Key words: Congenital Diaphragmatic Hernia; Conventional Mechanical Ventilation; High-Frequency Oscillatory Ventilation&#x0D; Citation: Kapuangan C, Ramlan AAW, Zahra R, Rahendra, Soenarto RF, Hanawi E. Conventional mechanical ventilation versus high-frequency oscillatory ventilation in congenital diaphragmatic hernia of neonates: a systematic review. Anaesth. pain intensive care 2022;26(6):000−000 ; DOI: 10.35975/apic.v26i6.2048

Conventional vs high-frequency ventilation for weaning from total liquid ventilation in lambs

ObjectiveTo compare conventional gas ventilation (GV) and high-frequency oscillatory ventilation (HFOV) for weaning from total liquid ventilation (TLV). MethodsSixteen lambs were anesthetized. After 1 h of TLV with perflubron (PFOB), they were assigned to either GV or HFOV for 2 h. Oxygen requirements, electrical impedance tomography and videofluoroscopic sequences, and respiratory system compliance were recorded. ResultsThe lambs under GV needed less oxygen at 20 min following TLV (40 [25, 45] and 83 [63, 98]%, p = 0.001 under GV and HFOV, respectively). During weaning, tidal volume distribution was increased in the nondependent regions in the GV group compared to baseline (p = 0.046). Furthermore, residual PFOB was observed in the most dependent region. No air was detected by fluoroscopy in that region at the end of expiration in the GV group. ConclusionGV offers a transient advantage over HFOV with regards to oxygenation for TLV weaning.

Abstract TP138: Prevalence And Risk Factors Associated With Cerebral Microbleeds In Patients With Acute Respiratory Distress Syndrome

Introduction: Acute respiratory distress syndrome (ARDS) is associated with pulmonary vascular endothelial injury. Cerebral microbleeds (CMB) have been reported in patients with critical illness such as ARDS, particularly involving the splenium of the corpus callosum and immediate subcortical white matter. We aimed to examine the prevalence and risk factors of CMB in ARDS. Methods: We reviewed patient data from an ARDS registry at a tertiary medical center from January 2010 to October 2018. Patients were excluded if MRI imaging was motion degraded or did not include susceptibility weighted imaging (SWI) or T2*weighted gradient echo sequences. CMB were defined as hypointense SWI or T2* lesions &lt;5 mm. Microbleeds were labeled as diffuse if there were ≥10 present in a region. ARDS rescue therapies included extracorporeal membrane oxygenation, inhaled vasodilators, recruitment maneuvers, high frequency oscillatory ventilation, neuromuscular blockade, and proning. Univariate analysis was performed to examine association with CMB. Results: Of the 678 patients with ARDS, 61 had MRI’s meeting inclusion criteria. CMB were present in 12 patients, with median age 62.5 years. Ten patients had lobar CMB, of which 4 were diffuse and also involved the cerebellum. There were 3 patients with CMB in the corpus callosum, all involving the splenium, of which 2 were diffuse among patients who had diffuse lobar involvement. Acute Physiology and Chronic Health Evaluation III and Sequential Organ Failure Assessment scores did not differ between those with and without CMB, but ARDS rescue therapies were more commonly used in patients with CMB (66.7% vs 22.4%, p=.003). CMB was associated with acute cerebral ischemia on MRI (41.7% with CMB vs 10.2% without CMB, p=.008). Conclusions: CMB are common in ARDS, mostly involving the cerebral lobes and cerebellum. CMB might be associated with ARDS rescue therapies and higher risk for ischemic infarcts.

Non-invasive High-Frequency Oscillatory Ventilation as Initial Respiratory Support for Preterm Infants With Respiratory Distress Syndrome.

Objectives: The aim of this study was to investigate the safety and feasibility of nHFOV as initial respiratory support in preterm infants with RDS.Methods: This study retrospectively analyzed the clinical data of 244 premature infants with RDS who were treated in our hospital from January 2016 to January 2019 and divided into the nHFOV group (n = 115) and the BiPAP group (n = 129) based on the initial respiratory support method.Results: Respiratory outcomes showed that the rate of NIV failure during the first 72 hours of life in the nHFOV group was significantly lower than that in the BiPAP group. The time of NIV in the nHFOV group was significantly shorter than that in the BiPAP group. The time of supplemental oxygen in the nHFOV group was significantly shorter than that in the BiPAP group. The incidence of air leakage syndrome in the nHFOV group was significantly lower than that in the BiPAP group, and the length of hospital stay of the nHFOV group was also significantly shorter than that in the BiPAP group. Although the rate of infants diagnosed with BPD was similar between the two groups, the rate of severe BPD in the nHFOV group was significantly lower than that in the BiPAP group.Conclusion: This study showed that nHFOV as initial respiratory support for preterm infants with RDS was feasible and safe compared to BiPAP. Furthermore, nHFOV can reduce the need for IMV and reduce the incidence of severe BPD and air leak syndrome.

Association between the IL-6 polymorphisms and coal workers’ pneumoconiosis in a Chinese Hui population

ObjectiveTo determine whether polymorphisms in IL-6 and IL-12 contribute to the etiology of coal workers’ pneumoconiosis (CWP) in a Chinese Hui population, and to evaluate the efficacy and safety of high frequency oscillatory ventilation (HFOV) in the treatment of CWP.IntroductionGenes and the environments interplay in the development of CWP, and the association between the potential functional polymorphisms in many genes and CWP have been reported.MethodsWe genotyped the IL-6-634C/G (rs1800796) and IL-12B-1188A/C (rs3212227) polymorphisms in a case-control study including 160 CWP patients and 150 dust-exposed control subjects of Chinese Hui population, and analyzed the associations between these genetic variants and CWP risk. We also evaluated the efficacy and safety of HFOV for whole lung lavage (WLL) in the treatment of CWP.ResultsCarrying the C allele of IL-6-634C/G (rs1800796) was associated with decreased risk of CWP ( p &lt; 0.05). No significant differences in allele or genotype frequencies of IL-12B-1188A/C was found between the CWP cases and control subjects ( p &gt; 0.05). Compared with CWP patients with routine WLL, CWP patients received HFOV showed better pulmonary functions. HFOV treatment also yield a significant higher efficient rate (97.50%) than WLL treatment (81.25%, p = 0.001). CWP patients receiving HFOV and WLL treatment both showed significantly increased serum contents of Clara cell protein 16 (CC16) and superoxide dismutase (SOD), and decreased serum contents of serum malonaldehyde (MDA). While the increasing of CC16 and SOD, and decreasing of MDA in patients receiving HFOV was more noticeable than patients receiving WLL.ConclusionsTaking together, the −634C/G polymorphisms in IL-6 play a role in the etiology of CWP. HFOV, when applied in CWP patients, significant improves their pulmonary functions.

Parvovirus B19 Intrauterine Infection and Eventration of the Diaphragm

Parvovirus B19 infection in pregnancy may have a poor outcome for the fetus. Ocular anomalies, brain damage with hydrocephalus and central nervous system (CNS) scarring, cleft lip and hypospadias, as well myocarditis and congenital heart disease have been reported. We present a case of a preterm female neonate born with ascites, hydrothorax and congenital diaphragmatic eventration (CDE), with a prenatal diagnosis of congenital diaphragmatic hernia (CDH). The neonate was born prematurely at 32 weeks gestation with caesarean section due to a previous caesarean delivery. She was immediately intubated in the delivery room, transferred in the Neonatal Intensive Care Unit (NICU) and supported with high frequency oscillatory ventilation (HFOV). The diagnosis of CDH was sonographically estimated from the 20th week of gestation and surgical correction was decided. During surgery CDE was diagnosed instead of CDH and despite postoperatively care the neonate developed disseminated intravascular coagulation and finally died in the 40th hour of life. Along with the identification of parvovirus B19 in the pleural fluid by PCR, the biopsy of the diaphragm revealed connective tissue, full of vasculature and absence muscle tissue. Although only cytomegalovirus, rubella, and toxoplasmosis were considered to be associated with CDE, parvovirus B19 might also be related to this congenital diaphragmatic malformation. In CDE, the function of the lungs can be compromised as a consequence of the compression applied by the abdominal organs. The neonatologists should include this condition in their differential diagnosis for a more direct and effective management.

Severe Bronchiolitis as a Cause of ARDS in Early Childhood. Pathophysiology and Strategies to Minimize Lung Injury

Bronchiolitis is one of the most frequent acute diseases of the lower respiratory tract in infants worldwide, and Respiratory Syncytial Virus remains the most common and aggressive viral disease. The course of the disease is usually benign, but its severity may change by evolving into parenchymal disease. In the more severe cases, its clinical and radiological characteristics may be consistent with acute respiratory distress syndrome. Management of these cases includes admission to paediatric intensive care and invasive mechanical ventilation. This paper reviews the definition of paediatric and neonatal acute respiratory distress syndrome, which was primarily designed and validated for adults. The article investigates the pathophysiology of paediatric acute respiratory distress syndrome further, describing how damage to the alveolar-capillary units, surfactant inactivation and inflammation occurs. Mechanisms that contribute to acute lung injury, such as volutrauma, barotrauma, stress and strain, are illustrated in detail, and an overview of the strategies that may help minimize neonatal lung injury and optimize ventilatory support is provided. These strategies include lung-protective mechanical ventilation, surfactant treatment, inhaled nitric oxide, high frequency oscillatory ventilation, recruiting manoeuvres, prone position and neuromuscular blocking agents. The objective is to help clinicians understand the peculiar pathophysiology of severe bronchiolitis and so guide them in preventing or attenuating lung injury during treatment. As such, this paper aims to contribute to defining optimal treatment of severe cases of bronchiolitis.

Management of Acute Respiratory Failure: A Case Report

In an Intensive Care Unit, acute respiratory distress syndrome (ARDS) is a serious condition. Non-cardiogenic pulmonary oedema was the prior name for it. It is caused by a variety of illnesses that cause lung injury, but sepsis is the most common cause. It causes interstitial and alveolar oedema, diffuse alveolar damage, refractory hypoxemia, and ventilation perfusion mismatch by damaging the alveolar capillary membrane. Dyspnoea with diffuse in ltration on chest X-ray is a typical clinical symptom. Low tidal volume, high positive end expiratory pressure (PEEP), and low plateau pressure are all used to treat ARDS. Prone placement improves patient perfusion and thereby increases the PaO/FiO ratio. To treat ARDS, doctors are increasingly turning to high frequency oscillation ventilation (HFOV)

High-Frequency Oscillatory Ventilation as a Rescue Mode for Refractory Hypercarbia in Children

High-Frequency Oscillatory Ventilation as a Rescue Mode for Refractory Hypercarbia in Children

High-Frequency Positive Pressure Ventilation as Primary Rescue Strategy for Patients with Congenital Diaphragmatic Hernia: A Comparison to High-Frequency Oscillatory Ventilation.

The aim of this article was to evaluate high-frequency positive pressure ventilation (HFPPV) compared with high-frequency oscillatory ventilation (HFOV) as a rescue ventilation strategy for patients with congenital diaphragmatic hernia (CDH). HFPPV is a pressure-controlled conventional ventilation method utilizing high respiratory rate and low positive end-expiratory pressure. Seventy-seven patients diagnosed with CDH from January 2005 to September 2019 who were treated with stepwise progression from HFPPV to HFOV versus only HFOV were included. Fisher's exact test and the Kruskal-Wallis test were used to compare outcomes. Patients treated with HFPPV + HFOV had higher survival to discharge (80 vs. 50%, p = 0.007) and to surgical intervention (95.6 vs. 68.8%, p = 0.003), with average age at repair 2 days earlier (p = 0.004). Need for extracorporeal membrane oxygenation (p = 0.490), inhaled nitric oxide (p = 0.585), supplemental oxygen (p = 0.341), and pulmonary hypertension medications (p = 0.381) were similar. In CDH patients who fail respiratory support with conventional ventilation, HFPPV may be used as an intermediary mode of rescue ventilation prior to HFOV without adverse effects. · HFPPV may be used as an intermediary mode of rescue ventilation prior to HFOV without adverse effect.. · HFPPV is more widely available and can mitigate the limitations faced when using HFOV.. · HFPPV allows for intra- or interhospital transfer of neonates with CDH..

The clinical effects of high-frequency oscillatory ventilation in the treatment of neonatal severe meconium aspiration syndrome complicated with severe acute respiratory distress syndrome

ObjectiveTo explore the efficacy and safety of high-frequency oscillatory ventilation (HFOV) in the treatment of severe meconium aspiration syndrome (MAS) complicated with severe acute respiratory distress syndrome (ARDS).MethodsA total of 65 infants with severe MAS complicated with severe ARDS were included in the study. The clinical efficacy of treatment for the HFOV group (n = 31) and the conventional mechanical ventilation (CMV) group (n = 34) was retrospectively analysed. The partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), PaO2/fraction of inspired oxygen (FiO2), and oxygen index values before and at 6, 12, 24, 48, and 72 h after mechanical ventilation, the mechanical ventilation time, oxygen inhalation time, incidence of complications, and outcomes of the two groups were compared.ResultsAt 6, 12, 24, and 48 h after mechanical ventilation, the PaO2 in the HFOV group was significantly higher than in the CMV group, while the PaCO2 in the HFOV group was significantly lower than in the CMV group (P < 0.05). At 6, 12, 24, 48, and 72 h after mechanical ventilation, PaO2/FiO2 in the HFOV group was significantly higher than in the CMV group, and the OI in the HFOV group was significantly lower than in the CMV group (P < 0.05). Mechanical ventilation time, oxygen inhalation time, and the incidence of air leakage were significantly lower in the HFOV than in the CMV group (P < 0.05).ConclusionsOverall, HFOV can effectively improve lung ventilation and oxygenation function, shorten ventilator treatment time, and reduce the incidence rate of air leakage for neonatal MAS, making it a safe and effective treatment option.

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.