High-frequency oscillatory ventilation is an effective treatment for severe pediatric acute respiratory distress syndrome with refractory hypoxemia

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

BACKGROUND

High-frequency oscillatory ventilation (HFOV) is an alternative mechanical ventilation mode proposed to reduce ventilator-induced lung injuries and improve clinical outcomes. The aim of this study was to determine the effects of HFOV compared to conventional mechanical ventilation (CMV) when used in children with hypoxemic respiratory failure.

METHODS

The literature search was conducted to identify all studies published before December 2020. Eligible studies included a population aged between 28 days and 18 years old, presented original data from randomized controlled trials (RCTs) or observational studies, compared the use of HFOV with CMV. Meta-analyses of the pooled data were performed by using random-effects models with inverse-variance weighting.

RESULTS

A total of 11 studies (2605 cases) were included, most of them evaluating patients with acute respiratory distress syndrome. The mean age of participants was 8.2 months and the mean oxygenation index of those included in the RCTs was 24.4. The effect of HFOV on mortality was not significant, and clinically significant harm or benefit could not be excluded (risk ratio [RR], 0.93; 95% confidence interval [CI], 0.72 to 1.20). No significant difference between groups was found in duration of mechanical ventilation (-2.23; 95% CI, -5.07 to 0.61), treatment failure (RR, 0.28; 95% CI, 0.08 to 1.02), and occurrence of barotrauma (RR, 0.88; 95% CI, 0.39 to 1.99).

CONCLUSION

The scarce evidence currently available does not allow us to conclude that HFOV has advantages over CMV and further studies are needed to clarify its role in the treatment of acute hypoxemic respiratory failure in children.

Efficacy comparison of high-frequency oscillatory ventilation with continuous nasal positive airway pressure in neonatal respiratory distress syndrome treatment

OBJECTIVES

To compare the treatment efficacy of high-frequency oscillatory ventilation (HFOV) with nasal continuous positive airway pressure (NCPAP) in the treatment of neonatal respiratory distress syndrome (NRDS) and its effect on the expression of high-mobility group protein B1 (HMGB1).

METHODS

A total of 180 infants with NRDS admitted to our hospital were included and randomly assigned into the HFOV group (receiving conventional therapy and HFOV), the NCPAP group (receiving conventional therapy and NCPAP), and the conventional group (receiving conventional therapy). Qi and blood indicators, heart rate, respiratory frequency, PCO₂, and PaO₂ were observed and recorded before and after treatment, together with complications after treatment. ELISA was performed for HMGB1 Results: A distinctly lower partial pressure of carbon dioxide (PCO₂) but higher arterial partial pressure of oxygen (PaO₂) was observed in the HFOV and NCPAP groups than in the conventional group (P < 0.05), whereas infants in the HFOV group exhibited slight differences in these two indicators from their counterparts in the NCPAP group (P > 0.05). The serum HMGB1 levels in both groups were significantly higher than those in the conventional group (P < 0.05).

DISCUSSION

Both HFOV and NCPAP are feasible in the treatment of NRDS and may play a role in the inhibition of HMGB1.

HFOV vs CMV for neonates with moderate-to-severe perinatal onset acute respiratory distress syndrome (NARDS): a propensity score analysis

This study aimed to evaluate whether high-frequency oscillatory ventilation (HFOV) could reduce mortality and the incidence of bronchopulmonary dysplasia (BPD) of perinatal-onset neonatal acute respiratory distress syndrome (NARDS) compared with conventional mechanical ventilation (CMV). Medical records were collected and retrospectively analyzed. Among the 700 neonates with NARDS who needed invasive ventilation, 501 (71.6%) received CMV, while 199 (28.4%) received HFOV. One-to-one propensity score matching (127:127) was used to match the baseline characteristics of patients who received CMV and HFOV. The results showed that birth weight and oxygenation index (OI) were independently associated with mortality in the multivariate logistic regression. No significant differences were observed in mortality or the incidence of BPD between the two groups. The incidence of intraventricular hemorrhage (IVH) and ventilation-free days were significantly lower in the HFOV group than in the CMV group (3.9 vs 11.80%, p=0.02; 15.226 vs 20.967 days, p=0.01). There were no significant differences between the two groups regarding other secondary outcomes.Conclusion: HFOV was associated with a decreased incidence of IVH in infants with NARDS compared with CMV. However, there were significantly more VFDs in the CMV group than in the HFOV group, and HFOV did not appear to be superior to CMV in decreasing the mortality and incidence of BPD in infants with NARDS. What is Known: • The diagnostic criteria of neonatal acute respiratory distress syndrome (Montreux criteria) were established in 2017. • To date, studies comparing high-frequency oscillatory ventilation and conventional mechanical ventilation in the treatment of neonatal acute respiratory distress syndrome are insufficient. What is New: • High-frequency oscillatory ventilation did not appear to be superior to conventional mechanical ventilation in decreasing the mortality and incidence of bronchopulmonary dysplasia in infants with moderate-to-severe perinatal-onset neonatal acute respiratory distress syndrome. • High-frequency oscillatory ventilation was associated with a decreased incidence of intraventricular hemorrhage in infants with moderate-to-severe perinatal-onset acute respiratory distress syndrome compared with conventional mechanical ventilation.

Inflammation product effects on dilatational mechanics can trigger the Laplace instability and acute respiratory distress syndrome

In the lungs, the Laplace pressure, ΔP = 2γ/R, would be higher in smaller alveoli than larger alveoli unless the surface tension, γ decreases with alveolar interfacial area, A, such that 2ε > γ in which ε = A(dγ/dA) is the dilatational modulus. In Acute Respiratory Distress Syndrome (ARDS), lipase activity due to the immune response to an underlying trauma or disease causes single chain lysolipid concentrations to increase in the alveolar fluids via hydrolysis of double-chain phospholpids in bacterial, viral, and normal cell membranes. Increasing lysolipid concentrations decrease the dilatational modulus dramatically at breathing frequencies if the soluble lysolipid has sufficient time to diffuse off the interface, causing 2ε < γ, thereby potentially inducing the "Laplace Instability", in which larger alveoli have a lower internal pressure than smaller alveoli. This can lead to uneven lung inflation, alveolar flooding, and poor gas exchange, typical symptoms of ARDS. While the ARDS lung contains a number of lipid and protein species in the alveolar fluid in addition to lysolipids, the surface activity and frequency dependent dilatational modulus of lysolipid suggest how inflammation may lead to the lung instabilities associated with ARDS. At high frequencies, even at high lysolipid concentrations, 2ε - γ > 0, which may explain the benefits ARDS patients receive from high frequency oscillatory ventilation.

MANAGEMENT OF ACUTE RESPIRATORY DISTRESS SYNDROME IN A CHILD WITH ADENOVIRUS PNEUMONIA: CASE REPORT AND LITERATURE REVIEW

OBJECTIVE

To report the case of a child who developed acute respiratory distress syndrome (ARDS) from a pulmonary infection by adenovirus.

CASE DESCRIPTION

A female patient aged 2 years and 6 months, weighting 10,295 grams developed fever, productive cough and vomiting, later on progressing to ARDS despite initial therapy in accordance with the institutional protocol for ARDS treatment. The child evolved to refractory hypoxemia and hypercapnia, requiring high parameters of mechanical pulmonary ventilation and use of vasoactive agents. In the treatment escalation, the patient received steroids, inhaled nitric oxide (iNO), was submitted to the prone position, started oscillatory high-frequency ventilation (HFOV) and extracorporeal membrane oxygenation (ECMO) was indicated due to severe refractory hypoxemia. During this time, the patient's clinical response was favorable to HFOV, improving oxygenation index and hypercapnia, allowing the reduction of vasoactive medications and mechanical ventilation parameters, and then the indication of ECMO was suspended. The patient was discharged after 26 days of hospital stay without respiratory or neurological sequelae.

COMMENTS

Adenovirus infections occur mainly in infants and children under 5 years of age and represent 2 to 5% of respiratory diseases among pediatric patients. Although most children with adenovirus develop a mild upper respiratory tract disease, more severe cases can occur. ARDS is a serious pulmonary inflammatory process with alveolar damage and hypoxemic respiratory failure; Adenovirus pneumonia in children may manifest as severe pulmonary morbidity and respiratory failure that may require prolonged mechanical ventilation. Exclusive pulmonary recruitment and HFOV are advantageous therapeutic options.

Comparing the Effect of Incentive Spirometry with Acapella on Blood Gases in Physiotherapy After Coronary Artery Bypass Graft

Objective

To compare the effect of incentive spirometry with Acapella (Smiths Medical Inc, Carlsbad, California) in physiotherapy after coronary artery bypass surgery.

Methods

A randomized controlled trial comparing incentive spirometry with Acapella was conducted in the intensive care unit of Chaudhary Pervaiz Elahi Institute of Cardiology (CPEIC) Multan. The study began from December 2017 to August 2019 after getting approval from the ethical committee of the hospital. Informed written consent was taken from all 270 patients who were included in the study. Patients who underwent coronary artery bypass graft (CABG) were divided into two groups by the lottery method. The primary end-point of the study was to check the blood gases on Day 3 after the procedure at room air and compare it with the baseline and with blood gases immediately after the procedure. SPSS 23 (IBM Corp., Armonk, NY) was used to analyze the data of this study. For qualitative variables in data such as gender, place of living, patients with any comorbidities, and education status were statistically analyzed in percentage and frequencies. For numerical variables, such as age, body mass index, blood gases values, distance covered in a six-minute walk test, and spirometry values were analyzed and statistically measured as mean and standard deviation. A P-value of less than .05 was considered significant.

Results

The mean partial pressure of oxygen (PaO2) of incentive spirometry was 58.1±2.31 and 67.2±3.24 after extubation and after three days, respectively. While the PaO2 of Acapella was 56.3±3.43 and 66.4±3.54 after extubation and after three days, respectively. The mean PCO2 of incentive spirometry was 41.4±3.26 and 36.1±2.11 after extubation and after three days, respectively. While the partial pressure of carbon dioxide (PCO2) of Acapella was 39.4±2.55 and 37.5±3.58 after extubation and after three days, respectively. The differences were statistically significant at p-value ≤0.05.

Conclusion

It was concluded that both Acapella and incentive spirometry treatment after coronary artery bypass graft improved blood gases.

Surviving sepsis campaign international guidelines for the management of septic shock and sepsis-associated organ dysfunction in children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 49 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 52 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 52 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 49 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

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.

Protective effects of the suppressed NF-κB/TLR4 signaling pathway on oxidative stress of lung tissue in rat with acute lung injury

The pathogenesis of acute lung injury (ALI) is characterized by lung inflammation and lung oxidative stress. The study was conducted in order to investigate the effect toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) exhibited on oxidative stress in ALI. After the rats had been assigned into different groups, arterial blood, white blood cell (WBC), lung permeability index (LPI), wet/dry (W/D) ratio, TLR4 and NF-κB expression and superoxide dismutase (SOD), myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), and reactive oxygen species (ROS) were examined. Afterward, the correlation between the levels of TLR4 and NF-κB was determined. Decreased levels of PaO₂ , SOD, MPO, and GSH accompanied by increased levels of PaCO₂ , WBC number, LPI and W/D ratio, MDA and ROS, as well as TLR4 and NF-κB expressions in the ALI, ALI + NF-κB inhibitor, and ALI + phosphate buffer saline groups were found. Inhibition of NF-κB resulted in increased PaO₂ and decreased PaCO₂ levels, WBC number, and LPI and W/D ratio. Decreased expression of NF-κB increased SOD, GSH, and MPO, but decreased MDA and ROS. We also found that NF-κB inhibition resulted in the improvement of ALI in rats. TLR4 and NF-κB expressions were negatively correlated with levels of SOD, MPO, and GSH, and positively correlated with MDA and ROS levels. In summary, our findings provided evidence that inhibition of the TLR4/NF-κB signaling pathway decreases oxidative stress, thereby improving ALI. As a result, NF-κB signaling pathway has shown potential as a therapeutic target in ALI therapy.

Effective Tidal Volume for Normocapnia in Very-Low-Birth-Weight Infants Using High-Frequency Oscillatory Ventilation

PURPOSE

Removal of CO₂ is much efficient during high-frequency oscillatory ventilation (HFOV) for preterm infants. However, an optimal carbon dioxide diffusion coefficient (DCO₂) and tidal volume (VT) have not yet been established due to much individual variance. This study aimed to analyze DCO₂ values, VT, and minute volume in very-low-birth-weight (VLBW) infants using HFOV and correlates with plasma CO₂ (pCO₂).

MATERIALS AND METHODS

Daily respiratory mechanics and ventilator settings from twenty VLBW infants and their two hundred seventeen results of blood gas analysis were collected. Patients were treated with the Dräger Babylog VN500 ventilator (Drägerwerk Ag & Co.) in HFOV mode. The normocapnia was indicated as pCO₂ ranging from 45 mm Hg to 55 mm Hg.

RESULTS

The measured VT was 1.7 mL/kg, minute volume was 0.7 mL/kg, and DCO₂ was 43.5 mL²/s. Mean results of the blood gas test were as follows: pH, 7.31; pCO₂, 52.6 mm Hg; and SpO₂, 90.5%. In normocapnic state, the mean VT was significantly higher than in hypercapnic state (2.1±0.5 mL/kg vs. 1.6±0.3 mL/kg), and the mean DCO₂ showed significant difference (68.4±32.7 mL²/s vs. 32.4±15.7 mL²/s). The DCO₂ was significantly correlated with the pCO₂ (p=0.024). In the receiver operating curve analysis, the estimated optimal cut-off point to predict the remaining normocapnic status was a VT of 1.75 mL/kg (sensitivity 73%, specificity 80%).

CONCLUSION

In VLBW infants treated with HFOV, VT of 1.75 mL/kg is recommended for maintaining proper ventilation.