Lung-Protective Mechanical Ventilation Strategies in Pediatric Acute Respiratory Distress Syndrome

Transpulmonary Pressure-Guided Mechanical Ventilation in Severe Acute Respiratory Distress Syndrome in the PICU: Single-Center Retrospective Study in North India, 2018-2021

OBJECTIVES

In this study, we have reviewed the association between esophageal pressure-guided positive end-expiratory pressure (PEEP) setting and oxygenation and lung mechanics with a conventional mechanical ventilation (MV) strategy in patient with moderate to severe pediatric acute respiratory distress syndrome (PARDS).

DESIGN

Retrospective cohort, 2018-2021.

SETTING

Tertiary PICU.

PATIENTS

Moderate to severe PARDS patients who required MV with PEEP of greater than or equal to 8 cm H 2 O.

INTERVENTIONS

Esophageal pressure (i.e., transpulmonary pressure [P TP ]) guided MV vs. not.

MEASUREMENTS AND MAIN RESULTS

We identified 26 PARDS cases who were divided into those who had been managed with P TP -guided MV (P TP group) and those managed with conventional ventilation strategy (non-P TP ). Oxygenation and lung mechanics were compared between groups at baseline (0 hr) and 24, 48, and 72 hours of MV. There were 13 patients in each group in the first 24 hours. At 48 and 72 hours, there were 11 in P TP group and 12 in non-P TP group. On comparing these groups, first, use of P TP monitoring was associated with higher median (interquartile range) mean airway pressure at 24 hours (18 hr [18-20 hr] vs. 15 hr [13-18 hr]; p = 0.01) and 48 hours (19 hr [17-19 hr] vs. 15 hr [13-17 hr]; p = 0.01). Second, use of P TP was associated with higher PEEP at 24, 48, and 72 hours (all p < 0.05). Third, use of P TP was associated with lower F io2 and greater Pa o2 to F io2 ratio at 72 hours. Last, there were 18 of 26 survivors, and we failed to identify an association between use of P TP monitoring and survival.

CONCLUSIONS

In this cohort of moderate to severe PARDS cases undergoing MV with PEEP greater than or equal to 8 cm H 2 O, we have identified some favorable associations of oxygenation status when P TP -guided MV was used vs. not. Larger studies are required.

The impact of PEEP on mechanical power and driving pressure in children with pediatric acute respiratory distress syndrome

BACKGROUND

Positive end-expiratory pressure (PEEP) is widely used to improve oxygenation and avoid alveolar collapse in mechanically ventilated patients with pediatric acute respiratory distress syndrome (PARDS). However, its improper use can be harmful, impacting variables associated with ventilation-induced lung injury, such as mechanical power (MP) and driving pressure (∆P). Our main objective was to assess the impact of increasing PEEP on MP and ∆P in children with PARDS.

INTERVENTIONS

Mechanically ventilated children on pressure-controlled volume-guaranteed mode were prospectively assessed for inclusion. PEEP was sequentially changed to 5, 12, 10, 8, and again to 5 cm H2O. After 10 min at each PEEP level, ventilatory data were collected and then variables of interest were determined. Respiratory system mechanics were measured using the least squares fitting method.

RESULTS

Thirty-one patients were included, with median age and weight of 6 months and 6.3 kg. Most subjects were admitted for acute viral bronchiolitis (45%) or community-acquired pneumonia (32%) and were diagnosed with mild (45%) or moderate (42%) PARDS. There was a significant increase in MP and ∆P at PEEP levels of 10 and 12 cm H2O. When PEEP was increased from 5 to 12 cm H2O, there was a relative increase in MP of 60.7% (IQR 49.3-82.9) and in ΔP of 33.3% (IQR 17.8-65.8). A positive correlation was observed between MP and ΔP (ρ = 0.59).

CONCLUSIONS

Children with mild or moderate PARDS may experience a significant increase in MP and ∆P with increased PEEP. Therefore, respiratory system mechanics and lung recruitability must be carefully evaluated during PEEP titration.

Lung-Protective Ventilation for Pediatric Acute Respiratory Distress Syndrome: A Nonrandomized Controlled Trial

OBJECTIVES

Despite the recommendation for lung-protective mechanical ventilation (LPMV) in pediatric acute respiratory distress syndrome (PARDS), there is a lack of robust supporting data and variable adherence in clinical practice. This study evaluates the impact of an LPMV protocol vs. standard care and adherence to LPMV elements on mortality. We hypothesized that LPMV strategies deployed as a pragmatic protocol reduces mortality in PARDS.

DESIGN

Multicenter prospective before-and-after comparison design study.

SETTING

Twenty-one PICUs.

PATIENTS

Patients fulfilled the Pediatric Acute Lung Injury Consensus Conference 2015 definition of PARDS and were on invasive mechanical ventilation.

INTERVENTIONS

The LPMV protocol included a limit on peak inspiratory pressure (PIP), delta/driving pressure (DP), tidal volume, positive end-expiratory pressure (PEEP) to F io2 combinations of the low PEEP acute respiratory distress syndrome network table, permissive hypercarbia, and conservative oxygen targets.

MEASUREMENTS AND MAIN RESULTS

There were 285 of 693 (41·1%) and 408 of 693 (58·9%) patients treated with and without the LPMV protocol, respectively. Median age and oxygenation index was 1.5 years (0.4-5.3 yr) and 10.9 years (7.0-18.6 yr), respectively. There was no difference in 60-day mortality between LPMV and non-LPMV protocol groups (65/285 [22.8%] vs. 115/406 [28.3%]; p = 0.104). However, total adherence score did improve in the LPMV compared to non-LPMV group (57.1 [40.0-66.7] vs. 47.6 [31.0-58.3]; p < 0·001). After adjusting for confounders, adherence to LPMV strategies (adjusted hazard ratio, 0.98; 95% CI, 0.97-0.99; p = 0.004) but not the LPMV protocol itself was associated with a reduced risk of 60-day mortality. Adherence to PIP, DP, and PEEP/F io2 combinations were associated with reduced mortality.

CONCLUSIONS

Adherence to LPMV elements over the first week of PARDS was associated with reduced mortality. Future work is needed to improve implementation of LPMV in order to improve adherence.

Successful management of pulmonary edema secondary to accidental electrocution in a young dog

BACKGROUND

Human records describe pulmonary edema as a life-threatening complication of electric shock. Successful management requires prompt recognition and intensive care. However, in companion animals, electrocutions are rarely reported, even though domestic environments are full of electrical devices and there is always the possibility of accidental injury. Therefore, it is important for veterinarians to know more about this condition in order to achieve successful patient outcomes.

CASE PRESENTATION

A 3-month-old male Labrador Retriever was presented with a history of transient loss of consciousness after chewing on a household electrical cord. On admission, the puppy showed an orthopneic position with moderate respiratory distress. Supplemental oxygen via nasal catheter was provided, but the patient showed marked worsening of respiratory status. Point-of-care ultrasound exams suggested neurogenic pulmonary edema due to electrical shock close to the central nervous system and increased B-lines without evidence of cardiac abnormalities. Mechanical ventilation of the patient was initiated using volume-controlled mode with a tidal volume of 9 to 15 ml/kg until reaching an end-tidal carbon dioxide ≤ 40 mm Hg, followed by a stepwise lung-recruitment maneuver in pressure-controlled mode with increases of the peak inspiratory pressure (15 to 20 cm H2O) and positive end-expiratory pressure (3 to 10 cm H2O) for 30 min, and return to volume-controlled mode with a tidal volume of 15 ml/kg until reaching a peripheral oxygen saturation ≥ 96%. Weaning from the ventilator was achieved in six hours, and the patient was discharged two days after admission without neurological or respiratory deficits.

CONCLUSIONS

We present a rather unusual case of a neurogenic pulmonary edema subsequent to accidental electrocution in a dog. Timely diagnosis by ultrasound and mechanical ventilation settings are described. Our case highlights that pulmonary edema should be considered a potentially life-threatening complication of electrical shock in small animal emergency and critical care medicine.

Positive end-expiratory pressure in the pediatric intensive care unit

Application of positive end-expiratory pressure (PEEP) targeted towards improving oxygenation is one of the components of the ventilatory management of pediatric acute respiratory distress syndrome (PARDS). Low end-expiratory airway pressures cause repetitive opening and closure of unstable alveoli, leading to surfactant dysfunction and parenchymal shear injury. Consequently, there is less lung volume available for tidal ventilation when there are atelectatic lung regions. This will increase lung strain in aerated lung areas to which the tidal volume is preferentially distributed. Pediatric critical care practitioners tend to use low levels of PEEP and inherently accept higher FiO2, but these practices may negatively affect patient outcome. The Pediatric Acute Lung Injury Consensus Conference (PALICC) suggests that PEEP should be titrated to oxygenation/oxygen delivery, hemodynamics, and compliance measured under static conditions as compared to other clinical parameters or any of these parameters in isolation in patients with PARDS, while limiting plateau pressure and/or driving pressure limits.

Invasive Ventilatory Support in Patients With Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide evidence for the Second Pediatric Acute Lung Injury Consensus Conference updated recommendations and consensus statements for clinical practice and future research on invasive mechanical ventilation support of patients with pediatric acute respiratory distress syndrome (PARDS).

DATA SOURCES

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

We included clinical studies of critically ill patients undergoing invasive mechanical ventilation for PARDS, January 2013 to April 2022. In addition, meta-analyses and systematic reviews focused on the adult acute respiratory distress syndrome population were included to explore new relevant concepts (e.g., mechanical power, driving pressure, etc.) still underrepresented in the contemporary pediatric literature.

DATA EXTRACTION

Title/abstract review, full text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development and Evaluation approach was used to identify and summarize relevant evidence and develop recommendations, good practice statements and research statements. We identified 26 pediatric studies for inclusion and 36 meta-analyses or systematic reviews in adults. We generated 12 recommendations, two research statements, and five good practice statements related to modes of ventilation, tidal volume, ventilation pressures, lung-protective ventilation bundles, driving pressure, mechanical power, recruitment maneuvers, prone positioning, and high-frequency ventilation. Only one recommendation, related to use of positive end-expiratory pressure, is classified as strong, with moderate certainty of evidence.

CONCLUSIONS

Limited pediatric data exist to make definitive recommendations for the management of invasive mechanical ventilation for patients with PARDS. Ongoing research is needed to better understand how to guide best practices and improve outcomes for patients with PARDS requiring invasive mechanical ventilation.

Pathobiology, Severity, and Risk Stratification of Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

To review the literature for studies published in children on the pathobiology, severity, and risk stratification of pediatric acute respiratory distress syndrome (PARDS) with the intent of guiding current medical practice and identifying important areas for future research related to severity and risk stratification.

DATA SOURCES

Electronic searches of PubMed and Embase were conducted from 2013 to March 2022 by using a combination of medical subject heading terms and text words to capture the pathobiology, severity, and comorbidities of PARDS.

STUDY SELECTION

We included studies of critically ill patients with PARDS that related to the severity and risk stratification of PARDS using characteristics other than the oxygenation defect. Studies using animal models, adult only, and studies with 10 or fewer children were excluded from our review.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize relevant evidence and develop recommendations for clinical practice. There were 192 studies identified for full-text extraction to address the relevant Patient/Intervention/Comparator/Outcome questions. One clinical recommendation was generated related to the use of dead space fraction for risk stratification. In addition, six research statements were generated about the impact of age on acute respiratory distress syndrome pathobiology and outcomes, addressing PARDS heterogeneity using biomarkers to identify subphenotypes and endotypes, and use of standardized ventilator, physiologic, and nonpulmonary organ failure measurements for future research.

CONCLUSIONS

Based on an extensive literature review, we propose clinical management and research recommendations related to characterization and risk stratification of PARDS severity.

PRISM III Score Predicts Short-Term Outcome in Children with ARDS on Conventional and High-Frequency Oscillatory Ventilation

Therapeutic recommendations for pediatric acute respiratory distress syndrome (PARDS) include conventional (CMV) and rescue high-frequency oscillatory mode (HFOV) of mechanical ventilation (MV). The pediatric risk of mortality (PRISM) is a frequently used mortality score for critically ill patients. In search of methods to recognize those patients, we analyzed the PRISM III score as a potential predictor of the short-term outcome in MV subjects with PARDS. A retrospective five-year study of PARDS in children on MV was conducted in the Pediatric ICU. Seventy patients were divided into two groups (age group <1 year and age group 1−7 years). The PRISM III score was used to assess the 28-day outcome and possible development of complications. The most common causes of PARDS were pneumonia and sepsis. Male sex, malnourishment, sepsis, and shock were significant indicators of poor outcome. The PRISM III score values were significantly higher in those who died, as well as in subjects requiring HFOV. The score had a significant prognostic value for short-term mortality. There was no significant difference in outcome based on the comparison of two modes of ventilation. A significantly higher score was noted in subjects who developed sepsis and cardiovascular insufficiency. The PRISM III score is a fair outcome predictor during the 28-day follow-up in MV subjects with PARDS, regardless of the ventilation mode.

Efficacy and safety of permissive hypercapnia in preterm infants: A systematic review

CONTEXT

In adults, permissive hypercapnia reduces mortality and ventilation duration. However, in preterm infants, the findings from past research regarding the efficacy and safety of permissive hypercapnia are controversial.

OBJECTIVE

To evaluate the efficacy and safety of permissive hypercapnia versus normocapnia in preterm infants on mechanical ventilation.

DATA SOURCES

MEDLINE, EMBASE, CENTRAL, and CINAHL STUDY SELECTION: Published randomized controlled trials (RCTs), non-RCTs, interrupted time series, cohort studies, case-control studies, and controlled before-and-after studies were included.

DATA EXTRACTION

Two reviewers independently screened the title, abstract, and full text, extracted data, assessed the risk of bias, and evaluated certainty of evidence (CoE) according to the Grading of Recommendations Assessment and Development and Evaluation approach. A meta-analysis of RCTs was performed using the random-effects model.

RESULTS

Four RCTs (693 infants) and one cohort study (371 infants) were included. No significant differences existed between the permissive hypercapnia and normocapnia groups for bronchopulmonary dysplasia (BPD) (risk ratio [RR], 0.94; 95% confidence interval [CI], 0.74-1.18; very low CoE) and a composite outcome of death or BPD (RR, 1.05; 95% CI, 0.90-1.23; very low CoE). Permissive hypercapnia may increase necrotizing enterocolitis (RR, 1.69; 95% CI, 0.98-2.91; very low CoE), but the null or trivial effect cannot be excluded. No significant differences existed between the two groups for any other outcome assessed (very low-to-low CoE).

LIMITATIONS

The sample sizes were less than the optimal sizes for all outcomes assessed, indicating the need for further trials.

CONCLUSIONS

Permissive hypercapnia did not have any significant benefit or harm in preterm infants.

Effect of Lung Protective Ventilation Combined With Flurbiprofen Axetil on Immune Function During Thoracoscopic Radical Resection of Lung Cancer

The decreased immune function of patients with lung cancer has always been the focus of clinical attention. However, the stress response caused by surgery, anesthesia and pain will further reduce the body's immune function and affect the prognosis of patients to a certain extent. It was found that both protective ventilation and flurbiprofen ester pretreatment could reduce the immunosuppression caused by stress response. In this study, 120 lung cancer patients treated with video-assisted thoracoscopic radical resection were divided into group A, group B, group C and group D, which were treated with conventional mechanical ventilation, lung protective ventilation, conventional mechanical ventilation + flurbiprofen axetil and lung protective ventilation + flurbiprofen axetil, respectively. The results showed that the levels of CD3+, CD4+, CD4/CD8+, and NK in groups A, B, and C were lower than T0 on T1, T2, and T3, while those indicators in group D were lower than T0 on T1 and T2 (P < 0.05). The above indicators in group D were higher than those in the other three groups on T1, T2, and T3 (P < 0.05). The above indicators were statistically significant compared with those in group A and group C, group B and group D, and group A and group B at T1, T2, and T3 (P < 0.05). The comparisons of CD3+, CD4+, CD4/CD8+, and NK among the four groups within different time groups, and the repeated - measures analysis of variance (repeated - measures ANOVA) showed that there were interactions among time, group, and between groups × within groups (P < 0.05). It was confirmed that lung protective ventilation combined with flurbiprofen axetil could alleviate the immunosuppression of patients undergoing thoracoscopic radical lung cancer, providing a new idea for clinical treatment.

The longitudinal course of pediatric acute respiratory distress syndrome and its time to resolution: A prospective observational study

BACKGROUND

The longitudinal course of patients with pediatric acute respiratory distress syndrome (PARDS) is not well described. In this study, we describe the oxygenation index (OI) and oxygen saturation index (OSI) in mild, moderate, and severe PARDS over 28 days and provide pilot data for the time to resolution of PARDS (T _res), as a short-term respiratory-specific outcome, hypothesizing that it is associated with the severity of PARDS and clinical outcomes.

METHODS

This prospective observational study recruited consecutive patients with PARDS. OI and OSI were trended daily over 28 days. T _res (defined as OI < 4 or OSI < 5.3 on 2 consecutive days) were described based on PARDS severity and analyzed with Poisson and logistic regression to determine its association with conventional outcomes [mechanical ventilation (MV) duration, intensive care unit (ICU) and hospital length of stay, 28-day ventilator-free days (VFD), and 28-day ICU-free days (IFD)].

RESULTS

There were 121 children included in this study, 33/121(27.3%), 44/121(36.4%), and 44/121(36.4%) in the mild, moderate, and severe groups of PARDS, respectively. OI and OSI clearly differentiated mild, moderate, and severe groups in the first 7days of PARDS; however, this differentiation was no longer present after 7days. Median T _res was 4 (interquartile range: 3, 6), 5 (4, 7), and 7.5 (7, 11.5) days; p < 0.001 for the mild, moderate, and severe groups of PARDS, respectively. T _res was associated with increased MV duration, ICU and hospital length of stay, and decreased VFD and IFD.

CONCLUSION

The oxygenation defect in PARDS took progressively longer to resolve across the mild, moderate, and severe groups. T _res is a potential short-term respiratory-specific outcome, which may be useful in addition to conventional clinical outcomes but needs further validation in external cohorts.

The Association Between Alveolar Dead Space Fraction and Mortality in Pediatric Acute Respiratory Distress Syndrome: A Prospective Cohort Study

BACKGROUND

Alveolar dead-space fraction (AVDSF), the volume of alveolar gas that does not participate in gas exchange, has been reported to predict mortality and morbidity in adults with acute respiratory distress syndrome (ARDS). This study aims to characterize AVDSF in patients with pediatric ARDS (PARDS), to determine its association with clinical outcomes and examine the validity of a previously studied cutoff (AVDSF > 0.25).

METHODS

This was a prospective cohort study performed in the setting of a lung protective mechanical ventilation protocol. AVDSF was calculated by the equation: AVDSF = [partial pressure of arterial carbon dioxide (P_aCO₂) - end tidal carbon dioxide (etCO₂)]/P_aCO₂. Receiver operating curve and Youden index were used to identify an AVDSF cutoff associated with mortality, which characterized "high or low AVDSF" groups. Correlation between AVDSF and clinical indices of severity were determined [including daily oxygenation index (OI), admission Pediatric Index of Mortality 2 (PIM 2) and Pediatric Logistic Organ Dysfunction (PELOD) scores]. The primary outcome, mortality in PARDS patients, was compared between the high and low AVDSF groups and analyzed in a multivariable logistic regression adjusting for inotrope use and PIM 2 score. Secondary outcomes included 28-day ventilator-free (VFD) and intensive care unit-free (IFD) days.

RESULTS

Sixty-nine PARDS patients with a median (interquartile range) age of 4.5 (0.8, 10.6) years were included in this analysis. Daily AVDSF correlated with daily OI (R ² = 0.10; p < 0.001). Mean AVDSF over the first 7 days of PARDS correlated with PIM 2 (R ² = 0.10; p = 0.010) and PELOD (R ² = 0.12; p = 0.004) scores. The greatest area under the curve identified an AVDSF cutoff of 0.22, which was close to the previously suggested 0.25. The high AVDSF group had higher mortality [7/19 (36.8%) vs. 5/50 (10.0%); p = 0.009] and lower VFD [2 (0, 18) vs. 21 (15, 24); p = 0.007] and IFD [0 (0, 16) vs. 16 (5, 21); p = 0.013]. In the multivariable model, being in the high AVDSF group [adjusted odds ratio 4.67 (95% CI: 1.12, 19.39)] was significantly associated with mortality.

CONCLUSIONS

High AVDSF was independently associated with increased mortality and decreased VFD and IFD. AVDSF may be complementary to oxygenation indices in risk stratifying PARDS and warrant further study.

The Association Between Oxygenation Status at 24 h After Diagnosis of Pulmonary Acute Respiratory Distress Syndrome and the 30-Day Mortality among Pediatric Oncological Patients

BACKGROUND

Pediatric oncology patients with acute respiratory distress syndrome (ARDS) secondary to pneumonia are at high risk of mortality. Our aim was to describe the epidemiology of ARDS in this clinical population and to identify the association between the oxygenation status at 24 h after diagnosis and the 30-day mortality rates, stratified by the severity of ARDS.

METHODS

This was a retrospective cohort study of 82 pediatric oncology patients, with a median age of 4 years, admitted to our pediatric intensive care unit with a diagnosis of ARDS between 2013 and 2021. Demographic and clinical factors were compared between the survivor (n = 52) and non-survivor (n = 30) groups. Univariate and multivariate Cox proportional hazards regression models were used to determine the association between the oxygenation status at 24 h after diagnosis and the 30-day mortality rates.

RESULTS

The mean airway pressure at ARDS diagnosis, PaO₂/FiO₂ (P/F) ratio, oxygenation index (OI) value, peak inspiratory pressure, and lactate level at 24 h after ARDS diagnosis, as well as complications (i.e., septicemia and more than two extrapulmonary organ failures) and adjunctive continuous renal replacement therapy, were significant mortality risk factors. After adjusting for other covariates, the oxygenation status P/F ratio (Hazard ratio [HR] = 0.98, 95% confidence interval [CI] = 0.96-1.00, P = 0.043) and OI value (HR = 1.12, 95% CI = 1.02-1.23, P = 0.016) at 24 h remained independent mortality risk factors. According to the Kaplan-Meier survival curve, a low P/F ratio (≤ 150) and high OI (>10) were associated with a higher risk of 30-day mortality (50.9 and 52.9%, respectively; both P < 0.05).

CONCLUSION

The P/F ratio and OI value measured at 24 h after ARDS diagnosis can provide a better stratification of patients according to ARDS disease severity to predict the 30-day mortality risk.

Ventilation‐induced epithelial injury drives biological onset of lung trauma in vitro and is mitigated with prophylactic anti‐inflammatory therapeutics

Mortality rates among patients suffering from acute respiratory failure remain perplexingly high despite the maintenance of blood oxygen homeostasis during ventilatory support. The biotrauma hypothesis advocates that mechanical forces from invasive ventilation trigger immunological mediators that spread systemically. Yet, how these forces elicit an immune response remains unclear. Here, a biomimetic in vitro three‐dimensional (3D) upper airways model allows to recapitulate lung injury and immune responses induced during invasive mechanical ventilation in neonates. Under such ventilatory support, flow‐induced stresses injure the bronchial epithelium of the intubated airways model and directly modulate epithelial cell inflammatory cytokine secretion associated with pulmonary injury. Fluorescence microscopy and biochemical analyses reveal site‐specific susceptibility to epithelial erosion in airways from jet‐flow impaction and are linked to increases in cell apoptosis and modulated secretions of cytokines IL‐6, ‐8, and ‐10. In an effort to mitigate the onset of biotrauma, prophylactic pharmacological treatment with Montelukast, a leukotriene receptor antagonist, reduces apoptosis and pro‐inflammatory signaling during invasive ventilation of the in vitro model. This 3D airway platform points to a previously overlooked origin of lung injury and showcases translational opportunities in preclinical pulmonary research toward protective therapies and improved protocols for patient care.

Randomized crossover trial to compare driving pressures in a closed-loop and a conventional mechanical ventilation mode in pediatric patients

INTRODUCTION

In mechanically ventilated patients, driving pressure (ΔP) represents the dynamic stress applied to the respiratory system and is related to ICU mortality. An evolution of the Adaptive Support Ventilation algorithm (ASV® 1.1) minimizes inspiratory pressure in addition to minimizing the work of breathing. We hypothesized that ASV 1.1 would result in lower ΔP than the ΔP measured in APV-CMV (controlled mandatory ventilation with adaptive pressure ventilation) mode with physician-tailored settings. The aim of this randomized crossover trial was therefore to compare ΔP in ASV 1.1 with ΔP in physician-tailored APV-CMV mode.

METHODS

Pediatric patients admitted to the PICU with heterogeneous-lung disease were enrolled if they were ventilated invasively with no detectable respiratory effort, hemodynamic instability, or significant airway leak around the endotracheal tube. We compared two 60-min periods of ventilation in APV-CMV and ASV 1.1, which were determined by randomization and separated by 30-min washout periods. Settings were adjusted to reach the same minute ventilation in both modes. ΔP was calculated as the difference between plateau pressure and total PEEP measured using end-inspiratory and end-expiratory occlusions, respectively.

RESULTS

There were 26 patients enrolled with a median age of 16 (9-25 [IQR]) months. The median ΔP for these patients was 10.4 (8.5-12.1 [IQR]) and 12.4 (10.5-15.3 [IQR]) cmH2O in the ASV 1.1 and APV-CMV periods, respectively (p < .001). The median tidal volume (VT) selected by the ASV 1.1 algorithm was 6.4 (5.1-7.3 [IQR]) ml/kg and RR was 41 (33 50 [IQR]) b/min, whereas the median of the same values for the APV-CMV period was 7.9 (6.8-8.3 [IQR]) ml/kg and 31 (26-41[IQR]) b/min, respectively. In both ASV 1.1 and APV-CMV modes, the highest ΔP was used to ventilate those patients with restrictive lung conditions at baseline.

CONCLUSION

In this randomized crossover trial, ΔP in ASV 1.1 was lower compared to ΔP in physician-tailored APV-CMV mode in pediatric patients with different lung conditions. The use of ASV 1.1 may therefore result in continued, safe ventilation in a heterogeneous pediatric patient group.

High burden of acquired morbidity in survivors of pediatric acute respiratory distress syndrome

INTRODUCTION

With improving mortality rates in pediatric acute respiratory distress syndrome (PARDS), functional outcomes in survivors are increasingly important. We aim to describe the change in functional status score (FSS) from baseline to discharge and to identify risk factors associated with poor functional outcomes.

METHODS

We examined clinical records of patients with PARDS admitted to our pediatric intensive care unit (PICU) from 2009 to 2016. Our primary outcome was acquired morbidity at PICU and hospital discharge (defined by an increase in FSS ≥3 points above baseline). We included severity of illness scores and severity of PARDS in our bivariate analysis for risk factors for acquired morbidity.

RESULTS

There were 181 patients with PARDS, of which 90 (49.7%) survived. Median pediatric index of mortality 2 score was 4.05 (1.22, 8.70) and 21 (23.3%) survivors had severe PARDS. A total of 59 (65.6%) and 14 (15.6%) patients had acquired morbidity at PICU and hospital discharge, respectively. Median baseline FSS was 6.00 (6.00, 6.25), which increased to 11.00 (8.75, 12.00) at PICU discharge before decreasing to 7.50 (6.00, 9.25) at hospital discharge. All patients had significantly higher FSS at both PICU and hospital discharge median compared to baseline. Feeding and respiratory were the most affected domains. After adjusting for severity of illness, severity categories of PARDS were not a risk factor for acquired morbidity.

CONCLUSION

Acquired morbidity in respiratory and feeding domains was common in PARDS survivors. Specific attention should be given to these two domains of functional outcomes in these children.

Ventilator-Weaning Pathway Associated With Decreased Ventilator Days in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

There is limited evidence on the impact of protocolized ventilator weaning in pediatric acute respiratory distress syndrome, despite utilization in clinical trials and clinical care. We aimed to determine whether protocolized ventilator weaning shortens mechanical ventilation duration and PICU length of stay in pediatric acute respiratory distress syndrome survivors.

DESIGN

Secondary analysis of a prospective pediatric acute respiratory distress syndrome (Berlin definition) cohort from July 2011 to June 2019 analyzed using interrupted time series analysis pre- and postimplementations of a ventilator-weaning pathway. We compared duration of invasive ventilation and PICU length of stay in survivors before and after implementation of a ventilator-weaning pathway. We excluded PICU nonsurvivors and subjects with greater than 100 ventilator days.

SETTING

Large academic tertiary-care PICU.

PATIENTS

Children with acute respiratory distress syndrome who survived to PICU discharge with less than or equal to 100 days of invasive mechanical ventilation.

INTERVENTIONS

Implementation of a ventilator-weaning pathway on May 2016.

MEASUREMENTS AND MAIN RESULTS

Of 723 children with acute respiratory distress syndrome, 132 subjects died and six subjects with ventilation greater than 100 days were excluded. Of the remaining 585 subjects, 375 subjects had acute respiratory distress syndrome prior to pathway intervention and 210 after. Patients in the preintervention epoch were younger, more likely to have infectious acute respiratory distress syndrome, and had increased use of alternative ventilator modes. Pathway adoption was rapid and sustained. Controlling for temporality, pathway implementation was associated with a decrease of a median 3.6 ventilator days (95% CI, -5.4 to -1.7; p < 0.001). There was no change in the reintubation rates. Results were robust to multiple sensitivity analyses adjusting for confounders.

CONCLUSIONS

Ventilator-weaning pathway implementation shortened invasive ventilation duration in pediatric acute respiratory distress syndrome survivors with no change in reintubation. The effect size of this intervention was comparable with those targeted in acute respiratory distress syndrome trials.

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.