Acute respiratory distress syndrome (ARDS) in children: Multicenter Collaborative Study of the French Group of Pediatric Intensive Care

Clinical outcome and associated factors of respiratory distress syndrome among preterm neonates admitted to the neonatal intensive care unit of Adama Hospital and Medical College

Objective

Aim of the study was to assess the clinical outcome and associated factors of respiratory distress syndrome among preterm neonates admitted to the neonatal intensive care unit of Adama Hospital and Medical College.

Methods

Hospital-based cross-sectional study was conducted using 242 randomly selected medical records of preterm neonates admitted to Adama comprehensive specialized hospital. Clinical outcome was categorized as poor if the neonate died or left against advice and good if discharged after improvement. Data were coded, entered into Epidata v.7.4.2 and exported to SPSS v.27 for analysis. After initial bi-variable logistic regression analysis, predictor variables with p-value of <0.2 were included in multivariable analysis. Significant association of factors with clinical outcome was claimed at p-value <0.05 and calculated 95% adjusted odds ratio.

Results

Majority of admissions were male (63.2%), mean birth weight of 1440.3 g (+321.2 SD) and sepsis (82%), hypothermia (73%), and apnea (21.5%) were leading comorbidities. One hundred fifty-two (62.8%) of preterm neonates had poor outcomes. Neonates born singleton were 47% less likely to develop poor clinical outcomes (adjusted odds ratio 0.53 (0.48-0.94). The odds of poor clinical outcomes were higher during the first 3 days of admission (adjusted odds ratio 3.83 (3.28-14.77). Extremely preterm neonates (adjusted odds ratio 4.16 (4.01-12.97), extremely low birth weight preterm neonates had higher odds of poor clinical outcome.

Conclusion

The study found higher poor clinical outcome among preterm neonates admitted with respiratory distress syndrome. Poor outcome was higher in lower gestational age, lower birth weight, twins and majority of it happened during 3 days of their life. Effective preventive care and initiation of low-cost, life-saving interventions including heated humidified high-flow nasal cannula and surfactant administration could significantly improve the clinical outcome of the neonates.

Risk Stratification in Pediatric Acute Respiratory Distress Syndrome: A Multicenter Observational Study

OBJECTIVES

The Pediatric Acute Lung Injury Consensus Conference developed a pediatric specific definition for acute respiratory distress syndrome (PARDS). In this definition, severity of lung disease is stratified into mild, moderate, and severe groups. We aim to describe the epidemiology of patients with PARDS across Asia and evaluate whether the Pediatric Acute Lung Injury Consensus Conference risk stratification accurately predicts outcome in PARDS.

DESIGN

A multicenter, retrospective, descriptive cohort study.

SETTING

Ten multidisciplinary PICUs in Asia.

PATIENTS

All mechanically ventilated children meeting the Pediatric Acute Lung Injury Consensus Conference criteria for PARDS between 2009 and 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Data on epidemiology, ventilation, adjunct therapies, and clinical outcomes were collected. Patients were followed for 100 days post diagnosis of PARDS. A total of 373 patients were included. There were 89 (23.9%), 149 (39.9%), and 135 (36.2%) patients with mild, moderate, and severe PARDS, respectively. The most common risk factor for PARDS was pneumonia/lower respiratory tract infection (309 [82.8%]). Higher category of severity of PARDS was associated with lower ventilator-free days (22 [17-25], 16 [0-23], 6 [0-19]; p < 0.001 for mild, moderate, and severe, respectively) and PICU free days (19 [11-24], 15 [0-22], 5 [0-20]; p < 0.001 for mild, moderate, and severe, respectively). Overall PICU mortality for PARDS was 113 of 373 (30.3%), and 100-day mortality was 126 of 317 (39.7%). After adjusting for site, presence of comorbidities and severity of illness in the multivariate Cox proportional hazard regression model, patients with moderate (hazard ratio, 1.88 [95% CI, 1.03-3.45]; p = 0.039) and severe PARDS (hazard ratio, 3.18 [95% CI, 1.68, 6.02]; p < 0.001) had higher risk of mortality compared with those with mild PARDS.

CONCLUSIONS

Mortality from PARDS is high in Asia. The Pediatric Acute Lung Injury Consensus Conference definition of PARDS is a useful tool for risk stratification.

Mortality in Pediatric Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

OBJECTIVE

Sparse and conflicting evidence exists regarding mortality risk from pediatric acute respiratory distress syndrome (ARDS). We aimed to determine the pooled mortality in pediatric ARDS and to describe its trend over time.

DATA SOURCES AND STUDY SELECTION

MEDLINE, EMBASE, and Web of Science were searched from 1960 to August 2015. Keywords or medical subject headings (MESH) terms used included "respiratory distress syndrome, adult," "acute lung injury," "acute respiratory insufficiency," "acute hypoxemic respiratory failure," "pediatrics," and "child." Study inclusion criteria were (1) pediatric patients aged 0 days to 18 years, (2) sufficient baseline data described in the pediatric ARDS group, and (3) mortality data. Randomized controlled trials (RCTs) and prospective observational studies were eligible.

DATA EXTRACTION AND SYNTHESIS

Data on study characteristics, patient demographics, measures of oxygenation, and mortality were extracted using a standard data extraction form. Independent authors conducted the search, applied the selection criteria, and extracted the data. Methodological quality of studies was assessed. Meta-analysis using a random-effects model was performed to obtain pooled estimates of mortality. Meta-regression was performed to analyze variables contributing to change in mortality over time. Eight RCTs and 21 observational studies (n = 2274 patients) were included. Pooled mortality rate was 24% (95% confidence interval [CI]: 19-31). There was a decrease in mortality rates over 3 epochs (≤2000, 2001-2009, and ≥2010: 40% [95% CI: 24-59], 35% [95% CI: 21-51], and 18% [95% CI: 12-26], respectively, P < .001). Observational studies reported a higher mortality rate than RCTs (27% [95% CI: 24-29] versus 16% [95% CI: 12-20], P < .001). Earlier year of publication was an independent factor associated with mortality.

CONCLUSION

Overall mortality rate in pediatric ARDS is approximately 24%. Studies conducted and published later were associated with better survival.

Relevant Outcomes in Pediatric Acute Respiratory Distress Syndrome Studies

Despite distinct epidemiology and outcomes, pediatric acute respiratory distress syndrome (PARDS) is often managed based on evidence extrapolated from treatment of adults. The impact of non-pulmonary processes on mortality as well as the lower mortality rate compared to adults with acute respiratory distress syndrome (ARDS) renders the utilization of short-term mortality as a primary outcome measure for interventional studies problematic. However, data regarding alternatives to mortality are profoundly understudied, and proposed alternatives, such as ventilator-free days, may be themselves subject to hidden biases. Given the neuropsychiatric and functional impairment in adult survivors of ARDS, characterization of these morbidities in children with PARDS is of paramount importance. The purpose of this review is to frame these challenges in the context of the existing pediatric literature, and using adult ARDS as a guide, suggest potential clinically relevant outcomes that deserve further investigation. The goal is to identify important areas of study in order to better define clinical practice and facilitate future interventional trials in PARDS.

Characterizing degree of lung injury in pediatric acute respiratory distress syndrome

OBJECTIVE

Although all definitions of acute respiratory distress syndrome use some measure of hypoxemia, neither the Berlin definition nor recently proposed pediatric-specific definitions proposed by the Pediatric Acute Lung Injury Consensus Conference utilizing oxygenation index specify which PaO2/FIO2 or oxygenation index best categorizes lung injury. We aimed to identify variables associated with mortality and ventilator-free days at 28 days in a large cohort of children with acute respiratory distress syndrome.

DESIGN

Prospective, observational, single-center study.

SETTING

Tertiary care, university-affiliated PICU.

PATIENTS

Two-hundred eighty-three invasively ventilated children with the Berlin-defined acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Between July 1, 2011, and June 30, 2014, 283 children had acute respiratory distress syndrome with 37 deaths (13%) at the Children's Hospital of Philadelphia. Neither initial PaO2/FO2 nor oxygenation index at time of meeting acute respiratory distress syndrome criteria discriminated mortality. However, 24 hours after, both PaO2/FIO2 and oxygenation index discriminated mortality (area under receiver operating characteristic curve, 0.68 [0.59-0.77] and 0.66 [0.57-0.75]; p < 0.001). PaO2/FIO2 at 24 hours categorized severity of lung injury, with increasing mortality rates of 5% (PaO2/FIO2, > 300), 8% (PaO2/FIO2, 201-300), 18% (PaO2/FIO2, 101-200), and 37% (PaO2/FIO2, ≤ 100) across worsening Berlin categories. This trend with 24-hour PaO2/FIO2 was seen for ventilator-free days (22, 19, 14, and 0 ventilator-free days across worsening Berlin categories; p < 0.001) and duration of ventilation in survivors (6, 9, 13, and 24 d across categories; p < 0.001). Similar results were obtained with 24-hour oxygenation index.

CONCLUSIONS

PaO2/FIO2 and oxygenation index 24 hours after meeting acute respiratory distress syndrome criteria accurately stratified outcomes in children. Initial values were not helpful for prognostication. Definitions of acute respiratory distress syndrome may benefit from addressing timing of oxygenation metrics to stratify disease severity.

The outcomes of children with pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide additional details and evidence behind the recommendations for outcomes assessment of patients with pediatric acute respiratory distress syndrome from the Pediatric Acute Lung Injury Consensus Conference.

DESIGN

Consensus conference of experts in pediatric acute lung injury.

METHODS

A panel of 27 experts met over the course of 2 years to develop a taxonomy to define pediatric acute respiratory distress syndrome and to make recommendations regarding treatment and research priorities. The outcomes subgroup comprised four experts. When published data were lacking, a modified Delphi approach emphasizing strong professional agreement was used.

RESULTS

The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 151 recommendations addressing the topics related to pediatric acute respiratory distress syndrome, seven of which related to outcomes after pediatric acute respiratory distress syndrome. All seven recommendations had strong agreement. Children with acute respiratory distress syndrome continue to have a high mortality, specifically, in relation to certain comorbidities and etiologies related to pediatric acute respiratory distress syndrome. Comorbid conditions, such as an immunocompromised state, increase the risk of mortality even further. Likewise, certain etiologies, such as non-pulmonary sepsis, also place children at a higher risk of mortality. Significant long-term effects were reported in adult survivors of acute respiratory distress syndrome: diminished lung function and exercise tolerance, reduced quality of life, and diminished neurocognitive function. Little knowledge of long-term outcomes exists in children who survive pediatric acute respiratory distress syndrome. Characterization of the longer term consequences of pediatric acute respiratory distress syndrome in children is vital to help identify opportunities for improved therapeutic and rehabilitative strategies that will lessen the long-term burden of pediatric acute respiratory distress syndrome and improve the quality of life in children.

CONCLUSIONS

The Consensus Conference developed pediatric-specific recommendations for pediatric acute respiratory distress syndrome regarding outcome measures and future research priorities. These recommendations are intended to promote optimization and consistency of care for children with pediatric acute respiratory distress syndrome and identify areas of uncertainty requiring further investigation.

Epidemiology of pediatric acute respiratory distress syndrome in singapore: risk factors and predictive respiratory indices for mortality

AIM

Acute respiratory distress syndrome (ARDS) represents the most severe form of acute lung injury. The aim of our study is to describe the epidemiology of pediatric ARDS in Singapore and compare the outcomes of ARDS using the following respiratory indices: PaO2/FiO2 ratio (P/F ratio), SpO2/FiO2 ratio (S/F ratio), oxygenation index (OI), and oxygen saturation index (OSI).

METHODS

We examined medical records of patients admitted to the Children's Intensive Care Unit in KK Women's and Children's Hospital from 2009 to 2012. Those who fulfilled criteria for the American-European Consensus Conference definition for ARDS were identified. Demographic, clinical, and radiographic information were extracted and analyzed.

RESULTS

We identified 70 patients with ARDS. Median age (interquartile range) was 6.2 (1.4, 10.4) years. The most common risk factor was pneumonia [50 (71%)]. Overall mortality was 44 (63%) patients. Thirty-two (56%) patients had an underlying chronic comorbidity; 18 (46%) were hematology-oncology conditions. Fifty-six (80%) patients had multiorgan dysfunction. Adjunct therapies used in our patients included inhaled nitric oxide [5 (7%)], prone position [22 (31%)], steroids [26 (37%)], and neuromuscular blockade [26 (37%)]. A high OI and low PF ratio after 24 h of diagnosis of ARDS were associated with mortality. From day 3 onward, all four respiratory indices appropriately differentiated survivors from non-survivors. Severity based on the S/F ratio and OSI demonstrated association with decreased ventilator free days and ICU free days.

CONCLUSION

Risk factors for mortality included having an underlying comorbidity, multiorgan dysfunction, a low PF ratio, and high OI at 24 h of ARDS. Abnormal SpO2-based measurements were reliable markers of poor outcomes in pediatric ARDS.

Acute respiratory distress syndrome in children: physiology and management

PURPOSE OF REVIEW

The present review seeks to review the pathophysiologic processes that underlie the development of acute respiratory distress syndrome (ARDS) in children. The review intends to provide the physiologic foundation for the treatment strategies that are associated with the most optimal outcome.

RECENT FINDINGS

In infants and children, ARDS remains a significant cause of morbidity and mortality. Although any infant or child can develop ARDS, children who have experienced trauma, pneumonia, aspiration, or immune compromise are at increased risk. Data indicate that adoption of an open-lung ventilation strategy, characterized by sufficient positive end-expiratory pressure to avoid atelectasis, a tidal volume that is limited to less than 5-7  cc/kg per breath and a plateau pressure of 30  cm of water or less provides the greatest likelihood of survival and minimizes lung injury. The relative benefits of strategies such as high frequency oscillatory ventilation, surfactant replacement therapy and inhaled nitric oxide are considered.

SUMMARY

ARDS remains a cause of significant mortality and morbidity in children. By employing sound physiologic principles, clinical outcomes can be optimized.

Partial liquid ventilation for the prevention of mortality and morbidity in paediatric acute lung injury and acute respiratory distress syndrome

BACKGROUND

Acute lung injury and acute respiratory distress syndrome are syndromes of severe respiratory failure. Children with acute lung injury or acute respiratory distress syndrome have high mortality and the survivors have significant morbidity. Partial liquid ventilation is proposed as a less injurious form of respiratory support for these children. Uncontrolled studies in adults have shown improvements in gas exchange and lung compliance with partial liquid ventilation. A single uncontrolled study in six children with acute respiratory syndrome showed some improvement in gas exchange during three hours of partial liquid ventilation. This review was originally published in 2004, updated in 2009 and again in 2012.

OBJECTIVES

To assess whether partial liquid ventilation reduces mortality or morbidity, or both, in children with acute lung injury or acute respiratory distress syndrome.

SEARCH METHODS

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 11); CINAHL (Cumulative Index to Nursing & Allied Health Literature) via Ovid (1982 to November 2011); Ovid MEDLINE (1950 to November 2011); and Ovid EMBASE (1982 to November 2011). The search was last performed in August 2008.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) which compared partial liquid ventilation with other forms of ventilation in children (aged 28 days to 18 years) with acute lung injury or acute respiratory distress syndrome. Trials had to report one or more of the following: mortality; duration of mechanical ventilation, respiratory support, oxygen therapy, stay in the intensive care unit, or stay in hospital; infection; long-term cognitive impairment, neurodevelopmental progress, or other long-term morbidities.

DATA COLLECTION AND ANALYSIS

We independently evaluated the quality of the relevant studies and extracted the data from the included studies.

MAIN RESULTS

Only one study enrolling 182 patients (reported as an abstract in conference proceedings) was identified and found eligible for inclusion; the authors reported only limited results. The trial was stopped prematurely and was, therefore, under-powered to detect any significant differences and at high risk of bias. The only available outcome of clinical significance was 28-day mortality. There was no statistically significant difference between groups, with a relative risk for 28-day mortality in the partial liquid ventilation group of 1.54 (95% confidence interval 0.82 to 2.9).

AUTHORS' CONCLUSIONS

There is no evidence from RCTs to support or refute the use of partial liquid ventilation in children with acute lung injury or acute respiratory distress syndrome. Adequately powered, high quality RCTs are still needed to assess its efficacy. Clinically relevant outcome measures should be assessed (mortality at discharge and later, duration of both respiratory support and hospital stay, and long-term neurodevelopmental outcomes). The studies should be published in full.

Fluid balance in critically ill children with acute lung injury

OBJECTIVES

In the Fluid and Catheter Treatment Trial (NCT00281268), adults with acute lung injury randomized to a conservative vs. liberal fluid management protocol had increased days alive and free of mechanical ventilator support (ventilator-free days). Recruiting sufficient children with acute lung injury into a pediatric trial is challenging. A Bayesian statistical approach relies on the adult trial for the a priori effect estimate, requiring fewer patients. Preparing for a Bayesian pediatric trial mirroring the Fluid and Catheter Treatment Trial, we aimed to: 1) identify an inverse association between fluid balance and ventilator-free days; and 2) determine if fluid balance over time is more similar to adults in the Fluid and Catheter Treatment Trial liberal or conservative arms.

DESIGN

Multicentered retrospective cohort study.

SETTING

Five pediatric intensive care units.

PATIENTS

Mechanically ventilated children (age≥1 month to <18 yrs) with acute lung injury admitted in 2007-2010.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Fluid intake, output, and net fluid balance were collected on days 1-7 in 168 children with acute lung injury (median age 3 yrs, median PaO2/FIO2 138) and weight-adjusted (mL/kg). Using multivariable linear regression to adjust for age, gender, race, admission day illness severity, PaO2/FIO2, and vasopressor use, increasing cumulative fluid balance (mL/kg) on day 3 was associated with fewer ventilator-free days (p=.02). Adjusted for weight, daily fluid balance on days 1-3 and cumulative fluid balance on days 1-7 were higher in these children compared to adults in the Fluid and Catheter Treatment Trial conservative arm (p<.001, each day) and was similar to adults in the liberal arm.

CONCLUSIONS

Increasing fluid balance on day 3 in children with acute lung injury at these centers is independently associated with fewer ventilator-free days. Our findings and the similarity of fluid balance patterns in our cohort to adults in the Fluid and Catheter Treatment Trial liberal arm demonstrate the need to determine whether a conservative fluid management strategy improves clinical outcomes in children with acute lung injury and support a Bayesian trial mirroring the Fluid and Catheter Treatment Trial.

The use of high frequency oscillatory ventilation in a pediatric oncology intensive care unit

BACKGROUND

High frequency oscillatory ventilation (HFOV) has been successfully used in the management of acute respiratory distress syndrome (ARDS) in children. The aim of our study is to determine its effectiveness in pediatric patients with cancer or post hematopoietic stem cell transplantation (HSCT) diagnosed with ARDS.

PROCEDURE

A retrospective case review, in a pediatric intensive care unit (PICU) in a tertiary-care oncology center in Amman, Jordan. Patients included were children with cancer and/or receiving allogeneic HSCT who were diagnosed with ARDS and placed on HFOV from January 2007 to February 2009.

RESULTS

Data from 12 pediatric oncology patients on HFOV were analyzed for demographics, oncological diagnosis, PRISM III scores, ventilator settings before switching to HFOV and 24 hours after switching, complications, and outcomes. Alveolar-arterial oxygen (A-a) gradient and oxygen index (OI) were calculated, and pressure of arterial CO(2) (PaCO(2) ) was measured before and 24 hours after switching. Endpoints were successful extubation and discharge, or death while intubated. After 24 hours on HFOV, the A-a gradient decreased significantly in all patients (from a median of 564-267 torr; P=0.001). OI decreased in all but two patients who died (median 17); PaCO(2) decrease was not significant. Five patients died (two of them post-HSCT) and the 7 (58%) survivors were weaned from HFOV (median, 9 days) and discharged.

CONCLUSIONS

HFOV improves gas exchange and is useful in managing critically ill children with cancer and post-HSCT patients who develop ARDS.

Management of acute lung injury and acute respiratory distress syndrome in children

BACKGROUND

Acute lung injury (ALI) and its more severe form, acute respiratory distress syndrome (ARDS), are devastating disorders of overwhelming pulmonary inflammation and hypoxemia, resulting in high morbidity and mortality.

AIM

To provide the clinician with a summary of the literature on the epidemiology, diagnosis, and an evidence-base for management of ALI/ARDS in children.

DATA SELECTION

PubMed search for clinical trials, selected literature review of other relevant studies on epidemiology and diagnosis. DATA SYNTHESIS AND RECOMMENDATIONS: Lower mortality combined with a relatively lower frequency of ALI/ARDS in children makes performance of clinical trials challenging. Based on expert opinion, the following are recommended: 1) avoid tidal volumes > or =10 mL/kg body weight; 2) keep plateau pressure < or =30 cm H2O, arterial pH at 7.30 to 7.45, and Pao2 60 to 80 torr (8 to 10.7 kPa) (Spo2 > or =90%); 3) provide sedation, analgesia, and stress ulcer prophylaxis; and 4) use a 10 g/dL hemoglobin threshold for packed red blood cell transfusion in unstable patients (shock or profound hypoxia). Evidence supports dropping the hemoglobin transfusion threshold to 7 g/dL once profound hypoxia and shock have resolved. Promising therapies for pediatric ALI/ARDS based on pediatric studies include endotracheal surfactant, high-frequency oscillatory ventilation, noninvasive ventilation, and use of extracorporeal membrane oxygenation as a rescue therapy. Promising therapies based on adult trials include use of corticosteroids for lung inflammation and fibrosis, use of 4 to 6 mL/kg tidal volumes and restrictive fluid management. Prone positioning, bronchodilators, inhaled nitric oxide, tight glucose control, and high-flow nasal cannula (HFNC) oxygen are therapies that require further study before they can be recommended for children with ALI/ARDS.

Incidence and outcomes of pediatric acute lung injury

OBJECTIVE

This population-based, prospective, cohort study was designed to determine the population incidence and outcomes of pediatric acute lung injury.

METHODS

Between 1999 and 2000, 1 year of screening was performed at all hospitals admitting critically ill children in King County, Washington. County residents 0.5 to 15 years of age who required invasive (through endotracheal tube or tracheostomy) or noninvasive (through full face mask) mechanical ventilation, regardless of the duration of mechanical ventilation, were screened. From this population, children meeting North American-European Consensus Conference acute lung injury criteria were eligible for enrollment. Postoperative patients who received mechanical ventilation for <24 hours were excluded. Data collected included the presence of predefined cardiac conditions, demographic and physiological data, duration of mechanical ventilation, and deaths. US Census population figures were used to estimate incidence. Associations between outcomes and subgroups identified a priori were assessed.

RESULTS

Thirty-nine children met the criteria for acute lung injury, resulting in a calculated incidence of 12.8 cases per 100000 person-years. Severe sepsis (with pneumonia as the infection focus) was the most common risk factor. The median 24-hour Pediatric Risk of Mortality III score was 9.0, and the mean +/- SD was 11.7 +/- 7.5. The hospital mortality rate was 18%, lower than that reported previously for pediatric acute lung injury. There were no statistically significant associations between age, gender, or risk factors and outcomes.

CONCLUSIONS

We present the first population-based estimate of pediatric acute lung injury incidence in the United States. Population incidence and mortality rates are lower than those for adult acute lung injury. Low mortality rates in pediatric acute lung injury may necessitate clinical trial outcome measures other than death.

Toward early identification of acute lung injury in the emergency department

BACKGROUND

There are no studies evaluating the epidemiology of pediatric acute lung injury (ALI) in the emergency department (ED), where early identification and interventions are most likely to be helpful. The purpose of this study was to describe the epidemiology of the ALI precursor acute hypoxemic respiratory failure (AHRF) in the ED.

METHODS

We analyzed 11,664 pediatric patient records from 16 EDs. Records were selected if oxygen saturation (SpO(2)) was recorded during the visit. Virtual partial pressure of oxygen (pO(2)) was calculated from SpO(2), thus allowing calculation of ratios of pO(2) to fraction of inspired oxygen (FiO(2)) (PFRs). Patients with a PFR < 300 were classified as having AHRF. Univariate analyses and logistic regression were used to test the association of clinical factors with the presence of AHRF and intubation.

RESULTS

AHRF criteria (ie, PFR < 300) were met in 121 (2.9%) of the 4,184 patients with an oxygenation measurement. The following variables were independently associated with ALI: higher Pediatric Risk of Admission II score (adjusted odds ratio [95% confidence interval (CI)] = 1.12 [1.08-1.16]; p < .001), higher heart rate (1.02 [1.01-1.03]; p = .009), a positive chest radiograph (2.35 [1.02-5.43]; p = .045), and lower temperature (0.49 [0.36-0.68]; p < .001).The final model had an R(2) = .20.

CONCLUSION

We found nonintubated AHRF to be prevalent in the ED. The low R(2) for the regression model for AHRF underscores the lack of criteria for early identification of patients with respiratory compromise. Our findings represent an important first step toward establishing the true incidence of ALI in the pediatric ED.

The epidemiology of acute respiratory distress syndrome in pediatric intensive care units in China

OBJECTIVE

To assess the incidence of, predisposing factors for, and the rates and relative risks of mortality from acute respiratory distress syndrome (ARDS) in pediatric patients.

DESIGN

A prospective study in 12 consecutive months from 2004 to 2005 in 25 pediatric intensive care units (PICUs).

PATIENTS AND SETTING

ARDS was diagnosed according to the 1994 American-European Consensus Conference definitions, applied to all severely ill admissions between 1 month and 14 years of age. The PICUs were in major municipalities and provincial cities, and half were university affiliated.

MEASUREMENTS AND RESULTS

From a total of 12,018 admissions, 7,269 were severely ill. One hundred and five (1.44%) patients developed ARDS and 64 (61.0%) died, which accounts for 13.2%, of the total ICU death (n = 485, 6.7%) or a nine times relative risk of dying. The median age at onset of ARDS was 24 months and 40% were less than 12 month old. Median time from PICU admission to the onset of ARDS was 16 h, and in 63% <24 h. Pneumonia (55.2%) and sepsis (22.9%) were the major predisposing factors for ARDS. These were respectively 14 and 5 times as high a death rate as those of the severely ill patients without ARDS.

CONCLUSIONS

ARDS has a high mortality in these Chinese PICUs, especially in those with pneumonia and sepsis, and adequate management including lung protective ventilation strategy is required.

Acute lung injury in pediatric intensive care in Australia and New Zealand: a prospective, multicenter, observational study

OBJECTIVE

Acute lung injury (ALI) is poorly defined in children. The objective of this prospective study was to clarify the incidence, demographics, management strategies, outcome, and mortality predictors of ALI in children in Australia and New Zealand.

DESIGN

Multicenter prospective study during a 12-month period.

SETTING

Intensive care unit.

PATIENTS

All children admitted to intensive care and requiring mechanical ventilation were screened daily for development of ALI based on American-European Consensus Conference guidelines. Identified patients were followed for 28 days or until death or discharge.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 117 cases of ALI during the study period, giving a population incidence of 2.95/100,000 <16 yrs. ALI accounted for 2.2% of pediatric intensive care unit admissions. Mortality was 35% for ALI, and this accounted for 30% of all pediatric intensive care unit deaths during the study period. Significant preadmission risk factors for mortality were chronic disease, older age, and immunosuppression. Predictors of mortality during admission were ventilatory requirements (peak inspiratory pressures, mean airway pressure, positive end-expiratory pressure) and indexes of respiratory severity on day 1 (Pao2/Fio2 ratio and oxygenation index). Higher maximum and median tidal volumes were associated with reduced mortality, even when corrected for severity of lung disease. Development of single and multiple organ failure was significantly associated with mortality.

CONCLUSIONS

ALI in children is uncommon but has a high mortality rate. Risk factors for mortality are easily identified. Ventilatory variables and indexes of lung severity were significantly associated with mortality.

Incidence of acute respiratory distress syndrome in German children and adolescents: A population-based study

OBJECTIVE

The objective of this study was to determine the epidemiology of acute respiratory distress syndrome (ARDS) in children and adolescents aged 1 mo to 18 yrs.

DESIGN

The authors conducted a population-based prospective multicenter survey from February 1 to 28,1997, June 1 to 30, 2001, and April 1 to 30, 2004.

SETTING

This study was conducted at 94 intensive care units (ICUs) in 1997, 92 ICUs in 2001 and 2004 in the district of Cologne, Germany with a population of 4.15 (1997), 4.28 (2001), and 4.35 million (2004), respectively. The survey was not confined to children's hospitals, but addressed all ICUs.

PATIENTS

This study consisted of children and adolescents aged 1 mo to 18 yrs. Term neonates and premature babies with a corrected age below 43 gestational weeks were excluded. ARDS was defined according to the consensus criteria (acute-onset pulmonary process of noncardiogenic origin, Pao(2)/FIo(2) ratio <200, bilateral alveolar infiltration in chest radiograph).

RESULTS

All ICUs at pediatric hospitals and all but seven adult ICUs collaborated. Incidence of ARDS was assessed as the number of patients entering ARDS criteria within the three study periods divided by the total population in this age group. During the study period, 12 pediatric patients were diagnosed as having ARDS. In five cases, onset was before the study period, representing a calculated prevalence of 5.5 x 10(-5) [3.1 x 10(-5); 9.6 x 10(-5)] cases per year and an incidence of 3. 2 x 10(-5) [1.5 x 10(-5); 6.6 x 10(-5)] cases per year in the age group under investigation.

CONCLUSION

This is the first population-based evaluation of the incidence of ARDS in the pediatric age group. It shows that the incidence of ARDS in this age group is low. This makes randomized studies on pediatric ARDS aiming on the end point "outcome" nearly impossible.

Partial liquid ventilation for the prevention of mortality and morbidity in paediatric acute lung injury and acute respiratory distress syndrome

BACKGROUND

Acute lung injury, and acute respiratory distress syndrome, are syndromes of severe respiratory failure. Children with acute lung injury or acute respiratory syndrome have high mortality and significant morbidity. Partial liquid ventilation is proposed as a less injurious form of respiratory support for these children. Uncontrolled studies in adults have shown improvement in gas exchange and lung compliance with partial liquid ventilation A single uncontrolled study in six children with acute respiratory syndrome showed some improvement in gas exchange during three hours of partial liquid ventilation.

OBJECTIVES

To assess whether partial liquid ventilation reduces either mortality or morbidity, or both, in children with acute lung injury or acute respiratory syndrome.

SEARCH STRATEGY

We searched The Cochrane Central Register of Controlled Trials (CENTRAL), The Cochrane Library issue 2, 2003; MEDLINE (1966 to April 2003); and CINAHL (1982 to April 2003); intensive care journals and conference proceedings; reference lists and 'grey literature'.

SELECTION CRITERIA

Randomized controlled trials which compared partial liquid ventilation with other forms of ventilation, in children (28 days - 18 years) with acute lung injury or acute respiratory syndrome, reporting one or more of the following: mortality; duration of mechanical ventilation, respiratory support, oxygen therapy, stay in the intensive care unit, or stay in hospital; infection; or long term cognitive impairment or neurodevelopmental progress or other long term morbidities.

DATA COLLECTION AND ANALYSIS

Two reviewers independently evaluated the quality of the relevant studies and extracted the data from the included studies.

MAIN RESULTS

Only one study enrolling 182 patients (only reported as an abstract in conference proceedings) was identified and found eligible for inclusion: the authors report only limited results. The trial was stopped prematurely and therefore under-powered to detect any significant differences. The only outcome of clinical significance available was 28 day mortality: there was no statistically significant difference between groups with a relative risk for 28 day mortality in the partial liquid ventilation group of 1.54 (95% confidence intervals of 0.82 to 2.9).

REVIEWERS' CONCLUSIONS

There is no evidence from randomized controlled trials to support or refute the use of partial liquid ventilation in children with acute lung injury or acute respiratory syndrome: adequately powered, high quality randomized controlled trials are still needed to assess its efficacy. Clinically relevant outcome measures should be assessed (mortality at discharge and later, duration of respiratory support and hospital stay, and long-term neurodevelopmental outcomes) and the studies should be published in full.

Acute respiratory distress syndrome in long-chain 3-hydroxyacyl-CoA dehydrogenase and mitochondrial trifunctional protein deficiencies

Inborn errors of metabolism have not previously been recognized as a risk factor for acute respiratory distress syndrome (ARDS). We report this complication in four patients with defects of the mitochondrial trifunctional protein (MTP). This enzyme catalyses three steps in the beta-oxidation of long-chain fatty acids. Three of the patients were homozygous for the 'common' 1528G>C mutation in the alpha-subunit of the MTP, giving rise to long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. The fourth patient did not carry this mutation but had severely decreased activities of long-chain 3-hydroxyacyl-CoA dehydrogenase and long-chain 3-ketoacyl-CoA thiolase. One patient died and histology in this patient showed severe interstitial pulmonary fibrosis. The other three patients recovered after being ventilated for up to 6 months. The high frequency of ARDS in patients with MTP defects suggests that this inborn error may be a risk factor for ARDS.

Current concepts in adult respiratory distress syndrome in children

Acute respiratory distress syndrome (ARDS) is an acute form of severe alveolar-capillary injury that evolves after a direct or indirect lung insult. It begins as noncardiogenic pulmonary edema and develops into a neutrophilic alveolitis, and, later, pulmonary fibrosis. Mortality remains high among children with ARDS, particularly when serious underlying conditions co-exist, sepsis occurs, and when there is multi-organ failure. Lung function improves with time among survivors, but pulmonary fibrosis may persist. Advances in the care of children with ARDS include the use of lung-protective ventilator strategies, permissive hypercapnia, inhaled nitric oxide, high-frequency ventilation, and extra-corporeal life support. These approaches reduce ventilator-associated lung injury and may improve survival when used in combination with one another. Interventions that reduce alveolar inflammation, enhance alveolar fluid removal, and reduce pulmonary fibrosis will further improve survival and recovery from ARDS in the future.

High-frequency oscillatory ventilation of the perfluorocarbon-filled lung: Dose-response relationships in an animal model of acute lung injury

OBJECTIVE

To examine dose-response relationships regarding the efficiency of gas exchange and hemodynamic function during high-frequency oscillation and partial liquid ventilation (HFO-PLV) of the perfluorocarbon (PFC)-treated lung in a model of acute lung injury.

SETTING

An animal research laboratory in a university medical center.

DESIGN

A prospective, randomized study comparing animals receiving varying doses (0, 5, 15, and 20 mL/kg) of perflubron during high-frequency oscillatory ventilation (HFOV) with mean airway pressure (Paw) optimized to achieve a minimal percutaneous oxygen saturation (Spo2).

SUBJECTS

Nineteen healthy swine (mean weight 28.9 kg) with saline lavage-induced acute lung injury.

METHODS

Animals were treated with repetitive saline lavage to achieve a uniform degree of acute lung injury (Spo2 < or =90% on an Fio2 of 1.0). After lung injury, subjects were converted to HFOV, and lung volume was optimized. HFO-PLV was initiated by instillation of perflubron at a rate of 0.5 mL.kg-1.min-1 to achieve total doses of 5, 15, and 20 mL/kg. After PFC dosing, the only experimental manipulation consisted of adjustment of Paw to achieve an Spo2 of 90% +/- 2% with Fio2 of 0.6. Gas exchange, hemodynamic variables, and pulmonary mechanics data were collected over a 1-hr period. Five control animals were not dosed with perflubron and remained on HFOV for the 1-hr period of data collection.

MEASUREMENTS AND MAIN RESULTS

After lung volume recruitment with HFOV, the initiation of HFO-PLV was best tolerated with the two lower doses in our protocol. There were essentially no changes in Paco2 or pH between groups over the dosing interval. After dosing, analysis of variance demonstrated a PFC dose-dependent effect for oxygenation index (p =.01) only; the lowest oxygenation index was found in the 15 mL/kg group (p =.01). In the 15 mL/kg group, the Paw decreased steadily from 20.6 +/- 3.4 cm H2O at the end of dosing to 18.0 +/- 4.9 cm H2O at 60 mins. The Pao2 increased from 113 +/- 51 torr (15.06 +/- 6.79 kPa) to 134 +/- 49 torr (17.86 +/- 6.53 kPa) during this period and was associated with a decreasing oxygenation index (from 11.4 +/- 2.0 to 9.3 +/- 1.5). The cardiac index and pulmonary vascular resistance did not change significantly during the dosing period and were relatively stable after the completion of dosing.

CONCLUSIONS

The combination of HFOV and perflubron administration was well tolerated hemodynamically and was not associated with deterioration of gas exchange during dosing. Our data suggest that the optimal dose of perflubron to achieve the lowest oxygenation index during HFO-PLV is between 5 and 15 mL/kg. The combination of HFOV and perflubron administration is a novel strategy in the treatment of acute lung injury that shows some promise and merits additional investigation. We hope in future studies to address the histopathologic effects of varying perflubron doses during HFOV in a long-term study of the lung-protective effects of HFO-PLV.

[Severe community-acquired pneumonia in immunocompetent children]

Severe community-acquired pneumonia (CAP) is still a serious disease with a high mortality rate, especially in developing countries. Children under 5 years are more prone to severe CAP. In this article, the authors review the definition and clinical criteria used in the initial evaluation and decision to hospitalize patients. The diagnosis approach requires only a limited number of laboratory tests before initiating the supportive measures and wide spectrum antimicrobial therapy. If the patient fails to respond favorably 48-72 hours after initiating therapy, more invasive investigations are indicated. After resolution, an immunological evaluation is warranted.

Incidence of acute respiratory distress syndrome: a comparison of two definitions

OBJECTIVES

To determine the incidence and outcome of acute respiratory distress syndrome (ARDS) in children by comparing two commonly used definitions: the lung injury score and the American-European Consensus Conference definition. The causes and risk for developing ARDS were also studied.

METHODS

Part prospective and retrospective analysis of 8100 consecutive hospital admissions from 1 June 1995 to 1 April 1997.

RESULTS

Twenty one patients fulfilled the criteria for ARDS. Both definitions identified the same group of patients. The incidence was 2.8/1000 hospital admissions or 4.2% of paediatric intensive care unit admissions. The main causes were sepsis and pneumonia. Mortality was 13 of 21. Factors predicting death were a high admission paediatric risk of mortality (PRISM) score (30.38 v 18.75) and the presence of multiple organ dysfunction syndrome (92% v 25%).

CONCLUSION

Both definitions identified similar groups of patients. The incidence in this population was higher than that reported elsewhere, but mortality and cause were similar to those in developed countries. Poor outcome was associated with sepsis, a high admission PRISM score, and simultaneous occurrence of other organ dysfunction.

[Current aspects of acute respiratory distress syndrome in children]

Acute respiratory distress syndrome (ARDS) is a frequent condition in pediatric intensive care units. The mortality remains high despite advances in conventional mechanical ventilation and aetiological treatment. Several animal studies have documented lung injury during mechanical ventilation with high tidal volume, and clinical investigations have shown that in human ARDS, most ventilation is distributed to the small areas of remaining aerated lung resulting in overdistension of these areas and lung injury ("baby lung" theory). Nevertheless the usefulness of extrapulmonary gas exchange remains much debated. New ventilatory strategies have been developed in order to reduce ventilator-induced lung injury and to improve systemic oxygenation but multicentric randomized clinical trials are needed before these strategies can be validated.