Multicenter randomized controlled trial of the effects of inhaled nitric oxide therapy on gas exchange in children with acute hypoxemic respiratory failure

Inhaled Nitric Oxide in Acute Respiratory Distress Syndrome Subsets: Rationale and Clinical Applications

Acute respiratory distress syndrome (ARDS) is a life-threatening condition, characterized by diffuse inflammatory lung injury. Since the coronavirus disease 2019 (COVID-19) pandemic spread worldwide, the most common cause of ARDS has been the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Both the COVID-19-associated ARDS and the ARDS related to other causes-also defined as classical ARDS-are burdened by high mortality and morbidity. For these reasons, effective therapeutic interventions are urgently needed. Among them, inhaled nitric oxide (iNO) has been studied in patients with ARDS since 1993 and it is currently under investigation. In this review, we aim at describing the biological and pharmacological rationale of iNO treatment in ARDS by elucidating similarities and differences between classical and COVID-19 ARDS. Thereafter, we present the available evidence on the use of iNO in clinical practice in both types of respiratory failure. Overall, iNO seems a promising agent as it could improve the ventilation/perfusion mismatch, gas exchange impairment, and right ventricular failure, which are reported in ARDS. In addition, iNO may act as a viricidal agent and prevent lung hyperinflammation and thrombosis of the pulmonary vasculature in the specific setting of COVID-19 ARDS. However, the current evidence on the effects of iNO on outcomes is limited and clinical studies are yet to demonstrate any survival benefit by administering iNO in ARDS.

Pulmonary Specific Ancillary Treatment for Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

We conducted an updated review of the literature on pulmonary-specific ancillary therapies for pediatric acute respiratory distress syndrome (PARDS) to provide an update to the Pediatric Acute Lung Injury Consensus Conference recommendations and statements about clinical practice and research.

DATA SOURCES

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

STUDY SELECTION

Searches were limited to children, PARDS or hypoxic respiratory failure and overlap with pulmonary-specific ancillary therapies.

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 evidence and develop recommendations. Twenty-six studies were identified for full-text extraction. Four clinical recommendations were generated, related to use of inhaled nitric oxide, surfactant, prone positioning, and corticosteroids. Two good practice statements were generated on the use of routine endotracheal suctioning and installation of isotonic saline prior to endotracheal suctioning. Three research statements were generated related to: the use of open versus closed suctioning, specific methods of airway clearance, and various other ancillary therapies.

CONCLUSIONS

The evidence to support or refute any of the specific ancillary therapies in children with PARDS remains low. Further investigation, including a focus on specific subpopulations, is needed to better understand the role, if any, of these various ancillary therapies in PARDS.

ARDS Clinical Practice Guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO2 (PaO2) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D), we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D), we suggest against routinely implementing NO inhalation therapy (GRADE 2C), and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jsicm.org/publication/guideline.html ). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

ARDS clinical practice guideline 2021

BACKGROUND

The joint committee of the Japanese Society of Intensive Care Medicine/Japanese Respiratory Society/Japanese Society of Respiratory Care Medicine on ARDS Clinical Practice Guideline has created and released the ARDS Clinical Practice Guideline 2021.

METHODS

The 2016 edition of the Clinical Practice Guideline covered clinical questions (CQs) that targeted only adults, but the present guideline includes 15 CQs for children in addition to 46 CQs for adults. As with the previous edition, we used a systematic review method with the Grading of Recommendations Assessment Development and Evaluation (GRADE) system as well as a degree of recommendation determination method. We also conducted systematic reviews that used meta-analyses of diagnostic accuracy and network meta-analyses as a new method.

RESULTS

Recommendations for adult patients with ARDS are described: we suggest against using serum C-reactive protein and procalcitonin levels to identify bacterial pneumonia as the underlying disease (GRADE 2D); we recommend limiting tidal volume to 4-8 mL/kg for mechanical ventilation (GRADE 1D); we recommend against managements targeting an excessively low SpO₂ (PaO₂) (GRADE 2D); we suggest against using transpulmonary pressure as a routine basis in positive end-expiratory pressure settings (GRADE 2B); we suggest implementing extracorporeal membrane oxygenation for those with severe ARDS (GRADE 2B); we suggest against using high-dose steroids (GRADE 2C); and we recommend using low-dose steroids (GRADE 1B). The recommendations for pediatric patients with ARDS are as follows: we suggest against using non-invasive respiratory support (non-invasive positive pressure ventilation/high-flow nasal cannula oxygen therapy) (GRADE 2D); we suggest placing pediatric patients with moderate ARDS in the prone position (GRADE 2D); we suggest against routinely implementing NO inhalation therapy (GRADE 2C); and we suggest against implementing daily sedation interruption for pediatric patients with respiratory failure (GRADE 2D).

CONCLUSIONS

This article is a translated summary of the full version of the ARDS Clinical Practice Guideline 2021 published in Japanese (URL: https://www.jrs.or.jp/publication/jrs_guidelines/). The original text, which was written for Japanese healthcare professionals, may include different perspectives from healthcare professionals of other countries.

Nitric oxide: Clinical applications in critically ill patients

Inhaled nitric oxide (iNO) acts as a selective pulmonary vasodilator and it is currently approved by the FDA for the treatment of persistent pulmonary hypertension of the newborn. iNO has been demonstrated to effectively decrease pulmonary artery pressure and improve oxygenation, while decreasing extracorporeal life support use in hypoxic newborns affected by persistent pulmonary hypertension. Also, iNO seems a safe treatment with limited side effects. Despite the promising beneficial effects of NO in the preclinical literature, there is still a lack of high quality evidence for the use of iNO in clinical settings. A variety of clinical applications have been suggested in and out of the critical care environment, aiming to use iNO in respiratory failure and pulmonary hypertension of adults or as a preventative measure of hemolysis-induced vasoconstriction, ischemia/reperfusion injury and as a potential treatment of renal failure associated with cardiopulmonary bypass. In this narrative review we aim to present a comprehensive summary of the potential use of iNO in several clinical conditions with its suggested benefits, including its recent application in the scenario of the COVID-19 pandemic. Randomized controlled trials, meta-analyses, guidelines, observational studies and case-series were reported and the main findings summarized. Furthermore, we will describe the toxicity profile of NO and discuss an innovative proposed strategy to produce iNO. Overall, iNO exhibits a wide range of potential clinical benefits, that certainly warrants further efforts with randomized clinical trials to determine specific therapeutic roles of iNO.

Advances in the Pharmacological Management of Pediatric Acute Respiratory Distress Syndrome

INTRODUCTION

Noninvasive mechanical ventilation is the main supportive measure used in patients with pediatric ARDS (PARDS), but adjunctive pharmacological therapies (corticosteroids, inhaled nitric oxide [iNO], surfactant replacement therapy and neuromuscular blocking drugs) are also used, although limited data exists to inform of this practice.

AREAS COVERED

The authors review the current challenges in the pharmacological management of PARDS and highlight the few certainties currently available.

EXPERT OPINION

Children with PARDS must not be treated as young adults with ARDS, essentially because children's lungs differ substantially from those of adults and PARDS occurs in children differently than ARDS in adults. Pharmacological treatments available for PARDS are relatively few and, since there is great uncertainty about their effectiveness also because of the extreme heterogeneity of this syndrome, it is necessary to conduct large clinical trials using currently available definitions and considering recent pathobiological knowledge. The aim is to identify homogeneous subgroups or phenotypes of children with PARDS that may benefit from the specific pharmaceutical approach examined. It will be then necessary to link endotypes and outcomes to appropriately target therapies in future trials, but this will be possible only after it will be possible to identify the different PARDS endotypes.

Inhalational Gases for Neuroprotection in Traumatic Brain Injury

Despite multiple prior pharmacological trials in traumatic brain injury (TBI), the search for an effective, safe, and practical treatment of these patients remains ongoing. Given the ease of delivery and rapid absorption into the systemic circulation, inhalational gases that have neuroprotective properties will be an invaluable resource in the clinical management of TBI patients. In this review, we perform a systematic review of both pre-clinical and clinical reports describing inhalational gas therapy in the setting of TBI. Hyperbaric oxygen, which has been investigated for many years, and some of the newest developments are reviewed. Also, promising new therapies such as hydrogen gas, hydrogen sulfide gas, and nitric oxide are discussed. Moreover, novel therapies such as xenon and argon gases and delivery methods using microbubbles are explored.

Early Use of Adjunctive Therapies for Pediatric Acute Respiratory Distress Syndrome: A PARDIE Study

Rationale: Few data exist to guide early adjunctive therapy use in pediatric acute respiratory distress syndrome (PARDS).Objectives: To describe contemporary use of adjunctive therapies for early PARDS as a framework for future investigations.Methods: This was a preplanned substudy of a prospective, international, cross-sectional observational study of children with PARDS from 100 centers over 10 study weeks.Measurements and Main Results: We investigated six adjunctive therapies for PARDS: continuous neuromuscular blockade, corticosteroids, inhaled nitric oxide (iNO), prone positioning, high-frequency oscillatory ventilation (HFOV), and extracorporeal membrane oxygenation. Almost half (45%) of children with PARDS received at least one therapy. Variability was noted in the median starting oxygenation index of each therapy; corticosteroids started at the lowest oxygenation index (13.0; interquartile range, 7.6-22.0) and HFOV at the highest (25.7; interquartile range, 16.7-37.3). Continuous neuromuscular blockade was the most common, used in 31%, followed by iNO (13%), corticosteroids (10%), prone positioning (10%), HFOV (9%), and extracorporeal membrane oxygenation (3%). Steroids, iNO, and HFOV were associated with comorbidities. Prone positioning and HFOV were more common in middle-income countries and less frequently used in North America. The use of multiple ancillary therapies increased over the first 3 days of PARDS, but there was not an easily identifiable pattern of combination or order of use.Conclusions: The contemporary description of prevalence, combinations of therapies, and oxygenation threshold for which the therapies are applied is important for design of future studies. Region of the world, income, and comorbidities influence adjunctive therapy use and are important variables to include in PARDS investigations.

Inhaled Nitric Oxide Use in Pediatric Hypoxemic Respiratory Failure

OBJECTIVES

To characterize contemporary use of inhaled nitric oxide in pediatric acute respiratory failure and to assess relationships between clinical variables and outcomes. We sought to study the relationship of inhaled nitric oxide response to patient characteristics including right ventricular dysfunction and clinician responsiveness to improved oxygenation. We hypothesize that prompt clinician responsiveness to minimize hyperoxia would be associated with improved outcomes.

DESIGN

An observational cohort study.

SETTING

Eight sites of the Collaborative Pediatric Critical Care Research Network.

PATIENTS

One hundred fifty-one patients who received inhaled nitric oxide for a primary respiratory indication.

MEASUREMENTS AND MAIN RESULTS

Clinical data were abstracted from the medical record beginning at inhaled nitric oxide initiation and continuing until the earliest of 28 days, ICU discharge, or death. Ventilator-free days, oxygenation index, and Functional Status Scale were calculated. Echocardiographic reports were abstracted assessing for pulmonary hypertension, right ventricular dysfunction, and other cardiovascular parameters. Clinician responsiveness to improved oxygenation was determined. One hundred thirty patients (86%) who received inhaled nitric oxide had improved oxygenation by 24 hours. PICU mortality was 29.8%, while a new morbidity was identified in 19.8% of survivors. Among patients who had echocardiograms, 27.9% had evidence of pulmonary hypertension, 23.1% had right ventricular systolic dysfunction, and 22.1% had an atrial communication. Moderate or severe right ventricular dysfunction was associated with higher mortality. Clinicians responded to an improvement in oxygenation by decreasing FIO2 to less than 0.6 within 24 hours in 71% of patients. Timely clinician responsiveness to improved oxygenation with inhaled nitric oxide was associated with more ventilator-free days but not less cardiac arrests, mortality, or additional morbidity.

CONCLUSIONS

Clinician responsiveness to improved oxygenation was associated with less ventilator days. Algorithms to standardize ventilator management may improve signal to noise ratios in future trials enabling better assessment of the effect of inhaled nitric oxide on patient outcomes. Additionally, confining studies to more selective patient populations such as those with right ventricular dysfunction may be required.

Successful use of inhaled epoprostenol as rescue therapy for pediatric ARDS

Severe pediatric ARDS remains a significant challenge for clinicians, and management strategies are essentially limited to lung protective ventilation strategies, and adjunct approaches such as prone positioning, steroids, surfactant, and inhaled nitric oxide in unique situations. Inhaled nitric oxide produces pulmonary vasodilation in ventilated regions of the lung, shunting blood away from poorly ventilated areas and thus optimizing the ventilation perfusion ratio. A subset of patients with ARDS are known to be non-responders to nitric oxide, and selective pulmonary vasodilators such as Epoprostenol can be useful as rescue therapy in such cases. We describe a case of severe pediatric ARDS in the setting of pre-existing pulmonary hypertension and Trisomy 21, whose clinical course improved remarkably once inhaled Epoprostenol was initiated.

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.

Inhaled nitric oxide use in neonates: Balancing what is evidence-based and what is physiologically sound

Inhaled nitric oxide is a powerful therapeutic used in neonatology. Its use is evidenced-based for term and near-term infants with persistent pulmonary hypertension; however, it is frequently used off-label both in term and preterm babies. This article reviews the off-label uses of iNO in infants. Rationale is discussed for a selective application of iNO based on physiologically guided principles, and new research avenues are considered.

The Current State of Pediatric Acute Respiratory Distress Syndrome

Pediatric acute respiratory distress syndrome (PARDS) is a significant cause of morbidity and mortality in children. Children with PARDS often require intensive care admission and mechanical ventilation. Unfortunately, beyond lung protective ventilation, there are limited data to support our management strategies in PARDS. The Pediatric Acute Lung Injury Consensus Conference (PALICC) offered a new definition of PARDS in 2015 that has improved our understanding of the true epidemiology and heterogeneity of the disease as well as risk stratification. Further studies will be crucial to determine optimal management for varying disease severity. This review will present the physiologic basis of PARDS, describe the unique pediatric definition and risk stratification, and summarize the current evidence for current standards of care as well as adjunctive therapies.

Association of Response to Inhaled Nitric Oxide and Duration of Mechanical Ventilation in Pediatric Acute Respiratory Distress Syndrome

OBJECTIVES

Literature regarding appropriate use of inhaled nitric oxide for pediatric acute respiratory distress syndrome is sparse. This study aims to determine if positive response to inhaled nitric oxide is associated with decreased mortality and duration of mechanical ventilation in pediatric acute respiratory distress syndrome.

DESIGN

Retrospective cohort study.

SETTING

Large pediatric academic medical center.

PATIENTS OR SUBJECTS

One hundred sixty-one children with pediatric acute respiratory distress syndrome and inhaled nitric oxide exposure for greater than or equal to 1 hour within 3 days of pediatric acute respiratory distress syndrome onset.

INTERVENTIONS

Patients with greater than or equal to 20% improvement in oxygenation index or oxygen saturation index by 6 hours after inhaled nitric oxide initiation were classified as "responders."

MEASUREMENTS AND MAIN RESULTS

Oxygenation index, oxygen saturation index, and ventilator settings were evaluated prior to inhaled nitric oxide initiation and 1, 6, 12, and 24 hours following inhaled nitric oxide initiation. Primary outcomes were mortality and duration of mechanical ventilation. Baseline characteristics, including severity of illness, were similar between responders and nonresponders. Univariate analysis showed no difference in mortality between responders and nonresponders (21% vs 21%; p = 0.999). Ventilator days were significantly lower in responders (10 vs 16; p < 0.001). Competing risk regression (competing risk of death) confirmed association between inhaled nitric oxide response and successful extubation (subdistribution hazard ratio = 2.11; 95% CI, 1.41-3.17; p < 0.001). Response to inhaled nitric oxide was associated with decreased utilization of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation and lower hospital charges (difference in medians of $424,000).

CONCLUSIONS

Positive response to inhaled nitric oxide was associated with fewer ventilator days, without change in mortality, potentially via reduced use of high-frequency oscillatory ventilation and extracorporeal membrane oxygenation. Future studies of inhaled nitric oxide for pediatric acute respiratory distress syndrome should stratify based on oxygenation response, given the association with favorable outcomes.

Pathophysiology and Management of Acute Respiratory Distress Syndrome in Children

Acute respiratory distress syndrome (ARDS) is a syndrome of noncardiogenic pulmonary edema and hypoxia that accompanies up to 30% of deaths in pediatric intensive care units. Pediatric ARDS (PARDS) is diagnosed by the presence of hypoxia, defined by oxygenation index or Pao₂/Fio₂ ratio cutoffs, and new chest infiltrate occurring within 7 days of a known insult. Hallmarks of ARDS include hypoxemia and decreased lung compliance, increased work of breathing, and impaired gas exchange. Mortality is often accompanied by multiple organ failure. Although many modalities to treat PARDS have been investigated, supportive therapies and lung protective ventilator support remain the mainstay.

Effect of Inhaled Nitric Oxide on Outcomes in Children With Acute Lung Injury: Propensity Matched Analysis From a Linked Database

OBJECTIVES

To evaluate the effect of inhaled nitric oxide on outcomes in children with acute lung injury.

DESIGN

Retrospective study with a secondary data analysis of linked data from two national databases. Propensity score matching was performed to adjust for potential confounding variables between patients who received at least 24 hours of inhaled nitric oxide (inhaled nitric oxide group) and those who did not receive inhaled nitric oxide (no inhaled nitric oxide group).

SETTING

Linked data from Virtual Pediatric Systems (LLC) database and Pediatric Health Information System.

PATIENTS

Patients less than 18 years old receiving mechanical ventilation for acute lung injury at nine participating hospitals were included (2009-2014).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 20,106 patients from nine hospitals were included. Of these, 859 patients (4.3%) received inhaled nitric oxide for at least 24 hours during their hospital stay. Prior to matching, patients in the inhaled nitric oxide group were younger, with more comorbidities, greater severity of illness scores, higher prevalence of cardiopulmonary resuscitation, and greater resource utilization. Before matching, unadjusted outcomes, including mortality, were worse in the inhaled nitric oxide group (inhaled nitric oxide vs no inhaled nitric oxide; 25.7% vs 7.9%; p < 0.001; standardized mortality ratio, 2.6 [2.3-3.1] vs 1.1 [1.0-1.2]; p < 0.001). Propensity score matching of 521 patient pairs revealed no difference in mortality in the two groups (22.3% vs 20.2%; p = 0.40; standardized mortality ratio, 2.5 [2.1-3.0] vs 2.3 [1.9-2.8]; p = 0.53). However, the other outcomes such as ventilation free days (10.1 vs 13.6 d; p < 0.001), duration of mechanical ventilation (13.8 vs 10.1 d; p < 0.001), duration of ICU and hospital stay (15.5 vs 12.2 d; p < 0.001 and 28.0 vs 24.1 d; p < 0.001), and hospital costs ($150,569 vs $102,823; p < 0.001) were significantly worse in the inhaled nitric oxide group.

CONCLUSIONS

This large observational study demonstrated that inhaled nitric oxide administration in children with acute lung injury was not associated with improved mortality. Rather, it was associated with increased hospital utilization and hospital costs.

A Quality Improvement Initiative to Standardize Use of Inhaled Nitric Oxide in the PICU

Background:

Inhaled nitric oxide (iNO) is a potent pulmonary vasodilator used off-label to treat refractory hypoxemia in the pediatric intensive care unit (PICU). However, clinical practice varies widely, and there is limited evidence to support this expensive therapy. Our objective was to test whether implementation of a clinical guideline for iNO therapy would decrease practice variability, reduce ineffective iNO utilization, and control iNO-related costs.

Methods:

We used quality improvement (QI) methodology to standardize the use of iNO in a single quaternary care PICU (noncardiac). All PICU patients receiving iNO therapy between January 1, 2010, and December 31, 2013, were included. The QI intervention was the development and implementation of a clinical guideline for iNO initiation, continuation, and weaning. iNO use was monitored using statistical process control charts.

Results:

We derived baseline data from 30 preguideline patients (35 separate iNO courses) compared with 33 postguideline patients (36 separate iNO courses). Despite similar baseline characteristics, disease severity, and degree of hypoxemia, postguideline patients had a shorter median [interquartile range (IQR)] duration of iNO therapy than preguideline patients [76 (48–124) hours versus 162 (87–290) hours; P < 0.0001]. We have sustained the reduced iNO usage throughout the postguideline period. Postguideline patients also had improved provider documentation and a median iNO cost savings of $4,600.

Conclusions:

Implementation of iNO usage guidelines was associated with decreased iNO usage and cost of iNO therapy in the PICU.

The effect of inhaled nitric oxide in acute respiratory distress syndrome in children and adults: a Cochrane Systematic Review with trial sequential analysis

Acute respiratory distress syndrome is associated with high mortality and morbidity. Inhaled nitric oxide has been used to improve oxygenation but its role remains controversial. Our primary objective in this systematic review was to examine the effects of inhaled nitric oxide administration on mortality in adults and children with acute respiratory distress syndrome. We included all randomised, controlled trials, irrespective of date of publication, blinding status, outcomes reported or language. Our primary outcome measure was all-cause mortality. We performed several subgroup and sensitivity analyses to assess the effect of inhaled nitric oxide. There was no statistically significant effect of inhaled nitric oxide on longest follow-up mortality (inhaled nitric oxide group 250/654 deaths (38.2%) vs. control group 221/589 deaths (37.5%; relative risk (95% CI) 1.04 (0.9-1.19)). We found a significant improvement in PaO₂ /F_I O₂ ratio at 24 h (mean difference (95% CI) 15.91 (8.25-23.56)), but not at 48 h or 72 h, while four trials indicated improved oxygenation in the inhaled nitric oxide group at 96 h (mean difference (95% CI) 14.51 (3.64-25.38)). There were no statistically significant differences in ventilator-free days, duration of mechanical ventilation, resolution of multi-organ failure, quality of life, length of stay in intensive care unit or hospital, cost-benefit analysis and methaemoglobin and nitrogen dioxide levels. There was an increased risk of renal impairment (risk ratio (95% CI) 1.59 (1.17-2.16)) with inhaled nitric oxide. In conclusion, there is insufficient evidence to support inhaled nitric oxide in any category of critically ill patients with acute respiratory distress syndrome despite a transient improvement in oxygenation, since mortality is not reduced and it may induce renal impairment.

Pulmonary Edema and Hypoxic Respiratory Failure

OBJECTIVES

The purpose of this chapter is to outline the causes, physiology, pathophysiology, and management strategies for hydrostatic and permeability pulmonary edema and hypoxic respiratory failure.

DATA SOURCE

MEDLINE and PubMed.

CONCLUSION

The pulmonary parenchyma and vasculature are at high risk in conditions where injury occurs to the lung and or heart. A targeted approach that uses strategies that optimize the particular pathophysiology of the parenchyma and vasculature is required.

Pediatric Acute Hypoxemic Respiratory Failure: Management of Oxygenation

Acute hypoxemic respiratory failure (AHRF) is one of the hallmarks of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which are caused by an inflammatory process initiated by any of a number of potential systemic and/or pulmonary insults that result in heterogeneous disruption of the capillary-pithelial interface. In these critically sick patients, optimizing the management of oxygenation is crucial. Physicians managing pediatric patients with ALI or ARDS are faced with a complex array of options influencing oxygenation. Certain treatment strategies can influence clinical outcomes, such as a lung protective ventilation strategy that specifies a low tidal volume (6 mL/kg) and a plateau pressure limit (30 cm H2O). Other strategies such as different levels of positive end expiratory pressure, altered inspiration to expiration time ratios, recruitment maneuvers, prone positioning, and extraneous gases or drugs may also affect clinical outcomes. This article reviews state-of-the-art strategies on the management of oxygenation in acute hypoxemic respiratory failure in children.

Inhaled nitric oxide for acute respiratory distress syndrome (ARDS) in children and adults

BACKGROUND

Acute hypoxaemic respiratory failure (AHRF) and mostly acute respiratory distress syndrome (ARDS) are critical conditions. AHRF results from several systemic conditions and is associated with high mortality and morbidity in individuals of all ages. Inhaled nitric oxide (INO) has been used to improve oxygenation, but its role remains controversial. This Cochrane review was originally published in 2003, and has been updated in 2010 and 2016.

OBJECTIVES

The primary objective was to examine the effects of administration of inhaled nitric oxide on mortality in adults and children with ARDS. Secondary objectives were to examine secondary outcomes such as pulmonary bleeding events, duration of mechanical ventilation, length of stay, etc. We conducted subgroup and sensitivity analyses, examined the role of bias and applied trial sequential analyses (TSAs) to examine the level of evidence.

SEARCH METHODS

In this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2015 Issue 11); MEDLINE (Ovid SP, to 18 November 2015), EMBASE (Ovid SP, to 18 November 2015), CAB, BIOSIS and the Cumulative Index to Nursing and Allied Health Literature (CINAHL). We handsearched the reference lists of the newest reviews and cross-checked them with our search of MEDLINE. We contacted the main authors of included studies to request any missed, unreported or ongoing studies. The search was run from inception until 18 November 2015.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs), irrespective of publication status, date of publication, blinding status, outcomes published or language. We contacted trial investigators and study authors to retrieve relevant and missing data.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and resolved disagreements by discussion. Our primary outcome measure was all-cause mortality. We performed several subgroup and sensitivity analyses to assess the effects of INO in adults and children and on various clinical and physiological outcomes. We presented pooled estimates of the effects of interventions as risk ratios (RRs) with 95% confidence intervals (CIs). We assessed risk of bias through assessment of trial methodological components and risk of random error through trial sequential analysis.

MAIN RESULTS

Our primary objective was to assess effects of INO on mortality. We found no statistically significant effects of INO on longest follow-up mortality: 250/654 deaths (38.2%) in the INO group compared with 221/589 deaths (37.5%) in the control group (RR 1.04, 95% CI 0.9 to 1.19; I² statistic = 0%; moderate quality of evidence). We found no statistically significant effects of INO on mortality at 28 days: 202/587 deaths (34.4%) in the INO group compared with 166/518 deaths (32.0%) in the control group (RR 1.08, 95% CI 0.92 to 1.27; I² statistic = 0%; moderate quality of evidence). In children, there was no statistically significant effects of INO on mortality: 25/89 deaths (28.1%) in the INO group compared with 34/96 deaths (35.4%) in the control group (RR 0.78, 95% CI 0.51 to 1.18; I² statistic = 22%; moderate quality of evidence).Our secondary objective was to assess the benefits and harms of INO. For partial pressure of oxygen in arterial blood (PaO2)/fraction of inspired oxygen (FiO2), we found significant improvement at 24 hours (mean difference (MD) 15.91, 95% CI 8.25 to 23.56; I² statistic = 25%; 11 trials, 614 participants; moderate quality of evidence). For the oxygenation index, we noted significant improvement at 24 hours (MD -2.31, 95% CI -2.73 to -1.89; I² statistic = 0%; five trials, 368 participants; moderate quality of evidence). For ventilator-free days, the difference was not statistically significant (MD -0.57, 95% CI -1.82 to 0.69; I² statistic = 0%; five trials, 804 participants; high quality of evidence). There was a statistically significant increase in renal failure in the INO groups (RR 1.59, 95% CI 1.17 to 2.16; I² statistic = 0%; high quality of evidence).

AUTHORS' CONCLUSIONS

Evidence is insufficient to support INO in any category of critically ill patients with AHRF. Inhaled nitric oxide results in a transient improvement in oxygenation but does not reduce mortality and may be harmful, as it seems to increase renal impairment.

Role of Inhaled Nitric Oxide in the Management of Severe Acute Respiratory Distress Syndrome

To date, there have been several systematic reviews with meta-analysis that have shown no reduction in mortality with the use of inhaled nitric oxide (iNO) in patients with acute respiratory distress syndrome (ARDS). Importantly, these reports fail to make a distinction between the pediatric and adult patient. The number of adult patients in these reviews are far greater than the number of pediatric patients, which makes it difficult to interpret the data regarding the role of iNO on the pediatric population. Extrapolating data from the adult population to the pediatric population is complicated as we know that physiology and the body's response to disease can be different between adult and pediatric patients. iNO has been demonstrated to improve outcomes in term and near-term infants with hypoxic respiratory failure associated with pulmonary hypertension. Recently, Bronicki et al. published a prospective randomized control trial investigating the impact of iNO on the pediatric patient population with acute respiratory failure. In this study, a benefit of decreased duration of mechanical ventilation and an increased rate of ECMO-free survival was demonstrated in patients who were randomized to receiving iNO, suggesting that there may be benefit to the use of iNO in pediatric ARDS (PARDS) that has not been demonstrated in adults. iNO has repeatedly been shown to transiently improve oxygenation in all age groups, and yet neonates and pediatric patients have shown improvement in other outcomes that have not been seen in adults. The mechanism that explains improvement with the use of iNO in these patient populations are not well understood but does not appear to be solely a result of sustained improvement in oxygenation. There are physiologic studies that suggest alternative mechanisms for explaining the positive effects of iNO, such as platelet aggregation inhibition and reduction in systemic inflammation. Hence, the role of iNO by various mechanisms and in various age groups warrants further investigation.

Pediatric Acute Respiratory Distress Syndrome: Fibrosis versus Repair

Clinical and basic experimental approaches to pediatric acute lung injury (ALI), including acute respiratory distress syndrome (ARDS), have historically focused on acute care and management of the patient. Additional efforts have focused on the etiology of pediatric ALI and ARDS, clinically defined as diffuse, bilateral diseases of the lung that compromise function leading to severe hypoxemia within 7 days of defined insult. Insults can include ancillary events related to prematurity, can follow trauma and/or transfusion, or can present as sequelae of pulmonary infections and cardiovascular disease and/or injury. Pediatric ALI/ARDS remains one of the leading causes of infant and childhood morbidity and mortality, particularly in the developing world. Though incidence is relatively low, ranging from 2.9 to 9.5 cases/100,000 patients/year, mortality remains high, approaching 35% in some studies. However, this is a significant decrease from the historical mortality rate of over 50%. Several decades of advances in acute management and treatment, as well as better understanding of approaches to ventilation, oxygenation, and surfactant regulation have contributed to improvements in patient recovery. As such, there is a burgeoning interest in the long-term impact of pediatric ALI/ARDS. Chronic pulmonary deficiencies in survivors appear to be caused by inappropriate injury repair, with fibrosis and predisposition to emphysema arising as irreversible secondary events that can severely compromise pulmonary development and function, as well as the overall health of the patient. In this chapter, the long-term effectiveness of current treatments will be examined, as will the potential efficacy of novel, acute, and long-term therapies that support repair and delay or even impede the onset of secondary events, including fibrosis.

Pulmonary specific ancillary treatment for pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide an overview of the current literature on pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome to determine recommendations for clinical practice and/or future research.

DATA SOURCES

PubMed, EMBASE, CINAHL, SCOPUS, and the Cochrane Library were searched from inception until January 2013 using the following keywords in various combinations: ARDS, treatment, nitric oxide, heliox, steroids, surfactant, etanercept, prostaglandin therapy, inhaled beta adrenergic receptor agonists, N-acetylcysteine, ipratroprium bromide, dornase, plasminogen activators, fibrinolytics or other anticoagulants, and children. No language restrictions were applied. References from identified articles were searched for additional publications.

STUDY SELECTION

All clinical studies pertaining to pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome were reviewed. If clinical pediatric data were sparse or unavailable, the findings from studies of adult acute respiratory distress syndrome and animal models that might be relevant to pediatric acute respiratory distress syndrome were examined.

DATA EXTRACTION

All relevant studies were reviewed and pertinent data abstracted.

DATA SYNTHESIS

Over the course of three international meetings, the pertinent findings of the literature review were discussed by a panel of 24 experts in the field representing 21 academic institutions and 8 countries. Recommendations developed and the supporting literature were distributed to all panel members without a conflict of interest and were scored by using the Research ANd Development/University of California, Los Angeles Appropriateness method. The modified Delphi approach was used as the methodology to achieve consensus among the panel.

CONCLUSIONS

Overall, the routine use of surfactant, inhaled nitric oxide, glucocorticoids, prone positioning, endotracheal suctioning, and chest physiotherapy cannot be recommended. Inhaled nitric oxide should only be used for patients with documented pulmonary hypertension and/or right ventricular failure. Prone positioning may be considered in patients with severe pediatric acute respiratory distress syndrome. Future studies are definitely warranted to establish the role, if any, of these ancillary treatment modalities in pediatric acute respiratory distress syndrome.

Multicenter randomized controlled trial of inhaled nitric oxide for pediatric acute respiratory distress syndrome

OBJECTIVES

To test the hypothesis that inhaled nitric oxide (iNO) would lead to improved oxygenation and a decrease in duration of mechanical ventilation in pediatric patients with acute respiratory distress syndrome.

STUDY DESIGN

A total of 55 children with acute respiratory distress syndrome were enrolled from 9 centers. Patients were randomized to iNO or placebo and remained on the study drug until death, they were free of ventilator support, or day 28 after the initiation of therapy.

RESULTS

Mean baseline oxygenation indexes (OIs) were 22.0 ± 18.4 and 25.6 ± 14.9 (iNO and placebo groups, respectively, P = .27). There was a trend toward an improved OI in the iNO group compared with the placebo group at 4 hours that became significant at 12 hours. There was no difference in the OI between groups at 24 hours. Days alive and ventilator free at 28 days was greater in the iNO group, 14.2 ± 8.1 and 9.1 ± 9.5 days (iNO and placebo groups, respectively, P = .05). Although overall survival at 28 days failed to reach statistical significance, 92% (22 of 24) in the iNO group and 72% (21 of 29) in the placebo group (P = .07), the rate of extracorporeal membrane oxygenation-free survival was significantly greater in those randomized to iNO 92% (22 of 24) vs 52% (15 of 29) for those receiving placebo (P < .01).

CONCLUSION

The use of iNO was associated with a significantly reduced duration of mechanical ventilation and significantly greater rate of extracorporeal membrane oxygenation-free survival.

Emerging drugs for acute lung injury

INTRODUCTION

Acute respiratory distress syndromes (ARDS) are devastating disorders of overwhelming pulmonary inflammation and hypoxemia, resulting in high morbidity and mortality.

AREAS COVERED

The main pharmacological treatment strategies have focused on the attempted inhibition of excessive inflammation or the manipulation of the resulting physiological derangement causing respiratory failure. Additionally, such interventions may allow reduced occurence mechanical ventilation injury. Despite promising preclinical and small clinical studies, almost all therapies have been shown to be unsuccessful in large-scale randomized controlled trials. The evidence for pharmacological treatment for ARDS is reviewed. Potential future treatments are also presented.

EXPERT OPINION

We suggest for future clinical trials addressing prevention and early intervention to attenuate lung injury and progression to respiratory failure.

Bronchiolitis

Everyone on the planet is exposed to respiratory syncytial virus (RSV) infection by the age of 2 years. Most infants admitted to the pediatric intensive care unit (PICU) for respiratory support during this infection are previously healthy, but their principal risk for needing PICU treatment is young age. That is, if you are born in October/November in the northern hemisphere, then your first winter exposure to RSV is likely to be when you are less than 4 months of age and vulnerable because of poor respiratory mechanical reserve (Alonso et al. 2007). However, if you are born in May/June, then you will be 7–8 months during your first winter exposure to RSV, much bigger and stronger and have more efficient thoracic and diaphragmatic mechanics. In the PICU, the main predictors of severe outcome in previously well infants appear to be young age, presence of apnea, and pulmonary consolidation on admission chest radiograph (Tasker et al. 2000; Lopez Guinea et al. 2007). Taken together, we can say that more severe RSV bronchiolitis in PICU practice is typically a problem of pulmonary consolidation, poor respiratory mechanics, and poor reserve, in the younger infant.

Adjunctive treatments in pediatric acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a devastating process that involves pulmonary inflammation, alveolar damage and hypoxemic respiratory failure. Although advances in management approaches over the past two decades have resulted in significantly improved outcomes, death from pediatric ARDS may still occur in up to 35% of patients. While invasive mechanical ventilation is an essential component of ARDS management, various adjuncts have been utilized as treatment for these patients. However, evidence-based data in infants and children in this area are lacking. In this article, the authors review the available evidence supporting (or not supporting) the use of non-ventilatory adjunctive strategies in the management of pediatric ARDS, including prone positioning, pulmonary vasodilators, β-agonists, steroids and surfactant.

Advances in monitoring and management of pediatric acute lung injury

This article focuses on the respiratory management and monitoring of pediatric acute lung injury (ALI) as a specific cause for respiratory failure. Definitive, randomized, controlled trials in pediatrics to guide optimal ventilatory management are few. The only adjunct therapy that has been proved to improve clinical outcome is low tidal volume ventilation, but only in adult patients. Careful monitoring of the patient's respiratory status with airway graphic analysis and capnography can be helpful. Definitive data are needed in the pediatric population to assist in the care of infants, children, and adolescents with ALI to improve survival and functional outcome.

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.

Inhaled nitric oxide therapy for acute respiratory distress syndrome in children

The aim of this study was to evaluate the effects of inhaled nitric oxide (iNO) therapy on oxygenation and mortality in children with acute respiratory distress syndrome (ARDS). Thirty-three children with ARDS and an arterial SatO2 <88% despite mechanical ventilation were analyzed. Patients in the iNO group were prospectively enrolled and treated with conventional therapy plus iNO. The control group consisted of retrospectively analyzed patients treated only with conventional therapy. A significant increase in PaO2/FiO2 ratio (25.6%) and decrease in oxygenation index (19.5%) was observed after 4 h of iNO treatment, when compared to baseline values. A positive response to iNO was detected in 69% of patients, and there was no difference between pulmonary and extrapulmonary ARDS. There was no difference in mortality and duration of mechanical ventilation between iNO and control group.

Current knowledge of acute lung injury and acute respiratory distress syndrome

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) continues to be a major cause of mortality in adult and pediatric critical care medicine. This article discusses the pulmonary sequelae associated with ALI and ARDS, the support of ARDS with mechanical ventilation, available adjunctive therapies, and experimental therapies currently being tested. It is hoped that further understanding of the fundamental biology, improved identification of the patient's inflammatory state, and application of therapies directed at multiple sites of action may ultimately prove beneficial for patients suffering from ALI/ARDS.

Factors associated with mortality in pediatric patients requiring extracorporeal life support for severe pneumonia

OBJECTIVES

In children with respiratory failure secondary to pneumonia, extracorporeal life support can be lifesaving. Our goal was to identify variables associated with mortality in children with pneumonia requiring extracorporeal life support.

DESIGN

Data query and abstraction from a multicenter, international registry of extracorporeal life support, the Extracorporeal Life Support Organization Registry.

SETTING

Extracorporeal Life Support Organization registry data from 1985 to 2010.

PATIENTS

Patients ≤ 18 yr of age who received extracorporeal life support for respiratory failure secondary to pneumonia.

INTERVENTIONS

None.

MEASUREMENTS AND OUTCOMES

Clinical variables, year of extracorporeal life support, and extracorporeal life support center location were collected. The primary outcome was survival at hospital discharge. Results are reported as predictive margins, which allow estimation of standardized mortality rates and differences for risk factors.

RESULTS

One thousand four hundred eighty-nine children were included. The median (interquartile range) age and duration of extracorporeal life support were 5.7 months (2.5-21.5) and 11 days (7-18). Arterial cannulation was performed in 65% of patients. Mortality was 39%. There was no relationship between mortality and age or pathogen. Duration of extracorporeal life support had a biphasic relationship on mortality; mortality decreased 1.3% per day on extracorporeal life support until 14 days and then increased by 1.8% per day thereafter. Other independent predictors of mortality (p < 0.05) were pre-extracorporeal life support factors including duration of mechanical ventilation, peak inspiratory pressure, arterial oxygen saturation, pH, cardiac arrest, need for an arterial cannula, decade of extracorporeal life support, international extracorporeal life support center, and decrease in FIO2 over the first 24 hrs on extracorporeal life support.

CONCLUSIONS

In children with severe pneumonia receiving extracorporeal life support, prognostic factors associated with increased risk of death included extracorporeal life support treatment exceeding 14 days, arterial cannulation, longer duration of mechanical ventilation, and decreased ability to wean ventilator FIO2 over the first 24 hrs on extracorporeal life support. Analysis of the Extracorporeal Life Support Organization registry can identify prognostic variables, which may influence medical decision making, resource utilization, and family counseling.

Pharmacotherapy for pulmonary hypertension

Pulmonary arterial hypertension is a serious disease with significant morbidity and mortality. Although it can occur idiopathically, it is more commonly associated with other cardiac or lung diseases. While most of the available therapies have been tested in adult populations and most therapies in children remain off-label, new reports and randomized trials are emerging that inform the treatment of pediatric populations. This review discusses currently available therapies for pediatric pulmonary hypertension, their biological rationales, and evidence for their clinical effectiveness.

The impact of mechanical ventilation time before initiation of extracorporeal life support on survival in pediatric respiratory failure: a review of the Extracorporeal Life Support Registry

OBJECTIVE

To evaluate the relationship between duration of mechanical ventilation before the initiation of extracorporeal life support and the survival rate in children with respiratory failure. Extracorporeal life support has been used as a rescue therapy for >30 yrs in children with severe respiratory failure. Previous studies suggest patients who received >7-10 days of mechanical ventilation were not acceptable extracorporeal life support candidates as a result of irreversible lung damage.

DESIGN

A retrospective review encompassing the past 10 yrs of the International Extracorporeal Life Support Organization Registry (January 1, 1999, to December 31, 2008).

SETTING

Extracorporeal Life Support Organization Registry database.

PATIENTS

A total of 1325 children (≥ 30 days and ≤ 18 yrs) met inclusion criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The following pre-extracorporeal life support variables were identified as independently and significantly related to the chance of survival: 1) >14 days of ventilation vs. 0-7 days was adverse (odds ratio, 0.32; p < .001); 2) the presence of a cardiac arrest was adverse (odds ratio, 0.56; p = .001); 3) pH per 0.1-unit increase was protective (odds ratio, 1.15; p < .001); 4) oxygenation index, per 10-unit increase was adverse (odds ratio, 0.95; p = .002); and 5) any diagnosis other than sepsis was related to a more favorable outcome. Patients requiring >7-10 or >10-14 days of pre-extracorporeal life support ventilation did not have a statistically significant decrease in survival as compared with patients who received 0-7 days.

CONCLUSIONS

There was a clear relationship between the number of mechanical ventilation days before the initiation of extracorporeal life support and survival. However; there was no statistically significant decrease in survival until >14 days of pre-extracorporeal life support ventilation was reached regardless of underlying diagnosis. We found no evidence to suggest that prolonged mechanical ventilation should be considered as a contraindication to extracorporeal life support in children with respiratory failure before 14 days.

Nitric oxide for the adjunctive treatment of severe malaria: hypothesis and rationale

We hypothesize that supplemental inhaled nitric oxide (iNO) will improve outcomes in children with severe malaria receiving standard antimalarial therapy. The rationale for the hypothesized efficacy of iNO rests on: (1) biological plausibility, based on known actions of NO in modulating endothelial activation; (2) pre-clinical efficacy data from animal models of experimental cerebral malaria; and (3) a human trial of the NO precursor l-arginine, which improved endothelial function in adults with severe malaria. iNO is an attractive new candidate for the adjunctive treatment of severe malaria, given its proven therapeutic efficacy in animal studies, track record of safety in clinical practice and numerous clinical trials, inexpensive manufacturing costs, and ease of administration in settings with limited healthcare infrastructure. We plan to test this hypothesis in a randomized controlled trial (ClinicalTrials.gov Identifier: NCT01255215).

Therapeutic approaches using nitric oxide in infants and children

Pulmonary hypertension contributes significantly to the morbidity and mortality associated with many pediatric pulmonary and cardiac diseases. Nitric oxide, a gas molecule, is a unique pharmaceutical agent that can be inhaled and thus delivered directly to the lung. Inhaled nitric oxide was approved by the FDA in 1999 as a therapy for infants with persistent pulmonary hypertension. Since then, the use of inhaled nitric oxide has expanded to other neonatal and pediatric conditions, and our knowledge of its properties and mechanisms of action has increased tremendously. This review discusses the physiology of nitric oxide signaling, the most common indications for its clinical use, and promising new investigations that may enhance endogenous production of nitric oxide and/or improve vascular response to it.

High-frequency oscillatory ventilation associated with inhaled nitric oxide compared to pressure-controlled assist/control ventilation and inhaled nitric oxide in children: Randomized, non-blinded, crossover study

PURPOSE

To compare the acute oxygenation effects of high-frequency oscillatory ventilation (HFOV) plus inhaled nitric oxide (iNO) with pressure-controlled assist/control ventilation (PCACV) plus iNO in acute hypoxemic respiratory failure (AHRF) children.

METHODS

Children with AHRF, aged between 1 month and 14 years under PCACV with PEEP ≥ 10 cmH(2) O were randomly assigned to PCACV (PCVG, n = 14) or HFOV (HFVG, n = 14) in a crossover design. Oxygenation indexes and hemodynamic variables were recorded at enrollment (Tind), 1 hr after PCACV start (T0) and then every 4 hr (T4h, etc.).

RESULTS

PO(2)/FiO(2) significantly increased after 4 hr compared to enrollment in both groups [(PCVG-Tind: 111.95 ± 37 < T4h: 143.88 ± 47.5 mmHg, P < 0.05; HFVG-Tind: 123.76 ± 33 < T4h: 194.61 ± 62.42 mmHg, P < 0.05)] without any statistical differences between groups. At T8h, PO(2)/FiO(2) was greater for HFVG compared with PCVG (HFVG: 227.9 ± 80.7 > PCVG: 171.21 ± 52.9 mmHg, P < 0.05). FiO(2) could be significantly reduced after 4 hr for HFVG (HFVG-T4h: 0.53 ± 0.09 < Tind: 0.64 ± 0.2; P < 0.05) but only after 8 hr for PCVG. Comparing groups at T8h, it was observed that FiO(2) decrease was greater for HFVG (HFVG: 0.47 ± 0.06 < PCVG: 0.58 ± 0.1; P < 0.05).

CONCLUSION

Both ventilatory techniques with iNO improve oxygenation. HFOV causes earlier FiO(2) reduction and increased PO(2)/FiO(2) ratio compared to PCACV at 8 hr. However, at the end of the protocol, there was no significant difference and no clinical improvement derived from the application of both ventilatory strategies with iNO. It is not possible to say what would have happened if a different conventional ventilatory mode and a fully protective ventilatory strategy had been used, given the fact that our study is non-blind, and that a limited number of patients were included in each group.