Defining acute lung disease in children with the oxygenation saturation index

Can the Oxygen Saturation Index Predict Severe Bronchopulmonary Dysplasia?

Background/Objectives: Even with improvements in perinatal care, bronchopulmonary dysplasia (BPD) continues to be a major challenge, especially in smaller and more premature infants. Early detection of severe BPD can improve treatment outcomes. This study aims to evaluate the correlation between the oxygen saturation index (OSI) and severe BPD/death in preterm infants, with a focus on the OSI's predictive value. Methods: In this retrospective observational study, infants with a gestational age of less than 32 weeks who required either invasive or non-invasive mechanical ventilation were included. Ventilator settings and OSI values were collected on days 3, 7, 14, 21, and 28 of life. The correlations between postnatal OSIs and outcomes such as death or severe BPD were analyzed using logistic regression. Results: Out of the 210 eligible infants, 54 (25.7%) either died or were diagnosed with severe BPD. In our study, OSI values on postnatal days 14, 21, and 28 were significantly higher in preterm infants who developed severe BPD or died, with mean OSI-14, OSI-21, and OSI-28 values of 4.9, 3.5, and 2.8, respectively. The OSI showed the highest sensitivity and specificity on postnatal days 14 and 21, with cut-off points of 3.6 and 3.1, respectively. We built a basic chart to predict severe BPD/death with OSI-14 and OSI-21 and delivery room intubation with 86% sensitivity and 84.5% specificity (increasing up to 98.8% specificity). Conclusions: This study showed that the diagnostic power of the OSI in predicting severe BPD or death was highest for OSI-14 and OSI-21. We demonstrated that calculating the OSI, a non-invasive clinical tool, can predict severe BPD/death in infants born before 32 weeks as early as the 14th day of life.

Correlation and predictive value of oxygenation and oxygen saturation indices in extremely preterm infants: a prospective study

Aims

This study aims to evaluate the association between the Oxygenation Index (OI) and the Oxygen Saturation Index (OSI) in extremely preterm infants. In addition, the study seeks to determine the predictive value of these indices for mortality in the first 7 days and Bronchopulmonary Dysplasia (BPD) at 36 weeks postmenstrual age (PMA).

Methods

This is a prospective observational study conducted at King Abdulaziz Medical City, Riyadh between October 2023 and May 2024, involving extremely preterm infants with clinical and ventilator data collected during the first 7 days of life. The predictive capabilities of OI and OSI for mortality within the first 7 days and BPD at 36 wks. PMA were assessed using Area Under the Curve (AUC) analysis, while associations between indices were explored through Spearman's correlation coefficient.

Results

The study included 85 infants with a mean birth weight of 856 grams (SD = 243) and a mean gestational age of 26 weeks (SD = 1.8). There was a strong positive correlation between OI and OSI overall (r = 0.848, p < 0.001, n = 85), with similar findings in both surviving (r = 0.831, p < 0.001, n = 71) and non-surviving groups (r = 0.896, p < 0.001, n = 14). Bland-Altman plots showed a mean difference of 3 between OI and OSI for all infants, with limits ranging from -4 to +8. Tighter agreement was observed in survivors with a mean difference of 2 and limit from -4 to +7, while non-survivors showed a larger mean difference of 4.5 and wider limits of agreement from -8 to +17. Receiver Operating Characteristic (ROC) analysis for survival prediction focused on indices measured within the first 24 h, demonstrating high predictive accuracy. Additionally, the mean daily values for OI and OSI between Day 4 and Day 7 were found to be predictive of BPD at 36 wk. PMA.

Conclusions

Measurements of OI and OSI within the first 24 h effectively predict mortality in extremely preterm infants. Additionally, daily mean values of OI and OSI from day 4 to day 7 were predictive of BPD at 36 weeks PMA. Further research is needed to refine these diagnostic thresholds to enhance neonatal care outcomes.

An Overview of Pediatric Pulmonary Complications During COVID-19 Pandemic: A Lesson for Future

BACKGROUND

The pediatric community is considered a suitable target for controlling the spread and mortality of viral diseases. In late December 2019, a respiratory disease due to the novel coronavirus, later COVID-19, hit the globe. The COVID-19 global disruption had direct and indirect impacts on different aspects of child health. Therefore, surveillance, preventive approaches, and treatment plans for children came into the spotlight.

OBJECTIVE

This study aims to discuss the clinical pictures as well as laboratory and radiological findings of the infected children during the COVID-19 pandemic. The focus of this study is to express the clinical manifestations of respiratory disease in pediatric SARS-CoV-2, available therapeutic options, vaccine recommendations, and long COVID sequelae in affected children. This review could serve as a hint for upcoming challenges in pediatric care during future pandemics.

RESULTS

The clinical presentation of COVID-19 in pediatrics can range from mild pulmonary disease to acute respiratory distress syndrome (ARDS). Supportive care is a crucial component of the management of pediatric COVID-19. However, the importance of specializing in how to treat patients with more severe conditions cannot be overstated. Additionally, clinicians must consider prevention strategies as well as potential complications.

CONCLUSION

Although the infected patients are dipping day by day, there is a lack of clinical guidelines for pediatric SARS-CoV-2-associated pulmonary diseases. Understanding of the physicians about all aspects of pediatric care during the COVID-19 pandemic could lead to enhanced quality of future patient care and safety, reduced costs of health policies, and surveil the risk that patients with respiratory viruses can expose to society.

Intelligent alert system for predicting invasive mechanical ventilation needs via noninvasive parameters: employing an integrated machine learning method with integration of multicenter databases

The use of invasive mechanical ventilation (IMV) is crucial in rescuing patients with respiratory dysfunction. Accurately predicting the demand for IMV is vital for clinical decision-making. However, current techniques are invasive and challenging to implement in pre-hospital and emergency rescue settings. To address this issue, a real-time prediction method utilizing only non-invasive parameters was developed to forecast IMV demand in this study. The model introduced the concept of real-time warning and leveraged the advantages of machine learning and integrated methods, achieving an AUC value of 0.935 (95% CI 0.933-0.937). The AUC value for the multi-center validation using the AmsterdamUMCdb database was 0.727, surpassing the performance of traditional risk adjustment algorithms (OSI(oxygenation saturation index): 0.608, P/F(oxygenation index): 0.558). Feature weight analysis demonstrated that BMI, Gcsverbal, and age significantly contributed to the model's decision-making. These findings highlight the substantial potential of a machine learning real-time dynamic warning model that solely relies on non-invasive parameters to predict IMV demand. Such a model can provide technical support for predicting the need for IMV in pre-hospital and disaster scenarios.

Achieved oxygen saturations and risk for bronchopulmonary dysplasia with pulmonary hypertension in preterm infants

OBJECTIVE

Characterisation of oxygen saturation (SpO2)-related predictors that correspond with both bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) development and survival status in infants with BPD-PH may improve patient outcomes. This investigation assessed whether (1) infants with BPD-PH compared with infants with BPD alone, and (2) BPD-PH non-survivors compared with BPD-PH survivors would (a) achieve lower SpO2 distributions, (b) have a higher fraction of inspired oxygen (FiO2) exposure and (c) have a higher oxygen saturation index (OSI).

DESIGN

Case-control study between infants with BPD-PH (cases) and BPD alone (controls) and by survival status within cases.

SETTING

Single-centre study in the USA.

PATIENTS

Infants born at <29 weeks' gestation and on respiratory support at 36 weeks' postmenstrual age.

EXPOSURES

FiO2 exposure, SpO2 distributions and OSI were analysed over the week preceding BPD-PH diagnosis.

MAIN OUTCOMES AND MEASURES

BPD-PH, BPD alone and survival status in infants with BPD-PH.

RESULTS

40 infants with BPD-PH were compared with 40 infants with BPD alone. Infants who developed BPD-PH achieved lower SpO2 compared with infants with BPD (p<0.001), were exposed to a higher FiO2 (0.50 vs 0.34; p=0.02) and had a higher OSI (4.3 vs 2.6; p=0.03). Compared with survivors, infants with BPD-PH who died achieved a lower SpO2 (p<0.001) and were exposed to a higher FiO2 (0.70 vs 0.42; p=0.049).

CONCLUSIONS

SpO2-related predictors differed between infants with BPD-PH and BPD alone and among infants with BPD-PH by survival status. The OSI may provide a non-invasive predictor for BPD-PH in preterm infants.

Assitenza ventilatoria non invasiva: dalla teoria alla pratica

Noninvasive respiratory assistance strategies are becoming part of everyday life for paediatricians, both in hospitals and territorial settings. In the acute condition, a timely and correct use of noninvasive respiratory support can improve the outcome of acute respiratory failure, decreasing the need for invasive mechanical ventilation. An increasing number of chronic patients can benefit from appropriate treatment with home ventilators. Respiratory assistance may be performed using High Flow Nasal Cannula (HFNC), Continuous Positive Airway Pressure (CPAP) or NonInvasive Ventilation (NIV), depending on the primary cause of respiratory failure. Understanding the working mechanisms of the different techniques and the golden rules to use them is crucial for a satisfying outcome.

Novel Oxygenation and Saturation Indices for Mortality Prediction in COVID-19 ARDS Patients: The Impact of Driving Pressure and Mechanical Power

Background: The oxygenation index (OI) and oxygen saturation index (OSI) are proven mortality predictors in pediatric and adult patients, traditionally using mean airway pressure (Pmean). We introduce novel indices, replacing Pmean with DP (ΔPinsp), MPdyn, and MPtot, assessing their potential for predicting COVID-19 acute respiratory distress syndrome (ARDS) mortality, comparing them to traditional indices. Methods: We studied 361 adult COVID-19 ARDS patients for 7 days, collecting ΔPinsp, MPdyn, and MPtot, OI-ΔPinsp, OI-MPdyn, OI-MPtot, OSI-ΔPinsp, OSI-MPdyn, and OSI-MPtot. We compared these in surviving and non-surviving patients over the first 7 intensive care unit (ICU) days using Mann-Whitney U test. Logistic regression receiver operating characteristic (ROC) analysis assessed AUC and CI values for ICU mortality on day three. We determined cut-off values using Youden's method and conducted multivariate Cox regression on parameter limits. Results: All indices showed significant differences between surviving and non-surviving patients on the third day of ICU care. The AUC values of OI-ΔPinsp were significantly higher than those of P/F and OI-Pmean (P values .0002 and <.0001, respectively). Similarly, AUC and CI values of OSI-ΔPinsp and OSI-MPdyn were significantly higher than those of SpO2/FiO2 and OSI-Pmean values (OSI-ΔPinsp: P < .0001, OSI-MPdyn: P values .047 and .028, respectively). OI-ΔPinsp, OSI-ΔPinsp, OI-MPdyn, OSI-MPdyn, OI-MPtot, and OSI-MPtot had AUC values of 0.72, 0.71, 0.69, 0.68, 0.66, and 0.64, respectively, with cut-off values associated with hazard ratios and P values of 7.06 (HR = 1.84, P = .002), 8.04 (HR = 2.00, P ≤ .0001), 7.12 (HR = 1.68, P = .001), 5.76 (HR = 1.70, P ≤ .0001), 10.43 (HR = 1.52, P = .006), and 10.68 (HR = 1.66, P = .001), respectively. Conclusions: Critical values of all indices were associated to higher ICU mortality rates and extended mechanical ventilation durations. The OI-ΔPinsp, OSI-ΔPinsp, and OSI-MPdyn indices displayed the strongest predictive capabilities for ICU mortality. These novel indices offer valuable insights for intensivists in the clinical management and decision-making process for ARDS patients.

Can Noninvasive Oxygen Saturation Index Match Invasive Oxygenation Index to Monitor Respiratory Disease in Critically Ill Children?-A Prospective Study

Respiratory illnesses are common indications for mechanical ventilation in children. The adequacy of ventilatory support for oxygenation is measured using arterial blood gas analysis and calculation of oxygenation index (OI). Due to invasive nature of arterial blood sampling needed to calculate OI, several researchers have replaced blood gas-derived partial pressure of oxygen values with oxygen saturation (SpO 2 ) obtained from pulse oximetry. This noninvasive index called oxygen saturation index (OSI) is found to be useful in neonates. Studies in pediatric population are lacking. In this prospective study on mechanically ventilated children, both OI and OSI were determined and compared against alveolar-arterial oxygen difference (AaDO 2 ). A total of 29 children were studied. Both OSI and OI had good correlation of 0.787 and 0.792 with AaDO 2 , respectively. OSI of 7.3 and 9.4 had good sensitivity and specificity for AaDO 2 cutoffs of 344 and 498, which represents moderate and severe respiratory illness, respectively. The correlation coefficients of both OSI and OI are similar against AaDO 2 . OSI can be used instead of OI for constant monitoring of children on mechanical ventilation. Arterial blood gas analysis and calculation of OI can be reserved for situations where SpO 2 measurement is unreliable.

Impact of the first 24 h of continuous kidney replacement therapy on hemodynamics, ventilation, and analgo-sedation in critically ill children

BACKGROUND

In a group of children admitted to the paediatric intensive care unit (PICU) receiving continuous kidney replacement therapy (CKRT), we aim to evaluate the data about their hemodynamic, ventilation and analgo-sedation profile in the first 24 h of treatment and possible associations with mortality.

METHODS

Retrospective cohort study of children admitted to the PICU of the University Hospital of Padova undergoing CKRT between January 2011 and March 2021. Data was collected at baseline (T0), after 1 h (T1) and 24 h (T24) of CKRT treatment. The differences in outcome measures were compared between these time points, and between survivors and non-survivors.

RESULTS

Sixty-nine patients received CKRT, of whom 38 (55%) died during the PICU stay. Overall, the vasoactive inotropic score and the adrenaline dose increased at T1 compared to T0 (p = 0.012 and p = 0.022, respectively). Compared to T0, at T24 patients showed an improvement in the following ventilatory parameters: Oxygenation Index (p = 0.005), Oxygenation Saturation Index (p = 0.013) PaO2/FiO2 ratio (p = 0.005), SpO2/FiO2 ratio (p = 0.002) and Mean Airway Pressure (p = 0.016). These improvements remained significant in survivors (p = 0.01, p = 0.027, p = 0.01 and p = 0.015, respectively) but not in non-survivors. No changes in analgo-sedative drugs have been described.

CONCLUSIONS

CKRT showed a significant impact on hemodynamics and ventilation in the first 24 h of treatment. We observed a significant rise in the inotropic/vasoactive support required after 1 h of treatment in the overall population, and an improvement in the ventilation parameters at 24 h only in survivors.

Study protocol for a randomised cross-over trial of Neurally adjusted ventilatory Assist for Neonates with Congenital diaphragmatic hernias: the NAN-C study

BACKGROUND

Neurally adjusted ventilatory assist (NAVA) is a mode of mechanical ventilation that delivers oxygen pressures in proportion to electrical signals of the diaphragm. The proportional assistance can be adjusted by the clinician to reduce the patient's work of breathing. Several case series of infants with congenital diaphragmatic hernias (CDH) have shown that NAVA may reduce oxygenation index and mean airway pressures. To date, no clinical trial has compared NAVA to standard methods of mechanical ventilation for babies with CDH.

METHODS

The aim of this dual-centre randomised cross-over trial is to compare post-operative NAVA with assist control ventilation (ACV) for infants with CDH. If eligible, infants will be enrolled for a ventilatory support tolerance trial (VSTT) to assess their suitability for randomisation. If clinically stable during the VSTT, infants will be randomised to receive either NAVA or ACV first in a 1:1 ratio for a 4-h period. The oxygenation index, respiratory severity score and cumulative sedative medication use will be measured.

DISCUSSION

Retrospective studies comparing NAVA to ACV in neonates with congenital diaphragmatic hernia have shown the ventilatory mode may improve respiratory parameters and benefit neonates. To our knowledge, this is the first prospective cross-over trial comparing NAVA to ACV.

TRIAL REGISTRATION

NAN-C was prospectively registered on ClinicalTrials.gov NCT05839340  Registered on May 2023.

Correlation and Prediction of Oxygen Index from Oxygen Saturation Index in Neonates with Acute Respiratory Failure

OBJECTIVE

The aim of this article was to evaluate the correlation between the oxygen index (OI) and the oxygen saturation index (OSI, measured by pulse oximetry and noninvasively) in neonates with acute respiratory failure and to predict the OI from the OSI.

STUDY DESIGN

A retrospective cohort study was conducted in neonates requiring invasive mechanical ventilation who had arterial blood gas between 2018 and 2019 at a neonatal intensive care unit. The correlation between OI and OSI was analyzed by using the Pearson correlation coefficient.

RESULTS

A total of 636 measurements from 68 neonates (35 preterm and 33 terms) were recruited into the study. There was a strong correlation between the OI and the OSI (r = 0.90) in all neonates. The correlation between the OI and the OSI in persistent pulmonary hypertension of the newborn, congenital cyanotic heart disease, and other causes of respiratory failure also showed a strong correlation (r = 0.88, 0.93, and 0.88, respectively). The correlation was strong in neonates with an oxygen saturation less than 85% (r = 0.88), those with oxygen saturation ranging from 85 to 95% (r = 0.87), and also in preterm and term infants (gestational age < 28, 28 - 34, 34 - 36, and ≥37 weeks, r = 0.87, 0.92, 0.89, and 0.90, respectively). There were strong accuracy measures of the OI for OI cutoffs of 5, 10, 15, and 20 (area under the curve > 0.85). The equation relating the OI and OSI was represented by: OI = (2.3 × OSI) - 4.

CONCLUSION

The OSI has a strong correlation with the OI, is a reliable assessor of the severity of respiratory failure in neonates without arterial sampling, and has high accuracy when the OI is less than 40.

KEY POINTS

· OSI is calculated as (FiO2 × mean airway pressure × 100)/SpO2.. · OSI is as effective tool as OI for assessing the severity of pediatric acute respiratory distress syndrome.. · OSI has a strong correlation with OI in neonatal respiratory failure..

Improved oxygenation in prone positioning of mechanically ventilated patients with COVID-19 acute respiratory distress syndrome is associated with decreased pulmonary shunt fraction: a prospective multicenter study

BACKGROUND

Prone position is used in acute respiratory distress syndrome and in coronavirus disease 2019 (Covid-19) acute respiratory distress syndrome (ARDS). However, physiological mechanisms remain unclear. The aim of this study was to determine whether improved oxygenation was related to pulmonary shunt fraction (Q's/Q't), alveolar dead space (Vd/Vtalv) and ventilation/perfusion mismatch (V'A/Q').

METHODS

This was an international, prospective, observational, multicenter, cohort study, including six intensive care units in Sweden and Poland and 71 mechanically ventilated adult patients.

RESULTS

Prone position increased PaO2:FiO2 after 30 min, by 78% (83-148 mm Hg). The effect persisted 120 min after return to supine (p < 0.001). The oxygenation index decreased 30 min after prone positioning by 43% (21-12 units). Q's/Q't decreased already after 30 min in the prone position by 17% (0.41-0.34). The effect persisted 120 min after return to supine (p < 0.005). Q's/Q't and PaO2:FiO2 were correlated both in prone (Beta -137) (p < 0.001) and in the supine position (Beta -270) (p < 0.001). V'A/Q' was unaffected and did not correlate to PaO2:FiO2 (p = 0.8). Vd/Vtalv increased at 120 min by 11% (0.55-0.61) (p < 0.05) and did not correlate to PaO2:FiO2 (p = 0.3). The ventilatory ratio increased after 30 min in the prone position by 58% (1.9-3.0) (p < 0.001). PaO2:FiO2 at baseline predicted PaO2:FiO2 at 30 min after proning (Beta 1.3) (p < 0.001).

CONCLUSIONS

Improved oxygenation by prone positioning in COVID-19 ARDS patients was primarily associated with a decrease in pulmonary shunt fraction. Dead space remained high and the global V'A/Q' measure could not explain the differences in gas exchange.

Effect of red blood cell storage time in pediatric cardiac surgery patients: A subgroup analysis of a randomized controlled trial

Objective

This study aimed to determine whether or not transfusion of fresh red blood cells (RBCs) reduced the incidence of new or progressive multiple organ dysfunction syndrome compared with standard-issue RBCs in pediatric patients undergoing cardiac surgery.

Methods

Preplanned secondary analysis of the Age of Blood in Children in Pediatric Intensive Care Unit study, an international randomized controlled trial. This study included children enrolled in the Age of Blood in Children in Pediatric Intensive Care Unit trial and admitted to a pediatric intensive care unit after cardiac surgery with cardiopulmonary bypass. Patients were randomized to receive either fresh (stored ≤7 days) or standard-issue RBCs. The primary outcome measure was new or progressive multiple organ dysfunction syndrome, measured up to 28 days postrandomization or at pediatric intensive care unit discharge, or death.

Results

One hundred seventy-eight patients (median age, 0.6 years; interquartile range, 0.3-2.6 years) were included with 89 patients randomized to the fresh RBCs group (median length of storage, 5 days; interquartile range, 4-6 days) and 89 to the standard-issue RBCs group (median length of storage, 18 days; interquartile range, 13-22 days). There were no statistically significant differences in new or progressive multiple organ dysfunction syndrome between fresh (43 out of 89 [48.3%]) and standard-issue RBCs groups (38 out of 88 [43.2%]), with a relative risk of 1.12 (95% CI, 0.81 to 1.54; P = .49) and an unadjusted absolute risk difference of 5.1% (95% CI, -9.5% to 19.8%; P = .49).

Conclusions

In neonates and children undergoing cardiac surgery with cardiopulmonary bypass, the use of fresh RBCs did not reduce the incidence of new or progressive multiple organ dysfunction syndrome compared with the standard-issue RBCs. A larger trial is needed to confirm these results.

Troponin I as an Independent Biomarker of Outcome in Children with Systemic Inflammatory Response

Cardiac troponin-I (cTnI) is a biomarker of myocardial injury with implications for clinical outcomes. May other contributing factors that could affect outcomes have not been uniformly considered in pediatric studies. We hypothesized that there is an association between admission serum cTnI and outcomes in critically ill children taking into account the magnitude of the acute systemic inflammatory response syndrome (SIRS), serum lactate concentrations, and nutritional status. Second, we tested for potential factors associated with elevated serum cTnI. This was a prospective cohort study in 104 children (median age: 21.3 months) consecutively admitted to a pediatric intensive care unit (PICU) of a teaching hospital with SIRS and without previous chronic diseases. Primary outcome variables were PICU-free days, ventilator-free days, and 30-day mortality. Exposure variables were serum cTnI concentration on admission, revised pediatric index of mortality (PIM2), pediatric logistic organ dysfunction (PELOD-2), hypotensive shock, C-reactive protein, procalcitonin, and serum lactate on admission, and malnutrition. Elevated cTnI (>0.01 μg/L) was observed in 24% of patients, which was associated with the reduction of ventilator-free days (β coefficient = - 4.97; 95% confidence interval [CI]: -8.03; -1.91) and PICU-free days (β coefficient = - 5.76; 95% CI: -8.97; -2.55). All patients who died had elevated serum cTnI. The increase of 0.1 μg/L in cTnI concentration resulted in an elevation of 2 points in the oxygenation index (β coefficient = 2.0; 95% CI: 1.22; 2.78, p  < 0.001). The PIM2 score, hypotensive shock in the first 24 hours, and serum lactate were independently associated with elevated cTnI on admission. We conclude that elevated serum cTnI on admission is independently associated with adverse outcomes in children with SIRS and without associated chronic diseases.

Correlation of ABO blood groups with treatment response and efficacy in infants with persistent pulmonary hypertension of the newborn treated with inhaled nitric oxide

OBJECTIVE

Not all infants with persistent pulmonary hypertension of the newborn (PPHN) respond to inhaled nitric oxide (iNO) therapy, as it is known to improve oxygenation in only 50% to 60% of cases. In this study, we investigated whether ABO blood groups were a relevant factor affecting the improvement of oxygenation by nitric oxide (NO) therapy in infants with PPHN.

METHODS

This study was a retrospective, multicenter, and cohort-controlled trial that involved 37 medical units. Infants with PPHN who met the inclusion criteria and were treated with NO (a vasodilator) alone from July 1, 2015, to June 30, 2020, were selected and assigned into three groups: blood type A, blood type B, and blood type O (there were only 7 cases of blood type AB, with a small number of cases, and therefore, blood type AB was excluded for further analysis). The response to iNO therapy was defined as an increase in the ratio of the partial pressure of arterial oxygen (PaO2)/fraction of inspired oxygen (FiO2) > 20% from the basal value after treatment. Oxygenation was assessed mainly based on the two values, oxygenation index (OI) and PaO2/FiO2. The correlation of ABO blood groups with responses to iNO therapy and their influence on the efficacy of iNO therapy was analyzed based on the collected data.

RESULTS

The highest proportion of infants with PPHN who eventually responded to iNO therapy was infants with blood type O. Infants with blood type O more readily responded to iNO therapy than infants with blood type B. Oxygenation after iNO treatment group was optimal in the blood type O group and was the worst in the blood type A group among the three groups. Infants with blood type O showed better efficacy than those with blood types A and B.

CONCLUSION

ABO blood groups are correlated with responses to iNO therapy in infants with PPHN, and different blood groups also affect the efficacy of NO therapy in infants with PPHN. Specifically, infants with blood type O have a better response and experience the best efficacy to iNO therapy.

Pulse oximetry for the diagnosis and management of acute respiratory distress syndrome

The diagnosis of acute respiratory distress syndrome (ARDS) traditionally requires calculation of the ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (PaO2/FiO2) using arterial blood, which can be costly and is not possible in many resource-limited settings. By contrast, pulse oximetry is continuously available, accurate, inexpensive, and non-invasive. Pulse oximetry-based indices, such as the ratio of pulse-oximetric oxygen saturation to FiO2 (SpO2/FiO2), have been validated in clinical studies for the diagnosis and risk stratification of patients with ARDS. Limitations of the SpO2/FiO2 ratio include reduced accuracy in poor perfusion states or above oxygen saturations of 97%, and the potential for reduced accuracy in patients with darker skin pigmentation. Application of pulse oximetry to the diagnosis and management of ARDS, including formal adoption of the SpO2/FiO2 ratio as an alternative to PaO2/FiO2 to meet the diagnostic criterion for hypoxaemia in ARDS, could facilitate increased and earlier recognition of ARDS worldwide to advance both clinical practice and research.

Measurement of lung oxygenation by near-infrared spectroscopy in preterm infants with respiratory distress syndrome: A proof-of-concept study

INTRODUCTION

Noninvasive markers more accurate than FiO₂ would be useful to assess the severity of RDS and guide its treatment. Our aim was to assess for the first time the possibility of continuously monitoring lung oxygenation (rSO₂ L) by near-infrared spectroscopy (NIRS) and to evaluate whether rSO₂ L correlates with other oxygenation indices and RDS severity.

METHODS

We carried out this proof-of-concept study on 20 preterm infants with RDS requiring noninvasive respiratory support. Patients were continuously studied for 24 h by NIRS and rSO₂ L was correlated with SpO₂ /FiO₂ ratio, a/APO₂ , and O.I.

RESULTS

The overall value of rSO₂ L was 80.1 ± 6.2%, without significant differences between the right and left hemithorax (80.2 ± 6.7 vs. 80.0 ± 5.7%; p = 0.869). Mean values of total, right, and left rSO₂ L did not significantly change during the 24-h study period. Linear regression analysis demonstrated a significant positive relationship between total rSO₂ L and SpO₂ /FiO₂ ratio (p < 0.001) and a/APO₂ (p = 0.040), and a negative relationship between total rSO₂ L and O.I. (r = -0.309; p = 0.022).

CONCLUSIONS

Continuous monitoring of rSO₂ L by NIRS in preterm infants with RDS is feasible and safe. The correlation of rSO₂ L with other indices of oxygenation and RDS severity supports the accuracy and reliability of this measurement.

Oxygen Saturation Index in Neonates with a Congenital Diaphragmatic Hernia: A Retrospective Cohort Study

INTRODUCTION

The oxygenation index (OI) is a marker for respiratory disease severity and adverse neonatal outcomes. The oxygen saturation index (OSI) is an alternative that allows for continuous noninvasive monitoring, but evidence for clinical use in critically ill neonates is scarce. The aim of this study was to evaluate the OSI as compared to the OI in term neonates with a congenital diaphragmatic hernia (CDH).

METHODS

A single-center retrospective cohort study was conducted including all live-born infants with an isolated CDH between June 2017 and December 2020. Paired values of the OI and OSI in the first 24 h after birth were collected. The relation between OI and OSI measurements was assessed, taking into account arterial pH, body temperature, and preductal versus postductal location of oxygen saturation measurement or arterial blood sampling. The predictive values for pulmonary hypertension, need for extracorporeal membrane oxygenation therapy, and survival at discharge were evaluated.

RESULTS

Of 33 subjects included, 398 paired values of the OI (median 5.8 [3.3-17.2]) and OSI (median 7.3 [3.6-14.4]) were collected. The OI and OSI correlated strongly (r = 0.77, p < 0.001). The OSI values corresponding to the clinically relevant OI values (10, 15, 20, and 40) were 8.9, 10.9, 12.9, and 20.9, respectively. The predictive values of the OI and OSI were comparable for all adverse neonatal outcomes. No difference was found in the area under the receiver operating characteristic curves for the OI and the OSI for adverse neonatal outcomes.

CONCLUSIONS

The OSI could replace the OI in clinical practice in infants with a CDH.

Bolus Gastric Feeds Improve Nutritional Delivery to Mechanically Ventilated Pediatric Medical Patients: Results of the COntinuous vs BOlus (COBO2) Multi-Center Trial

BACKGROUND

Comparison of bolus (BGF) versus continuous gastric feeding (CGF) with respect to timing and delivery of energy and protein in mechanically ventilated pediatric patients has not been investigated. We hypothesized that bolus delivery would shorten time to goal nutrition and increase the percentage of goal feeds delivered.

METHODS

Multi-center, prospective, randomized comparative effectiveness trial conducted in seven Pediatric ICUs (PICUs). Eligibility criteria: 1 month - 12 years of age, intubated within 24 hours of PICU admission, expected duration of ventilation at least 48 hours, eligible to begin enteral nutrition within 48 hours.

EXCLUSION CRITERIA

acute or chronic gastrointestinal pathology, or acute surgery.

RESULTS

We enrolled 158 mechanically ventilated children between October 2015 and April 2018; 147 patients were included in the analysis (BGF = 72, CGF = 75). The BGF group was slightly older than CGF, otherwise the two groups had similar demographic characteristics. There was no difference in the percentage of patients in each group that achieved goal feeds. Time to goal feeds was shorter in the BGF [Hazard Ratio 1.5 (CI 1.02-2.33); P = 0.0387]. Median percentage of target kilocalories [median kcal 0.78 vs 0.59; p = <.0001], and median percentage of protein delivered [median pro 0.77 vs 0.59; p = <.0001] was higher for BGF patients. There was no difference in serial oxygen saturation index between groups.

CONCLUSION

Our study demonstrated shorter time to achieve goal nutrition via BGF compared to CGF in mechanically ventilated pediatric patients. This resulted in increased delivery of target energy and nutrition. Further study is needed in other PICU populations. This article is protected by copyright. All rights reserved.

Effects of inverse ratio ventilation combined with lung protective ventilation on pulmonary function in patients with severe burns for surgery

Objective

To investigate the effects of inverse ratio ventilation combined with lung-protective ventilation on pulmonary function and inflammatory factors in severe burn patients undergoing surgery. Populations and Methods: Eighty patients with severe burns undergoing elective surgery were divided randomly into two groups: control (CG, n = 40) and experiment (EG, n = 40). The CG had conventional ventilation, whereas the EG were ventilated with tidal volume (TV) of 6–8 ml/kg, I (inspiration): E (expiration) of 2:1, and positive end-expiratory pressure (PEEP) 5 cm H2O. The following variables were evaluated before (T0), 1 h after start of surgery (T1) and after surgery (T2): oxygenation index (OI), partial pressure of carbon dioxide (PaCO₂), TV, peak airway pressure (Ppeak), mean airway pressure (Pmean), PEEP, pulmonary dynamic compliance (Cdyn), alveolar–arterial difference of oxygen partial pressure D(A-a)O₂, lactic acid (Lac), interleukin (IL)-6 and IL-10, and lung complications. Results: At T1 and T2 time points, the OI, Pmean and Cdyn were significantly greater in the EG than in the CG while the TV, Ppeak, D(A-a)O₂, IL-6 and IL-10 were significantly smaller in the EG than in the CG. At the end of the surgery, the Lac was significantly smaller in the EG than in the CG (1.28 ± 0.19 vs. 1.40 ± 0.23 mmol/L). Twenty-four hours after the surgery, significantly more patients had hypoxemia (27.5 vs. 10.0%), increased expectoration (45.0 vs. 22.5%), increased lung texture or exudation (37.5 vs. 17.5%) in the CG than in the EG. Conclusions: Inverse ratio ventilation combined with lung-protective ventilation can reduce Ppeak, increase Pmean and Cdyn, improve the pulmonary oxygenation function, and decrease ILs in severe burn surgery patients.

Ductal Flow Ratio as Measure of Transition in Preterm Infants After Birth: A Pilot Study

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth. Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth. Methods: Echocardiography was performed in preterm infants born <32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO₂, SpO₂, and SpO₂/FiO₂ (SF) ratio. The DA flow ratio of infants receiving physiological-based cord clamping (PBCC) or time-based cord clamping (TBCC) were compared. Results: Measurements from 16 infants were analysed (median [IQR] GA 29 [27-30] weeks; birthweight 1,176 [951-1,409] grams). R-L DA shunting was 16 [17-27] ml/kg/min and L-R was 110 [81-124] ml/kg/min. The DA flow ratio was 0.18 [0.11-0.28], SpO₂ 94 [93-96]%, FiO₂ was 23 [21-28]% and SF ratio 4.1 [3.3-4.5]. There was a moderate correlation between DA flow ratio and SpO₂ [correlation coefficient (CC) -0.415; p = 0.110], FiO₂ (CC 0.384; p = 0.142) and SF ratio (CC -0.356; p = 0.175). There were no differences in DA flow measurements between infants where PBBC or TBCC was performed. Conclusion: In this pilot study we observed a non-significant positive correlation between DA flow ratio at 1 h after birth and oxygenation parameters in preterm infants.

Correlation of Oxygen Index, Oxygen Saturation Index, and PaO2/FiO2 Ratio in Invasive Mechanically Ventilated Adults

Background

With the oxygen saturation index (OSI) being a noninvasive surrogate for oxygen index (OI) and P/F ratio, examining the correlation between PaO₂/FiO₂ (P/F ratio), OI, and OSI in mechanically ventilated adults will benefit in those settings where arterial blood gas monitoring is not readily accessible.

Materials and methods

Data were collected for patients ≥18 years who were under invasive (endotracheal intubation) mechanical ventilation at medical or surgical wards in a tertiary care hospital.

Results

After natural log transformation, the correlations between P/F ratio and OI (r = −0.94) and OI and OSI (r = 0.82) were strong, but weaker between P/F ratio and OSI (r = −0.69).

Conclusion

Future bigger studies are needed to evaluate whether monitoring OSI and/or OI over P/F ratio will impact treatment outcomes.

How to cite this article

Vadi S. Correlation of Oxygen Index, Oxygen Saturation Index, and PaO₂/FiO₂ Ratio in Invasive Mechanically Ventilated Adults. Indian J Crit Care Med 2021;25(1):54–55.

Phenotypes and personalized medicine in the acute respiratory distress syndrome

Although the acute respiratory distress syndrome (ARDS) is well defined by the development of acute hypoxemia, bilateral infiltrates and non-cardiogenic pulmonary edema, ARDS is heterogeneous in terms of clinical risk factors, physiology of lung injury, microbiology, and biology, potentially explaining why pharmacologic therapies have been mostly unsuccessful in treating ARDS. Identifying phenotypes of ARDS and integrating this information into patient selection for clinical trials may increase the chance for efficacy with new treatments. In this review, we focus on classifying ARDS by the associated clinical disorders, physiological data, and radiographic imaging. We consider biologic phenotypes, including plasma protein biomarkers, gene expression, and common causative microbiologic pathogens. We will also discuss the issue of focusing clinical trials on the patient's phase of lung injury, including prevention, administration of therapy during early acute lung injury, and treatment of established ARDS. A more in depth understanding of the interplay of these variables in ARDS should provide more success in designing and conducting clinical trials and achieving the goal of personalized medicine.

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.

The Effect of Imputation of PaO2/FIO2 From SpO2/FIO2 on the Performance of the Pediatric Index of Mortality 3

OBJECTIVES

To investigate if the performance of Pediatric Index of Mortality 3 is improved by including imputed values for the PaO2/FIO2 ratio where measurements of PaO2 or FIO2 are missing.

DESIGN

A prospective observational study.

SETTING

A bi-national pediatric intensive care registry.

PATIENTS

The records of 37,983 admissions of children less than 16 years old admitted to 19 ICUs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Seven published equations describing an association between PaO2/FIO2 and oxygen saturation measured by pulse oximetry (SpO2)/FIO2 were used to derive an alternative variable d100 × FIO2/PaO2 for the Pediatric Index of Mortality 3 variable 100 × FIO2/PaO2. Six equations exclude SpO2/FIO2 values if SpO2 is greater than 96-98%. 100 × FIO2/PaO2 was missing in 72% of patient records primarily due to missing PaO2, d100 × FIO2/PaO2 was missing in 71% of patient records if values of SpO2greater than 97% were excluded or in 17% of patient records if all measurements of SpO2 were included. Univariable analysis supported the inclusion of SpO2 values greater than 97%. Compared to the standard Pediatric Index of Mortality 3 model, two alternative models imputing 100 × FIO2/PaO2 from d100 × FIO2/PaO2 only if 100 × FIO2/PaO2 was missing, or using d100 × FIO2/PaO2 values exclusively, resulted in a small but statistically significant improvements in discrimination of Pediatric Index of Mortality 3 (area under the receiver operator curve 0.9068 [0. 8965-0. 9171]; 0.9083 [0.8981-0.9184]; 0.9087 [0.8987-0.9188], respectively).

CONCLUSIONS

Imputation of the PaO2/FIO2 ratio in cases where arterial sampling was not performed resulted in a large reduction in the rate of missing data if all values of SpO2 were included. The imputation technique improved the discrimination of Pediatric Index of Mortality 3; however, the magnitude of the increment in overall model performance was small. A possible benefit of the approach is reducing the potential for bias resulting from variation in practice for invasive monitoring of oxygenation.

Prognostic relevance and inter-observer reliability of chest-imaging in pediatric ARDS: a pediatric acute respiratory distress incidence and epidemiology (PARDIE) study

Purpose

Definitions of acute respiratory distress syndrome (ARDS) include radiographic criteria, but there are concerns about reliability and prognostic relevance. This study aimed to evaluate the independent relationship between chest imaging and mortality and examine the inter-rater variability of interpretations of chest radiographs (CXR) in pediatric ARDS (PARDS).

Methods

Prospective, international observational study in children meeting Pediatric Acute Lung Injury Consensus Conference (PALICC) criteria for PARDS, which requires new infiltrate(s) consistent with pulmonary parenchymal disease, without mandating bilateral infiltrates. Mortality analysis focused on the entire cohort, whereas inter-observer variability used a subset of patients with blinded, simultaneous interpretation of CXRs by intensivists and radiologists.

Results

Bilateral infiltrates and four quadrants of alveolar consolidation were associated with mortality on a univariable basis, using CXRs from 708 patients with PARDS. For patients on either invasive (IMV) or non-invasive ventilation (NIV) with PaO₂/FiO₂ (PF) ratios (or SpO₂/FiO₂ (SF) ratio equivalent) > 100, neither bilateral infiltrates (OR 1.3 (95% CI 0.68, 2.5), p = 0.43), nor 4 quadrants of alveolar consolidation (OR 1.6 (0.85, 3), p = 0.14) were associated with mortality. For patients with PF ≤ 100, bilateral infiltrates (OR 3.6 (1.4, 9.4), p = 0.01) and four quadrants of consolidation (OR 2.0 (1.14, 3.5), p = 0.02) were associated with higher mortality. A subset of 702 CXRs from 233 patients had simultaneous interpretations. Interobserver agreement for bilateral infiltrates and quadrants was “slight” (kappa 0.31 and 0.33). Subgroup analysis showed agreement did not differ when stratified by PARDS severity but was slightly higher for children with chronic respiratory support (kappa 0.62), NIV at PARDS diagnosis (kappa 0.53), age > 10 years (kappa 0.43) and fluid balance > 40 ml/kg (kappa 0.48).

Conclusion

Bilateral infiltrates and quadrants of alveolar consolidation are associated with mortality only for those with PF ratio ≤ 100, although there is high- inter-rater variability in these chest-x ray parameters.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06074-7) contains supplementary material, which is available to authorized users.

Prediction of outcome in patients with ARDS: A prospective cohort study comparing ARDS-definitions and other ARDS-associated parameters, ratios and scores at intubation and over time

Background

Early recognition of high-risk-patients with acute respiratory distress syndrome (ARDS) might improve their outcome by less protracted allocation to intensified therapy including extracorporeal membrane oxygenation (ECMO). Among numerous predictors and classifications, the American European Consensus Conferenece (AECC)- and Berlin-definitions as well as the oxygenation index (OI) and the Murray-/Lung Injury Score are the most common. Most studies compared the prediction of mortality by these parameters on the day of intubation and/or diagnosis of ARDS. However, only few studies investigated prediction over time, in particular for more than three days.

Objective

Therefore, our study aimed at characterization of the best predictor and the best day(s) to predict 28-days-mortality within four days after intubation of patients with ARDS.

Methods

In 100 consecutive patients with ARDS severity according to OI (mean airway pressure*F_iO₂/p_aO₂), modified Murray-score without radiological points (Murray_mod), AECC- and Berlin-definition, were daily documented for four days after intubation. In the subgroup of 49 patients with transpulmonary thermodilution (TPTD) monitoring (PiCCO), extravascular lung water index (EVLWI) was measured daily.

Primary endpoint

Prediction of 28-days-mortality (Area under the receiver-operating-characteristic curve (ROC-AUC)); IBM SPSS 26.

Results

In the totality of patients the best prediction of 28-days-mortality was found on day-1 and day-2 (mean ROC-AUCs for all predictors/scores: 0.632 and 0.620). OI was the best predictor among the ARDS-scores (AUC=0.689 on day-1; 4-day-mean AUC = 0.625). AECC and Murray_mod had 4-day-means AUCs below 0.6. Among the 49 patients with TPTD, EVLWI (4-day-mean AUC=0.696) and OI (4-day-mean AUC=0.695) were the best predictors. AUCs were 0.789 for OI on day-1, and 0.786 for EVLWI on day-2. In binary regression analysis of patients with TPTD, EVLWI (B=-0.105; Wald=7.294; p=0.007) and OI (B=0.124; Wald=7.435; p=0.006) were independently associated with 28-days-mortality. Combining of EVLWI and OI provided ROC-AUCs of 0.801 (day-1) and 0.824 (day-2). Among the totality of patients, the use of TPTD-monitoring „per se“ and a lower SOFA-score were independently associated with a lower 28-days-mortality.

Conclusions

Prognosis of ARDS-patients can be estblished within two days after intubation. The best predictors were EVLWI and OI and their combination. TPTD-monitoring „per se“ was independently associated with reduced mortality.

The immediate efficacy of inhaled nitric oxide treatment in preterm infants with acute respiratory failure during neonatal transport

AIM

The aim of our review was to describe the clinical response to inhaled nitric oxide (iNO) in a series of preterm babies in respiratory failure during uplift transfers to a neonatal intensive care unit.

METHODS

We performed a retrospective review of critical newborns with gestational age <34⁺⁰  weeks transferred from January 2013 to December 2018. Data were extracted from our Clinical Information System for transport. The primary measure of this review was to assess whether a significant improvement in the oxygenation saturation index (OSI) occurred following the use of iNO.

RESULTS

Thirty preterm babies <34⁺⁰  weeks were included in our review. OSI, as a measure of oxygenation, did not statistically improve as an immediate response to iNO from referral to receiving hospital (17.1 vs 16.4; P = .7). We found that pH (7.15 vs 7.29; P = .004) and pCO2 (8.1 vs 6.3; P = .05) significantly improved probably based on ventilation management.

CONCLUSION

Following the recommendations of the American Academy of Paediatrics and other organizations, iNO should not routinely be used during the neonatal transfer of preterm babies <34⁺⁰ in respiratory failure. We need to conduct further studies to establish which selected preterm patients would benefit from being treated with iNO.

Frequency of Pediatric Acute Respiratory Distress Syndrome Based on Oxygen Saturation Index in Pediatric Intensive Care Unit of a Developing Country

Objectives

To determine the frequency of pediatric acute respiratory distress syndrome based on oxygen saturation index in pediatric intensive care unit of a developing country.

Methods

We conducted a retrospective study of all children admitted in pediatric intensive care unit (PICU) of Aga Khan University Hospital, Karachi from July 2017 to June 2018 with respiratory rate >40 breaths/minute, shortness of breath, and bluish discoloration of skin and mucous membranes. The diagnosis of acute respiratory distress syndrome (ARDS) was made on the basis of standard operational definitions as mentioned (fulfilling criteria for ARDS).

Results

During the one-year study period 150 patients with age range of one month to 16 years were admitted fulfilling the inclusion criteria. Mean age was 38.27 ± 53.13 months, and 92 (61.33%) were male with male to female ratio of 1.6:1. Mean duration of symptoms was 1.23 ± 0.42 days. Frequency of pediatric acute respiratory distress syndrome using oxygen saturation index admitted in a pediatric ICU was 23 (15.33%) patients.

Conclusion

This study has shown that the frequency of pediatric acute respiratory distress syndrome is quite high.

Effect of Fresh vs Standard-issue Red Blood Cell Transfusions on Multiple Organ Dysfunction Syndrome in Critically Ill Pediatric Patients: A Randomized Clinical Trial

IMPORTANCE

The clinical consequences of red blood cell storage age for critically ill pediatric patients have not been examined in a large, randomized clinical trial.

OBJECTIVE

To determine if the transfusion of fresh red blood cells (stored ≤7 days) reduced new or progressive multiple organ dysfunction syndrome compared with the use of standard-issue red blood cells in critically ill children.

DESIGN, SETTING, AND PARTICIPANTS

The Age of Transfused Blood in Critically-Ill Children trial was an international, multicenter, blinded, randomized clinical trial, performed between February 2014 and November 2018 in 50 tertiary care centers. Pediatric patients between the ages of 3 days and 16 years were eligible if the first red blood cell transfusion was administered within 7 days of intensive care unit admission. A total of 15 568 patients were screened, and 13 308 were excluded.

INTERVENTIONS

Patients were randomized to receive either fresh or standard-issue red blood cells. A total of 1538 patients were randomized with 768 patients in the fresh red blood cell group and 770 in the standard-issue group.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was new or progressive multiple organ dysfunction syndrome, measured for 28 days or to discharge or death.

RESULTS

Among 1538 patients who were randomized, 1461 patients (95%) were included in the primary analysis (median age, 1.8 years; 47.3% girls), in which there were 728 patients randomized to the fresh red blood cell group and 733 to the standard-issue group. The median storage duration was 5 days (interquartile range [IQR], 4-6 days) in the fresh group vs 18 days (IQR, 12-25 days) in the standard-issue group (P < .001). There were no significant differences in new or progressive multiple organ dysfunction syndrome between fresh (147 of 728 [20.2%]) and standard-issue red blood cell groups (133 of 732 [18.2%]), with an unadjusted absolute risk difference of 2.0% (95% CI, -2.0% to 6.1%; P = .33). The prevalence of sepsis was 25.8% (160 of 619) in the fresh group and 25.3% (154 of 608) in the standard-issue group. The prevalence of acute respiratory distress syndrome was 6.6% (41 of 619) in the fresh group and 4.8% (29 of 608) in the standard-issue group. Intensive care unit mortality was 4.5% (33 of 728) in the fresh group vs 3.5 % (26 of 732) in the standard-issue group (P = .34).

CONCLUSIONS AND RELEVANCE

Among critically ill pediatric patients, the use of fresh red blood cells did not reduce the incidence of new or progressive multiple organ dysfunction syndrome (including mortality) compared with standard-issue red blood cells.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01977547.

The Effects of Furosemide on Oxygenation in Mechanically Ventilated Children with Bronchiolitis

Fluid balance management, including diuretic administration, may influence outcomes among mechanically ventilated children. We retrospectively compared oxygenation saturation index (OSI) before and after the initial furosemide bolus among 65 mechanically ventilated children. Furosemide was not associated with a significant change in median OSI (6.25 [interquartile range: 5.01-7.92] vs. 6.06 [4.73-7.54], p  = 0.48), but was associated with expected changes in fluid balance and urine output. Secondary analysis suggested more favorable effects of furosemide in children with worse baseline OSI. The reported common use of furosemide by pediatric intensivists obligates further study to better establish its efficacy, or lack thereof, in mechanically ventilated children.

Evaluation of pulse oximetry as a surrogate for PaO2 in awake dogs breathing room air and anesthetized dogs on mechanical ventilation

OBJECTIVE

To evaluate the ability of arterial hemoglobin oxygen saturation measurement via pulse oximetry (SpO2 ) to serve as a surrogate for PaO2 in dogs.

DESIGN

Two-part study: prospective observational and retrospective components.

SETTING

University teaching hospital.

ANIMALS

Ninety-two dogs breathing room air prospectively enrolled on a convenience basis. Retrospective evaluation of 1,033 paired SpO2 and PaO2 measurements from 62 dogs on mechanical ventilation.

INTERVENTIONS

Dogs with concurrent SpO2 and PaO2 measured on room air had a data sheet completed with blood gas analysis. SpO2 , PaO2 , and FiO2 values were collected from medical records of dogs on mechanical ventilation.

MEASUREMENTS AND MAIN RESULTS

Predicted PaO2 was calculated from SpO2 using the dog oxyhemoglobin dissociation curve. The correlation coefficient between measured and predicted PaO2 was 0.49 (P < 0.0001) in room air dogs and 0.74 (P < 0.0001) in ventilated dogs. In room air dogs, Bland-Altman analysis between measured minus predicted PaO2 versus the average showed a mean bias of -6.0 mm Hg (95% limit of agreement, -35 to 23 mm Hg). The correlation coefficient between PaO2 /FiO2 and SpO2 /FiO2 ratios was 0.76 (P < 0.0001). After combining data sets, receiver operating characteristic curve analysis showed the optimal cutoff value for detecting hypoxemia (PaO2  < 80 mm Hg) was an SpO2 of 95%, with sensitivity and specificity of 77.8% and 89.5%, respectively. Using this cutoff, 6.9% of SpO2 readings failed to detect hypoxemia, whereas 7.2% predicted hypoxemia that was not present.

CONCLUSIONS

The SpO2 was not clinically suitable as a surrogate for PaO2 , though it performed better in mechanically ventilated dogs. As sensitivity for the detection of hypoxemia was poor, pulse oximetry does not appear to be an acceptable screening test. The SpO2 /FiO2 ratio may have value for evaluation of anesthetized dogs on supplemental oxygen. Arterial blood gas analysis remains ideal for assessment of oxygenation.

Optimization and anti-inflammatory evaluation of methyl gallate derivatives as a myeloid differentiation protein 2 inhibitor

Myeloid differentiation protein 2 (MD2) is a co-receptor of toll-like receptor 4 (TLR4) responsible for the recognition of lipopolysaccharide (LPS) and mediates a series of TLR4-dependent inflammatory responses in inflammatory lung diseases including acute lung injury (ALI). Targeting MD2 thus may provide a therapeutic strategy against these lung diseases. In this study, we identified a novel compound 4k with the potent anti-inflammatory activity among 39 methyl gallate derivatives (MGDs). MGD 4k exhibited a high binding affinity to MD2, which in turn prevented the formation of the LPS/MD2/TLR4 complex. In addition, MGD 4k significantly reversed the upregulation of LPS-induced inflammatory mediators such as tumor necrosis factor-α, interleukin-6, intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and monocyte chemoattractant protein-1 in vitro and in vivo. Mechanistically, MGD 4k performed anti-inflammatory function by inactivating JNK, ERK and p38 signaling pathways. Taken together, our study identified MGD 4k as a novel potential therapeutic agent for ALI through inhibiting MD2, inflammatory responses, and major inflammation-associated signaling pathways.

Equilibration Time Required for Respiratory System Compliance and Oxygenation Response Following Changes in Positive End-Expiratory Pressure in Mechanically Ventilated Children

OBJECTIVES

Increases in positive end-expiratory pressure are implemented to improve oxygenation through the recruitment and stabilization of collapsed alveoli. However, the time it takes for a positive end-expiratory pressure change to have maximum effect upon oxygenation and pulmonary compliance has not been adequately described in children. Therefore, we sought to quantify the time required for oxygenation and pulmonary system compliance changes in children requiring mechanical ventilation.

DESIGN

Retrospective analysis of continuous data.

SETTINGS

Multidisciplinary ICU of a pediatric university hospital.

PATIENTS

Mechanically ventilated pediatric subjects.

INTERVENTIONS

A case was eligible for analysis if during a 90-minute window following an increase in positive end-expiratory pressure, no other changes to the ventilator were made, ventilator and physiologic data were continuously available and a positive oxygenation response was observed. Time to 90% (T90) of the maximum change in oxygenation and compliance was computed. Differences between oxygenation and compliance T90 were compared using a paired t test. The effect of severity of illness (by oxygen saturation index) upon oxygenation and compliance was analyzed.

MEASUREMENTS AND MAIN RESULTS

A total of 200 subjects were enrolled and 1,150 positive end-expiratory pressure change cases were analyzed. Of these, 54 subjects with 171 positive end-expiratory pressure change case were included in the analysis (67% were responders).Changes in dynamic compliance (T90 = 38 min) preceded changes in oxygenation (T90 = 71 min; p < 0.001). Oxygenation response differed depending on severity of illness quantified by oxygen saturation index; lung dysfunction was associated with a longer response time (p = 0.001).

CONCLUSIONS

T90 requires 38 and 71 minutes for dynamic pulmonary compliance and oxygenation, respectively; the latter was directly observed to be dependent upon severity of illness. To our knowledge, this is the first report of oxygenation and compliance equilibration data following positive end-expiratory pressure increases in pediatric mechanically ventilated subjects.

Accuracy of oxygen saturation index in determining the severity of respiratory failure among preterm infants with respiratory distress syndrome

BACKGROUND

To evaluate the severity of respiratory failure among newborns with respiratory distress syndrome (RDS), oxygenation index (OI) has been implemented. In the present study, we assessed the accuracy of oxygen saturation index (OSI) in determining the severity of respiratory failure.

METHODS

A cross-sectional study was carried out in the NICUs of two Iranian Hospitals (Tehran, Iran) in 2018. Preterm neonates with RDS entered the study. Immediately after admission, the severity of RDS was determined based on RDS scoring system. Then, 2 CC of arterial blood was withdrawn and sent to laboratory determining blood gases. Simultaneously, the level of peripheral capillary oxygen saturation (SpO₂) was read using pulse oximeter and recorded. OI and OSI were measured using the formulae. Receiver Operating Characteristic curve, Kappa agreement coefficient and accuracy, sensitivity and specificity was used to compare the OI and OSI results.

RESULTS

In the study, 95 neonates were considered. Based on ROC curves, the appropriate cut off with AUC = 0.99 for severe respiratory failure was OSI >8. The sensitivity, specificity, negative predicted value, and positive predicted value for the OSI Cut off >8 were 100, 98, 0.97 and 100%, respectively. The overall accuracy and Kappa agreement between OSI and OI was 0.96 and 0.98%, respectively.

CONCLUSION

Our results showed that OSI with high sensitivity, specificity values could predict the severity of respiratory failure in preterm neonates with RDS.

Acute Respiratory Failure in Pediatric Hematopoietic Cell Transplantation: A Multicenter Study

OBJECTIVES

Acute respiratory failure is common in pediatric hematopoietic cell transplant recipients and has a high mortality. However, respiratory prognostic markers have not been adequately evaluated for this population. Our objectives are to assess respiratory support strategies and indices of oxygenation and ventilation in pediatric allogeneic hematopoietic cell transplant patients receiving invasive mechanical ventilation and investigate how these strategies are associated with mortality.

DESIGN

Retrospective, multicenter investigation.

SETTING

Twelve U.S. pediatric centers.

PATIENTS

Pediatric allogeneic hematopoietic cell transplant recipients with respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two-hundred twenty-two subjects were identified. PICU mortality was 60.4%. Nonsurvivors had higher peak oxygenation index (38.3 [21.3-57.6] vs 15.0 [7.0-30.7]; p < 0.0001) and oxygen saturation index (24.7 [13.8-38.7] vs 10.3 [4.6-21.6]; p < 0.0001), greater days with FIO2 greater than or equal to 0.6 (2.4 [1.0-8.5] vs 0.8 [0.3-1.6]; p < 0.0001), and more days with oxygenation index greater than 18 (1.4 [0-6.0] vs 0 [0-0.3]; p < 0.0001) and oxygen saturation index greater than 11 (2.0 [0.5-8.8] vs 0 [0-1.0]; p < 0.0001). Nonsurvivors had higher maximum peak inspiratory pressures (36.0 cm H2O [32.0-41.0 cm H2O] vs 30.0 cm H2O [27.0-35.0 cm H2O]; p < 0.0001) and more days with peak inspiratory pressure greater than 31 cm H2O (1.0 d [0-4.0 d] vs 0 d [0-1.0 d]; p < 0.0001). Tidal volume per kilogram was not different between survivors and nonsurvivors.

CONCLUSIONS

In this cohort of pediatric hematopoietic cell transplant recipients with respiratory failure in the PICU, impaired oxygenation and use of elevated ventilator pressures were common and associated with increased mortality.

Acute respiratory failure and the kinetics of neutrophil recovery in pediatric hematopoietic cell transplantation: a multicenter study

In this multicenter study, we investigated the kinetics of neutrophil recovery in relation to acuity and survival among 125 children undergoing allogeneic hematopoietic cell transplantation (allo-HCT) who required invasive mechanical ventilation (IMV). Recovery of neutrophils, whether prior to or after initiation of IMV, was associated with a significantly decreased risk of death relative to never achieving neutrophil recovery. A transient increase in acuity (by oxygenation index and vasopressor requirements) occurred among a subset of the patients who achieved neutrophil recovery after initiation of IMV; 61.5% of these patients survived to discharge from the intensive care unit (ICU). Improved survival among patients who subsequently achieved neutrophil recovery on IMV was not limited to those with peri-engraftment respiratory distress syndrome. The presence of a respiratory pathogen did not affect the risk of death while on IMV but was associated with an increased length of IMV (p < 0.01). Among patients undergoing HCT who develop respiratory failure and require advanced therapeutic support, neutrophil recovery at time of IMV and/or presence of a respiratory pathogen should not be used as determining factors when counseling families about survival.

Risk Stratification Using Oxygenation in the First 24 Hours of Pediatric Acute Respiratory Distress Syndrome

OBJECTIVE

Oxygenation measured 24 hours after acute respiratory distress syndrome onset more accurately stratifies risk, relative to oxygenation at onset, in both children and adults. However, waiting 24 hours is problematic, especially for interventions that are more efficacious early in the disease course. We aimed to delineate whether oxygenation measured at timepoints earlier than 24 hours would retain predictive validity in pediatric acute respiratory distress syndrome.

DESIGN

Observational cohort study.

SETTING

Two large, academic PICUs.

PATIENTS

Invasively ventilated children with acute respiratory distress syndrome.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PaO2/FIO2 and oxygenation index (mean airway pressure × FIO2 × 100)/PaO2) were measured at acute respiratory distress syndrome onset, at 6, 12, 18, and 24 hours after in 459 children at the Children's Hospital of Philadelphia. Neither PaO2/FIO2 nor oxygenation index at acute respiratory distress syndrome onset discriminated outcome. Between 6 and 24 hours, both PaO2/FIO2 (area under receiver operating curve for mortality between 0.57 and 0.62; p = 0.049-0.002) and oxygenation index (area under receiver operating curve, 0.60-0.62; p = 0.006-0.001) showed good discrimination and calibration across multiple outcomes, including mortality, ventilator-free days at 28 days, ventilator days in survivors, and probability of extubation, given competing risk of death. The utility of oxygenation at 12 hours was confirmed in an independent cohort from the Children's Hospital of Los Angeles.

CONCLUSION

Oxygenation measured between 6 and 12 hours of acute respiratory distress syndrome onset accurately stratified outcomes in children. Our results have critical implications for the design of trials, especially for interventions with greater impact in early acute respiratory distress syndrome.

Unnecessary harm is avoided by reliable paediatric index of mortality2 scores without arterial gas sampling

AIM

To investigate whether unnecessary harm could be avoided in children admitted to paediatric intensive care (PICU), we analysed the impact of arterial blood gas on the paediatric index of mortality score2 (PIM2) and the derived predicted death rate (PDR).

METHODS

From January 1, 2008 to December 31, 2010, 1793 consecutive admissions, newborn infants to 16 years of age (median 0.71 years) from a single, tertiary PICU in Gothenburg Sweden, were collected. Admission information on arterial oxygen tension (PaO₂ ) and fraction of inspired oxygen (FiO₂ ) was extracted from 990 admissions.

RESULTS

There was close agreement between PIM2 score and PDR regardless of whether the PaO₂ /FiO₂ ratio was omitted or not. In the subgroup of admissions with a respiratory admission diagnosis, the inclusion of the PaO₂ /FiO₂ ratio increased the accuracy of the PIM2 score as well as the PDR. The standard mortality ratio was slightly but not significantly overestimated by excluding the PaO₂ /FiO₂ ratio.

CONCLUSION

To avoid unnecessary harm to children admitted to PICU, an arterial blood gas analysis should only be performed if clinically indicated or if the child has a respiratory admission diagnosis. Estimation of the PIM2 score and PDR will not be less accurate by this approach.

Bolus vs Continuous Nasogastric Feeds in Mechanically Ventilated Pediatric Patients: A Pilot Study

BACKGROUND

Malnutrition increases the risk of mortality and morbidity in the pediatric intensive care unit (PICU). Barriers to adequate delivery of enteral nutrition (EN) include hemodynamic instability, feeding interruptions and intolerance, and lack of standardized feeding protocols. The most recent guidelines on nutrition support for the critically ill child describe a paucity of evidence around the best method to deliver EN. There is an untested clinical assumption that bolus gastric feeding (B-GF) in intubated patients is associated with aspiration events, lung injury, and associated morbidity compared with continuous gastric feeding (C-GF). This study compared the effectiveness and safety of C-GF vs B-GF in intubated pediatric patients.

METHODS

We enrolled randomized patients aged 1 month-12 years who were intubated within 24 hours and received EN starting within 48 hours of admission to a C-GF or B-GF group. Goal-directed EN volume and caloric density were increased every 3 and 12 hours, respectively, to target. Feeding interruptions and intolerance events were recorded.

RESULTS

Twenty-five subjects were enrolled (B-GF = 11; C-GF = 14). At 24 hours, B-GF was associated with higher energy and protein delivery (P < 0.007) and was associated with faster time to goal volume (median B-GF = 15 hours; C-GF = 29.5 hours). No aspiration events resulting in additional lung injury were noted for either group (P = 0.866).

CONCLUSIONS

B-GF was associated with superior delivery of EN with a comparable safety profile to C-GF. Further study is needed to compare both EN methods in other PICU populations.

Sepsis and Pediatric Acute Respiratory Distress Syndrome

The epidemiology of the acute respiratory distress syndrome (ARDS) in pediatric sepsis is poorly defined. With significant data extrapolated from adult studies in sepsis and ARDS, sometimes with uncertain applicability, better pediatric-specific guidelines and dedicated investigations are warranted. The recent publication of a consensus definition for pediatric ARDS (PARDS) is the first step in addressing this knowledge gap. The aim of this review is to frame our current understanding of PARDS as it relates to pediatric sepsis, encompassing epidemiology, pathophysiology, and management. We argue that addressing the role of PARDS in pediatric sepsis requires significant attention to details with respect to how PARDS and sepsis are defined to accurately describe their epidemiology, natural history, and outcomes. Finally, we highlight certain aspects of PARDS management as they relate to the septic child and offer suggestion for future directions in this field.

Extended use of the modified Berlin Definition based on age-related subgroup analysis in pediatric ARDS

Background

Pediatric acute respiratory distress syndrome (pARDS) is a rare but very severe condition. Management of the condition remains a major challenge for pediatric intensive care specialists.

Objective

To perform a descriptive assessment of pARDS based on the modified Berlin Definition by using the SpO₂/FiO₂ ratio in order to establish an extended patient registry divided into age-related subgroups.

Methods

The data of all children on mechanical ventilation for respiratory failure admitted between 2005 and 2012 were reviewed retrospectively for this study. The age of patients ranged from newborns >37 weeks, up to children <18 years. Inclusion criteria were based on the modified Berlin Definition of pARDS. The following data were collected: demographic data, primary diagnosis, ventilation settings, and use of supportive treatment, in addition to mechanical ventilation (inhaled nitric oxide, surfactant, corticosteroids, prone positioning, and extracorporeal membrane oxygenation).

Results

In all, 93 children where included: 35% were newborns, 29% infants, 24% toddlers, and 12% school children; 66% were male and 34% were female patients. The most common primary diagnosis was viral pneumonia (21%) and 55% of the children were diagnosed with severe ARDS. The median duration of stay on the pediatric intensive care unit was 16 days (10/27). In total, 66 children (71%) had direct lung injury and 18 (19%) had indirect lung injury. More than 80% of all children needed more than one supportive care therapy. The overall survival rate was 77%.

Conclusion

This study is a valuable report about pediatric patients with ARDS and allows for an important extension of the application of the modified Berlin Definition in all age groups.

The impact of early enteral nutrition on pediatric acute respiratory failure

BACKGROUND AND AIMS

Children who are critically ill undergo metabolic stress and it is important that they receive adequate calories and protein in order to recover. Our objective was to investigate the impact of early enteral nutrition (EEN) on pediatric intensive care (PICU) patients with acute respiratory failure.

METHODS

A retrospective cohort study was performed on all patients admitted to a 20 bed PICU at a tertiary children's hospital over a 30 month period. Inclusion criteria were: intubation on admission or within 24 h of admission, ventilation over 48 h and enteral nutrition initiated on ventilatory support. Baseline patient characteristics and nutritional, ventilatory and overall outcome data were collected. Subgroup analysis was performed comparing those that received EEN (goal in 72 h) and those that did not.

RESULTS

Patients that received EEN had a shorter PICU and overall length of stay 8.7 vs 10.7 and 17.5 vs 22; p < 0.05 and received a higher percentage of goal Kcal and protein (71 vs 54, and 61 vs 51%, p < 0.002) in the PICU. After adjusting for age and severity of illness, EEN was still associated with decreased PICU and overall length of stay. More patients with feeding intolerance were on vasoactive agents (33 vs 9%, p = 0.02), but intolerance was not associated with use of motility agents or degree of respiratory failure. Feeds were interrupted in 19% of patients, most commonly for procedures.

CONCLUSIONS

In PICU patients with acute respiratory failure, EEN is associated with shorter PICU and overall length of stay and delivery of higher percentage of goal Kcal and protein by tube feeds. Feeds are commonly interrupted despite efforts to achieve EEN and patients receiving vasoactive agents have feeds held more commonly for perceived intolerance.

Oxygen Saturation Index for assessment of respiratory failure in neonates

Introduction: Acute respiratory failure (ARF) is the most common problem seen in the preterm and term infants admitted to neonatal intensive care units. Etiology is not uniform, and mostly depend on gestational age. For adequate treatment is certainly important to recognize and treat underlying disease, but at the same time, we have to supply adequate respiratory support, tissue perfusion and oxygen deliveries. For a good outcome we need reliable estimation method for functional state of respiratory system, as well as monitoring the effects of treatment. Current assessment ARF is with blood gas, chest X-ray and Oxygenation index (OI). OI is quite aggressive assessment method for neonates, because it involves arterial blood sampling. Promoted in recent studies, Oxygen saturation index (OSI) measured by pulse oximetry, attempts to objectively score respiratory disease with parameters available non-invasively. The aim of our research is to evaluate correlation between OSI and OI in neonates with ARF requiring mechanical ventilation. Material and methods: In a retrospective cohort study 101 neonates were selected, treated at the Department of intensive therapy and care, Pediatric clinic of Tuzla, due to ARF requiring mechanical ventilation. We reviewed data such as gestational age, birth weight, gender, Apgar scores, values of Score for Neonatal Acute Physiology-Perinatal Extension, all the parameters from the arterial blood gas analysis, pulse oximetry values, Oxygenation Index and Oxygenation Saturation Index, that were calculated by the formulas. OSI and OI were calculated and correlated. Mean values of OSI and OI correlated with Pearson's coefficient of 0.76; p < 0.0001 (95% CI = 0.66-0.83). OSI correlated with SNAP-PE with Pearson's coefficient of 0.52; p < 0.0001 (95% CI = 0.36-0.65). Comparing the values of OSI between patients who died and those who survived, we found that OSI correlated with the outcome with Spearman's coefficient of -0.47; p < 0.0001 (95% CI = -0.16 - -0.31). Bland-Altman plot confirmed correlation between OSI and OI in mean values, identifying discrepancy between two indices for extreme values.In conclusion, OSI correlates significantly with OI in infants with respiratory failure. This noninvasive method of oxygenation assessment, utilizing pulse oximetry, can be used to assess the severity of ARF and mortality risk in neonates.

High-Frequency Oscillatory Ventilation Use and Severe Pediatric ARDS in the Pediatric Hematopoietic Cell Transplant Recipient

INTRODUCTION

The effectiveness of high-frequency oscillatory ventilation (HFOV) in the pediatric hematopoietic cell transplant patient has not been established. We sought to identify current practice patterns of HFOV, investigate parameters during HFOV and their association with mortality, and compare the use of HFOV to conventional mechanical ventilation in severe pediatric ARDS.

METHODS

This is a retrospective analysis of a multi-center database of pediatric and young adult allogeneic hematopoietic cell transplant subjects requiring invasive mechanical ventilation for critical illness from 2009 through 2014. Twelve United States pediatric centers contributed data. Continuous variables were compared using a Wilcoxon rank-sum test or a Kruskal-Wallis analysis. For categorical variables, univariate analysis with logistic regression was performed.

RESULTS

The database contains 222 patients, of which 85 subjects were managed with HFOV. Of this HFOV cohort, the overall pediatric ICU survival was 23.5% (n = 20). HFOV survivors were transitioned to HFOV at a lower oxygenation index than nonsurvivors (25.6, interquartile range 21.1-36.8, vs 37.2, interquartile range 26.5-52.2, P = .046). Survivors were transitioned to HFOV earlier in the course of mechanical ventilation, (day 0 vs day 2, P = .002). No subject survived who was transitioned to HFOV after 1 week of invasive mechanical ventilation. We compared subjects with severe pediatric ARDS treated only with conventional mechanical ventilation versus early HFOV (within 2 d of invasive mechanical ventilation) versus late HFOV. There was a trend toward difference in survival (conventional mechanical ventilation 24%, early HFOV 30%, and late HFOV 9%, P = .08).

CONCLUSIONS

In this large database of pediatric allogeneic hematopoietic cell transplant subjects who had acute respiratory failure requiring invasive mechanical ventilation for critical illness with severe pediatric ARDS, early use of HFOV was associated with improved survival compared to late implementation of HFOV, and the subjects had outcomes similar to those treated only with conventional mechanical ventilation.

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.

Correlation Between PaO2/FIO2 and Peripheral Capillary Oxygenation/FIO2 in Burned Children With Smoke Inhalation Injury

OBJECTIVES

Determine whether the peripheral capillary oxygenation/FIO2 ratio correlates with the PaO2/FIO2 ratio in burned children with smoke inhalation injury, with the goal of understanding if the peripheral capillary oxygenation/FIO2 ratio can serve as a surrogate for the PaO2/FIO2 ratio for the diagnosis of acute respiratory distress syndrome.

DESIGN

Retrospective chart review.

SETTING

Shriners Hospitals for Children-Galveston.

PATIENTS

All burned children with smoke inhalation injury who were admitted from 1996 to 2014 and had simultaneously obtained peripheral capillary oxygenation, FIO2 and PaO2 measurements.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two hundred seventy-three patients (63% male, 8 ± 5 yr, 53% ± 24% total body surface area burns) were analyzed. Peripheral capillary oxygenation/FIO2 ratios were divided into four subgroups based on peripheral capillary oxygenation values (≤ 100%, ≤ 98%, ≤ 95%, and ≤ 92%). Significance was accepted at r greater than 0.81. The r (number of matches) was 0.66 (23,072) for less than or equal to 100%, 0.87 (18,932) for less than or equal to 98%, 0.89 (7,056) for less than or equal to 95%, and 0.93 (4,229) for less than or equal to 92%. In the subgroup of patients who developed acute respiratory distress syndrome, r was 0.65 (8,357) for less than or equal to 100%, 0.89 (7,578) for less than or equal to 98%, 0.89 (4,115) for less than or equal to 95%, and 0.91 (2,288) less than or equal to 92%.

CONCLUSIONS

PaO2/FIO2 and peripheral capillary oxygenation/FIO2 strongly correlate in burned children with smoke inhalation injury, with a peripheral capillary oxygenation of less than 92% providing the strongest correlation. Thus, peripheral capillary oxygenation/FIO2 ratio may be able to serve as surrogate for PaO2/FIO2, especially when titrating FIO2 to achieve a peripheral capillary oxygenation of 90-95% (i.e., in the acute respiratory distress syndrome range).