Predicting outcome in neonatal hypoxic respiratory failure with the score for neonatal acute physiology (SNAP) and highest oxygen index (OI) in the first 24 hours of admission

Associations between oxygen saturation Index and oxygenation index in neonates with congenital diaphragmatic hernia

Objective

To explore the relationship between Oxygenation Index (OI) and Oxygen Saturation Index (OSI) among infants with Congenital Diaphragmatic Hernia (CDH), both within the first 24 h after birth and in extended observations in those who survived until their surgical intervention.

Methods

Seven- years retrospective review of CDH cases at a single Level III neonatal intensive care unit. The correlations of various combinations of OI-OSI pairs were assessed using the Spearman's rho Correlation Coefficient. Additionally, during the initial 24 h, the correlations between admission (first), best (lowest), highest, and mean OI and OSI values were determined. The predictive ability of the first 24 h oxygen and oxygen saturation indices for mortality and other adverse outcomes were assessed using the Area Under the Curve (AUC) analysis.

Results

Thirty-seven infants with CDH were included in the analysis. A strong correlation was observed between all pairs of OI/OSI (2,289) (Spearman's rho = 0.843), matched pairs of Postductal OI/OSI (1,232 pairs) (Spearman's rho = 0.835) and the unmatched pairs of Postductal OI and Preductal OSI (1,057 pairs) (Spearman's rho = 0.852). Using the regression equations for all pairs, matched and unmatched OI/OSI pairs, we deduced that for clinically pertinent OI thresholds of 10, 15, 20 and 40, the corresponding OSI values were 5, 8, 11, and 23, respectively. Furthermore, in the first 24 h, strong correlations were evident between OI/OSI: at admission (Spearman's rho = 0.783), best OI/OSI (Spearman's rho = 0.848), and highest OI/OSI (Spearman's rho = 0.921). The most robust correlation was observed between the mean OI/OSI with a Spearman's rho of 0.928. First (AUC = 0.849), best (AUC = 0.927), highest (AUC = 0.942) and mean day 1 OI (AUC = 0.946) were all predictive of mortality. Similarly, first (AUC = 1.00), best (AUC = 0.989), highest (AUC = 1.00) and the mean OSI in day 1 (AUC = 0.978) were all predictive of mortality. All of the OIs and OSIs in day 1 except for the admission OSI (AUC = 0.683) were predictive of pulmonary hypertension. Additionally, all of OI and OSI indices in the first 24-hour except for the best day 1 OI (AUC = 0.674) were predictive of the need for rescue HFOV.

Conclusion

There were a strong correlation between the OI and OSI in infants with CDH. Oxygenation indices and OSI in the first 24 h were predictive of mortality and other adverse outcomes in infants with CDH.

Assessing hypoxic respiratory failure in mechanically ventilated neonates: A comparative study of oxygen saturation index and oxygenation index

OBJECTIVE

To investigate the correlation between oxygen saturation index (OSI) and oxygenation index (OI) for evaluating the blood oxygenation status in neonates with respiratory failure requiring mechanical ventilation support and to assess the predictive capability of OSI in determining clinically relevant OI cutoffs.

METHODS

A prospective study was conducted on neonates who received invasive mechanical ventilation at the neonatal intensive care unit of tertiary hospital in Vietnam. Bland-Altman analysis was utilized to evaluate the agreement between OSI and OI.

RESULTS

A total of 123 neonates, including both term and preterm infants, were included in the study. A high agreement rate of 94.3% within the 95% limits of agreement (between OI and OSI), with a narrow similarity value of 3.3 (95% CI: -5.1 to 11.8) and high correlation coefficient (r = 0.791, p<0.001) was observed. The OSI cut-off value for predicting an OI of >15 was determined to be 7.45, with a sensitivity of 100% and a specificity of 87.4% (AUC 0.955; 95% CI: 0.922-0.989, p < 0.05). Similarly, an OSI cutoff value of 9.9 corresponded to an OI of 25, displaying a sensitivity of 100% and specificity of 87.4% (AUC 0.92). The receiver operating characteristic (ROC) curves for OSI exhibited statistically significant results (p < 0.05).

CONCLUSION

The findings demonstrate a strong correlation between OSI and OI in neonates with respiratory failure. Furthermore, OSI, as a non-invasive method, can serve as a substitute for OI to evaluate the severity of hypoxic respiratory failure and lung injury in neonates.

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..

Risk factors of transient tachypnea of the newborn developing into pulmonary hypertension of the newborn: a case-control study

Background

Transient tachypnea of the newborn (TTN) is the consequence of delayed resorption of lung fluid. When TTN develops, the infant may develop severe hypoxemia and progress to persistent pulmonary hypertension of the newborn (PPHN).

Objectives

To examine factors associated with the development of PPHN in TTN infants.

Methods

This retrospective study comprised 23 infants in whom a diagnosis of TTN with PPHN (TTN-PPHN) was confirmed and 59 infants with severe TTN without PPHN who required mechanical ventilation between 2009 and 2018 at Songklanagarind Hospital, Thailand. Logistic regression was used to assess factors associated with TTN and PPHN.

Results

The factors identified by univariate analysis that were associated with development of PPHN were oxygen saturation (SpO2) <90% and respiratory rate (RR) ≥70 breaths/min at the time of admission, mean airway pressure (MAP) ≥8 cmH2O, oxygen index (OI) ≥10, partial pressure of oxygen (PaO2) ≤60, partial pressure of carbon dioxide (PCO2) ≥45 mmHg, and infants who did not receive positive pressure ventilation (PPV). In multivariate analyses, RR ≥70 breaths/min (adjusted odds ratio [aOR] 9.96, 95% confidence interval [CI] 2.1-47.29, P < 0.001) and OI ≥10 (aOR 29.22, 95% CI 4.46-191.23, P < 0.001) remained statistically significantly associated with PPHN.

Conclusions

High RR and high OI were factors associated with PPHN in TTN infants.

Worsened short-term clinical outcomes in a cohort of patients with iNO-unresponsive PPHN: a case for improving iNO responsiveness

OBJECTIVES

To identify distinguishing characteristics of neonates with persistent pulmonary hypertension of the newborn (PPHN) unresponsive to inhaled nitric oxide (iNO) and evaluate the use of milrinone in this cohort.

STUDY DESIGN

Retrospective chart review of 99 neonates with PPHN treated with iNO over a five-year period at a quaternary neonatal intensive care unit.

RESULTS

Neonates with iNO-unresponsive PPHN had an increased number of ventilator days (10 vs 7 days, p = 0.02), greater length of hospital stay (30 vs 22 days, p = 0.02), and increased risk of death or ECMO than iNO-responsive neonates (p = 0.03). Inhaled NO non-responders treated with milrinone had improved oxygenation (p < 0.03) and no change in systemic hemodynamics.

CONCLUSION

Neonates with iNO-unresponsive PPHN had worse clinical outcomes than iNO responders. Milrinone may be a safe and effective adjuvant therapy, although large-scale studies are lacking. Identifying early predictors of iNO response and novel strategies to enhance iNO responsiveness should be prioritized.

Monocyte Chemoattractant Protein-1, a Possible Biomarker of Multiorgan Failure and Mortality in Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) leads to increased patients’ mortality and medical expenditure. Monocyte chemoattractant protein-1 (MCP-1) plays a role in the pathogenesis of lung inflammation and infection. Therefore, the plasma concentration of MCP-1 was assessed and correlated with the clinical course in VAP patients. This retrospective observational study recruited 45 healthy volunteers, 12 non-VAP subjects, and 30 VAP patients. The diagnostic criteria for VAP were based on the American Thoracic Society guidelines, and the level of plasma MCP-1 was determined by ELISA. Plasma MCP-1 concentration was significantly elevated in the acute stage in VAP patients when compared with the control (p < 0.0001) and non-VAP patient groups (p = 0.0006). Subsequently, it was remarkably decreased following antibiotic treatment. Moreover, plasma MCP-1 concentration was positively correlated with indices of pulmonary dysfunction, including the lung injury score (p = 0.02) and the oxygenation index (p = 0.02). When patients with VAP developed adult respiratory distress syndrome (ARDS), their plasma MCP-1 concentrations were significantly higher than those of patients who did not develop ARDS (p = 0.04). Moreover, plasma MCP-1 concentration was highly correlated with organ failure scores, including simplified acute physiology score II (SAPS II, p < 0.0001), sequential organ failure assessment score (SOFA, p < 0.0001), organ dysfunctions and/or infection (ODIN, p < 0.0001), predisposition, insult response and organ dysfunction (PIRO, p = 0.005), and immunodeficiency, blood pressure, multilobular infiltrates on chest radiograph, platelets and hospitalization 10 days before onset of VAP (IBMP-10, p = 0.004). Our results demonstrate that plasma MCP-1 is an excellent marker for recognizing VAP when the cut-off level is set to 347.18 ng/mL (area under the curve (AUC) = 0.936, 95% CI = 0.863–0.977). In conclusion, MCP-1 not only could be a biological marker related to pulmonary dysfunction, organ failure, and mortality in patients with VAP, but also could be used for early recognition of VAP.

Evaluation of Oxygen Saturation Index Compared With Oxygenation Index in Neonates With Hypoxemic Respiratory Failure

IMPORTANCE

Oxygenation index (OI), an invasive measurement, is routinely used as a marker of severity of hypoxemic respiratory failure in neonates. Oxygen saturation index (OSI) is a noninvasive measurement and has been shown to be a reliable surrogate marker of OI in children and adults with respiratory failure.

OBJECTIVES

To evaluate the correlation of OI with OSI and to derive and validate predictive OI from noninvasive OSI measurements for clinically relevant OI values.

DESIGN, SETTING, AND PARTICIPANTS

For this retrospective cohort study, 220 neonates requiring invasive mechanical ventilation for hypoxic respiratory failure during the first 3 days of admission were recruited from a level III neonatal intensive care unit during a 6-year period, from January 1, 2012, to December 31, 2017. Data were analyzed from January 2017 to December 2017.

MAIN OUTCOMES AND MEASURES

The primary outcome was correlation of OI with OSI, analyzed using Pearson correlation coefficient. The secondary outcome was derivation and validation of OI from OSI. The data were split into derivative samples, from which a predictive equation for OI was derived using generalized linear model, and a validation sample was used to assess the predictive ability of the derived OI. Bland-Altman plot was used to assess agreement between derived OI and measured OI.

RESULTS

A total of 1442 paired OI and OSI measurements from 220 infants (190 preterm and 30 term; median [interquartile range] gestational age, 29 [26-33] weeks; mean [SD] birth weight, 1602 [1092] g) were recorded during the study. The median (interquartile range) number of samples was 5 (3-9) per patient. Overall, OI and OSI showed strong correlation (r = 0.89). The correlation was stronger in preterm infants (<28 weeks, r = 0.93; 28-33 weeks, r = 0.93) and within an oxygen saturation range of 85% to 95% (r = 0.94). The predictive derivative equation showed a strong linear association and good agreement in both derivation and validation data sets, with strong accuracy measures of derived OI for OI cutoffs of 5, 10, 15, 20, and 25.

CONCLUSIONS AND RELEVANCE

A strong correlation of OI with OSI was found. Derived OI from OSI was in good agreement and strongly predictive of clinically relevant OI cutoffs from 5 to 25. Oxygenation index derived from noninvasive sources may be useful to reliably assess severity of respiratory failure and response to therapy on a continuous basis.

Assessment of sickness severity of illness in neonates: review of various neonatal illness scoring systems

Sickness severity scores are widely used for neonates admitted to neonatal intensive care units to predict severity of illness and risk of mortality and long-term outcome. These scores are also used frequently for quality assessment among various neonatal intensive care unit and hospital. Accurate and reliable measures of severity of illness are required for unbiased and reliable comparisons especially for benchmarking or comparative quality improvement care studies. These scores also serve to control for population differences when performing studies such as clinical trials, outcome evaluations, and evaluation of resource utilisation. Although presently there are multiple scores designed for neonates' sickness assessment but none of the score is ideal. Each score has its own advantages and disadvantages. We did literature search for identifying all neonatal sickness severity score and in this review article, we discuss these scores along with their merits and demerits.

Is the SNAP-II score useful for predicting mortality in mechanically ventilated in neonates within the first 12 hours of admission?

Background

Respiratory failure is a most serious neonatal disorder. A severity of illness assessment should be performed for mechanically ventilated infants to predict the probability of hospital mortality and to assist clinical decision making.

Objectives

To evaluate the ability of the Score for Neonatal Acute Physiology, version II (SNAP-II) to predict the mortality risk for the infants who are mechanically ventilated with positive pressure ventilation (PPV) at a neonatal intensive care unit (NICU).

Methods

A prospective observational cohort study was performed in a 12-bed level III NICU at Hat Yai Hospital between January 2010 and December 2010.

Results

During the study period, 46 infants were ventilated with PPV at admission. Of these, 8 died (17%) and 30 survived (83%). The overall mean SNAP-II score was significantly higher in the group of infants who died compared with those who survived (36.5 ± 11.5 vs. 22.3 ± 13.6, P < 0.01, respectively).The area under the receiver operating characteristic curve for the SNAP-II was 0.79 (95% confidence interval (CI) 0.66 to 0.92, P = 0.01). Every one-point increment of SNAP-II was associated with an odds ratio of 1.08 (95% CI 1.02 to 1.14, P < 0.01). The stratification of the two sets of scores when compared between groups showed that infants who had SNAP-II scores of ≥32 had the highest mortality risk with an odds ratio of 9.7 (95% CI 1.7 to 56.5) with sensitivity of 75.0% and specificity of 76.3%.

Conclusion

SNAP-II scores can significantly predict mortality in infants requiring mechanical PPV.

A comprehensive study of clinical biomarkers, use of inotropic medications and fluid resuscitation in newborns with persistent pulmonary hypertension

Persistent pulmonary hypertension of the newborn (PPHN) is associated with high morbidity and mortality. This study evaluated clinical outcomes in PPHN in relation to echocardiographic (EC) markers, score of neonatal acute physiology, perinatal extension, version II (SNAPPE II) scores, inotropic agent use, and the amount of fluid received as boluses. In this retrospective chart analysis of 98 neonates with PPHN born at >34 weeks' gestation, we compared two cohorts of newborns: those who received inhaled nitric oxide and mechanical ventilation only, and who survived to discharge (Group 1); and those who required extracorporeal membrane oxygenation (ECMO) or who died (Group 2). Of 21 EC parameters assessed, seven were significantly different between Group 1 and Group 2. Eleven (24.4%) newborns in Group 2 had decreased left ventricular (LV) function, compared with three (5.1%) in Group 1 (p = 0.011). Median SNAPPE II scores were significantly higher in Group 2 than in Group 1 (p < 0.001). Newborns in Group 2 also received a significantly higher amount of fluid as boluses during the first 7 days of hospitalization compared with Group 1 (p = 0.018). Following logistic regression analysis, only the difference in total SNAPPE II score retained statistical significance (p < 0.001); however, the total amount of fluid administered as boluses trended higher (p = 0.087) for newborns in Group 2. Our findings show that SNAPPE II scores may help guide counseling for parents of newborns with PPHN regarding the likelihood of death or the need for ECMO. Limiting fluid boluses may improve outcomes in newborns with high SNAPPE II scores and decreased LV function.

Target versus actual oxygenation index at initiation of inhaled nitric oxide in neonates with hypoxic respiratory failure: survey results from 128 patient cases

BACKGROUND

Inhaled nitric oxide (iNO) is a well-established treatment for neonatal hypoxic respiratory failure (HRF). However, iNO therapy initiation criteria have not been standardized. This report describes a follow-up survey administered to neonatologists who had completed an Awareness, Trial, and Usage Survey. The objectives were to compare stated target oxygenation index (OI) versus actual OI at which iNO is initiated in respondents' patients and identify factors associated with iNO initiation at other levels.

METHODS

Neonatologists provided iNO-treated HRF patient data. Target and actual OI at initiation were determined. Patient groups were stratified by actual OI deviation from target [<4; at (±3); above: 4-10, 11-20, >20; not measured]. Reasons for above-target OI were determined.

RESULTS

Of 83 invited neonatologists, 26 (31%) participated, providing data for 128 patients; 85/128 patients (66%) had OI measured at initiation with neonatologist-stated mean target OI 18.8±5.8. Actual mean OI was 26.2±10.3. iNO was initiated ≤ target in 30/85 patients (35%); most [55/85 (65%)] had iNO initiated when OI was above target. Patients aged ≤1 day and those receiving a fraction of inspired oxygen (FiO2) of 1.0 for more than 1 h had highest OIs at initiation.

CONCLUSIONS

Among surveyed neonatologists who treat infants with HRF with pulmonary hypertension (PH), there is a disparity between stated target versus actual OI for iNO initiation, particularly among infants <1 day old and those receiving FiO2 of 1.0 for more than 1 h. In term/near-term neonates with HRF with PH, neonatologists should consider implementing treatment protocols to ensure iNO initiation at stated target OI levels.

Addition of SNAP to perinatal risk factors improves the prediction of bronchopulmonary dysplasia or death in critically ill preterm infants

Background

Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in premature infants. The score for neonatal acute physiology (SNAP) is a physiologic severity index for neonatal intensive care and correlates well with neonatal mortality and clinical outcomes. The prognostic value of the SNAP score for BPD in preterm infants remains to be clarified. The aim of the study was to determine whether SNAP can predict the development of BPD or death, and to investigate the contribution of SNAP to the predictive accuracy of other potential perinatal risk factors for the adverse outcome in critically ill preterm infants.

Methods

We conducted a study in 160 critically ill preterm infants with less than 33 gestational weeks. The original SNAP score was prospectively calculated based on 28 items collected during the first 24 hours of admission. The potential perinatal risk factors were assessed during the first 72 hours of life. Major outcome measures were BPD and mortality before the time of BPD screening.

Results

Of the 160 infants, 17 died and 41 developed BPD. The SNAP score was significantly associated with BPD or death (odds ratio [OR] =1.28; 95% confidence interval [CI], 1.16-1.41; p <0.001), even after adjustment for gestational age (OR =1.27; 95% CI, 1.13-1.41; p <0.001). High SNAP score was an independent predictor of BPD or death (area under the curve [AUC] =0.78; 95% CI, 0.70-0.85; p <0.001), with additional predictive value when combined with other perinatal risk factors. Multivariate regression analysis resulted in a final model, including SNAP, gestational age, apnea of prematurity, patent ductus arteriosus, and surfactant use as independent risk factors, with a higher predictive accuracy compared with individual components (AUC =0.92; 95% CI, 0.87-0.96; p <0.001).

Conclusions

SNAP is associated with adverse outcome of BPD or death. High SNAP scores are predictive of BPD or death in critically ill preterm infants, and add prognostic value to other perinatal risk factors.

Impact of sepsis on the urinary level of interleukin-18 and cystatin C in critically ill neonates

BACKGROUND

Urinary interleukin-18 (uIL-18) and cystatin C (uCysC) are biomarkers of acute kidney injury (AKI). We hypothesized that in non-AKI neonates, the level of uIL-18 and uCysC would be higher in those with sepsis compared to those without sepsis. The aims of this study were to determine the association between urinary biomarkers and sepsis in non-AKI critically ill neonates, and to evaluate whether uIL-18 and uCysC could serve as predictors of sepsis in this population.

METHODS

The study included 111 non-AKI critically ill neonates with acute clinical deterioration suggestive of sepsis: 26 with infection, 57 without infection, and 28 were assigned to the unclassified group. Urinary samples were collected and a full sepsis screen was performed at the time of enrollment.

RESULTS

The level of uIL-18, but not uCysC, was significantly elevated in non-AKI septic neonates. Urinary IL-18 was an independent factor associated with sepsis assessed by multivariate analysis, had odds ratio of 1.73 (95 % CI 1.15 to 2.58, p = 0.008), and achieved the area under the receiver operating characteristic curve of 0.74 for predicting the presence of sepsis in non-AKI critically ill neonates.

CONCLUSIONS

Sepsis has an impact on the level of uIL-18, but not on the uCysC in non-AKI neonates, suggesting systemic infection might influence the diagnostic value of uIL-18 to detect AKI in the general population.

Urine interleukin-18 and cystatin-C as biomarkers of acute kidney injury in critically ill neonates

BACKGROUND

Urinary interleukin-18 and cystatin-C are suggested to be biomarkers for predicting acute kidney injury (AKI). The aims of this study are to examine whether the urinary concentrations of interleukin-18 and cystatin-C vary with gestational age and other factors in non-AKI control neonates, and to determine whether urinary interleukin-18 and cystatin-C can predict AKI development in non-septic critically ill neonates, independently of potential confounders.

METHODS

We enrolled 62 non-septic critically ill neonates. Urine was collected every 48-72 h during the first 10 days of life.

RESULTS

Urinary concentration of cystatin-C, but not interleukin-18, decreased with increasing gestational age and body weight, but not with increasing postnatal age in non-AKI control neonates. Both urinary interleukin-18 and cystatin-C were associated with AKI, even after controlling for gestational and postnatal age, birth weight, gender, Apgar score and the score for neonatal acute physiology in non-septic critically ill neonates. Urinary interleukin-18 and cystatin-C had odds ratios of 2.27 and 2.07, and achieved the area under-the-receiver-operating-characteristic curve of 0.72 and 0.92, respectively, for predicting AKI.

CONCLUSIONS

The urinary concentration of cystatin-C, but not interleukin-18, may decrease with increasing renal maturity. Both urinary interleukin-18 and cystatin-C are independently predictive of AKI in non-septic critically ill neonates.

Patch repair is an independent predictor of morbidity and mortality in congenital diaphragmatic hernia

BACKGROUND

Infants with congenital diaphragmatic hernia (CDH) have variable outcomes. There is a considerable potential benefit in being able to predict perinatally, which infants have severe hypoplasia and are thus more likely to die or survive with significant morbidity. We examine the relationship between a need for patch repair of CDH (PR) and outcome, using a national database.

METHODS

Baseline characteristics of patients undergoing PR or non-patch repair (NPR) were compared. Multivariate analysis was performed to determine the association of PR with mortality and morbidity independent of other known predictors.

RESULTS

Baseline characteristics of PR and NPR infants were similar although those infants with PR had higher SNAP-II scores. PR was an independent predictor of mortality with an odds ratio of 17.1 (95%CI 2.0-149.2) and was independently associated with secondary outcome measures of morbidity, including the need for oxygen at discharge and the duration of ventilation.

CONCLUSIONS

Infants requiring PR have significantly higher mortality and suffer greater morbidity than those undergoing NPR. This association is independent of other known predictors of mortality. Identifying prenatal features associated with this high risk group would be of great clinical value.

Predicting mortality in infants with persistent pulmonary hypertension of the newborn with the Score for Neonatal Acute Physiology-Version II (SNAP-II) in Thai neonates

AIM

To evaluate the ability of the Score for Neonatal Acute Physiology-Version II (SNAP-II) to predict mortality in infants with persistent pulmonary hypertension of the newborn (PPHN).

METHODS

A prospective cohort study of 41 infants with PPHN admitted to our neonatal intensive care unit between June 2008 and March 2010, who underwent a SNAP-II test within 12 h of admission.

RESULTS

Of the 41 infants, 14 died (34.1%) and 27 survived (65.9%). The SNAP-II scores were significantly higher in infants who died (50.1 ± 18.5 vs. 35.7 ± 16.8, P=0.02). Each point increase in the SNAP score increased the odds of mortality by 1.04 [95% confidence interval (CI) 1.01-1.07, P<0.01]. Infants who had a SNAP-II score of ≥ 43 had the greatest mortality risk with an odds ratio (OR) of 10.00 (95% CI 1.03-97.50). The SNAP-II model showed moderate discrimination in predicting mortality with a result of 0.72 (95% CI 0.56-0.88) under the receiver operating characteristic curve. The lowest blood pressure, lowest PaO(2)/FIO(2) ratio, and urine output within the first 12 h of admission were also independently found to be good predictors of an increased risk for death.

CONCLUSION

The SNAP-II scoring system significantly predicted mortality. PPHN infants with a SNAP-II score of ≥ 43 had the greatest mortality risk.

Predictors of death or bronchopulmonary dysplasia in preterm infants with respiratory failure

OBJECTIVES

To identify the variables that predict death/physiologic bronchopulmonary dysplasia (BPD) in preterm infants with severe respiratory failure.

STUDY DESIGN

The study was a secondary analysis of data from the NICHD Neonatal Research Network trial of inhaled nitric oxide (iNO) in preterm infants. Stepwise logistic regression models and Classification and Regression Tree (CART) models were developed for the outcome of death or physiologic BPD (O(2) at 36 weeks post-menstrual age).

RESULT

Death and/or BPD was associated with lower birth weight, higher oxygen requirement, male gender, additional surfactant doses, higher oxygenation index and outborn status, but not the magnitude of response in PaO(2) to iNO. The positive predictive value of the CART model was 82% at 95% sensitivity.

CONCLUSIONS

The major factors associated with death/BPD were an increased severity of respiratory failure, lower birth weight, male gender and outborn status, but not the magnitude of initial response to iNO.

Hypoxic respiratory failure: etiology and outcomes at one referral center 2000 through 2005

OBJECTIVE

We calculated in a referral population of term and near-term infants with hypoxic respiratory failure (HRF) as a primary presenting problem the overall survival rate, the need for extracorporeal membrane oxygenation (ECMO) and the incidence of apparently irreversible disorders.

STUDY DESIGN

All infants >or=36-week gestation admitted at <or=72 h of age from 2000 through 2005 were identified. The worst (highest) oxygen index (OI) was calculated and outcomes were noted.

RESULTS

A total of 630 infants were reviewed and 315 infants were identified with primary diagnosis of HRF; four infants died before discharge. One hundred seventy-seven infants had OI <or=14; 71 had OI of 15 to 25; and 67 had OI of >25. A total of 32 infants received ECMO, including all four who died, two with histologic evidence of pulmonary malformations and two with septic shock.

CONCLUSION

Term or near-term infants with isolated HRF are likely to survive, given the low incidence of pulmonary disorders not supportable by inhaled nitric oxide or ECMO.

Hypoxic respiratory failure in the late preterm infant

Hypoxic respiratory failure in late preterm infants has received increased attention in the last decade, and while the incidence is low, it accounts for a significant number of admissions to neonatal ICUs because of the large number of late preterm births in the United States and worldwide. Causes of respiratory distress include transient tachypnea of the newborn, surfactant deficiency, pneumonia, and pulmonary hypertension. The physiologic mechanisms underlying delayed transition caused by surfactant deficiency and poor fetal lung fluid absorption have been reviewed recently elsewhere. This article focuses on the less-explored problem of severe hypoxic respiratory failure in the late preterm infant and discusses potential strategies for management.