Effect of changes in inspired oxygen tension on indexes of oxygenation in ventilated neonates

Respiratory Severity Score greater than or equal to 2 at birth is associated with an increased risk of mortality in infants with birth weights less than or equal to 1250 g

OBJECTIVE

Respiratory Severity Score (RSS), the product of mean airway pressure and the fraction of inspired oxygen may estimate the severity of neonatal lung disease. We aimed to determine if RSS on the first day of life is associated with mortality and/or comorbidities in infants born less than or equal to 1250 g.

METHODS

Data were extracted from the NYS Perinatal Data System for premature inborn infants from 2006 to 2016 born between 400 and 1250 g (N = 730). RSS was divided into three categories: less than 2 (low, n = 310), 2-5 (moderate, n = 265), greater than 5 (high, n = 155). The primary outcome was mortality. Logistic regression determined associations with composite outcomes of death or respiratory morbidity (respiratory support after 36 weeks postmenstrual age), death or neurologic morbidity (periventricular leukomalacia) or high-grade intraventricular hemorrhage), and death/severe morbidity (death or neurologic morbidity or respiratory morbidity or stage ≥ III retinopathy of prematurity or necrotizing enterocolitis) by RSS category.

RESULTS

Birthweight and gestational age were lower with the increasing RSS category (p < .001 for both). Mode of delivery, antenatal steroids, and maternal age did not differ by RSS. In adjusted analyses, there were increased odds of mortality in infants with moderate RSS (odds ratio [95% confidence intervals]: 3.1 (1.7-5.4) and high 4.5 (2.5-8.2). These groups had higher odds of death or respiratory morbidity, death or neurologic morbidity, and death/severe morbidity.

CONCLUSION

Higher RSS (≥2) is associated with an increased risk of mortality and morbidities in infants born less than or equal to 1250 g.

Prediction of respiratory failure in late-preterm infants with respiratory distress at birth

The aim of this study was to evaluate indices of respiratory failure in terms of their ability to predict respiratory impairment and need for ventilatory support in late-preterm neonates with respiratory distress. Arterial blood gas data during the first 12 postnatal hours or until intubation were recorded in 155 neonates with gestational age 34(0/7)-36(6/7) weeks admitted in the NICU with respiratory distress between January 2006 and June 2008. Alveolar-arterial oxygen tension difference (A-aDO(2)), arterial to alveolar oxygen tension ratio (a/A ratio), and partial arterial oxygen tension to inspired oxygen fraction ratio (PaO(2)/FiO(2)) were calculated. Considering the worst single value of each parameter, receiver operating characteristic curve analyses and area under the curve (AUC) comparisons were used to evaluate their predictive performance. Fifty-five neonates (35.5%) required mechanical ventilation. The predictive performances of the maximum A-aDO(2) (AUC 0.97), minimum a/A ratio (AUC 0.95), and minimum PaO(2)/FiO(2) (AUC 0.95) were similar. The A-aDO(2) at a threshold of >200 mmHg proved to be more effective than the other parameters, having excellent positive and negative likelihood ratios of 24.5 and 0.02, respectively. This threshold was achieved by 98.25% of the neonates who developed respiratory failure at a median of 3 h before the ventilatory support to be definitely decided. Composite indices, such as A-aDO(2), a/A ratio, and PaO(2)/FiO(2), can reasonably predict respiratory failure in late-preterm neonates with respiratory distress, allowing for closer monitoring, early medical intervention, or transfer to a level III neonatal unit.

Assessing mortality risk in very low birthweight infants: a comparison of CRIB, CRIB-II, and SNAPPE-II

BACKGROUND

Illness severity scores are increasingly used for risk adjustment in clinical research and quality assessment. Recently, a simplified version of the score for neonatal acute physiology (SNAPPE-II) and a revised clinical risk index for babies (CRIB-II) score have been published.

AIM

To compare the discriminatory ability and goodness of fit of CRIB, CRIB-II, and SNAPPE-II in a cohort of neonates < 1500 g birth weight (VLBWI).

METHODS

Data from 720 VLBWI, admitted to 12 neonatal units in Lombardy (Northern Italy) participating in a regional network, were analysed. The discriminatory ability of the scores was assessed measuring the area under the receiver operating characteristic curve (AUC). Outcome measure was in-hospital death.

RESULTS

CRIB and CRIB-II showed greater discrimination than SNAPPE-II (AUC 0.90 and 0.91 v 0.84, p < 0.0004), partly because of the poor quality of some of the data required for the SNAPPE-II calculation-for example, urine output-but also because of the relative weight given to some items. In addition to each score, several variables significantly influenced survival in logistic regression models. Antenatal steroid prophylaxis, singleton birth, absence of congenital anomalies, and gestational age were independent predictors of survival for all scores, in addition to caesarean section and not being small for gestation (for SNAPPE-II) and a five minute Apgar score of > or = 7 (for SNAPPE-II and CRIB).

CONCLUSIONS

CRIB and CRIB-II had greater discriminatory ability than SNAPPE-II. Risk adjustment using all scores is imperfect, and other perinatal factors significantly influence VLBWI survival. CRIB-II seems to be less confounded by these factors.