Outcomes of hypoxic respiratory failure at birth associated with previable rupture of membranes

L'utilisation du monoxyde d'azote inhalé chez les nouveau-nés

Le monoxyde d'azote inhalé (NOi), un vasodilatateur pulmonaire sélectif, est utilisé pour le traitement des nouveau-nés en insuffisance respiratoire hypoxémique (IRH) associée à une hypertension pulmonaire persistante du nouveau-né. Idéalement, il doit commencer à être administré après la confirmation échocardiographique de ce type d'hypertension. L'utilisation de NOi est recommandée chez les nouveau-nés peu prématurés ou à terme chez qui survient une IRH malgré des stratégies d'oxygénation ou de ventilation optimales. Cependant, il n'est pas recommandé d'y recourir systématiquement chez les nouveau-nés prématurés sous assistance respiratoire. On peut l'envisager comme traitement de secours chez les nouveau-nés prématurés en IRH précoce associée à une rupture prolongée des membranes ou à un oligoamnios, ou en IRH tardive en cas d'hypertension pulmonaire liée à une dysplasie bronchopulmonaire et accompagnée d'une insuffisance ventriculaire droite marquée. On peut aussi l'envisager chez les nouveau-nés atteints d'une hernie diaphragmatique congénitale qui présentent une IRH persistante, malgré un recrutement pulmonaire optimal, des signes échocardiographiques d'hypertension pulmonaire suprasystémique et un fonctionnement ventriculaire gauche approprié.

Inhaled nitric oxide use in newborns

Inhaled nitric oxide (iNO), a selective pulmonary vasodilator, is used as a therapeutic modality in infants with hypoxemic respiratory failure (HRF) associated with persistent pulmonary hypertension of the newborn (PPHN). iNO should ideally be initiated following echocardiographic confirmation of PPHN. Use of iNO is recommended in late preterm and term infants who develop HRF despite optimal oxygenation and ventilation strategies. However, routine iNO use in preterm infants on respiratory support is not recommended. iNO may be considered as a rescue modality in preterm infants with early-onset HRF when associated with prolonged rupture of membranes or oligohydramnios, or late-onset HRF in the context of bronchopulmonary dysplasia-associated pulmonary hypertension (PH) with severe right ventricular failure. A trial of iNO may also be considered for infants with congenital diaphragmatic hernia with persistent HRF despite optimal lung recruitment, and with echocardiographic evidence of supra-systemic PH and adequate left ventricular function.

Clinical burden associated with therapies for cardio-pulmonary critical decompensation in preterm neonates across Canadian neonatal intensive care units

The aim of this retrospective cohort study was to study the clinical burden associated with cardio-pulmonary critical decompensations (CPCDs) in preterm neonates and factors associated with mortality. Through the Canadian Neonatal Network (30 tertiary NICUs, 2010-2017), we identified infants < 32-week gestational age with CPCDs, defined by "significant exposure" to cardiotropes and/or inhaled nitric oxide (iNO): (1) either therapy for ≥ 3 consecutive days, (2) both for ≥ 2 consecutive days, or (3) any exposure within 2 days of death. Early CPCDs (≤ 3 days of age) and late CPCDs (> 3 days) were examined separately. Outcomes included CPCD-incidence, mortality, and inter-site variability using standardized ratios (observed/adjusted expected rate) and network funnel plots. Mixed-effects analysis was used to quantify unit-level variability in mortality. Overall, 10% of admissions experienced CPCDs (n = 2915). Late CPCDs decreased by ~ 5%/year, while early CPCDs were unchanged during the study period. Incidence and CPCD-associated mortality varied between sites, for both early (0.6-7.5% and 0-100%, respectively) and late CPCDs (2.5-15% and 14-83%, respectively), all p < 0.01. Units' late-CPCD incidence and mortality demonstrated an inverse relationship (slope =  -2.5, p < 0.01). Mixed-effects analysis demonstrated clustering effect, with 6.4% and 8.6% of variability in mortality after early and late CPCDs respectively being site-related, unexplained by available patient-level characteristics or unit volume. Mortality was higher with combined exposure than with only-cardiotropes or only-iNO (41.3%, 24.8%, 21.5%, respectively; p < 0.01).

CONCLUSIONS

Clustering effects exist in CPCD-associated mortality among Canadian NICUs, with higher incidence units showing lower mortality. These data may aid network-level benchmarking, patient-level risk stratification, parental counseling, and further research and quality improvement work.

WHAT IS KNOWN

• Preterm neonates remain at high risk of acute and chronic complications; the most critically unwell require therapies such as cardiotropic drugs and inhaled nitric oxide. • Infants requiring these therapies are known to be at high risk for adverse neonatal outcomes and for mortality.

WHAT IS NEW

• This study helps illuminate the national burden of acute cardio-pulmonary critical decompensation (CPCD), defined as the need for cardiotropic drugs or inhaled nitric oxide, and highlights the high risk of morbidity and mortality associated with this disease state. • Significant nationwide variability exists in both CPCD incidence and associated mortality; a clustering effect was observed with higher incidence sites showing lower CPCD-associated mortality.

Early Hypoxic Respiratory Failure in Extreme Prematurity: Mortality and Neurodevelopmental Outcomes

OBJECTIVES

To evaluate the survival and neurodevelopmental impairment (NDI) in extremely low birth weight (ELBW) infants at 18 to 26 months with early hypoxemic respiratory failure (HRF). We also assessed whether African American infants with early HRF had improved outcomes after exposure to inhaled nitric oxide (iNO).

METHODS

ELBW infants ≤1000 g and gestational age ≤26 weeks with maximal oxygen ≥60% on either day 1 or day 3 were labeled as "early HRF" and born between 2007 and 2015 in the Neonatal Research Network were included. Using a propensity score regression model, we analyzed outcomes and effects of exposure to iNO overall and separately by race.

RESULTS

Among 7639 ELBW infants born ≤26 weeks, 22.7% had early HRF. Early HRF was associated with a mortality of 51.3%. The incidence of moderate-severe NDI among survivors was 41.2% at 18 to 26 months. Mortality among infants treated with iNO was 59.4%. Female sex (adjusted odds ratio [aOR]: 2.4, 95% confidence interval [CI]: 1.8-3.3), birth weight ≥720 g (aOR: 2.3, 95% CI: 1.7-3.1) and complete course of antenatal steroids (aOR: 1.6, 95% CI: 1.1-2.2) were associated with intact survival. African American infants had a similar incidence of early HRF (21.7% vs 23.3%) but lower exposure to iNO (16.4% vs 21.6%). Among infants with HRF exposed to iNO, intact survival (no death or NDI) was not significantly different between African American and other races (aOR: 1.5, 95% CI: 0.6-3.6).

CONCLUSIONS

Early HRF in infants ≤26 weeks' gestation is associated with high mortality and NDI at 18 to 26 months. Use of iNO did not decrease mortality or NDI. Outcomes following iNO exposure were not different in African American infants.