Long-term outcome of preterm infants treated with nasal continuous positive airway pressure

Stimulating and maintaining spontaneous breathing during transition of preterm infants

Most preterm infants breathe at birth, but need additional respiratory support due to immaturity of the lung and respiratory control mechanisms. To avoid lung injury, the focus of respiratory support has shifted from invasive towards non-invasive ventilation. However, applying effective non-invasive ventilation is difficult due to mask leak and airway obstruction. The larynx has been overlooked as one of the causes for obstruction, preventing face mask ventilation from inflating the lung. The larynx remains mostly closed at birth, only opening briefly during a spontaneous breath. Stimulating and supporting spontaneous breathing could enhance the success of non-invasive ventilation by ensuring that the larynx remains open. Maintaining adequate spontaneous breathing and thereby reducing the need for invasive ventilation is not only important directly after birth, but also in the first hours after admission to the NICU. Respiratory distress syndrome is an important cause of respiratory failure. Traditionally, treatment of RDS required intubation and mechanical ventilation to administer exogenous surfactant. However, new ways have been implemented to administer surfactant and preserve spontaneous breathing while maintaining non-invasive support. In this narrative review we aim to describe interventions focused on stimulation and maintenance of spontaneous breathing of preterm infants in the first hours after birth.

Plasma Leak From the Circulation Contributes to Poor Outcomes for Preterm Infants: A Working Hypothesis

Preterm infants are at high risk of death and disability resulting from brain injury. Impaired cardiovascular function leading to poor cerebral oxygenation is a significant contributor to these adverse outcomes, but current therapeutic approaches have failed to improve outcome. We have re-examined existing evidence regarding hypovolemia and have concluded that in the preterm infant loss of plasma from the circulation results in hypovolemia; and that this is a significant driver of cardiovascular instability and thus poor cerebral oxygenation. High capillary permeability, altered hydrostatic and oncotic pressure gradients, and reduced lymphatic return all combine to increase net loss of plasma from the circulation at the capillary. Evidence is presented that early hypovolemia occurs in preterm infants, and that capillary permeability and pressure gradients all change in a way that promotes rapid plasma loss at the capillary. Impaired lymph flow, inflammation and some current treatment strategies may further exacerbate this plasma loss. A framework for testing this hypothesis is presented. Understanding these mechanisms opens the way to novel treatment strategies to support cardiovascular function and cerebral oxygenation, to replace current therapies, which have been shown not to change outcomes.

Development of egocentric and allocentric spatial orientation abilities in children born preterm with very low birth weight

BACKGROUND

Very low birth weight preterm infants show neuropsychological alterations in functions such as memory or visuospatial skills, although certain related functions, such as spatial orientation, have not been studied.

OBJECTIVES

To compare children born preterm and at term between the ages of 5 and 7 years on egocentric and allocentric spatial orientation, and relate their performance to visuospatial skills, behavior, memory in daily environments, and perinatal risk factors.

STUDY DESIGN

Observational cross-sectional study.

SUBJECTS

88 very low birth weight children born preterm and 59 controls.

OUTCOME MEASURES

IQ (RIST), visuospatial skills (NEPSY II: Route Finding and Geometric Puzzles), spatial orientation (Egocentric and Allocentric Spatial Memory Test - Children's Version), behavior (BASC questionnaire for parents), memory in everyday environments (ECM-Q questionnaire for parents), and perinatal risk factors (collected from medical records).

RESULTS

Children born preterm obtain significantly lower scores than controls on the RIST, Route Finding, and Allocentric Spatial Memory Tests. Although spatial orientation is related to other neuropsychological variables in both premature and control children, there is no meaningful association with behavior or daily memory in children born preterm. The perinatal risk factors that are associated the most with visuospatial and orientation problems are surgical procedures and peri- and intraventricular hemorrhages.

CONCLUSIONS

Children born preterm with low birth weight present difficulties in their spatial orientation, and for this reason, we propose including these types of tasks in the usual neuropsychological evaluation.

Early Bubble Continuous Positive Airway Pressure: Investigating Interprofessional Best Practices for the NICU Team

Premature neonates delivered <32 completed weeks gestation are unprepared to handle the physiologic demands of extrauterine life. Within the respiratory system, alveolar instability and collapse can cause decreased functional residual capacity, impaired oxygenation, and hypoxemia leading to respiratory distress syndrome. Supportive measures are indicated immediately after birth to establish physiologic stability including bubble continuous positive airway pressure (CPAP) or endotracheal intubation and mechanical ventilation. CPAP is a noninvasive, gentle mode of ventilation that can mitigate the effects of lung immaturity, but prolonged use can increase the risk for nasal breakdown. Strategies to mitigate this risk must be infused as best practices in the NICU environment. The purpose of this article is to propose an evidence-based best practice care bundle for the early initiation of CPAP in the delivery room and associated skin barrier protection strategies for premature neonates <32 weeks gestation and weighing <1,500 g.

Cerebral vascular regulation and brain injury in preterm infants

Cerebrovascular lesions, mainly germinal matrix hemorrhage and ischemic injury to the periventricular white matter, are major causes of adverse neurodevelopmental outcome in preterm infants. Cerebrovascular lesions and neuromorbidity increase with decreasing gestational age, with the white matter predominantly affected. Developmental immaturity in the cerebral circulation, including ongoing angiogenesis and vasoregulatory immaturity, plays a major role in the severity and pattern of preterm brain injury. Prevention of this injury requires insight into pathogenesis. Cerebral blood flow (CBF) is low in the preterm white matter, which also has blunted vasoreactivity compared with other brain regions. Vasoreactivity in the preterm brain to cerebral perfusion pressure, oxygen, carbon dioxide, and neuronal metabolism is also immature. This could be related to immaturity of both the vasculature and vasoactive signaling. Other pathologies arising from preterm birth and the neonatal intensive care environment itself may contribute to impaired vasoreactivity and ineffective CBF regulation, resulting in the marked variations in cerebral hemodynamics reported both within and between infants depending on their clinical condition. Many gaps exist in our understanding of how neonatal treatment procedures and medications have an impact on cerebral hemodynamics and preterm brain injury. Future research directions for neuroprotective strategies include establishing cotside, real-time clinical reference values for cerebral hemodynamics and vasoregulatory capacity and to demonstrate that these thresholds improve long-term outcomes for the preterm infant. In addition, stimulation of vascular development and repair with growth factor and cell-based therapies also hold promise.

Change in care among nonenrolled patients during and after a randomized trial

OBJECTIVE

Parkland Memorial Hospital (PMH) participated in Surfactant, Positive Pressure, and Oxygenation Randomized Trial (SUPPORT), an unblinded controlled trial, in which preterm neonates of 24(0/7) to 27(6/7) weeks' gestational age (GA) were randomized in the delivery room (DR) to endotracheal intubation or nasal continuous positive airway pressure. We hypothesized that DR intubation could change in nonenrolled patients at PMH and that the change would be larger than in comparable centers not participating in the trial.

METHODS

The PMH Cohort included eligible but nonenrolled neonates of 24(0/7) to 27(6/7) weeks (primary) and noneligible neonates of 28 to 34(6/7) weeks (confirmatory). A subset (24(0/7)-29(6/7)weeks) of that cohort was compared with a contemporaneous cohort born in centers participating in the Vermont Oxford Network (VON). We used a Poisson regression model to obtain adjusted relative risks (RRs) of DR intubation (during/after SUPPORT versus before SUPPORT) for PMH and for VON along with the ratio of these RRs.

RESULTS

In the PMH cohort (n = 3527), the proportion of DR intubation decreased during/after SUPPORT in the lower GA group (adjusted RR 0.76, 95% confidence interval [CI] 0.59-0.96) and the upper GA group (adjusted RR 0.57, 95% CI 0.46-0.70). Compared with the RR for DR intubation in VON, the RR at PMH was smaller in the lower (ratio of RR 0.76, 95% CI 0.65-0.87) and the upper GA group (ratio of RR 0.52, 95% CI 0.39-0.68).

CONCLUSIONS

A center's participation in an unblinded randomized trial may affect process of care of nonenrolled patients.

Outcome of extremely low gestational age newborns after introduction of a revised protocol to assist preterm infants in their transition to extrauterine life

AIM

To evaluate the outcome of a cohort of extremely low gestational age newborn infants (ELGAN) below 26-week gestation who were treated following a revised, gentle delivery room protocol to assist them in the transition and adaptation to extrauterine life.

METHODS

A cohort of infants with a gestational age (GA) below 26 weeks (study group; n = 164) was treated according to a revised delivery room protocol. The protocol included an optimized prenatal management, strict use of continuous positive airway pressure (CPAP), avoiding mechanical ventilation and early administration of surfactant without intubation. The parameters management of respiratory distress syndrome, survival, neonatal morbidity and neurodevelopmental outcome were compared with a historical control group (n = 44).

RESULTS

Seventy-four per cent of the study group infants were initially treated with CPAP and surfactant administration without intubation. In comparison with the control group, significantly less children were intubated in the delivery room (24% vs. 41%) and needed mechanical ventilation (51% vs. 72%; both p < 0.05). Furthermore, compared with the historical control overall mortality (20% vs. 39%), rate of bronchopulmonary dysplasia (18% vs. 37%) and IVH > II° (10% vs. 33%) in survivors were significantly lower during the observational period (all p < 0.05). Neurodevelopmental outcome was normal in 70% of examined study group infants.

CONCLUSIONS

A revised delivery room management protocol was applied safely to infants with a GA below 26 completed weeks with improved rates of survival and morbidity.

Neurodevelopmental outcomes of extremely low birth weight infants ventilated with continuous positive airway pressure vs. mechanical ventilation

OBJECTIVE

To compare continuous positive airway pressure (CPAP) vs. traditional mechanical ventilation (MV) at 24 h of age as predictors of neurodevelopmental (ND) outcomes in extremely low birth weight (ELBW) infants at 18-22 months corrected gestational age (CGA).

METHODS

Infants ≤1000 g birth weight born from January 2000 through December 2006 at two hospitals at the Cincinnati site of the National Institute of Child Health and Human Development Neonatal Research Network were evaluated comparing CPAP (n = 198) vs. MV (n = 109). Primary outcomes included the Bayley Score of Infant Development Version II (BSID-II), presence of deafness, blindness, cerebral palsy, bronchopulmonary dysplasia and death.

RESULTS

Ventilatory groups were similar in gender, rates of preterm prolonged rupture of membranes, antepartum hemorrhage, use of antenatal antibiotics, steroids, and tocolytics. Infants receiving CPAP weighed more, were older, were more likely to be non-Caucasian and from a singleton pregnancy. Infants receiving CPAP had better BSID-II scores, and lower rates of BPD and death.

CONCLUSIONS

After adjusting for acuity differences, ventilatory strategy at 24 h of age independently predicts long-term neurodevelopmental outcome in ELBW infants.

Surfactant in spontaneous breathing with nCPAP: neurodevelopmental outcome at early school age of infants ≤ 27 weeks

AIM

In 2001, we implemented the 'surfactant without intubation' (SWI) method to administer surfactant during spontaneous breathing with nasal continuous positive airway pressure in preterm infants. To determine whether application of the SWI method in infants born at ≤ 27 weeks gestational age influences early school age outcome.

METHODS

A historical control cohort was compared to an interventional cohort, when the SWI method had become part of primary respiratory support. According to the overall results of psychometric and neurological examinations, children were classified as showing no functional impairment, minor or major impairments.

RESULTS

Out of 79 surviving children, 54 (68%, two children not completely classifiable) were assessed at a median age of 6 5/12 years [25 (32%) lost to follow-up]. Thirteen of 31 (42%, interventional cohort) vs. 8 of 21 (38%, control cohort) children had no functional impairment, 16 (52%) vs. 9 (43%) showed minor, and 2 (7%) vs. 4 (19%) major impairments.

CONCLUSION

There was no statistically significant difference regarding neurodevelopmental school age outcome in children treated after implementing the SWI procedure, even though surviving infants had been more immature and survival rates had increased.

Neurodevelopmental outcomes of preterm infants

PURPOSE OF REVIEW

Preterm birth is emerging as a major public health problem in the USA. Improvements in preterm birth and survival rates translate to increasing numbers of preterm survivors, and many develop motor, cognitive and sensory impairments.

RECENT FINDINGS

The review discusses the recently reported prevalence of neurodevelopmental disabilities in preterm survivors, in addition to studies of factors associated with neurodevelopmental outcome.

SUMMARY

A 2007 report from the Institute of Medicine emphasizes preterm birth as an increasingly common complex condition with multiple risk factors resulting from multiple gene-environmental interactions, leading to birth before 37 weeks gestation, neonatal complications and a disproportionately high contribution to neurodevelopmental disability rates. The increased risk of cerebral palsy with decreasing gestational age categories is well documented, but recent studies highlight the range and severity of cognitive, sensory, language, visual-perceptual, attention and learning deficits in very preterm children. Combined with increasingly sophisticated neuroimaging studies to identify perinatal risk factors, neurodevelopmental follow-up of neonatal intensive care unit trials offers the potential to really improve our understanding of how the preterm brain develops, is injured and recovers from injuries. Knowledge of what influences neurodevelopmental outcomes is key to developing better treatment strategies.

What is new in ventilation strategies for the neonate?

A large number of ventilation strategies are now available for the neonate. This review has focused on new information, that is, studies published since 2000 and the implication of their results for current clinical practice. Meta-analysis of randomised trials has demonstrated that assist control and synchronous intermittent mandatory ventilation (SIMV) shortens the duration of ventilation only if started in the recovery rather than the early stage of respiratory disease. A recent randomised trial demonstrated pressure-regulated volume control ventilation may also have no advantages if started early. Weaning by SIMV with pressure support is better (reducing oxygen dependency) than SIMV alone. Meta-analysis of volume-targeted ventilation demonstrated significant reductions in the duration of ventilation and pneumothorax, but the trials were small and of different designs. Volume guarantee may provide more consistent blood gas control. The level of volume targeting appears to be crucial to the success of this technique. Meta-analysis of randomised trials of prophylactic high-frequency oscillation trials has shown a modest reduction in bronchopulmonary dysplasia. Randomised trials have failed to confirm the advantages of nasal continuous positive airway pressure (NCPAP) seen in various non-randomised studies; however, the randomised trials reported to date have been small. Inhaled nitric oxide (NO) does not improve the outcome of prematurely born infants with severe respiratory failure, but early low-dose prolonged iNO appears to have benefits that merit further testing. More randomised trials with long-term outcomes are required to identify the optimal ventilation strategy(ies) for the neonate.

A randomized, controlled trial of delivery-room respiratory management in very preterm infants

BACKGROUND

Initial ventilation strategy may play an important role in the development of bronchopulmonary dysplasia in very preterm infants. Early nasal continuous positive airway pressure is an accepted approach, but randomized clinical trials are lacking. Our aim was to determine whether early nasal continuous positive airway pressure, preceded by a sustained inflation, is more effective and less injurious in very preterm infants than conventional intervention.

METHODS

Two hundred seven very preterm infants were assigned randomly in the delivery room to either a sustained inflation through a nasopharyngeal tube followed by early nasal continuous positive airway pressure (early functional residual capacity intervention) or repeated manual inflations with a self-inflating bag and mask followed by nasal continuous positive airway pressure, if necessary, after arrival at the NICU. The primary outcome measure was intubation <72 hours of age and bronchopulmonary dysplasia at 36 weeks was used as secondary outcome. This trial was registered as an early functional residual capacity intervention trial (ISRCTN 12757724).

RESULTS

In the early functional residual capacity intervention group, fewer infants were intubated at <72 hours of age or received >1 dose of surfactant, and the average duration of ventilatory support was less. Infants in the early functional residual capacity intervention group developed bronchopulmonary dysplasia less frequently.

CONCLUSIONS

A sustained inflation followed by early nasal continuous positive airway pressure, delivered through a nasopharyngeal tube, is a more efficient strategy than repeated manual inflations with a self-inflating bag and mask followed by nasal continuous positive airway pressure on admission to the NICU.