Despite dramatic improvements in survival rates of preterm infants over the last 50 years, there have been no significant further improvements in survival or morbidity rates over the most recent 10 years.1,2 Survival rates among infants with a birth weight of 500 to 1500 g in participating centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network of the United States were 84% in 1995–1996 and 85% in 1997–2002; the survival rate without major neonatal morbidity (which included bronchopulmonary dysplasia [BPD], intraventricular hemorrhage, and necrotizing enterocolitis) was unchanged (70%) between these 2 time periods.1 Similar findings were observed in epidemiologic data from Norway and Germany, which were published almost coincidentally.2,3 New paradigms for addressing care of extremely preterm infants may be necessary to achieve further improvements in outcome.Before the last decade, increased survival rates of preterm infants had been attributed to regionalization of high-risk pregnancies, use of prenatal corticosteroids, and an aggressive approach to perinatal therapy.4 Birth in a high-risk perinatal center with a higher level of neonatal care is associated with better survival rates than birth in a center that provides a lower level of care,5 and mortality and morbidity rates are increased for the most immature infants who require transport after birth.6 Some of the major morbidities associated with extreme prematurity such as BPD and intraventricular/periventricular hemorrhage could potentially be affected by management in the first minutes of life. However, the principles of care that occur in the NICU are not always used in the delivery room (DR). Care of the smallest preterm infants in the DR has received very little attention in newborn-resuscitation protocols. It is only with the most recent edition of the Neonatal Resuscitation Program textbook7 that a chapter dedicated to preterm infants was introduced.The tools used during newborn resuscitation are generally rudimentary, and monitoring is traditionally based on clinical examination alone, which can have substantial subjectivity.8 Recent surveys have revealed that even in the most developed countries, equipment used for newborn resuscitation is frequently not any more advanced than in less developed countries.9–12 Conversely, adult-resuscitation protocols incorporate advanced monitoring from the first moments of resuscitation.13 It seems that use of the best available tools and principles of preterm infant care in the DR would help achieve a stable transition from fetal life, minimizing risks of serious morbidity.As many as 7% of delivery services in the United States admit infants directly into a bed in an adjacent NICU, immediately providing an appropriate, monitored environment.12 However, most existing facilities cannot create such a proximal relationship between the DR and the NICU. Equipping the existing DR resuscitation space with supplies that are currently used routinely in the ICU will allow a higher level of care from the first moments of life.Therefore, we suggest that incorporation of an intensive care environment into the DR could enhance survival rates and reduce morbidity of extremely preterm infants.Although only ∼10% of all infants require some resuscitative interventions during the immediate transition from fetal life,7 decreasing gestational age is associated with increasing need for resuscitative interventions. We reviewed DR interventions over a 5-year period from the University of California San Diego Medical Center and found that 92% of such infants received positive pressure ventilation, 61% were intubated in the DR, 10% received chest compressions, and 1.5% received epinephrine.14 In another study, 40% of the infants at the threshold of viability had a temperature of <35°C on admission to the ICU.15Ventilation is the most common resuscitative intervention performed in the DR and may influence the development of BPD.16 Barotrauma and/or volutrauma are responsible in experimental animals for the activation of specific genes and the subsequent release of proinflammatory mediators that trigger this cascade of events.17–19 In experimental animals it has been shown that significant pathologic changes in the lung, including epithelial damage, protein leak into the alveolar spaces, and inhibition of surfactant function, may be induced by administering only a few inflations with high tidal volumes immediately after birth and thereafter may be exacerbated by the use of mechanical ventilation.20–23The occurrence of BPD varies widely according to center, and the use of early continuous positive airway pressure (CPAP) has been associated with low rates of BPD.24,25 In addition, positive end-expiratory pressure (PEEP) is considered essential during mechanical ventilation for any respiratory problems of the newborn.25 However, tools for providing manual ventilation do not all have the ability to provide PEEP and CPAP. Self-inflating bags are the most commonly used resuscitation devices worldwide and are used in 40% of the DRs in the United States. These devices do not provide CPAP, and they provide inconsistent PEEP even with a PEEP valve.26 Flow-inflating bags have the ability to provide both CPAP and PEEP but require significant training and experience to be used effectively.26 The T-piece resuscitator may be desirable because pressures, including CPAP and PEEP, can be set and delivered at target levels easily without a significant chance of unintended overshoot of pressure.27 For infants who require positive pressure inflations, the goal is to deliver a pressure and tidal volume that will lead to adequate lung inflation without inducing additional lung injury. Tracy et al28 have shown that hyperventilation occurs frequently in the intubated ventilated preterm infant during resuscitation when chest rise is used as a marker for determining the level of pressure delivered.Mask ventilation can be difficult in the first minutes of life with frequent occurrences of obstructed inflations. Additional methods of monitoring ventilation can be used to ensure the presence of a patent airway, such as use of a colorimetric carbon dioxide detector or an end-tidal carbon dioxide detector.29 Measurement of tidal volume can be accomplished with flow sensors with manual ventilating devices30 or with the use of mechanical ventilators to provide consistent inflations. Further evaluation using these monitoring devices may enable a more informed approach to ventilation with the intention of limiting associated lung injury.Studies in human neonates have shown that the use of pure oxygen during resuscitation may cause oxidative stress,31,32 damage the myocardium and kidney,33 and/or negatively influence survival.34–37 Two recent prospective randomized clinical trials were performed to evaluate the effectiveness of variable oxygen concentration during newborn resuscitation of preterm infants.38,39 These trials demonstrated that successful resuscitation of preterm infants can be achieved by using a low initial fraction of inspired oxygen (iFio2 = 0.30) but not air (iFio2 = 0.21) as the initial gas admixture. The average oxygen concentration used to achieve target oxygen saturations within the first 5 to 10 minutes of life and avoid bradycardia was 30% to 40% in both studies. In addition, the use of a low iFio2 allows an achievement of a target saturation of 85% at 10 minutes after cord clamping with lower oxygen load.38 To provide adequate oxygenation during initial transition by using a targeted oxygen saturation protocol in the DR, pulse oximeters, blenders, and a source of compressed air are essential. Because the average duration of DR care is >20 minutes, these tools are also critical for avoiding hyperoxia after the initial transition.14Efforts to limit heat loss of preterm infants in the DR during resuscitation and transport have been broadly recommended by most of the national resuscitation programs worldwide.40 Minimizing heat loss is extremely difficult because of high evaporative heat loss exacerbated by a large temperature gradient from the skin to the ambient air and physical characteristics of the premature infant.41 The use of polyethylene occlusive skin wrapping used without drying has been shown to reduce temperature loss in the DR.42 It is probably most sensible to use this practice in conjunction with skin-temperature probes and servo control of radiant-warmer output to avoid hyperthermia and a drop in the heater output when in full-power manual mode for >15 minutes. An increase in the DR temperature will also greatly facilitate the maintenance of adequate core temperatures in the extremely low birth weight infant. Admission temperatures that are in the hypothermic range have been associated with increased risk for mortality and late-onset sepsis.43 Therefore, every effort should be made to keep the preterm infant's temperature within normal limits during resuscitation and transport.One of the most important signs of successful transition is maintenance of a normal heart rate. The occurrence of bradycardia is most frequently a reflection of inadequate lung inflation, and heart rate is an important decision point in the resuscitation protocol. Auscultation is the most accurate clinical method of determining the heart rate but remains difficult in some situations and occupies 1 individual during the resuscitation.44 The continuous demonstration of heart rate allows the resuscitation team to continuously reevaluate interventions. This can be facilitated by the use of a monitor, such as a pulse oximeter or electrocardiography monitor, which frees an individual to perform other tasks. Electrocardiography leads can be applied quickly and can provide an electrographic heart rate display within 30 seconds.45 Pulse oximeters applied immediately can provide a reliable heart rate within 90 seconds and are also useful for monitoring oxygenation.46 Both monitors can be used as ongoing indicators of the adequacy of resuscitation interventions.Accumulated evidence suggests that resuscitation of extremely preterm infants should be individually adjusted and gentle. To achieve this goal, we propose the following. Intensive care of newborns at the highest risk begins antenatally and should be continued with equal or greater attention throughout transition, in the DR, and into the NICU. Instituting such practices may help achieve further improvements in outcome for the most preterm infants.
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Vento et al. (2008) studied this question.
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