Carta Revisado por pares

Assisting the Onset of Breathing—Can Neonatologists and Babies Work Better Together?

2012; Elsevier BV; Volume: 162; Issue: 3 Linguagem: Inglês

10.1016/j.jpeds.2012.10.056

ISSN

1097-6833

Autores

Kajsa Bohlin,

Tópico(s)

Infant Development and Preterm Care

Resumo

See related article, p 457The lungs of a preterm infant are developmentally immature, but usually not injured at birth. Because of the immaturity, the lungs can be easily harmed and our initial efforts to assist the onset of breathing may be of crucial importance. If the first few minutes of life should be considered a “golden time” in terms of ventilator management and later respiratory outcome remains to be determined. However, it is clear that delivery room care will have an impact on how well the baby transitions to extra-uterine life and will set the stage for the baby in the neonatal intensive care unit.In this issue of The Journal, Schilleman et al report an evaluation of the first five minutes of mask ventilation in preterm infants after birth.1Schilleman K. van der C.L.M. Hooper S.B. Lopriore E. Walther F.J. te Pas A.B. Evaluating manual inflations and breathing during mask ventilation in preterm infants at birth.J Pediatr. 2013; 162: 457-463Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar One of the main findings is that many infants breathe spontaneously during and between manual inflations. In the updated consensus guidelines for neonatal resuscitation, positive pressure ventilation should be considered after an initial 30 seconds evaluation after birth in infants with heart rate below 100 and gasping or apnea.2Perlman J.M. Wyllie J. Kattwinkel J. et al.Part 11: neonatal resuscitation: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations.Circulation. 2010; 122: S516-S538Crossref PubMed Scopus (533) Google Scholar However, recently developed normograms for changes in heart rate in the first minutes of life show that the median heart rate is below 100 at 1 minute after birth in term infants requiring no medical intervention, and that in infants born preterm, the normal rise in heart rate after birth is even slower.3Dawson J.A. Kamlin C.O. Wong C. et al.Changes in heart rate in the first minutes after birth.Arch Dis Child Fetal Neonatal Ed. 2010; 95: F177-F181Crossref PubMed Scopus (129) Google Scholar Respiration after birth is assessed by chest movements and auscultation. Chest excursions previously were shown by Schilleman et al to be very subjective as a guide to adequate ventilation, even in a standardized setting with a manikin.4Brugada M. Schilleman K. Witlox R.S. Walther F.J. Vento M. Te Pas A.B. Variability in the assessment of ‘adequate’ chest excursion during simulated neonatal resuscitation.Neonatology. 2011; 100: 99-104Crossref PubMed Scopus (22) Google Scholar Hence, if the decision to start full resuscitation is based only on the 2 vital characteristics of heart rate and respirations at a very early time point, it is possible that babies who can have a smooth transition from fetal to extra-uterine life will receive unnecessary interventions. In fact, despite the evidence that starting with a noninvasive ventilation strategy is feasible and safe even in extremely preterm infants,5Finer N.N. Carlo W.A. Walsh M.C. et al.Early CPAP versus surfactant in extremely preterm infants.N Engl J Med. 2010; 362: 1970-1979Crossref PubMed Scopus (824) Google Scholar, 6Dunn M.S. Kaempf J. de Klerk A. et al.Randomized trial comparing three approaches to the initial respiratory management of preterm neonates.Pediatrics. 2011; 128: e1069-e1076Crossref PubMed Scopus (338) Google Scholar many infants will still get intubated in the delivery room.7Fellman V. Hellstrom-Westas L. Norman M. et al.One-year survival of extremely preterm infants after active perinatal care in Sweden.JAMA. 2009; 301: 2225-2233Crossref PubMed Scopus (501) Google Scholar Intubation is often performed as part of a clinical routine and motivated by the aim of administering surfactant as early as possible, rather than reflecting a clear need for mechanical ventilation support. Earlier this year, the Cochrane review of prophylactic versus selective use of surfactant was updated and now includes more recent large trials that incorporate the current practice of greater antenatal steroid use and delivery room stabilization with continuous positive airway pressure (CPAP). The conclusion is that prophylactic surfactant can no longer be recommended as it does not offer any advantages in clinical outcome. Instead early stabilization on CPAP and selective surfactant treatment is associated with a decreased risk for death or bronchopulmonary dysplasia.8Rojas-Reyes M.X. Morley C.J. Soll R. Prophylactic vs selective use of surfactant in preventing morbidity and mortality in preterm infants.Cochrane Database Syst Rev. 2012; 3: CD000510PubMed Google Scholar Nevertheless, for infants to be supported on CPAP, they must breathe spontaneously—and most babies do. O'Donnell reported that in a cohort of 61 preterm infants with a mean gestational age of 26 weeks, the majority cried and 80% breathed immediately after birth without intervention.9O'Donnell C.P. Kamlin C.O. Davis P.G. Morley C.J. Crying and breathing by extremely preterm infants immediately after birth.J Pediatr. 2010; 156: 846-847Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar Schilleman's present study supports that reporting spontaneous breaths being recorded in 23 out of 27 infants, starting at a median of 10 seconds after initiation of positive pressure ventilation. Although the median tidal volume of spontaneous breaths was lower than that of inflations, mask ventilation was often associated with large leaks reducing the delivered tidal volume. The effect of resuscitation, measured as improvement in heart rate, was independent of mask leak, suggesting the infant's own respiratory effort actually contributes to the outcome of resuscitation.On the other hand, when a breath coincides with an inflation, there is a risk that the tidal volume increases to levels at which only a few large breaths may be injurious.10Björklund L.J. Ingimarsson J. Curstedt T. et al.Manual ventilation with a few large breaths at birth compromises the therapeutic effect of subsequent surfactant replacement in immature lambs.Pediatr Res. 1997; 42: 348-355Crossref PubMed Scopus (479) Google Scholar In this respect, leaks during mask ventilation may in part be protective and the infant's own breathing effort may contribute to the wide range of both inter- and intravariability in ventilation efficiency seen in resuscitators. Therefore, when aiming to develop and improve ventilation techniques during resuscitation, the current research suggests that the focus should be on more accurately identifying breathing in the preterm infant at birth and applying positive pressure ventilation synchronized with the infants own breathing. The importance of recognizing breathing is also illustrated by the fact that only 4 out of 27 infants in the study by Schilleman et al required delivery room intubation. Hence, despite a perceived need for positive pressure ventilation to aid the transition, the majority of infants could be stabilized and transferred to the neonatal intensive care unit on CPAP.As we try to unravel the answer to the question of how to best protect the preterm infant from lung injury and promote a healthy lung development, addressing delivery room management is the first step. Sometimes, despite our efforts, most preterm babies will try to breath, and improving our skills in recognizing that and adjust the support accordingly will allow a “soft-landing” with smooth transition to extra-uterine life, less need for invasive ventilation, and improved chances for a good long-term outcome. See related article, p 457The lungs of a preterm infant are developmentally immature, but usually not injured at birth. Because of the immaturity, the lungs can be easily harmed and our initial efforts to assist the onset of breathing may be of crucial importance. If the first few minutes of life should be considered a “golden time” in terms of ventilator management and later respiratory outcome remains to be determined. However, it is clear that delivery room care will have an impact on how well the baby transitions to extra-uterine life and will set the stage for the baby in the neonatal intensive care unit. See related article, p 457 See related article, p 457 In this issue of The Journal, Schilleman et al report an evaluation of the first five minutes of mask ventilation in preterm infants after birth.1Schilleman K. van der C.L.M. Hooper S.B. Lopriore E. Walther F.J. te Pas A.B. Evaluating manual inflations and breathing during mask ventilation in preterm infants at birth.J Pediatr. 2013; 162: 457-463Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar One of the main findings is that many infants breathe spontaneously during and between manual inflations. In the updated consensus guidelines for neonatal resuscitation, positive pressure ventilation should be considered after an initial 30 seconds evaluation after birth in infants with heart rate below 100 and gasping or apnea.2Perlman J.M. Wyllie J. Kattwinkel J. et al.Part 11: neonatal resuscitation: 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations.Circulation. 2010; 122: S516-S538Crossref PubMed Scopus (533) Google Scholar However, recently developed normograms for changes in heart rate in the first minutes of life show that the median heart rate is below 100 at 1 minute after birth in term infants requiring no medical intervention, and that in infants born preterm, the normal rise in heart rate after birth is even slower.3Dawson J.A. Kamlin C.O. Wong C. et al.Changes in heart rate in the first minutes after birth.Arch Dis Child Fetal Neonatal Ed. 2010; 95: F177-F181Crossref PubMed Scopus (129) Google Scholar Respiration after birth is assessed by chest movements and auscultation. Chest excursions previously were shown by Schilleman et al to be very subjective as a guide to adequate ventilation, even in a standardized setting with a manikin.4Brugada M. Schilleman K. Witlox R.S. Walther F.J. Vento M. Te Pas A.B. Variability in the assessment of ‘adequate’ chest excursion during simulated neonatal resuscitation.Neonatology. 2011; 100: 99-104Crossref PubMed Scopus (22) Google Scholar Hence, if the decision to start full resuscitation is based only on the 2 vital characteristics of heart rate and respirations at a very early time point, it is possible that babies who can have a smooth transition from fetal to extra-uterine life will receive unnecessary interventions. In fact, despite the evidence that starting with a noninvasive ventilation strategy is feasible and safe even in extremely preterm infants,5Finer N.N. Carlo W.A. Walsh M.C. et al.Early CPAP versus surfactant in extremely preterm infants.N Engl J Med. 2010; 362: 1970-1979Crossref PubMed Scopus (824) Google Scholar, 6Dunn M.S. Kaempf J. de Klerk A. et al.Randomized trial comparing three approaches to the initial respiratory management of preterm neonates.Pediatrics. 2011; 128: e1069-e1076Crossref PubMed Scopus (338) Google Scholar many infants will still get intubated in the delivery room.7Fellman V. Hellstrom-Westas L. Norman M. et al.One-year survival of extremely preterm infants after active perinatal care in Sweden.JAMA. 2009; 301: 2225-2233Crossref PubMed Scopus (501) Google Scholar Intubation is often performed as part of a clinical routine and motivated by the aim of administering surfactant as early as possible, rather than reflecting a clear need for mechanical ventilation support. Earlier this year, the Cochrane review of prophylactic versus selective use of surfactant was updated and now includes more recent large trials that incorporate the current practice of greater antenatal steroid use and delivery room stabilization with continuous positive airway pressure (CPAP). The conclusion is that prophylactic surfactant can no longer be recommended as it does not offer any advantages in clinical outcome. Instead early stabilization on CPAP and selective surfactant treatment is associated with a decreased risk for death or bronchopulmonary dysplasia.8Rojas-Reyes M.X. Morley C.J. Soll R. Prophylactic vs selective use of surfactant in preventing morbidity and mortality in preterm infants.Cochrane Database Syst Rev. 2012; 3: CD000510PubMed Google Scholar Nevertheless, for infants to be supported on CPAP, they must breathe spontaneously—and most babies do. O'Donnell reported that in a cohort of 61 preterm infants with a mean gestational age of 26 weeks, the majority cried and 80% breathed immediately after birth without intervention.9O'Donnell C.P. Kamlin C.O. Davis P.G. Morley C.J. Crying and breathing by extremely preterm infants immediately after birth.J Pediatr. 2010; 156: 846-847Abstract Full Text Full Text PDF PubMed Scopus (80) Google Scholar Schilleman's present study supports that reporting spontaneous breaths being recorded in 23 out of 27 infants, starting at a median of 10 seconds after initiation of positive pressure ventilation. Although the median tidal volume of spontaneous breaths was lower than that of inflations, mask ventilation was often associated with large leaks reducing the delivered tidal volume. The effect of resuscitation, measured as improvement in heart rate, was independent of mask leak, suggesting the infant's own respiratory effort actually contributes to the outcome of resuscitation. On the other hand, when a breath coincides with an inflation, there is a risk that the tidal volume increases to levels at which only a few large breaths may be injurious.10Björklund L.J. Ingimarsson J. Curstedt T. et al.Manual ventilation with a few large breaths at birth compromises the therapeutic effect of subsequent surfactant replacement in immature lambs.Pediatr Res. 1997; 42: 348-355Crossref PubMed Scopus (479) Google Scholar In this respect, leaks during mask ventilation may in part be protective and the infant's own breathing effort may contribute to the wide range of both inter- and intravariability in ventilation efficiency seen in resuscitators. Therefore, when aiming to develop and improve ventilation techniques during resuscitation, the current research suggests that the focus should be on more accurately identifying breathing in the preterm infant at birth and applying positive pressure ventilation synchronized with the infants own breathing. The importance of recognizing breathing is also illustrated by the fact that only 4 out of 27 infants in the study by Schilleman et al required delivery room intubation. Hence, despite a perceived need for positive pressure ventilation to aid the transition, the majority of infants could be stabilized and transferred to the neonatal intensive care unit on CPAP. As we try to unravel the answer to the question of how to best protect the preterm infant from lung injury and promote a healthy lung development, addressing delivery room management is the first step. Sometimes, despite our efforts, most preterm babies will try to breath, and improving our skills in recognizing that and adjust the support accordingly will allow a “soft-landing” with smooth transition to extra-uterine life, less need for invasive ventilation, and improved chances for a good long-term outcome. Evaluating Manual Inflations and Breathing during Mask Ventilation in Preterm Infants at BirthThe Journal of PediatricsVol. 162Issue 3PreviewTo investigate inflations (initial sustained inflations and consecutive inflations) and breathing during mask ventilation in preterm infants at birth. Full-Text PDF

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