Pediatric Research | 2021
Neonatal chest compressions: time to act
Abstract
In 1992, American Heart Association (AHA) published new guidelines for newborn resuscitation and underlined that early administration of 100% oxygen is important: “If respiratory efforts are absent or inadequate so that assisted ventilation is required, 100% oxygen should be delivered by positive-pressure ventilation using a face mask or endotracheal tube”, and further: “The hazards of administering too much oxygen during the brief period required for a resuscitation should not be a concern. Today, we know there are several reasons to be concerned about excess oxygen administration during neonatal resuscitation. During the past 10–20 years, there has been a dramatic shift regarding applying supplemental oxygen for newborn resuscitation. This was first manifested by the World Health Organization’s guidelines for newborn resuscitation in 1998, which suggested to resuscitate with air instead of 100% O2, 2 and subsequently by the International Liaison Committee on Resuscitation’s guidelines in 2010 recommending “it is best to start with air in term or nearterm infants in need of positive pressure ventilation in the delivery room”. This paradigmatic change was initiated by two clinical studies in 1993 and 1998 testing out air versus 100% oxygen for newborn resuscitation and two meta-analyses in 2004 and 2005 summarizing the data. Figure 1 summarizes present recommendations regarding oxygen therapy in newly born infants. For term or near-term infants, initial FiO2 is 0.21. For preterm infants, start with 0.21 from term to 32 weeks and 0.3 for <32 weeks gestational age. Titrate FiO2 to target a SpO2 of 80–85% at 5 min. During chest compressions (CCs), FiO2 is 1.0. After return of spontaneous circulation, wean to FiO2 of 0.21 (somewhat higher FiO2 may be needed in preterm and term infants with lung disease). Titrate according to pre-ductal SpO2. The two studies from the 1990s were also important demonstrating that newborn resuscitation could be evidence based, which initiated a series of experimental and clinical studies in this field. However, one important component of the newborn resuscitation algorithm, CCs, was not studied and recommendations have hardly been changed for ≥30 years. One reason for such a static attitude might be that CCs are carried out so rarely it is difficult to perform randomized trials with sufficient power. Therefore, different FiO2s and compression-to-ventilation (C/V) ratios as well have mostly been tested out in animal studies. One recent study also tested out continuous CCs with asynchronous ventilation in an asphyxiated newborn lamb model. A higher carotid blood flow and cerebral oxygen delivery compared to C/V 3:1 was found. Due to lack of human data, the present Neonatal Resuscitation Program (NRP) therefore still recommends using 100% O2 during CCs with a C/V ratio of 3:1. However, according to NRP FiO2 should be adjusted based on SpO2 after return of spontaneous circulation (ROSC). The supplemental oxygen concentration may be decreased based on pulse oximetry to target a predefined physiological level to reduce the risks associated with hyperoxia. Weaning and titrating FiO2 immediately after ROSC to maintain preductal saturations in the 85–95% range is recommended. However, Badurdeen et al. demonstrated in near-term asphyxiated lambs that 100% O2 during CCs until ROSC with subsequent weaning to SpO2 of 88–95% is characterized by excess cerebral oxygenation. There are two fundamental unanswered questions regarding oxygenation and CCs: