Original article Klingenberg C, Sobotka KS, Ong T, et al. Arch Dis Child Fetal Neonatal Ed (2012). doi:10.1136/archdischild-2012-301787 F1 of F7 1 Department of Paediatrics, University Hospital of North Norway, Tromsø, Norway 2 Paediatric Research Group, Faculty of Health Sciences, University of Tromsø, Tromsø, Norway 3 The Ritchie Centre, Monash Institute of Medical Research, Monash University, Melbourne, Australia 4 Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia 5 Department of Pediatrics, Medical University, Graz, Austria 6 Neonatal Research, Royal Women’s Hospital, Melbourne, Australia Correspondence to Claus Klingenberg, Department of Paediatrics, University Hospital of North Norway, N-9038 Tromsø, Norway; claus.klingenberg@unn.no Both CK and KS contributed equally to this study Received 6 February 2012 Accepted 30 May 2012 ABSTRACT Objective The 2010 ILCOR neonatal resuscitation guidelines do not specify appropriate inflation times for the initial lung inflations in apnoeic newborn infants. The authors compared three ventilation strategies immediately after delivery in asphyxiated newborn lambs. Design Experimental animal study. Setting Facility for animal research. Subjects Eighteen near-term lambs (weight 3.5–3.9 kg) delivered by caesarean section. Interventions Asphyxia was induced by occluding the umbilical cord and delaying ventilation onset (10–11 min) until mean carotid blood pressure (CBP) was ≤22 mm Hg. Animals were divided into three groups (n=6) and ventilation started with: (1) inflation times of 0.5 s at a ventilation rate 60/min, (2) five 3 s inflations or (3) a single 30 s inflation. Subsequent ventilation used inflations at 0.5 s at 60/min for all groups. Main outcome measures Times to reach a heart rate (HR) of 120 bpm and a mean CBP of 40 mm Hg. Secondary outcome was change in lung compliance. Results Median time to reach HR 120 bpm and mean CBP 40 mm Hg was significantly shorter in the single 30 s inflation group (8 s and 74 s) versus the 5×3 s inflation group (38 s and 466 s) and the conventional ventilation group (64 s and 264 s). Lung compliance was significantly better in the single 30 s inflation group. Conclusion A single sustained inflation of 30 s immediately after birth improved speed of circulatory recovery and lung compliance in near-term asphyxiated lambs. This approach for neonatal resuscitation merits further investigation. INTRODUCTION Successful resuscitation of bradycardic, apnoeic neonates requires adequate ventilation. 1 2 The optimal ventilation strategy immediately after birth, when the lungs are liquid-fi lled, has not been determined. In term asphyxiated infants, there is a lack of evidence to support any spe- cific ventilation strategy for the initial inflations, although one sustained inflation (SI) of 2–5 s has been shown to improve functional residual capacity (FRC). 3 4 However, to the best of our knowledge, no clinical trials in term infants and no experiments with term or near-term animals have evaluated the effect of different initial infla- tion times during resuscitation. The International Liaison Committee on Resuscitation (ILCOR) states that, ‘to establish Effect of sustained inflation duration; resuscitation of near-term asphyxiated lambs Claus Klingenberg, 1,2 Kristina S Sobotka, 3 Tracey Ong, 3 Beth J Allison, 3 Georg M Schmölzer, 3,5,6 Timothy J M Moss, 3,4 Graeme R Polglase, 3 Jennifer A Dawson, 6 Peter G Davis, 6 Stuart B Hooper 3,4 initial lung inflation in apnoeic newborn infants, initiation of ventilation at birth can be accom- plished with either shorter or longer inspiratory times’. 2 However, there is a ‘transatlantic divide’ 5 in how to interpret the ILCOR evidence. The American Heart Association recommends that during neonatal resuscitation ‘assisted ventilation should be delivered at a rate of 40 to 60 breaths per minute’, but does not explicitly suggest using longer inflation times for the initial inflations. 6 In contrast, the revised European guidelines rec- ommend that ‘one should maintain the inflation pressure for 2–3 s for the fi rst five inflations as this will help to expand the lungs. Subsequently, babies should be ventilated at a rate of about 30 breaths per minute allowing approximately 1 s for each inflation’. 7 Initiating respiratory support with SIs may improve FRC by providing enough pressure for a sufficient period of time to allow the liquid and the air/liquid interface to move through the air- ways and into the alveoli. Imaging studies in pre- term rabbits demonstrated that inflation times of 10–20 s duration, combined with a positive end expiratory pressure (PEEP), immediately after delivery accelerated lung aeration compared with What is already known on this topic ▶ Current resuscitation guidelines state that both short and long inflation times may be used for the establishment of initial lung inflation ▶ Sustained inflations may improve functional residual capacity by allowing an appropriate time-constant for the air/liquid interface to move into the distal airway. What this study adds ▶ Speed of circulatory recovery was similar when using either 5×3 s inflations or immediate conventional ventilation in near- term asphyxiated lambs ▶ A single sustained inflation of 30 s immediately after birth improved speed of circulatory recovery and lung compliance in near-term asphyxiated lambs. 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