Anthony R. Rafferty

Self-inflating bags versus T-piece resuscitator to deliver sustained inflations in a preterm lamb model

Objective In neonatal resuscitation, the use of a sustained inflation (SI) may facilitate lung aeration. Previous studies comparing different resuscitation devices have shown that one model of self-inflating bag (SIB) could not deliver an SI. We aimed to compare the delivery of an SI using four SIBs with that of a T-piece. Study design In intubated preterm lambs, we compared four models of SIB fitted with a positive end expiratory pressure (PEEP) valve to a T-piece using a gas flow of 8 L/min. Four operators aimed to deliver three SIs of 20 cm H2O for 30 s. The study was repeated with the PEEP valve removed and again with no flow. We measured duration of SI, average inflation pressure (IP) and analysed the shape of the pressure curves. Results 204 combinations were analysed. Mean (SD) duration of SI was Ambu 6(2)s, Laerdal 14(8)s, Parker Healthcare 5(1)s, Mayo Healthcare 33(2)s and T-piece 33(1)s. Mean (SD) average IP was Ambu 17(3)cm H2O, Laerdal 17(3)cm H2O, Parker Healthcare 12(5)cm H2O, Mayo Healthcare 21(2)cm H2O and T-piece 20(0)cm H2O. Duration of SI and average IP was significantly different between SIBs (all p<0.001). The findings were substantially unchanged when PEEP valve and flow were removed (all p>0.05). Only the Mayo system delivered SIs with duration and average IP not significantly different from the T-piece (p>0.05). Conclusions The performance of the four SIBs tested varied considerably. Some are able to deliver an SI even in the absence of gas flow. This may be useful in a resource-limited setting with no gas supply.

A Randomized Trial of Conditioned or Unconditioned Gases for Stabilizing Preterm Infants at Birth

Objective To determine whether the use of heated‐humidified gases for respiratory support during the stabilization of infants <30 weeks of gestational age (GA) in the delivery room reduces rates of hypothermia on admission to the neonatal intensive care unit (NICU). Study design A multicenter, unblinded, randomized trial was conducted in Melbourne, Australia, between February 2013 and June 2015. Infants <30 weeks of GA were randomly assigned to receive either heated‐humidified gases or unconditioned gases during stabilization in the delivery room and during transport to NICU. Infants born to mothers with pyrexia >38°C were excluded. Primary outcome was rate of hypothermia on NICU admission (rectal temperature <36.5°C). Results A total of 273 infants were enrolled. Fewer infants in the heated‐humidified group were hypothermic on admission to NICU (36/132 [27%]) compared with controls (61/141 [43%], P < .01). There was no difference in rates of hyperthermia (>37.5°C); 20% (27/132) in the heated‐humidified group compared with 16% (22/141) in the controls (P = .30). There were no differences in mortality or respiratory outcomes. Conclusions The use of heated‐humidified gases in the delivery room significantly reduces hypothermia on admission to NICU in preterm infants, without increased risk of hyperthermia. Clinical Trial Registration Australian and New Zealand Clinical Trials Register (www.anzctr.org.au) ACTRN12613000093785.

Neonatal Resuscitation in Resource-Limited Settings: Titrating Oxygen Delivery without an Oxygen Blender

OBJECTIVE To test whether 4 commonly used self-inflating bags with a reservoir in situ can reliably deliver different oxygen concentrations (21%-100%) using a portable oxygen cylinder with flows of ≤5 L/min. STUDY DESIGN Four self-inflating bags (from Laerdal, Ambu, Parker Healthcare, and Mayo Healthcare) were tested to provide positive pressure ventilation to a manikin at 60 inflations/min by 4 operators. Oxygen delivery was measured for 2 minutes, combining oxygen flows (0.25, 0.5, 1, 5 L/min) and peak inspiratory pressures (PIPs 20-25, 35-40 cmH2O). RESULTS Combinations (n=128) were performed twice. Oxygen delivery depended upon device, oxygen flow, and PIP. All self-inflating bags delivered mean oxygen concentrations of <40% with 0.25 L/min, regardless of PIP. Three self-inflating bags delivered ≤40% with flow 0.5 L/min at PIP 35-40 cmH2O, whereas all delivered >40% at PIP 20-25 cmH2O. With 1 L/min, 3 self-inflating bags delivered 40%-60% at PIP 35-40 cmH2O and all delivered >60% at PIP 20-25 cmH2O. With 5 L/min, all self-inflating bags delivered close to or 100%, regardless of PIP. Differences in oxygen delivery between self-inflating bags were statistically significant (P<.001) even when differences were not clinically important. CONCLUSION Self-inflating bags with a reservoir in situ can deliver a variety of oxygen concentrations without a blender, from <40% with 0.25 L/min oxygen flow to 100% with 5 L/min. The adjustment of oxygen flow may be a useful method of titrating oxygen in settings where air-oxygen blenders are unavailable.

The accuracy of delivery of target pressures using self‐inflating bag manometers in a benchtop study

We tested whether operators using manometers attached to self‐inflating bags could accurately deliver set targeted peak inspiratory pressures (PIPs) compared to the Neopuff™ T‐piece resuscitator (TPR).

Inflammation, lipids and aortic intima‐media thickness in newborns following chorioamnionitis

This study investigated whether chorioamnionitis was associated with increased inflammation, dyslipidaemia and adverse cardiovascular phenotypes in the immediate postnatal period.

Neonatal mannequin comparison of the Upright self-inflating bag and snap-fit mask versus standard resuscitators and masks: leak, applied load and tidal volumes

Objective Neonatal mask ventilation is a difficult skill to acquire and maintain. Mask leak is common and can lead to ineffective ventilation. The aim of this study was to determine whether newly available neonatal self-inflating bags and masks could reduce mask leak without additional load being applied to the face. Design Forty operators delivered 1 min episodes of mask ventilation to a mannequin using the Laerdal Upright Resuscitator, a standard Laerdal infant resuscitator (Laerdal Medical) and a T-Piece Resuscitator (Neopuff), using both the Laerdal snap-fit face mask and the standard Laerdal size 0/1 face mask (equivalent sizes). Participants were asked to use pressure sufficient to achieve ‘appropriate’ chest rise. Leak, applied load, airway pressure and tidal volume were measured continuously. Participants were unaware that load was being recorded. Results There was no difference in mask leak between resuscitation devices. Leak was significantly lower when the snap-fit mask was used with all resuscitation devices, compared with the standard mask (14% vs 37% leak, P<0.01). The snap-fit mask was preferred by 83% of participants. The device-mask combinations had no significant effect on applied load. Conclusions The Laerdal Upright Resuscitator resulted in similar leak to the other resuscitation devices studied, and did not exert additional load to the face and head. The snap-fit mask significantly reduced overall leak with all resuscitation devices and was the mask preferred by participants.

PS-198 Topical Glyceryl Trinitrate Ointment To Aid Umbilical Artery Cannulation In Neonates

Background and aims Umbilical artery cannulation is a common neonatal procedure that is often challenging because umbilical arteries constrict after birth. We aimed to determine whether the topical application of a vasodilating ointment prior to cannulation increases success and decreases the time taken to cannulate. Methods Discarded umbilical cords were collected immediately after delivery and two 3 cm sections proximal to the baby were used for the study. 0.1mL topical Glyceryl Trinitrate (GTN) ointment (0.2% w/w) was applied to the surface of one section for 5 min prior to cannulation, whereas the second section acted as the control. After ointment removal, medical staff blinded to intervention attempted to cannulate one artery in each section. We assessed cannulation success, time to cannulate, and correct treatment identification for each participant. Results 14 experienced (9 Fellows, 5 Consultants) and 9 junior (Registrars) medical staff attempted 46 cannulations. Experienced participants successfully cannulated 100% of treated and control sections with no significant difference in mean (SD) time to cannulate (98 (75)s and 97(51)s respectively, p = 0.97). Junior participants cannulated 89% and 67% of treated and control sections respectively (p = 0.69), and mean (SD) time to cannulate was 132 (78)s and 106 (53)s respectively (p = 0.42). GTN treated arteries were correctly identified by 43% of experienced and 22% of junior participants (p = 0.47). Conclusions This study suggests that topical application of GTN does not increase successful cannulation of umbilical arteries by experienced staff. More participants or prolonged GTN application time may be needed to confirm these findings in junior staff.

PO-0695 Delivery Room Management Of Extremely Preterm Infants In A Tertiary Neonatal Centre: A Ten Year Review

Background and aims In the delivery room (DR), respiratory support for preterm infants has traditionally been provided through mechanical ventilation following intubation, which is known to increase neonatal morbidities including BPD and sepsis. The Nasal CPAP or Intubation at birth for very preterm infants (COIN) Trial demonstrated that infants spontaneously breathing at birth may be managed in the DR with non invasive support (CPAP) rather than intubation, which may be preferred. We aimed to review the management of extremely preterm infants in the DR at the Royal Women’s Hospital (RWH) during a ten-year period and evaluate whether respiratory support practices differed during and after the COIN trial. Methods We compared DR resuscitation practices (obtained from the neonatal database) of infants born between 25+0 and 28+6 weeks gestation at RWH between 2003–2006 and 2007–2012. Results 1013 infants were included in the study, 97% of which received respiratory support in the DR during the ten-year period (Figure 1). Mean gestation (SD) and birth weight (SD) were 27+0 (1.11) weeks and 947(244) grams, respectively. There was a substantial decrease in the number of newborns intubated in the DR between 2003–2006 (58%) and 2007–2012 (47%) (p = 0.05). The number of infants intubated in the DR remains highest at lower gestational ages. Conclusion There has continued to be an increase in the use of CPAP instead of intubation in the DR since completion of the COIN trial, suggesting a change in clinical practice. Abstract PO-0695 Figure 1