Two hands are better than one: Positive pressure ventilation in a preterm neonatal manikin model

Approximately 10% of newborn infants require some assistance to establish regular breathing at birth.1, 2 The need to progress resuscitation beyond ventilation and commence cardiac compressions and epinephrine administration is rare (<1%) and may signal poor ventilation technique in as many as 50% of such situations.2 Respiratory support is typically delivered to newborn infants via positive pressure ventilation (PPV) using an appropriately sized facemask (Figure 1). Previous studies investigating mask leak in modified newborn manikin models have shown high levels of leak (up to 65%), even in participants with many years of experience.3, 4 Few studies have examined the optimum mask hold to achieve the lowest possible leak during PPV. Our primary aim was to compare a two-handed (TH) hold of the facemask when delivering PPV during neonatal resuscitation with a one-handed (OH) hold. A secondary aim was to investigate if the level of clinical experience influenced PPV provision. Medical and nursing staff within the neonatal and paediatric departments of Cork University Maternity Hospital and Cork University Hospital, respectively, were invited to participate. Staff holding a valid certificate in either Neonatal Resuscitation Program seventh edition or Advanced Paediatric Life Support sixth edition were eligible. All participants reviewed the study information leaflet and signed a consent form before participating. This was a randomised crossover trial. The Neopuff T-piece Infant Resuscitator (Fisher & Paykel Healthcare, Auckland, NZ) with a size 35-mm facemask (RD-803 nose/mouth mask, Fisher & Paykel Healthcare, Auckland, NZ) and premature neonatal manikin (Premature Anne leak-free manikin, Stavanger, Norway) were used. Neopuff settings were preset with a peak positive inspiratory pressure of 20 cm H2O, a positive end-expiratory pressure of 5 cm H2O and compliance of 0.1 mL/cmH20. A Philips Respironics Respiratory Function monitor (Novametrix, CT, USA) was used to measure variables via a flow sensor between the mask and the Neopuff. Participants were requested to give inflations at a rate of 40–60 inflations per min and inflation data were captured using NM3 software. Participants were allowed a brief period of familiarisation. They performed 2 min of ventilation, followed by a 2-min break before commencing the second simulation using the alternate technique. The median mask leak, tidal volume (TV) and inflations per minute during the second minute of each session for each participant was calculated and used in the analysis. In the TH setting, the participant held the face mask in position with both hands, while inflations were delivered by one of two study investigators (AM and TB). Participants and study investigators were blinded to the onscreen data, but could adjust their hold per their normal practice. Statistical analyses were performed using IBM SPSS Statistics (version 28.0, IBM Corp., Armonk, NY, USA). Period and cross over effects were tested using the Mann–Whitney U test and if absent, outcome measures were compared between the two methods using the Wilcoxon signed-rank (matched pairs) test and related samples Hodges–Lehmann median difference (95% confidence interval [CI]). Spearman's correlation coefficient (rs) was used to investigate the relationship between years of experience and leak. The Mann–Whitney U test was used to compare leak values (OH and TH separately) between professional roles (Nurse, SHO, Registrar/Fellow, Consultant). All tests were two-sided and a p < 0.05 was considered statistically significant. A priori sample size calculation indicated that a sample of 39 participants would be necessary to show an absolute reduction in leak of 30% with OH technique to less than 10% with TH technique using a Wilcoxon signed-rank (matched pairs) test with a type 1 error of 5%, power of 80%, a two-tailed test and assuming a standard deviation of difference in leak of 40%. Of the 52 medical and nursing staff available, 41 were eligible for inclusion. One participant was excluded due to poor quality recording. Thirty-five were neonatal or paediatric doctors, and five were neonatal nurses. Years of experience ranged from 1 to 28 years, with a median (interquartile range, IQR) of 5.5 (3–11) years. A total of 1350 inflations were analysed. There was no difference in inflations per minute between the two techniques (p = 0.123). No period or carry over effects were observed for mask leak or tidal volume. Median mask leak was greater with OH (median [IQR]: 12.3% [5.5%–49.1%]) compared with TH (median [IQR]: 5.2% [2.6%–14.6%]) (Hodges–Lehmann median difference between OH and TH [95% CI]: 8.0% [0.2%–27.7%]), (p = 0.041) (Figure 2). TVs were similar between the groups; median (IQR) 4.16 mL/inflation (3.65–7.11) in the OH group, and 3.87 mL/inflation (3.70–4.71) in the TH group (p = 0.270). There was no difference between years of experience and OH (rs = −0.24, p = 0.128) or TH leak values (rs = −0.10, p = 0.551) or professional group and OH (p = 0.381) or TH (p = 0.774) leak values. In this simulated study, we found the median leak was significantly lower using the TH technique compared to the OH technique (Hodges–Lehmann median difference between OH and TH [95% CI]: 8.0% [0.2%–27.7%]). These findings are similar to Tracy et al,4 although they reported mean values. However, this is a much lower median leak than previous studies, where reported mask leak varies from 30% to 60%.3 This low leak may be due to the artificial nature of the scenario. The analysis of the second minute only may have also contributed to the lower levels of leak, along with the fact that we used a preterm manikin, which may have made it easier to form a good seal. We feel this adds strength to the finding of lower leak with TH technique, as it is more likely to be an accurate representation of the best inflations each participant can deliver with each technique. The limitations of this study are shared by similar studies on manikins. A manikin, while an effective learning tool, can never provide the same cues in relation to clinical deterioration and improvement as a neonate. When using positive pressure ventilation in a neonatal manikin model, TH technique is superior to OH technique in reducing mask leak. Further clinical trials of OH versus TH hold are warranted in the delivery suite. Anne Murray: Writing – original draft; formal analysis; conceptualization; methodology; investigation; project administration; data curation. Tom Beechinor: Investigation; writing – original draft; conceptualization; project administration; methodology; data curation. Vicki Livingstone: Formal analysis; writing – review and editing; supervision; methodology; validation. Eugene Dempsey: Conceptualization; writing – review and editing; supervision; methodology; investigation; formal analysis; project administration. Open access funding provided by IReL. This study was performed within the principles of the Declaration of Helsinki. Approval was granted by the Cork Research Ethics Committee (ECM 3 (II) 11/05/2021 and ECM (g) 12/11/2019). Written informed consent was obtained from all participants in relation to participating in this study.