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Objective: In extremely preterm infants, different target ranges for pulse oximeter saturation (SpO 2 ) may affect mortality and morbidity. Thus, the impact of technical changes potentially affecting measurements should be assessed. We studied SpO 2 readings from different sensors for systematic deviations., Design: Single-centre, randomised, triple crossover study., Setting: Tertiary neonatal intensive care unit., Patients: 24 infants, born at <32 weeks' gestation, with current weight <1500 g and without right-to-left shunt via a patent ductus arteriosus., Interventions: Simultaneous readings from three SpO 2 sensors (Red Diamond (RD), Photoplethysmography (PPG), Low Noise Cabled Sensors (LNCS)) were logged at 0.5 Hz over 6 hour/infant and compared with LNCS as control using analysis of variance. Sensor position was randomly allocated and rotated every 2 hours. Seven different batches each were used., Outcomes: Primary outcome was the difference in SpO 2 readings. Secondary outcomes were differences between sensors in the proportion of time within the SpO 2 -target range (90-95 (100)%)., Results: Mean gestational age at birth (±SD) was 27 4/7 (±2 3/7 ) weeks, postnatal age 20 (±20) days. 134 hours of recording were analysed. Mean SpO 2 (±SD) was 94.0% (±3.8; LNCS) versus 92.2% (±4.0; RD; p<0.0001) and 94.5% (±3.9; PPG; p<0.0001), respectively. Mean SpO 2 difference (95% CI) was -1.8% (-1.9 to -1.8; RD) and 0.5% (0.4 to 0.5; PPG). Proportion of time in target was significantly lower with RD sensors (84.8% vs 91.7%; p=0.0001) and similar with PPG sensors (91.1% vs 91.7%; p=0.63)., Conclusion: There were systematic differences in SpO 2 readings between RD sensors versus LNCS. These findings may impact mortality and morbidity of preterm infants, particularly when aiming for higher SpO 2 -target ranges (eg, 90-95%)., Trial Registration Number: DRKS00027285., Competing Interests: Competing interests: CFP received advisory board-honoraria from Masimo, Irvine, California in 09/2020. All other authors have indicated they have no conflicts of interests relevant to this article to disclose. AF and CFP declare that Masimo generously supported SpO2 measurements in a previous and an ongoing clinical trial. In this study, Masimo provided also the required LNCS, RD and PPG sensors. However, Masimo had no impact on the design of this study, analysis of the data and writing of this manuscript., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Mechanisms of non-invasive high-frequency oscillatory ventilation (nHFOV) in preterm infants are unclear. We aimed to compare lung volume changes during apnoeas in preterm infants on nHFOV and nasal continuous positive airway pressure (nCPAP)., Methods: Analysis of electrical impedance tomography (EIT) data from a randomised crossover trial comparing nHFOV with nCPAP in preterm infants at 26-34 weeks postmenstrual age. EIT data were screened by two reviewers to identify apnoeas ≥10 s. End-expiratory lung impedance (EELI) and tidal volumes (V T ) were calculated before and after apnoeas. Oxygen saturation (SpO 2 ) and heart rate (HR) were extracted for 60 s after apnoeas., Results: In 30 preterm infants, 213 apnoeas were identified. During apnoeas, oscillatory volumes were detectable during nHFOV. EELI decreased significantly during apnoeas (∆EELI nCPAP: -8.0 (-11.9 to -4.1) AU/kg, p<0.001; ∆EELI nHFOV: -3.4 (-6.5 to -0.3), p=0.03) but recovered over the first five breaths after apnoeas. Compared with before apnoeas, V T was increased for the first breath after apnoeas during nCPAP (∆V T : 7.5 (3.1 to 11.2) AU/kg, p=0.001). Falls in SpO 2 and HR after apnoeas were greater during nCPAP than nHFOV (mean difference (95% CI): SpO 2 : 3.6% (2.7 to 4.6), p<0.001; HR: 15.9 bpm (13.4 to 18.5), p<0.001)., Conclusion: Apnoeas were characterised by a significant decrease in EELI which was regained over the first breaths after apnoeas, partly mediated by a larger V T . Apnoeas were followed by a considerable drop in SpO 2 and HR, particularly during nCPAP, leading to longer episodes of hypoxemia during nCPAP. Transmitted oscillations during nHFOV may explain these benefits., Trial Registration Number: ACTRN12616001516471., Competing Interests: Competing interests: VDG and CMR declare that they received an EIT monitor free of charge for a different research project by SenTec AG. All other authors declare that they have no conflict of interest., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Non-invasive high-frequency oscillatory ventilation (nHFOV) is an extension of nasal continuous positive airway pressure (nCPAP) support in neonates. We aimed to compare global and regional distribution of lung volumes during nHFOV versus nCPAP., Methods: In 30 preterm infants enrolled in a randomised crossover trial comparing nHFOV with nCPAP, electrical impedance tomography data were recorded in prone position. For each mode of respiratory support, four episodes of artefact-free tidal ventilation, each comprising 30 consecutive breaths, were extracted. Tidal volumes (V T ) in 36 horizontal slices, indicators of ventilation homogeneity and end-expiratory lung impedance (EELI) for the whole lung and for four horizontal regions of interest (non-gravity-dependent to gravity-dependent; EELI NGD , EELI midNGD , EELI midGD , EELI GD ) were compared between nHFOV and nCPAP. Aeration homogeneity ratio (AHR) was determined by dividing aeration in non-gravity-dependent parts of the lung through gravity-dependent regions., Main Results: Overall, 228 recordings were analysed. Relative V T was greater in all but the six most gravity-dependent lung slices during nCPAP (all p<0.05). Indicators of ventilation homogeneity were similar between nHFOV and nCPAP (all p>0.05). Aeration was increased during nHFOV (mean difference (95% CI)=0.4 (0.2 to 0.6) arbitrary units per kilogram (AU/kg), p=0.013), mainly due to an increase in non-gravity-dependent regions of the lung (∆EELI NGD =6.9 (0.0 to 13.8) AU/kg, p=0.028; ∆EELI midNGD =6.8 (1.2 to 12.4) AU/kg, p=0.009). Aeration was more homogeneous during nHFOV compared with nCPAP (mean difference (95% CI) in AHR=0.01 (0.00 to 0.02), p=0.0014)., Conclusion: Although regional ventilation was similar between nHFOV and nCPAP, end-expiratory lung volume was higher and aeration homogeneity was slightly improved during nHFOV. The aeration difference was greatest in non-gravity dependent regions, possibly due to the oscillatory pressure waveform. The clinical importance of these findings is still unclear., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: We sought to determine the effect of stimulation during positive pressure ventilation (PPV) on the number of spontaneous breaths, exhaled tidal volume (VTe), mask leak and obstruction., Design: Secondary analysis of a prospective, randomised trial comparing two face masks., Setting: Single-centre delivery room study., Patients: Newborn infants ≥34 weeks' gestation at birth., Methods: Resuscitations were video recorded. Tactile stimulations during PPV were noted and the timing, duration and surface area of applied stimulus were recorded. Respiratory flow waveforms were evaluated to determine the number of spontaneous breaths, VTe, leak and obstruction. Variables were recorded throughout each tactile stimulation episode and compared with those recorded in the same time period immediately before stimulation., Results: Twenty of 40 infants received tactile stimulation during PPV and we recorded 57 stimulations during PPV. During stimulation, the number of spontaneous breaths increased (median difference (IQR): 1 breath (0-3); p adj <0.001) and VTe increased (0.5 mL/kg (-0.5 to 1.7), p adj =0.028), whereas mask leak (0% (-20 to 1), p adj =0.12) and percentage of obstructed inflations (0% (0-0), p adj =0.14) did not change, compared with the period immediately prior to stimulation. Increased duration of stimulation (p adj <0.001) and surface area of applied stimulus (p adj =0.026) were associated with a larger increase in spontaneous breaths in response to tactile stimulation., Conclusions: Tactile stimulation during PPV was associated with an increase in the number of spontaneous breaths compared with immediately before stimulation without a change in mask leak and obstruction. These data inform the discussion on continuing stimulation during PPV in term infants., Trial Registration Number: Australian and New Zealand Clinical Trial Registry (ACTRN12616000768493)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Application of a face mask may induce apnoea and bradycardia, possibly via the trigeminocardiac reflex (TCR). We aimed to describe rates of apnoea and bradycardia in term and late-preterm infants following facemask application during neonatal stabilisation and compare the effects of first facemask application with subsequent applications., Design: Subgroup analysis of a prospective, randomised trial comparing two face masks., Setting: Single-centre study in the delivery room PATIENTS: Infants>34 weeks gestational age at birth METHODS: Resuscitations were video recorded. Airway flow and pressure were measured using a flow sensor. The effect of first and subsequent facemask applications on spontaneously breathing infants were noted. When available, flow waveforms as well as heart rate (HR) were assessed 20 s before and 30 s after each facemask application., Results: In total, 128 facemask applications were evaluated. In eleven percent of facemask applications infants stopped breathing. The first application was associated with a higher rate of apnoea than subsequent applications (29% vs 8%, OR (95% CI)=4.76 (1.41-16.67), p=0.012). On aggregate, there was no change in median HR over time. In the interventions associated with apnoea, HR dropped by 38bpm [median (IQR) at time of facemask application: 134bpm (134-150) vs 96bpm (94-102) 20 s after application; p=0.25] and recovered within 30 s., Conclusions: Facemask applications in term and late-preterm infants during neonatal stabilisation are associated with apnoea and this effect is more pronounced after the first compared with subsequent applications. Healthcare providers should be aware of the TCR and vigilant when applying a face mask to newborn infants., Trial Registration Number: ACTRN12616000768493., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)