Predictors of 24-h outcome in newborns in need of positive pressure ventilation at birth

Neonatal outcomes and resuscitation practices following the addition of heart rate-guidance to basic resuscitation

AIM

To evaluate the impact of heart rate-guided basic resuscitation compared to Helping Babies Breathe on neonatal outcomes and resuscitation practices in the Democratic Republic of the Congo.

METHODS

We conducted a pre-post clinical trial comparing heart rate-guided basic resuscitation to Helping Babies Breathe in three facilities, enrolling in-born neonates ≥28 weeks gestation. We collected observational data during a convenience sample of resuscitations and extracted clinical data from the medical record for all participants. We evaluated our primary outcome of effective breathing at three minutes after birth among newborns not breathing well at 30 seconds after birth employing generalized linear models using maximum likelihood estimation.

RESULTS

Among 1,284 newborns with observational data, there was no difference in the proportion effectively breathing at three minutes (adjusted relative risk 1.08 [95% CI 0.81, 1.45]). Among 145 receiving bag mask ventilation, time to bag mask ventilation decreased 64.3 seconds during heart rate-guided resuscitation (p<0.001). Among 10,906 enrolled in the trial, perinatal mortality was unchanged (adjusted relative risk 1.19 [95% CI 0.96, 1.48]) and death before discharge increased (adjusted relative risk 1.43 [95% CI 1.03, 1.99]). Expert review of stillborn cases demonstrated a stillbirth misclassification rate of 33.3% during Helping Babies Breathe versus 5.9% in heart rate-guided resuscitation.

CONCLUSION

During heart rate-guided basic resuscitation, time to bag mask ventilation was reduced by greater than one minute. The increase in death before discharge and unchanged perinatal mortality may be due to resuscitation of newborns with a higher risk of mortality who were previously presumed stillborn. A cluster-randomized trial of heart rate-guided basic resuscitation is needed to evaluate its impact on neonatal mortality in low-resource settings.

A critical appraisal of tools for delivery room assessment of the newborn infant

Assessment of an infant's condition in the delivery room represents a prerequisite to adequately initiate medical support. In her seminal paper, Virginia Apgar described five parameters to be used for such an assessment. However, since that time maternal and neonatal care has changed; interventions were improved and infants are even more premature. Nevertheless, the Apgar score is assigned to infants worldwide but there are concerns about low interobserver reliability, especially in preterm infants. Also, resuscitative interventions may preclude the interpretation of the score, which is of concern when used as an outcome parameter in delivery room intervention studies. Within the context of these changes, we performed a critical appraisal on how to assess postnatal condition of the newborn including the clinical parameters of the Apgar score, as well as selected additional parameters and a proposed new scoring system. The development of a new scoring system that guide clinicians in assessing infants and help to decide how to support postnatal adaptation is discussed. IMPACT: This critical paper discusses the reliability of the Apgar score, as well as additional parameters, in order to improve assessment of a newborn's postnatal condition. A revised neonatal scoring system should account for infant maturity and the interventions administered. Delivery room assessment should be directed toward determining how much medical support is needed and how the infant responds to these interventions.

Prevalence of bradycardia in 4876 newborns in the first minute after birth and association with positive pressure ventilation: a population-based cross-sectional study

OBJECTIVE

To determine the prevalence of bradycardia in the first minute after birth and association with positive pressure ventilation (PPV).

METHOD

A population-based cross-sectional study was conducted from June 2019 to December 2021 at Stavanger University Hospital, Norway. Parents consented to participation during pregnancy, and newborns ≥28 weeks' gestation were included at birth. Heart rate (HR) was captured immediately after birth and continuously for the first minute(s). Time of birth was registered on a tablet. Provision of PPV was captured using video.

RESULTS

Of 4876 included newborns, 164 (3.4%) did not breathe (two-thirds) or breathed ineffectively (one-third) and received PPV at birth. HR in the first minute had a wide distribution. The prevalence of first measured HR <100 and <60 beats/minute at median 16 s was 16.3% and 0.6%, respectively. HR increased in most cases. At 60 s, 3.7% had HR <100 beats/minute, of which 82% did not require PPV. In total, 25% of newborns had some registered HR <100 beats/minute during the first minute, of which 95% did not require PPV. Among newborns who received PPV, 76% and 62% had HR ≥100 beats/minute at 60 s and at start PPV, respectively.

CONCLUSION

Bradycardia with HR <100 bpm in the first minute of life was frequent, but mostly self-resolved. Among the 4% of newborns that remained bradycardic at 60 s, only 20% received PPV. Two-thirds of resuscitated newborns had HR ≥100 beats/minute at start PPV. None of the ventilated newborns were breathing adequately at start PPV.

TRIAL REGISTRATION NUMBER

NCT03849781.

Development and Implementation of a Game-Based Neonatal Resuscitation Refresher Training: Effect on Registered Nurse Knowledge, Skills, Motivation, Engagement

Game-based learning theory and Google Docs Editors suite were used to develop an online, self-directed neonatal resuscitation refresher training for registered nurses to improve their resuscitation knowledge and skills and enhance their learning motivation and engagement. Results indicated that a self-directed, online game-based refresher training was motivating, engaging, and improved nurses' resuscitation knowledge and skill performance. Nurse professional development practitioners can use similar game-based online materials to enhance learning.

Exhaled CO2 monitoring to guide non-invasive ventilation at birth: a systematic review

OBJECTIVE

Measuring exhaled carbon dioxide (ECO2) during non-invasive ventilation at birth may provide information about lung aeration. However, the International Liaison Committee on Resuscitation (ILCOR) only recommends ECO2 detection for confirming endotracheal tube placement. ILCOR has therefore prioritised a research question that needs to be urgently evaluated: 'In newborn infants receiving intermittent positive pressure ventilation by any non-invasive interface at birth, does the use of an ECO2 monitor in addition to clinical assessment, pulse oximetry and/or ECG, compared with clinical assessment, pulse oximetry and/or ECG only, decrease endotracheal intubation in the delivery room, improve response to resuscitation, improve survival or reduce morbidity?'.

DESIGN

Systematic review of randomised and non-randomised studies identified by Ovid MEDLINE, Embase and Cochrane CENTRAL search until 1 August 2022.

SETTING

Delivery room.

PATIENTS

Newborn infants receiving non-invasive ventilation at birth.

INTERVENTION

ECO2 measurement plus routine assessment compared with routine assessment alone.

MAIN OUTCOME MEASURES

Endotracheal intubation in the delivery room, response to resuscitation, survival and morbidity.

RESULTS

Among 2370 articles, 23 were included; however, none had a relevant control group. Although studies indicated that the absence of ECO2 may signify airway obstruction and ECO2 detection may precede a heart rate increase in adequately ventilated infants, they did not directly address the research question.

CONCLUSIONS

Evidence to support the use of an ECO2 monitor to guide non-invasive positive pressure ventilation at birth is lacking. More research on the effectiveness of ECO2 measurement in addition to routine assessment during non-invasive ventilation of newborn infants at birth is needed.

PROSPERO REGISTRATION NUMBER

CRD42022344849.

Use of Suctioning during Newborn Resuscitation and Its Effects on Heart Rate in a Low-Resource Setting, Tanzania

Suctioning of newborns immediately after birth, as part of delivery room resuscitation, is only recommended if the airway is obstructed. The aim of this study was to describe the use of suctioning during newborn resuscitation among survivors versus those who died within 3 days and potential suction-related heart rate responses and associations to newborn characteristics. This was a retrospective observational study from July 2013 to July 2016 in a referral hospital in rural Tanzania. Research assistants observed and documented all deliveries, newborn resuscitations were video-recorded, and newborn heart rates were captured with a dry-electrode electrocardiogram. Liveborn infants ≥34 weeks gestation who received ventilation and with complete datasets were eligible. All 30 newborns who died were included, and a total of 46 survivors were selected as controls. Videos were annotated and heart rate patterns were observed before and after the suction events. Suctioning was performed more frequently than recommended. No differences were found in suctioning characteristics between newborns who died versus those who survived. In 13% of suction events, a significant heart rate change (i.e., arrhythmia or brief/sustained >15% fall in heart rate) was observed in relation to suctioning. This represents a potential additional harm to already depressed newborns undergoing resuscitation.

Newborns requiring resuscitation: Two thirds have heart rate ≥100 beats/minute in the first minute after birth

AIM

The aim was to study the prevalence of bradycardia at birth in newborns requiring positive pressure ventilation (PPV), distribution of first measured heart rate (HR), changes in HR before start of PPV and HR response to PPV.

METHODS

A population-based study including newborns ≥30 weeks' gestation receiving PPV at birth. HR was captured immediately after birth and continuously throughout resuscitation using the dry-electrode ECG device NeoBeat. Time of birth was registered in the Liveborn app. Provision of PPV was captured by video.

RESULTS

We included 98 newborns receiving PPV at birth. Among newborns with HR measured within 60 s after birth, median (quartiles) first HR was 112 (84, 149) bpm recorded 19 (14, 37) s after birth, of which 33% had first HR <100 and 10% had first HR <60 bpm respectively. First HR was widely distributed. Median HR at start PPV 69 s after birth was 129 bpm. In newborns with an initial low HR, HR typically remained low for 20 s of PPV before increasing rapidly over the next 20-30 s.

CONCLUSIONS

First measured HR was ≥100 bpm in two thirds of newborns receiving PPV. In bradycardic infants, HR did not increase until after 20 s of PPV.

Delayed and Interrupted Ventilation with Excess Suctioning after Helping Babies Breathe with Congolese Birth Attendants

There is a substantial gap in our understanding of resuscitation practices following Helping Babies Breathe (HBB) training. We sought to address this gap through an analysis of observed resuscitations following HBB 2nd edition training in the Democratic Republic of the Congo. This is a secondary analysis of a clinical trial evaluating the effect of resuscitation training and electronic heart rate monitoring on stillbirths. We included in-born, liveborn neonates ≥28 weeks gestation whose resuscitation care was directly observed and documented. For the 2592 births observed, providers dried/stimulated before suctioning in 97% of cases and suctioned before ventilating in 100%. Only 19.7% of newborns not breathing well by 60 s (s) after birth ever received ventilation. Providers initiated ventilation at a median 347 s (>five minutes) after birth; no cases were initiated within the Golden Minute. During 81 resuscitations involving ventilation, stimulation and suction both delayed and interrupted ventilation with a median 132 s spent drying/stimulating and 98 s suctioning. This study demonstrates that HBB-trained providers followed the correct order of resuscitation steps. Providers frequently failed to initiate ventilation. When ventilation was initiated, it was delayed and interrupted by stimulation and suctioning. Innovative strategies targeting early and continuous ventilation are needed to maximize the impact of HBB.

Impact of immediate and continuous heart rate feedback by dry electrode ECG on time to initiation of ventilation after birth: protocol for a randomised controlled trial

INTRODUCTION

3%-8% of newborns need positive pressure ventilation (PPV) after birth. Heart rate (HR) is considered the most sensitive indicator of the newborns' condition and response to resuscitative interventions. According to guidelines, HR should be assessed and PPV initiated within 60 s after birth in non-breathing newborns. Dry electrode ECG can provide accurate feedback on HR immediately after birth and continuously during resuscitation. The impact of early and continuous HR feedback is unknown.

METHOD AND ANALYSIS

This single-centre randomised controlled trial seeks to determine if HR feedback by dry electrode ECG immediately after birth and continuously during newborn resuscitation results in more timely initiation of PPV, improved ventilation and short-term outcomes compared with standard HR assessment.In all newborns≥34 gestational weeks, the dry electrode ECG sensor is placed on the upper abdomen immediately after birth as an additional modality of HR assessment. The device records and stores HR signals. In intervention subjects, the HR display is visible to guide decision-making and further management, in control subjects the display is masked. Standard HR assessment is by stethoscope, gel-electrode ECG and/or pulse oximetry (PO).Time of birth is registered in the Liveborn app. Time of initiation and duration of PPV is calculated from video recordings. Ventilation parameters are retrieved from the ventilation monitor, oxygen saturation and HR from the PO and gel-electrode ECG monitors.The primary endpoint is proportion of resuscitated newborns who receive PPV within 60 s after birth. To detect a 50% increase with power of 90% using an overall significance level of 0.05 and 1 interim analysis, 169 newborns are needed in each group.

ETHICS AND DISSEMINATION

Approval by the Norwegian National Research Ethics Committee West (2018/338). Parental consent is sought at routine screening early in pregnancy. The results will be published in peer-reviewed journal and presented at conferences.

TRIAL REGISTRATION NUMBER

NCT03849781.

Delivery Room ST Segment Analysis to Predict Short Term Outcomes in Near-Term and Term Newborns

BACKGROUND

ST-segment changes to the fetal electrocardiogram (ECG) may indicate fetal acidosis. No large-scale characterization of ECG morphology immediately after birth has been performed, but ECG is used for heart rate (HR) assessment. We aimed to investigate ECG morphology immediately after birth in asphyxiated infants, using one-lead dry-electrode ECG developed for HR measurement.

METHODS

Observational study in Tanzania, between 2013-2018. Near-term and term infants that received bag-mask ventilation (BMV), and healthy controls, were monitored with one-lead dry-electrode ECG with a non-diagnostic bandwidth. ECGs were classified as normal, with ST-elevations or other ST-segment abnormalities including a biphasic ST-segment. We analyzed ECG morphology in relation to perinatal variables or short-term outcomes.

RESULTS

A total of 494 resuscitated and 25 healthy infants were included. ST-elevations were commonly seen both in healthy infants (7/25; 28%) and resuscitated (320/494; 65%) infants. The apparent ST-elevations were not associated with perinatal variables or short-term outcomes. Among the 32 (6.4%) resuscitated infants with "other ST-segment abnormalities", duration of BMV was longer, 1-min Apgar score lower and normal outcomes less frequent than in the resuscitated infants with normal ECG or ST-elevations.

CONCLUSIONS

ST-segment elevation was commonly seen and not associated with negative outcomes when using one-lead dry-electrode ECG. Other ST-segment abnormalities were associated with prolonged BMV and worse outcome. ECG with appropriate bandwidth and automated analysis may potentially in the future aid in the identification of severely asphyxiated infants.

Comparison of Heart Rate Feedback from Dry-Electrode ECG, 3-Lead ECG, and Pulse Oximetry during Newborn Resuscitation

Background: Assessment of heart rate (HR) is essential during newborn resuscitation, and comparison of dry-electrode ECG technology to standard monitoring by 3-lead ECG and Pulse Oximetry (PO) is lacking. Methods: NeoBeat, ECG, and PO were applied to newborns resuscitated at birth. Resuscitations were video recorded, and HR was registered every second. Results: Device placement time from birth was median (quartiles) 6 (4, 18) seconds for NeoBeat versus 138 (97, 181) seconds for ECG and 152 (103, 216) seconds for PO. Time to first HR presentation from birth was 22 (13, 45) seconds for NeoBeat versus 171 (129, 239) seconds for ECG and 270 (185, 357) seconds for PO. Proportion of time with HR feedback from NeoBeat during resuscitation from birth was 85 (69, 93)%, from arrival at the resuscitation table 98 (85, 100)%, and during positive pressure ventilation 100 (95, 100)%. For ECG, these proportions were, 25 (0, 43)%, 28 (0, 56)%, and 33 (0, 66)% and for PO, 0 (0, 16)%, 0 (0, 16)%, and 0 (0, 18)%. All p < 0.0001. Conclusions: NeoBeat was faster to place, presented HR more rapidly, and provided feedback on HR for a larger proportion of time during ongoing resuscitation compared to 3-lead ECG and PO.

SaferBirths bundle of care protocol: a stepped-wedge cluster implementation project in 30 public health-facilities in five regions, Tanzania

Background

The burden of stillbirth, neonatal and maternal deaths are unacceptably high in low- and middle-income countries, especially around the time of birth. There are scarce resources and/or support implementation of evidence-based training programs. SaferBirths Bundle of Care is a well-proven package of innovative tools coupled with data-driven on-the-job training aimed at reducing perinatal and maternal deaths. The aim of this project is to determine the effect of scaling up the bundle on improving quality of intrapartum care and perinatal survival.

Methods

The project will follow a stepped-wedge cluster implementation design with well-established infrastructures for data collection, management, and analysis in 30 public health facilities in regions in Tanzania. Healthcare workers from selected health facilities will be trained in basic neonatal resuscitation, essential newborn care and essential maternal care. Foetal heart rate monitors (Moyo), neonatal heart rate monitors (NeoBeat) and skills trainers (NeoNatalie Live) will be introduced in the health facilities to facilitate timely identification of foetal distress during labour and improve neonatal resuscitation, respectively. Heart rate signal-data will be automatically collected by Moyo and NeoBeat, and newborn resuscitation training by NeoNatalie Live.

Given an average of 4000 baby-mother pairs per year per health facility giving an estimate of 240,000 baby-mother pairs for a 2-years duration, 25% reduction in perinatal mortality at a two-sided significance level of 5%, intracluster correlation coefficient (ICC) to be 0.0013, the study power stands at 0.99.

Discussion

Previous reports from small-scale Safer Births Bundle implementation studies show satisfactory uptake of interventions with significant improvements in quality of care and lives saved. Better equipped and trained birth attendants are more confident and skilled in providing care. Additionally, local data-driven feedback has shown to drive continuous quality of care improvement initiatives, which is essential to increase perinatal and maternal survival. Strengths of this research project include integration of innovative tools with existing national guidelines, local data-driven decision-making and training. Limitations include the stepwise cluster implementation design that may lead to contamination of the intervention, and/or inability to address the shortage of healthcare workers and medical supplies beyond the project scope.

Trial registration

Name of Trial Registry: ISRCTN Registry.

Trial registration number: ISRCTN30541755.

Date of Registration: 12/10/2020.

Type of registration: Prospectively Registered.

Expired carbon dioxide during newborn resuscitation as predictor of outcome

AIM

To explore and compare expired CO₂ (ECO₂) and heart rate (HR), during newborn resuscitation with bag-mask ventilation, as predictors of 24-h outcome.

METHODS

Observational study from March 2013 to June 2017 in a rural Tanzanian hospital. Side-stream measures of ECO₂, ventilation parameters, HR, clinical information, and 24-h outcome were recorded in live born bag-mask ventilated newborns with initial HR < 120 bpm. We analysed the data using logistic regression models and compared areas under the receiver operating curves (AUC) for ECO₂ and HR within three selected time intervals after onset of ventilation (0-30 s, 30.1-60 s and 60.1-300 s).

RESULTS

Among 434 included newborns (median birth weight 3100 g), 378 were alive at 24 h, 56 had died. Both ECO₂ and HR were independently significant predictors of 24-h outcome, with no differences in AUCs. In the first 60 s of ventilation, ECO₂ added extra predictive information compared to HR alone. After 60 s, ECO₂ lost significance when adjusted for HR. In 70% of newborns with initial ECO₂ <2% and HR < 100 bpm, ECO₂ reached ≥2% before HR ≥ 100 bpm. Survival at 24 h was reduced by 17% per minute before ECO₂ reached ≥2% and 44% per minute before HR reached ≥100 bpm.

CONCLUSIONS

Higher levels and a faster rise in ECO₂ and HR during newborn resuscitation were independently associated with improved survival compared to persisting low values. ECO₂ increased before HR and may serve as an earlier predictor of survival.

European Resuscitation Council Guidelines 2021: Newborn resuscitation and support of transition of infants at birth

The European Resuscitation Council has produced these newborn life support guidelines, which are based on the International Liaison Committee on Resuscitation (ILCOR) 2020 Consensus on Science and Treatment Recommendations (CoSTR) for Neonatal Life Support. The guidelines cover the management of the term and preterm infant. The topics covered include an algorithm to aid a logical approach to resuscitation of the newborn, factors before delivery, training and education, thermal control, management of the umbilical cord after birth, initial assessment and categorisation of the newborn infant, airway and breathing and circulation support, communication with parents, considerations when withholding and discontinuing support.

[Newborn resuscitation and support of transition of infants at birth]

The European Resuscitation Council has produced these newborn life support guidelines, which are based on the International Liaison Committee on Resuscitation (ILCOR) 2020 Consensus on Science and Treatment Recommendations (CoSTR) for Neonatal Life Support. The guidelines cover the management of the term and preterm infant. The topics covered include an algorithm to aid a logical approach to resuscitation of the newborn, factors before delivery, training and education, thermal control, management of the umbilical cord after birth, initial assessment and categorisation of the newborn infant, airway and breathing and circulation support, communication with parents, considerations when withholding and discontinuing support.

Achieving Country-Wide Scale for Helping Babies Breathe and Helping Babies Survive

Helping Babies Breathe (HBB) was piloted in 2009 as a program targeted to reduce neonatal mortality (NM). The program has morphed into a suite of programs termed Helping Babies Survive that includes Essential Care for Every Baby. Since 2010, the HBB and Helping Babies Survive training programs have been taught to >850 000 providers in 80 countries. Initial HBB training is associated with a significant improvement in knowledge and skills. However, at refresher training, there is a knowledge-skill gap evident, with a falloff in skills. Accumulating evidence supports the role for frequent refresher resuscitation training in facilitating skills retention. Beyond skill acquisition, HBB has been associated with a significant reduction in early NM (<24 hours) and fresh stillbirth rates. To evaluate the large-scale impact of the growth of skilled birth attendants, we analyzed NM rates in sub-Saharan Africa (n = 11) and Nepal (as areas of growing HBB implementation). All have revealed a consistent reduction in NM at 28 days between 2009 and 2018; a mean reduction of 5.34%. The number of skilled birth attendants, an indirect measure of HBB sustained rollout, reveals significant correlation with NM, fresh stillbirth, and perinatal mortality rates, highlighting HBB's success and the need for continued efforts to train frontline providers. A novel live newborn resuscitation trainer as well as a novel app (HBB Prompt) have been developed, increasing knowledge and skills while providing simulation-based repeated practice. Ongoing challenges in sustaining resources (financial and other) for newborn programming emphasize the need for innovative implementation strategies and training tools.

Establishment of functional residual capacity at birth: Observational study of 821 neonatal resuscitations

AIM OF THE STUDY

Establishing functional residual capacity (FRC) during positive pressure ventilation (PPV) of apnoeic neonates is critical for survival. This may be difficult due to liquid-filled airways contributing to low lung compliance. The objectives were to describe initial PPV, changes in lung compliance and establishment of FRC in near-term/term neonates ≥36 weeks gestation at birth.

METHODS

Observational study of all neonatal resuscitations between 01.07.13 and 30.06.18 in a Tanzanian referral hospital. Perinatal events and characteristics were observed and recorded by trained research assistants. PPV were performed using self-inflating bag-masks without positive end-expiratory pressure (PEEP). Ventilation signals (pressure/flow), expired CO₂ (ECO₂) and heart rate were recorded by resuscitation monitors.

RESULTS

19,587 neonates were born, 1451 received PPV, of these 821 of median (p25, p75) birthweight 3180 (2844, 3500) grams and gestation 38 (37, 40) weeks had ≥20 ventilations and complete datasets. There was a significant increase in expired volume (from 3.3 to 6.0 ml/kg), ECO₂ (0.3-2.4%), lung compliance (0.13-0.19 ml/kg/mbar) and heart rate (109-138 beats/min) over the first 20 PPVs. Inflation volume, time, and peak inflation pressure (PIP) were stable around 12-13 ml/kg, 0.45 s, and 36 mbar, respectively.

CONCLUSIONS

The combination of increasing expired volumes, ECO₂, and heart rate with decreasing inflation/expired volume ratios and constant PIP, suggests establishment of FRC during the first 20 PPVs in near-term/term neonates using a self-inflating bag-mask without PEEP, the most common device worldwide for ventilating non-breathing neonates. Initial lung compliance is low, and with short inflation times, higher than recommended PIP seem necessary to deliver adequate tidal volumes.

Heart Rate Assessment during Neonatal Resuscitation

Approximately 10% of newborn infants require some form of respiratory support to successfully complete the fetal-to-neonatal transition. Heart rate (HR) determination is essential at birth to assess a newborn’s wellbeing. Not only is it the most sensitive indicator to guide interventions during neonatal resuscitation, it is also valuable for assessing the infant’s clinical status. As such, HR assessment is a key step at birth and throughout resuscitation, according to recommendations by the Neonatal Resuscitation Program algorithm. It is essential that HR is accurate, reliable, and fast to ensure interventions are delivered without delay and not prolonged. Ineffective HR assessment significantly increases the risk of hypoxic injury and infant mortality. The aims of this review are to summarize current practice, recommended techniques, novel technologies, and considerations for HR assessment during neonatal resuscitation at birth.

Brief asphyxial state following immediate cord clamping accelerates onset of left-to-right shunting across the ductus arteriosus after birth in preterm lambs

Reversal of shunting across the ductus arteriosus from right-to-left to left-to-right is a characteristic feature of the birth transition. Given that immediate cord clamping (ICC) followed by an asphyxial cord clamp-to-ventilation (CC-V) interval may augment left ventricular (LV) output and central blood flows after birth, we tested the hypothesis that an asphyxial CC-V interval accelerates the onset of postnatal left-to-right ductal shunting. High-fidelity central blood flow signals were obtained in anesthetized preterm lambs (gestation 128 ± 2 days) after ICC followed by a nonasphyxial (∼40 s, n = 9) or asphyxial (∼90 s, n = 9) CC-V interval before mechanical ventilation for 30 min after birth. Left-to-right ductal flow segments were related to aortic isthmus and descending aortic flow profiles to quantify sources of ductal shunting. In the nonasphyxial group, phasic left-to-right ductal shunting was initially minor after birth, but then rose progressively to 437 ± 164 ml/min by 15 min (P < 0.001). However, in the asphyxial group, this shunting increased from 24 ± 21 to 199 ± 93 ml/min by 15 s after birth (P < 0.001) and rose further to 471 ± 190 ml/min by 2 min (P < 0.001). This earlier onset of left-to-right ductal shunting was supported by larger contributions (P < 0.001) from direct systolic LV flow and retrograde diastolic discharge from an arterial reservoir/windkessel located in the descending aorta and its major branches, and associated with increased pulmonary arterial blood flow having a larger ductal component. These findings suggest that the duration of the CC-V interval after ICC is an important modulator of left-to-right ductal shunting, LV output and pulmonary perfusion at birth.NEW & NOTEWORTHY This birth transition study in preterm lambs demonstrated that a brief (∼90 s) asphyxial interval between umbilical cord clamping and ventilation onset resulted in earlier and greater left-to-right shunting across the ductus arteriosus after birth. This greater shunting 1) resulted from an increased left ventricular output associated with a higher systolic left-to-right ductal flow and increased retrograde diastolic discharge from a lower body arterial reservoir/windkessel, and 2) was accompanied by greater lung perfusion after birth.

Smartphone app for neonatal heart rate assessment: an observational study

BACKGROUND

Heart rate (HR) assessment is crucial in neonatal resuscitation, but pulse oximetry (PO) and electrocardiography (ECG) are rarely accessible in low-resource to middle-resource settings. This study evaluated a free-of-charge smartphone application, NeoTap, which records HR with a screen-tapping method bypassing mental arithmetic calculations.

METHODS

This observational study was carried out during three time periods between May 2015 and January 2019 in Uganda in three phases. In phase 1, a metronome rate (n=180) was recorded by low-end users (midwives) using NeoTap. In phase 2, HR (n=69) in breathing neonates was recorded by high-end users (paediatricians) using NeoTap versus PO. In phase 3, HR (n=235) in non-breathing neonates was recorded by low-end users using NeoTap versus ECG.

RESULTS

In high-end users the mean difference was 3 beats per minute (bpm) higher with NeoTap versus PO (95% agreement limits -14 to 19 bpm), with acquisition time of 5 seconds. In low-end users, the mean difference was 6 bpm lower with NeoTap versus metronome (95% agreement limits -26 to 14 bpm) and 3 bpm higher with NeoTap versus ECG in non-breathing neonates (95% agreement limits -48 to 53 bpm), with acquisition time of 2.7 seconds. The agreement between NeoTap and ECG was good in the HR categories of 60-99 bpm and ≥100 bpm; HR <60 bpm had few measurements (kappa index 0.71, 95% CI 0.63 to 0.79).

CONCLUSION

HR could be accurately and rapidly assessed using a smartphone application in breathing neonates in a low-resource setting. Clinical assessment by low-end users was less accurate with wider CI but still adds clinically important information in non-breathing neonates. The authors suggest low-end users may benefit from auscultation-focused training. More research is needed to evaluate its feasibility in clinical use.

Predictors for expired CO2 in neonatal bag-mask ventilation at birth: observational study

BACKGROUND

Expired carbon dioxide (ECO2) indicates degree of lung aeration immediately after birth. Favourable ventilation techniques may be associated with higher ECO2 and a faster increase. Clinical condition will however also affect measured values. The aim of this study was to explore the relative impact of ventilation factors and clinical factors on ECO2 during bag-mask ventilation of near-term newborns.

METHODS

Observational study performed in a Tanzanian rural hospital. Side-stream measures of ECO2, ventilation data, heart rate and clinical information were recorded in 434 bag-mask ventilated newborns with initial heart rate <120 beats per minute. We studied ECO2 by clinical factors (birth weight, Apgar scores and initial heart rate) and ventilation factors (expired tidal volume, ventilation frequency, mask leak and inflation pressure) in random intercept models and Cox regression for time to ECO2 >2%.

RESULTS

ECO2 rose non-linearly with increasing expired tidal volume up to >10 mL/kg, and sufficient tidal volume was critical for the time to reach ECO2 >2%. Ventilation frequency around 30/min was associated with the highest ECO2. Higher birth weight, Apgar scores and initial heart rate were weak, but significant predictors for higher ECO2. Ventilation factors explained 31% of the variation in ECO2 compared with 11% for clinical factors.

CONCLUSIONS

Our findings indicate that higher tidal volumes than currently recommended and a low ventilation frequency around 30/min are associated with improved lung aeration during newborn resuscitation. Low ECO2 may be used to identify unfavourable ventilation technique. Clinical factors are also associated with persistently low ECO2 and must be accounted for in the interpretation.