Stimulating and maintaining spontaneous breathing during transition of preterm infants

From intra- to extra-uterine: early phase design of a transfer to extra-uterine life support through medical simulation

Introduction

Extra-uterine life support technology could provide a more physiologic alternative for the treatment of extremely premature infants, as it allows further fetal growth and development ex utero. Animal studies have been carried out which involved placing fetuses in a liquid-filled incubator, with oxygen supplied through an oxygenator connected to the umbilical vessels. Hence, by delaying lung exposure to air, further lung development and maturation can take place. This medical intervention requires adjustments to current obstetric procedures to maintain liquid-filled lungs through a so-called transfer procedure.

Methods

Our objective was to develop obstetric device prototypes that allow clinicians to simulate this birth procedure to safely transfer the infant from the mother's uterus to an extra-uterine life support system. To facilitate a user-centered design, implementation of medical simulation during early phase design of the prototype development was used. First, the requirements for the procedure and devices were established, by reviewing the literature and through interviewing direct stakeholders. The initial transfer device prototypes were tested on maternal and fetal manikins in participatory simulations with clinicians.

Results & discussion

Through analysis of recordings of the simulations, the prototypes were evaluated on effectiveness, safety and usability with latent conditions being identified and improved. This medical simulation-based design process resulted in the development of a set of surgical prototypes and allowed for knowledge building on obstetric care in an extra-uterine life support context.

The influence of chorioamnionitis on respiratory drive and spontaneous breathing of premature infants at birth: a narrative review

Most very premature infants breathe at birth but require respiratory support in order to stimulate and support their breathing. A significant proportion of premature infants are affected by chorioamnionitis, defined as an umbrella term for antenatal inflammation of the foetal membranes and umbilical vessels. Chorioamnionitis produces inflammatory mediators that potentially depress the respiratory drive generated in the brainstem. Such respiratory depression could maintain itself by delaying lung aeration, hampering respiratory support at birth and putting infants at risk of hypoxic injury. This inflammatory-mediated respiratory depression may contribute to an association between chorioamnionitis and increased requirement of neonatal resuscitation in premature infants at birth. This narrative review summarises mechanisms on how respiratory drive and spontaneous breathing could be influenced by chorioamnionitis and provides possible interventions to stimulate spontaneous breathing.  Conclusion: Chorioamnionitis could possibly depress respiratory drive and spontaneous breathing in premature infants at birth. Interventions to stimulate spontaneous breathing could therefore be valuable. What is Known: • A large proportion of premature infants are affected by chorioamnionitis, antenatal inflammation of the foetal membranes and umbilical vessels. What is New: • Premature infants affected by chorioamnionitis might be exposed to higher concentrations of respiratory drive inhibitors which could depress breathing at birth. • Premature infants affected by chorioamnionitis seem to be associated with a higher and more extensive requirement of resuscitation at birth.

Transferring an extremely premature infant to an extra-uterine life support system: a prospective view on the obstetric procedure

To improve care for extremely premature infants, the development of an extrauterine environment for newborn development is being researched, known as Artificial Placenta and Artificial Womb (APAW) technology. APAW facilitates extended development in a liquid-filled incubator with oxygen and nutrient supply through an oxygenator connected to the umbilical vessels. This setup is intended to provide the optimal environment for further development, allowing further lung maturation by delaying gas exposure to oxygen. This innovative treatment necessitates interventions in obstetric procedures to transfer an infant from the native to an artificial womb, while preventing fetal-to-neonatal transition. In this narrative review we analyze relevant fetal physiology literature, provide an overview of insights from APAW studies, and identify considerations for the obstetric procedure from the native uterus to an APAW system. Lastly, this review provides suggestions to improve sterility, fetal and maternal well-being, and the prevention of neonatal transition.

Variation in delivery room management of preterm infants across Europe: a survey of the Union of European Neonatal and Perinatal Societies

The aim of the present study, endorsed by the Union of European Neonatal and Perinatal Societies (UENPS) and the Italian Society of Neonatology (SIN), was to analyze the current delivery room (DR) stabilization practices in a large sample of European birth centers that care for preterm infants with gestational age (GA) < 33 weeks. Cross-sectional electronic survey was used in this study. A questionnaire focusing on the current DR practices for infants < 33 weeks' GA, divided in 6 neonatal resuscitation domains, was individually sent to the directors of European neonatal facilities, made available as a web-based link. A comparison was made between hospitals grouped into 5 geographical areas (Eastern Europe (EE), Italy (ITA), Mediterranean countries (MC), Turkey (TUR), and Western Europe (WE)) and between high- and low-volume units across Europe. Two hundred and sixty-two centers from 33 European countries responded to the survey. At the time of the survey, approximately 20,000 very low birth weight (VLBW, < 1500 g) infants were admitted to the participating hospitals, with a median (IQR) of 48 (27-89) infants per center per year. Significant differences between the 5 geographical areas concerned: the volume of neonatal care, ranging from 86 (53-206) admitted VLBW infants per center per year in TUR to 35 (IQR 25-53) in MC; the umbilical cord (UC) management, being the delayed cord clamping performed in < 50% of centers in EE, ITA, and MC, and the cord milking the preferred strategy in TUR; the spotty use of some body temperature control strategies, including thermal mattress mainly employed in WE, and heated humidified gases for ventilation seldom available in MC; and some of the ventilation practices, mainly in regard to the initial FiO2 for < 28 weeks' GA infants, pressures selected for ventilation, and the preferred interface to start ventilation. Specifically, 62.5% of TUR centers indicated the short binasal prongs as the preferred interface, as opposed to the face mask which is widely adopted as first choice in > 80% of the rest of the responding units; the DR surfactant administration, which ranges from 44.4% of the birth centers in MC to 87.5% in WE; and, finally, the ethical issues around the minimal GA limit to provide full resuscitation, ranging from 22 to 25 weeks across Europe. A comparison between high- and low-volume units showed significant differences in the domains of UC management and ventilation practices.    Conclusion: Current DR practice and ethical choices show similarities and divergences across Europe. Some areas of assistance, like UC management and DR ventilation strategies, would benefit of standardization. Clinicians and stakeholders should consider this information when allocating resources and planning European perinatal programs. What is Known: • Delivery room (DR) support of preterm infants has a direct influence on both immediate survival and long-term morbidity. • Resuscitation practices for preterm infants often deviate from the internationally defined algorithms. What is New: • Current DR practice and ethical choices show similarities and divergences across Europe. Some areas of assistance, like UC management and DR ventilation strategies, would benefit of standardization. • Clinicians and stakeholders should consider this information when allocating resources and planning European perinatal programs.

Knowledge gaps in optimal umbilical cord management at birth

In 2014 the World Health Organisation recommended providing placental blood to all newborn infants by waiting for at least one minute before clamping the umbilical cord. Mounting evidence supports providing a placental transfusion at the time of birth for all infants. The optimal time before clamping and cutting the umbilical cord is still not yet known, and debate exists around other cord management issues. The newborn's transition phase from intra- to extra-uterine life and the effects of blood volume on the many necessary adaptations are understudied. How best to support these adaptations guides our suggested research questions. Parents' perceptions of enrolling their unborn infant into a study play important parts in the conduct of such trials. This article aims to address these topics and suggest research questions for further studies.

Low-Cost SpO2 Integrated Neonatal CPAP Device for Low Resource Setting

Introduction

More than 60% of preterm births take place in South Asia and sub-Saharan Africa, making prematurity a primary cause of neonatal mortality. Even though continuous positive airway pressure (CPAP) is a popular treatment for respiratory distress syndrome (RDS) and is safe, practicable, and efficient for use in LMICs, it is crucial to ensure that neonates receive the full benefits of the therapy by monitoring their blood oxygen level.

Methods

A centrifugal fan, power source, control system, and sensors are all included in our design. A centrifugal fan was created to provide air at positive pressure in the range of approximately 4 cmH2O to 20 cmH2O utilizing revolving blades (impeller), a DC motor, and a fixed component. The control unit contains a microcontroller to handle sensor data. The proportional-integral (PI) controller board's external potentiometer is used to set the pressure level.

Results

To ascertain whether the prototype satisfies the design requirements, it was constructed and put through several iterations and testing. The proposed device's prototype was tested for accuracy, affordability, and usability. The centrifugal fan speed measurement was accurate to within 94.5%, while the oxygen concentration sensor reading was accurate to within 98.5%.

Conclusion

The design investigates viability of a straightforward, inexpensive, portable SpO2 integrated neonatal CPAP device for use in the delivery room in low-resource countries and to evaluates methods for measuring flows during CPAP treatment by monitoring the level of oxygen in the blood and pressure level delivered by the device using the lowest and safest setting that yields useful results.

Cardiac Asystole at Birth Re-Visited: Effects of Acute Hypovolemic Shock

Births involving shoulder dystocia or tight nuchal cords can deteriorate rapidly. The fetus may have had a reassuring tracing just before birth yet may be born without any heartbeat (asystole). Since the publication of our first article on cardiac asystole with two cases, five similar cases have been published. We suggest that these infants shift blood to the placenta due to the tight squeeze of the birth canal during the second stage which compresses the cord. The squeeze transfers blood to the placenta via the firm-walled arteries but prevents blood returning to the infant via the soft-walled umbilical vein. These infants may then be born severely hypovolemic resulting in asystole secondary to the loss of blood. Immediate cord clamping (ICC) prevents the newborn's access to this blood after birth. Even if the infant is resuscitated, loss of this large amount of blood volume may initiate an inflammatory response that can enhance neuropathologic processes including seizures, hypoxic-ischemic encephalopathy (HIE), and death. We present the role of the autonomic nervous system in the development of asystole and suggest an alternative algorithm to address the need to provide these infants intact cord resuscitation. Leaving the cord intact (allowing for return of the umbilical cord circulation) for several minutes after birth may allow most of the sequestered blood to return to the infant. Umbilical cord milking may return enough of the blood volume to restart the heart but there are likely reparative functions that are carried out by the placenta during the continued neonatal-placental circulation allowed by an intact cord.

Effect of clinical chorioamnionitis on breathing effort in premature infants at birth: a retrospective case-control study

RATIONALE

Antenatal inflammation, usually associated with chorioamnionitis, is a major cause of premature birth. As inflammation could depress respiratory drive, we have examined the effect of clinical chorioamnionitis (CCA) on spontaneous breathing in premature infants at birth.

METHODS

Infants with CCA born <30 weeks' gestation were matched with control infants based on gestational age (±6 days), birth weight (±300 g), antenatal corticosteroids, sex and general anaesthesia. The primary outcome was breathing effort, assessed as minute volume (MV) of spontaneous breathing. We also measured tidal volume (Vt), respiratory rate (RR) and apnoea in the first 5 min and additional physiological parameters in the first 10 min after start of respiratory support.

RESULTS

Ninety-two infants were included (n=46 CCA infants vs n=46 controls; median (IQR) gestational age 26⁺⁴ (25⁺⁰-27⁺⁶) vs 26⁺⁶ (25⁺¹-28⁺³) weeks). MV and Vt were significantly lower (MV: 43 (17-93) vs 70 (31-119) mL/kg/min, p=0.043; Vt: 2.6 (1.9-3.6) vs 2.9 (2.2-4.8) mL/kg/breath, p=0.046), whereas RR was similar in CCA infants compared with controls. Incidence of apnoea was higher (5 (2-6) vs 2 (1-4), p=0.002), and total duration of apnoea was longer (90 (21-139) vs 35 (12-98) s, p=0.025) in CCA infants. CCA infants took significantly longer to reach an oxygen saturation >80% (3:37 (2:10-4:29) vs 2:25 (1:06-3:52) min, p=0.016) and had a lower oxygen saturation at 5 min (77 (66-92) vs 91 (68-94) %, p=0.028), despite receiving more oxygen (62 (48-76) vs 54 (43-73) %, p=0.036).

CONCLUSION

CCA is associated with reduced breathing effort and oxygenation in premature infants at birth.

Positive pressure ventilation at birth

OBJECTIVE

To review the current state of the art of positive pressure ventilation (PPV) during resuscitation FINDINGS: The frequency of PPV during delivery room resuscitation varies across settings and gestational age subgroups. Goal targets and parameters for delivery room PPV remain undefined. The T-piece resuscitator provides the most consistent pressures during PPV and may improve clinical outcomes. The laryngeal mask may be an important alternative interface for PPV, but more data are needed to identify the optimal role of the supraglottic airway during PPV. No objective monitors of PPV have conclusively demonstrated improved outcomes to date.

CONCLUSION

More information, including real-world data from population-based studies, is needed to provide data-driven guidelines for positive pressure ventilation during neonatal transition after birth.

Technology in the delivery room supporting the neonatal healthcare provider's task

Very preterm infants are a unique and highly vulnerable group of patients that have a narrow physiological margin within which interventions are safe and effective. The increased understanding of the foetal to neonatal transition marks the intricacy of the rapid and major physiological changes that take place, making delivery room stabilisation and resuscitation an increasingly complex and sophisticated activity for caregivers to perform. While modern, automated technologies are progressively implemented in the neonatal intensive care unit (NICU) to enhance the caregivers in providing the right care for these patients, the technology in the delivery room still lags far behind. Diligent translation of well-known and promising technological solutions from the NICU to the delivery room will allow for better support of the caregivers in performing their tasks. In this review we will discuss the current technology used for stabilisation of preterm infants in the delivery room and how this could be optimised in order to further improve care and outcomes of preterm infants in the near future.

Making the Argument for Intact Cord Resuscitation: A Case Report and Discussion

We use a case of intact cord resuscitation to argue for the beneficial effects of an enhanced blood volume from placental transfusion for newborns needing resuscitation. We propose that intact cord resuscitation supports the process of physiologic neonatal transition, especially for many of those newborns appearing moribund. Transfer of the residual blood in the placenta provides the neonate with valuable access to otherwise lost blood volume while changing from placental respiration to breathing air. Our hypothesis is that the enhanced blood flow from placental transfusion initiates mechanical and chemical forces that directly, and indirectly through the vagus nerve, cause vasodilatation in the lung. Pulmonary vascular resistance is thereby reduced and facilitates the important increased entry of blood into the alveolar capillaries before breathing commences. In the presented case, enhanced perfusion to the brain by way of an intact cord likely led to regained consciousness, initiation of breathing, and return of tone and reflexes minutes after birth. Paramount to our hypothesis is the importance of keeping the umbilical cord circulation intact during the first several minutes of life to accommodate physiologic neonatal transition for all newborns and especially for those most compromised infants.

Tactile Stimulation in Newborn Infants With Inadequate Respiration at Birth: A Systematic Review

CONTEXT

For many years the International Liaison Committee on Resuscitation has recommended the use of tactile stimulation for initial management of infants born with inadequate respiratory effort at birth without systematically examining its effectiveness.

OBJECTIVE

Systematic review to compare the effectiveness of tactile stimulation with routine handling in newly born term and preterm infants.

DATA SOURCES

Medline, Embase, Cochrane CENTRAL, along with clinical trial registries.

STUDY SELECTION

Randomized and non-randomized studies were included based on predetermined criteria.

DATA EXTRACTION

Data were extracted independently by authors. Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) was used to assess risk of bias in non-randomized studies. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to assess the certainty of evidence.

RESULTS

Among 2455 unique articles identified, 2 observational studies were eligible and qualitatively summarized. Because one of the studies was at critical risk of bias, only the other study including 243 preterm infants on continuous positive airway pressure with clinical indications for tactile stimulation was analyzed. It showed a reduction in tracheal intubation in infants receiving tactile stimulation compared with no tactile stimulation (12 of 164 vs 14 of 79, risk ratio of 0.41 [95% confidence interval 0.20 to 0.85]); however, the certainty of evidence was very low.

LIMITATIONS

The available data were limited and only from observational studies.

CONCLUSIONS

A potential benefit of tactile stimulation was identified but was limited by the very low certainty of evidence. More research is suggested to evaluate the effectiveness as well as the optimal type and duration of tactile stimulation.

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.

Feasibility and Effect of Physiological-Based CPAP in Preterm Infants at Birth

Background: Preterm infants are commonly supported with 5-8 cmH₂O CPAP. However, animal studies demonstrate that high initial CPAP levels (12-15 cmH₂O) which are then reduced (termed physiological based (PB)-CPAP), improve lung aeration without adversely affecting cardiovascular function. We investigated the feasibility of PB-CPAP and the effect in preterm infants at birth. Methods: Preterm infants (24-30 weeks gestation) were randomized to PB-CPAP or 5-8 cmH₂O CPAP for the first 10 min after birth. PB-CPAP consisted of 15 cmH₂O CPAP that was decreased when infants were stabilized (heart rate ≥100 bpm, SpO₂ ≥85%, FiO₂ ≤ 0.4, spontaneous breathing) to 8 cmH₂O with steps of ~2/3 cmH₂O/min. Primary outcomes were feasibility and SpO₂ in the first 5 min after birth. Secondary outcomes included physiological and breathing parameters and short-term neonatal outcomes. Planned enrollment was 42 infants. Results: The trial was stopped after enrolling 31 infants due to a low inclusion rate and recent changes in the local resuscitation guideline that conflict with the study protocol. Measurements were available for analysis in 28 infants (PB-CPAP n = 8, 5-8 cmH₂O n = 20). Protocol deviations in the PB-CPAP group included one infant receiving 3 inflations with 15 cmH₂O PEEP and two infants in which CPAP levels were decreased faster than described in the study protocol. In the 5-8 cmH₂O CPAP group, three infants received 4, 10, and 12 cmH₂O CPAP. During evaluations, caregivers indicated that the current PB-CPAP protocol was difficult to execute. The SpO₂ in the first 5 min after birth was not different [61 (49-70) vs. 64 (47-74), p = 0.973]. However, infants receiving PB-CPAP achieved higher heart rates [121 (111-130) vs. 97 (82-119) bpm, p = 0.016] and duration of mask ventilation was shorter [0:42 (0:34-2:22) vs. 2:58 (1:36-6:03) min, p = 0.020]. Infants in the PB-CPAP group required 6:36 (5:49-11:03) min to stabilize, compared to 9:57 (6:58-15:06) min in the 5-8 cmH2O CPAP group (p = 0.256). There were no differences in short-term outcomes. Conclusion: Stabilization of preterm infants with PB-CPAP is feasible but tailoring CPAP appeared challenging. PB-CPAP did not lead to higher SpO₂ but increased heart rate and shortened the duration of mask ventilation, which may reflect faster lung aeration.

[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.

Ductal Flow Ratio as Measure of Transition in Preterm Infants After Birth: A Pilot Study

Background: Cardiovascular changes during the transition from intra- to extrauterine life, alters the pressure gradient across the ductus arteriosus (DA). DA flow ratio (R-L/L-R) has been suggested to reflect the infant's transitional status and could potentially predict neonatal outcomes after preterm birth. Aim: Determine whether DA flow ratio correlates with oxygenation parameters in preterm infants at 1 h after birth. Methods: Echocardiography was performed in preterm infants born <32 weeks gestational age (GA), as part of an ancillary study. DA flow was measured at 1 h after birth. DA flow ratio was correlated with FiO₂, SpO₂, and SpO₂/FiO₂ (SF) ratio. The DA flow ratio of infants receiving physiological-based cord clamping (PBCC) or time-based cord clamping (TBCC) were compared. Results: Measurements from 16 infants were analysed (median [IQR] GA 29 [27-30] weeks; birthweight 1,176 [951-1,409] grams). R-L DA shunting was 16 [17-27] ml/kg/min and L-R was 110 [81-124] ml/kg/min. The DA flow ratio was 0.18 [0.11-0.28], SpO₂ 94 [93-96]%, FiO₂ was 23 [21-28]% and SF ratio 4.1 [3.3-4.5]. There was a moderate correlation between DA flow ratio and SpO₂ [correlation coefficient (CC) -0.415; p = 0.110], FiO₂ (CC 0.384; p = 0.142) and SF ratio (CC -0.356; p = 0.175). There were no differences in DA flow measurements between infants where PBBC or TBCC was performed. Conclusion: In this pilot study we observed a non-significant positive correlation between DA flow ratio at 1 h after birth and oxygenation parameters in preterm infants.

Reflexes that impact spontaneous breathing of preterm infants at birth: a narrative review

Some neural circuits within infants are not fully developed at birth, especially in preterm infants. Therefore, it is unclear whether reflexes that affect breathing may or may not be activated during the neonatal stabilisation at birth. Both sensory reflexes (eg, tactile stimulation) and non-invasive ventilation (NIV) can promote spontaneous breathing at birth, but the application of NIV can also compromise breathing by inducing facial reflexes that inhibit spontaneous breathing. Applying an interface could provoke the trigeminocardiac reflex (TCR) by stimulating the trigeminal nerve resulting in apnoea and a reduction in heart rate. Similarly, airflow within the nasopharynx can elicit the TCR and/or laryngeal chemoreflex (LCR), resulting in glottal closure and ineffective ventilation, whereas providing pressure via inflations could stimulate multiple receptors that affect breathing. Stimulating the fast adapting pulmonary receptors may activate Head's paradoxical reflex to stimulate spontaneous breathing. In contrast, stimulating the slow adapting pulmonary receptors or laryngeal receptors could induce the Hering-Breuer inflation reflex or LCR, respectively, and thereby inhibit spontaneous breathing. As clinicians are most often unaware that starting primary care might affect the breathing they intend to support, this narrative review summarises the currently available evidence on (vagally mediated) reflexes that might promote or inhibit spontaneous breathing at birth.