Cardiocirculatory monitoring during immediate fetal-to-neonatal transition: a systematic qualitative review of the literature

Cardiac output calculation using the Liljestrand and Zander formula: is this method applicable during immediate transition after birth? - A post hoc analysis

The transition from intrauterine to extrauterine life is a critical period for neonates. Assessing the cardiovascular transition during this period immediately after birth is crucial but challenging. The present study compares adjusted estimated cardiac output values calculated by the Liljestrand and Zander formula (COest/adj LaZ) with non-invasively measured cardiac output values (CO-bioimpedance) during immediate transition after birth. We performed a secondary outcome analysis of a prospective observational study in preterm and term neonates. Ten and 15 min after birth, arterial blood pressure and heart rate were assessed, and CO-bioimpedance was measured using electrical bioimpedance method (Aesculon monitor, Osypka, Germany). We calculated COest/adj LaZ and compared it to CO-bioimpedance. Further, we performed a correlation analysis. Thirty-two neonates with a median (IQR) gestational age of 37.0 (32.0-39.4) weeks were included. Mean ± SD CO-bioimpedance was 0.62 ± 0.15 l/min, and COest/adj LaZ was calculated to be 0.64 ± 0.10 l/min, whereby both correlated significantly (p = 0.025, r = 0.359) with each other.  Conclusion: The present study demonstrates high comparability of COest/adj LaZ and CO-bioimpedance in neonates during immediate transition after birth, suggesting that cardiac output can be derived in a cost-effective and feasible manner if other methods are not available. What is Known: • Echocardiography is considered the gold standard for non-invasive CO evaluation, but its feasibility during the immediate transition period is limited. What is New: • Non-invasive methods such as CO-bioimpedance for cardiac output (CO) measurement and the Liljestrand and Zander (LaZ) formula for estimating CO offer promising alternatives during the immediate transition period.

Evaluating a Novel Infant Heart Rate Detector for Neonatal Resuscitation Efforts: Protocol for a Proof-of-Concept Study

BACKGROUND

Over 10 million newborns worldwide undergo resuscitation at birth each year. Pediatricians may use electrocardiogram (ECG), pulse oximetry (PO), and stethoscope in determining heart rate (HR), as HR guides the need for and steps of resuscitation. HR must be obtained quickly and accurately. Unfortunately, the current diagnostic modalities are either too slow, obtaining HR in more than a minute, or inaccurate. With time constraints, a reliable robust heart rate detector (HRD) modality is required. This paper discusses a protocol for conducting a methods-based comparison study to determine the HR accuracy of a novel real-time HRD based on 3D-printed dry-electrode single-lead ECG signals for cost-effective and quick HR determination. The HRD's HR results are compared to either clinical-grade ECG or PO monitors to ensure robustness and accuracy.

OBJECTIVE

The purpose of this study is to design and examine the feasibility of a proof-of-concept HRD that quickly obtains HR using biocompatible 3D-printed dry electrodes for single-lead neonatal ECG acquisition. This study uses a novel HRD and compares it to the gold-standard 3-lead clinical ECG or PO in a hospital setting.

METHODS

A cross-sectional study is planned to be conducted in the neonatal intensive care unit or postpartum unit of a large community teaching hospital in Toronto, Canada, from June 2023 to June 2024. In total, 50 newborns will be recruited for this study. The HRD and an ECG or PO monitor will be video recorded using a digital camera concurrently for 3 minutes for each newborn. Hardware-based signal processing and patent-pending embedded algorithm-based HR estimation techniques are applied directly to the raw collected single-lead ECG and displayed on the HRD in real time during video recordings. These data will be annotated and compared to the ECG or PO readings at the same points in time. Accuracy, F1-score, and other statistical metrics will be produced to determine the HRD's feasibility in providing reliable HR.

RESULTS

The study is ongoing. The projected end date for data collection is around July 2024.

CONCLUSIONS

The study will compare the novel patent-pending 3D-printed dry electrode-based HRD's real-time HR estimation techniques with the state-of-the-art clinical-grade ECG or PO monitors for HR accuracy and examines how fast the HRD provides reliable HR. The study will further provide recommendations and important improvements that can be made to implement the HRD for clinical applications, especially in neonatal resuscitation efforts. This work can be seen as a stepping stone in the development of robust dry-electrode single-lead ECG devices for HR estimations in the pediatric population.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/45512.

Insights into Neonatal Cerebral Autoregulation by Blood Pressure Monitoring and Cerebral Tissue Oxygenation: A Qualitative Systematic Review

OBJECTIVE

The aim of this qualitative systematic review was to identify publications on blood pressure monitoring in combination with cerebral tissue oxygenation monitoring during the first week after birth focusing on cerebral autoregulation.

METHODS

A systematic search was performed on PubMed. The following search terms were used: infants/newborn/neonates, blood pressure/systolic/diastolic/mean/MAP/SAP/DAP, near-infrared spectroscopy, oxygenation/saturation/oxygen, and brain/cerebral. Additional studies were identified by a manual search of references in the retrieved studies and reviews. Only human studies were included.

RESULTS

Thirty-one studies focused on preterm neonates, while five included preterm and term neonates. In stable term neonates, intact cerebral autoregulation was shown by combining cerebral tissue oxygenation and blood pressure during immediate transition, while impaired autoregulation was observed in preterm neonates with respiratory support. Within the first 24 h, stable preterm neonates had reduced cerebral tissue oxygenation with intact cerebral autoregulation, while sick neonates showed a higher prevalence of impaired autoregulation. Further cardio-circulatory treatment had a limited effect on cerebral autoregulation. Impaired autoregulation, with dependency on blood pressure and cerebral tissue oxygenation, increased the risk of intraventricular hemorrhage and abnormal neurodevelopmental outcomes.

CONCLUSIONS

Integrating blood pressure monitoring with cerebral tissue oxygenation measurements has the potential to improve treatment decisions and optimizes neurodevelopmental outcomes in high-risk neonates.

Electrocardiogram for heart rate evaluation during preterm resuscitation at birth: a randomized trial

BACKGROUND

Although electrocardiogram (ECG) can detect heart rate (HR) faster compared to pulse oximetry, it remains unknown if routine use of ECG for delivery room (DR) resuscitation reduces the time to stabilization in preterm infants.

METHODS

Neonates <31 weeks' gestation were randomized to either an ECG-displayed or an ECG-blinded HR assessment in the DR. HR, oxygen saturation, resuscitation interventions, and clinical outcomes were compared.

RESULTS

During the study period, 51 neonates were enrolled. The mean gestational age in both groups was 28 ± 2 weeks. The time to stabilization, defined as the time from birth to achieve HR ≥100 b.p.m., as well as oxygen saturation within goal range, was not different between the ECG-displayed and the ECG-blinded groups [360 (269, 435) vs 345 (240, 475) s, p = 1.00]. There was also no difference in the time to HR ≥100 b.p.m. [100 (75, 228) vs 138 (88, 220) s, p = 0.40] or duration of positive pressure ventilation (PPV) [345 (120, 558) vs 196 (150, 273) s, p = 0.36]. Clinical outcomes were also similar between groups.

CONCLUSIONS

Although feasible and safe, the use of ECG in the DR during preterm resuscitation did not reduce time to stabilization.

IMPACT

Although feasible and apparently safe, routine use of the ECG in the DR did not decrease time to HR >100 b.p.m., time to stabilization, or use of resuscitation interventions such as PPV for preterm infants <31 weeks' gestational age. This article adds to the limited randomized controlled trial evidence regarding the impact of routine use of ECG during preterm resuscitation on DR clinical outcomes. Such evidence is important when considering recommendations for routine use of the ECG in the DR worldwide as such a recommendation comes with a significant cost burden.

Cardiac Output and Cerebral Oxygenation in Term Neonates during Neonatal Transition

The immediate transition from foetus to neonate includes substantial changes, especially concerning the cardiovascular system. Furthermore, the brain is one of the most vulnerable organs to hypoxia during this period. According to current guidelines for postnatal stabilization, the recommended parameters for monitoring are heart rate (HR) and arterial oxygen saturation (SpO₂). Recently, there is a growing interest in advanced monitoring of the cardio-circulatory system and the brain to get further objective information about the neonate’s condition during the immediate postnatal transition after birth. The aim of the present study was to combine cardiac output (CO) and brain oxygenation monitoring in term neonates after caesarean section in order to analyse the potential influence of CO on cerebral oxygenation during neonatal transition. This was a monocentric, prospective, observational study. For non-invasive cardiac output measurements, the electrical velocimetry (EV) method (Aesculon Monitor, Osypka Medical, CA, USA) was used. The pulse oximeter probe for SpO₂ and HR measurements was placed on the right hand or wrist. The cerebral tissue oxygen index (cTOI) was measured using a NIRO-200NX monitor with the near-infrared spectroscopy (NIRS) transducer on the right frontoparietal head. Monitoring started at minute 1 and was continued until minute 15 after birth. At minutes 5, 10, and 15 after birth, mean CO was calculated from six 10 s periods (with beat-to-beat analysis). During the study period, 99 term neonates were enrolled. Data from neonates with uncomplicated transitions were analysed. CO showed a tendency to decrease until minute 10. During the complete observational period, there was no significant correlation between CO and cTOI. The present study was the first to investigate a possible correlation between CO and cerebral oxygenation in term infants during the immediate neonatal transition. In term infants with uncomplicated neonatal transition after caesarean section, CO did not correlate with cerebral oxygenation.

Sex related difference in cardiac output during neonatal transition in term neonates

Background

The immediate transition from foetus to neonate includes substantial changes especially concerning the cardiovascular system. As sex related differences have been shown in cardiovascular medicine, this topic warrants further investigation in neonatology. Aim: The aim of this present study was to measure cardiac output (CO) and cerebral oxygenation (cTOI) non-invasively in term neonates and to investigate potential sex related differences between female and male neonates after birth.

Methods

This is a mono-centric prospective observational study. For CO-measurements, the electrical velocimetry method was used. The pulse oximetry for arterial oxygen saturation and heart-rate measurements was placed on the right hand or wrist. cTOI was measured using a NIRO 200NX monitor. The near-infrared spectroscopy probe was positioned on the right side of forehead in each infant. Monitoring started at minute 1 and was continued until minute 15 after birth. At minutes 5, 10, and 15 after birth, CO was calculated as an average out of six 10-second periods.

Results

99 term neonates were enrolled. In our study population, we could identify 54 female and 45 male neonates. Males had higher cardiac output compared to females throughout the observational period, with a significant difference in minute 15 after birth (217, 95% CI: 203-231 mL/kg/min versus 178, 95% CI: 163-192 mL/kg/min; P<0.001). cTOI, SpO₂, and HR did not differ between male and female neonates.

Conclusions

The present work is the first to investigate sex related differences concerning cardiac output in term neonates during postnatal transition, showing a significantly higher cardiac output in male neonates 15 minutes after birth.

Chronological echocardiographic evaluation of left ventricular systolic and diastolic function in term and premature neonatal calves

Echocardiographic studies in human neonatology has demonstrated that prematurity can lead to cardiovascular dysfunction and especially compromises the left ventricular (LV) systolic and diastolic functions. As echocardiographic studies have not been performed on cardiovascular dysfunction in premature calves, we echocardiographically evaluated and compared the LV systolic and diastolic function in full-term and premature calves. We followed the hemodynamical changes of LV during first 3 days of life. Twenty premature calves and 10 healthy term calves were enrolled in the study. 2D, M-mode and Doppler echocardiographic examinations were performed at days 1, 2 and 3 after birth to evaluate LV systolic and diastolic functions. Our findings demonstrated that not only was there LV diastolic dysfunction (55% premature calves, 10% term calf at day 1; 65% premature calves, 10% term calf at day 2 and, 75% premature calves, 20% term calf at day 3), but also LV systolic dysfunction (55% premature calves, 60% term calf at day 1; 55% premature calves, 50% term calf at day 2, and 45% premature calves, 40% term calf at day 3) deteriorated in both term and premature calves. In conclusion, the present study, which was the first comparative echocardiographic assessment of LV systolic and diastolic functions in term and premature newborn calves, showed that both systolic and diastolic dysfunctions might occur in term and premature calves.

Comparison of cut and intact cord milking regarding cerebral oxygenation, hemodynamic and hematological adaptation of term infants

OBJECTIVE

Although both delayed umbilical cord clamping and intact umbilical cord milking (I-UCM) provide the effective placental transfusion at birth, these procedures may not be used in neonates needing resuscitation. The aim of this study is to investigate the effect of cut umbilical cord milking (C-UCM), which permits resuscitation during an immediate transition period (ITP).

METHODS

Sixty-two healthy term infants were randomly divided into C-UCM and I-UCM groups at birth. Approximately 30-cm length of cord was milked towards the baby 2-4 times within 20 seconds after birth in both C-UCM and I-UCM groups while the umbilical cord was cut in the former, and intact in the latter. Heart rate, arterial oxygen saturation (SpO₂), cerebral regional oxygen saturation (crSO₂) (2nd-15th min), blood pressure (BP) (within 15-30 min), residual placental blood volume (RPBV), and hemoglobin levels (at the sixth hour) were monitored during ITP.

RESULTS

There were no significant differences in terms of mean gestational age (w) [(39.0 ± 1.2) versus (38.8 ± 1.1)], birth weight (g) [(3351.45 ± 254.30) versus (3256.94 ± 285.52)], Apgar scores at the 5th min (10 ± 0 versus 10 ± 0), first breathing time (sec) (5.4 ± 3.8 versus 5.7 ± 4.1), SpO₂, crSO₂, BP (mmHg) [(52.9 ± 6.9) versus (51.8 ± 5.7)], hemoglobin levels (g/dl) [(17.7 ± 1.8) versus (18.4 ± 1.4)], and RPBV (ml/kg) [(23.9 ± 4.7) versus (22.9 ± 5.4)] between C-UCM and I-UCM groups (p > .05).

CONCLUSION

This study showed that C-UCM is as effective as I-UCM on cerebral oxygenation, hemodynamic and hematological adaptation of term infants in ITP. We suggest that C-UCM can provide additional placental transfusion in term neonates exposed to early cord clamping.

Neonatal hemodynamics and management of hypotension in newborns

Hemodynamic instability is frequent in high-risk infants admitted to neonatal intensive care units. However, monitoring and treatment strategies of those conditions might show variations among the units. Different factors can compromise hemodynamic status in preterm/ term infants. Treatment options mostly include volume replacement, inotropes and/or vasopressors (dopamine, dobutamine, epinephrine and milrinone) and hydrocortisone. In general, these treatments are driven by predetermined protocols, which are not patient-based. According to the current knowledge, a physiology-driven approach that takes the individual characteristics of the newborn into consideration is accepted to be more suitable. In neonatal hemodynamics, important determinants are cardiac output, systemic vascular resistance, blood pressure, regional tissue perfusion and oxygenation. The novel technological methods, "targeted neonatal echocardiography" and "near-infrared spectroscopy" can help to delineate the underlying pathophysiology better, when added to the clinical assessment. In this review, strategies for the assessment of neonatal hemodynamics, as well as etiology, monitoring, and treatment of hemodynamic instability in preterm and term infants are presented.

Monitoring heart rate in the delivery room

Resuscitation algorithms and guidelines highlight the importance of heart rate (HR) in determining interventions and assessing their effect. However, the actual HR values used are historical based upon normal physiology, and HR at birth may be affected by mode of delivery and timing of cord clamping as well as respiratory status and condition at delivery. Furthermore, the most accurate and effective ways to assess and monitor HR in the newborn infant are only now becoming established. This article examines the importance of HR values and the most widely used methods of estimation as well as some newer modalities which are being developed.

Chronological Echocardiographic Changes in Healthy Term Neonates within Postnatal 72 Hours Using Doppler Studies

BACKGROUND

This study evaluated echocardiographic changes in full-term healthy neonates during early transitional period from postnatal 0-72 hours at 12-hour intervals by echocardiography.

METHODS

This was a prospective, observational, and longitudinal single-center cohort study. Morphometric, functional, systolic, diastolic, and tissue Doppler imaging (TDI) parameters (patent ductus arteriosus [PDA], aorta, superior vena cava [SVC], stroke volume [SV], cardiac output [CO], cardiac index [CI], early diastolic flow velocity [E], late diastolic flow velocity [A], early filling in TDI [E'], peak systolic annular velocity in TDI [S'], late velocity peak in TDI [A'], and myocardial performance index [MPI]) were evaluated in left ventricle (LV) and right ventricle (RV) with 56 newborns.

RESULTS

Sizes and peak velocities of PDA before postnatal 24 hours were significantly changed than those after postnatal 24 hours. Aortic velocity time integral (VTI), systolic blood pressure (BP), LV SV/kg, LV CO/kg, LV CI, and SVC flow/LV CO before 24 hours showed significantly changes than those after 24 hours. Also, LV and RV MPI before 24 hours were significantly higher than those after 24 hours. LV E/E' was significantly higher than RV E/E'.

CONCLUSION

Postnatal 24 hours is critical time for hemodynamic closure of PDA because aortic VTI, systolic BP, LV SV, LV CO, LV CI, and SVC flow/LV CO showed simultaneously significant changes after 24 hours at the same time as 24 hours of physiological closure of PDA. Chronological and dramatic changes of systolic, diastolic, and TDI parameters during early postnatal period can be used to compile normal baseline data of healthy full-term neonates.

The Successful Immediate Neonatal Transition to Extrauterine Life

Purpose:

To define and describe the processes underlying the successful neonatal transition to extrauterine life and methods to assess the transition.

Method:

Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Web of Science, and Google Scholar were searched using a combination of the key words neonate, neonatal, newborn, transition, respiratory OR pulmonary, cardiac, metabolic, pH, umbilical cord, and assessment. Articles in English and German were reviewed. The final sample of articles consisted of one randomized controlled trial, 30 observational studies using human neonates, one observational study using rabbit pups, one secondary analysis, three systematic reviews, and 23 review articles.

Major Findings:

The pertinent findings in regard to normal events in the respiratory, cardiovascular, and metabolic transitions are reviewed and summarized. We address the underlying factors necessary for the transition to extrauterine life, specify the consequences of a successful transition, and review common assessment approaches.

Conclusion:

Available evidence indicates that the successful immediate transition to extrauterine life should be completed within 1–3 hr after birth, though some adaptive processes can fail as late as 24–48 hr after birth. Further research is necessary to identify a feasible, easily used, noninvasive method to assess the status of a neonate’s transition to extrauterine life.

Blood Pressure during the Immediate Neonatal Transition: Is the Mean Arterial Blood Pressure Relevant for the Cerebral Regional Oxygenation?

BACKGROUND

Measurement of mean arterial blood pressure (MABP) is feasible during neonatal transition.

OBJECTIVE

The objective of this study was to investigate a potential influence of MABP on the cerebral regional oxygen saturation (crSO2) in preterm and term infants during the immediate neonatal transition.

MATERIALS AND METHODS

Preterm and term infants were included in this observational study. The crSO2 was measured by near-infrared spectroscopy with the INVOS 5100C (Somanetics Corp., Troy, MI, USA) during the immediate neonatal transition (15 min after birth). The near-infrared spectroscopy sensor was applied to the left forehead. Furthermore, a pulse oximeter was applied to monitor arterial oxygen saturation (SpO2) and heart rate (HR). Fifteen minutes after birth, blood pressure was measured noninvasively at the left upper arm. Cerebral fraction tissue oxygen extraction (cFTOE) was calculated from SpO2 and crSO2. To investigate a potential association between crSO2/cFTOE and MABP, we performed a correlation analysis.

RESULTS

A total of 462 preterm and term infants (186/292) were included. Mean gestational age was 31.0 ± 3.5 weeks for preterm infants and 38.9 ± 0.8 weeks for full term infants. Mean birth weight was 1.591 ± 630 g in preterm infants and 3.331 ± 461 g in term infants. There was a significant negative correlation between MABP and cFTOE (ρ = -0.19, p = 0.03) in preterm infants but not in term infants (ρ = 0.05, p = 0.39). There was no significant correlation between MABP and crSO2 in either group.

CONCLUSION

MABP has an impact on cerebral oxygenation in preterm infants. Therefore, blood pressure monitoring during the immediate neonatal transition might be relevant for improving cerebral oxygenation especially in preterm infants.

Social Birth: Rites of Passage for the Newborn

Rites of passage mark important changes during human life and, for the neonate, its transition from intrauterine life into society. Their original intent was to purify the body from blood and meconium. But the cleansing rites had a spiritual dimension from the very start. When the rites of Mesopotamian, Egyptian, Jewish, Greek, Roman, Hindu, Nordic, Muslim, Maya, and Christian cultures are briefly compared, they reveal a remarkable similarity. What most rites had in common was the cleansing of the body, or sprinkling it with water; special clothing; the exorcism of evil spirits; blessings and prayers for good spirits; and a name-giving ceremony and a feast for family, relatives, and friends. Before this rite, the infant's social existence was incomplete and it could easily be abandoned or killed, as was usual in cases of severe malformations. Infant baptism originated in the 4th century CE with the concept of original sin. Emergency baptism originated in the 12th century and had a profound influence on the development of obstetrics and neonatal care. Rites of passage defined, but also set an end to, the liminal status between life and death in a phase of high mortality and partial personhood, and granted the right to live for the infant.

Optimising Intravenous Volume Resuscitation of the Newborn in the Delivery Room: Practical Considerations and Gaps in Knowledge

Volume resuscitation (VR) for the treatment of newborn shock is a rare but potentially lifesaving intervention. Conducting clinical studies to assess the effectiveness of VR in the delivery room during newborn stabilization is challenging. We review the available literature and current management guidelines to determine which infants will benefit from VR, the frequency of VR, and the choice of agents used. In addition, the potential role for placental transfusion in the prevention of newborn shock is explored.

Enhanced Monitoring of the Preterm Infant during Stabilization in the Delivery Room

Monitoring of preterm infants in the delivery room (DR) remains limited. Current guidelines suggest that pulse oximetry should be available for all preterm infant deliveries, and that if intubated a colorimetric carbon dioxide detector should provide verification of correct endotracheal tube placement. These two methods of assessment represent the extent of objective monitoring of the newborn commonly performed in the DR. Monitoring non-invasive ventilation effectiveness (either by capnography or respiratory function monitoring) and cerebral oxygenation (near-infrared spectroscopy) is becoming more common within research settings. In this article, we will review the different modalities available for cardiorespiratory and neuromonitoring in the DR and assess the current evidence base on their feasibility, strengths, and limitations during preterm stabilization.