Hemodynamic Assessment and Monitoring of Premature Infants

Acid base and metabolic parameters of the umbilical cord blood and cerebral oxygenation immediately after birth

Objective

Aim was to investigate whether acid-base and metabolic parameters obtained from arterial umbilical cord blood affect cerebral oxygenation after birth in preterm neonates with respiratory support and in term neonates without respiratory support.

Study design

This was a post-hoc analysis of secondary outcome parameters of a prospective observational study including preterm neonates with and term neonates without respiratory support. Non-asphyxiated neonates with cerebral oxygenation measured with near-infrared spectroscopy during the first 15 min and with blood gas analyses from arterial umbilical cord blood were included. Arterial oxygen saturation (SpO2) and heart rate (HR) were monitored with pulse oximetry. Potential correlations were investigated between acid-base and metabolic parameters (pH-value, bicarbonate, base-excess, and lactate) and crSO2/cFTOE 5 min after birth.

Results

Seventy-seven neonates were included: 14 preterm neonates with respiratory support (mean gestational age [GA] 31.4 ± 4.1 weeks; mean birth weight [BW] 1,690 ± 640 g) and 63 term neonates without respiratory support (GA 38.7 ± 0.8 weeks; BW 3,258 ± 443 g). Mean crSO2 5 min after birth was 44.0% ± 24.2% in preterm and 62.2% ± 20.01% in term neonates. Mean cFTOE 5 min after birth was 0.46 ± 0.06 in preterm and 0.27 ± 0.19 in term neonates. In preterm neonates with respiratory support higher lactate was significantly associated with lower crSO2 and SpO2 and tended to be associated with higher cFTOE. In term neonates without respiratory support no significant correlations were found.

Conclusion

In non-asphyxiated preterm neonates with respiratory support, lactate levels were negatively associated with crSO2 and SpO2, whereas in term neonates without respiratory support no associations were observed.

Asphyxia, Therapeutic Hypothermia, and Pulmonary Hypertension

Neonates with a perinatal hypoxic insult and subsequent neonatal encephalopathy are at risk of acute pulmonary hypertension (aPH) in the transitional period. The phenotypic contributors to aPH following perinatal asphyxia include a combination of hypoxic vasoconstriction of the pulmonary vascular bed, right heart dysfunction, and left heart dysfunction. Therapeutic hypothermia is the standard of care for neonates with moderate-to-severe hypoxic ischemic encephalopathy. This review summarizes the underlying risk factors, causes of aPH in neonates with perinatal asphyxia, discusses the unique phenotypical contributors to disease, and explores the impact of the initial insult and subsequent therapeutic hypothermia on aPH.

Effects of apparatus dead space on volumetric capnograms in neonates with healthy lungs: a simulation study

BACKGROUND

Volumetric capnography in healthy ventilated neonates showed deformed waveforms, which are supposedly due to technological limitations of flow and carbon dioxide sensors.

AIMS

This bench study analyzed the role of apparatus dead space on the shape of capnograms in simulated neonates with healthy lungs.

METHODS

We simulated mechanical breaths in neonates of 2, 2.5, and 3 kg of body weight using a neonatal volumetric capnography simulator. The simulator was fed by a fixed amount of carbon dioxide of 6 mL/kg/min. Such simulator was ventilated in a volume control mode using fixed ventilatory settings with a tidal volume of 8 mL/kg and respiratory rates of 40, 35, and 30 breaths per minute for the 2, 2.5 and 3 kg neonates, respectively. We tested the above baseline ventilation with and without an additional apparatus dead space of 4 mL.

RESULTS

Simulations showed that adding the apparatus dead space to baseline ventilation increased the amount of re-inhaled carbon dioxide in all neonates: 0.16 ± 0.01 to 0.32 ± 0.03 mL (2 kg), 0.14 ± 0.02 to 0.39 ± 0.05 mL (2.5 kg), and 0.13 ± 0.01 to 0.36 ± 0.05 mL (3 kg); (p < .001). Apparatus dead space was computed as part of the airway dead space, and therefore, the ratio of airway dead space to tidal volume increased from 0.51 ± 0.04 to 0.68 ± 0.06, from 0.43 ± 0.04 to 0.62 ± 0.01 and from 0.38 ± 0.01 to 0.60 ± 0.02 in the 2, 2.5 and 3 kg simulated neonates, respectively (p < .001). Compared to baseline ventilation, adding apparatus dead space decreased the ratio of the volume of phase III to VT size from 31% to 11% (2 kg), from 40% to 16% (2.5 kg) and from 50% to 18% (3 kg); (p < .001).

CONCLUSIONS

The addition of a small apparatus dead space artificially deformed the volumetric capnograms in simulated neonates with healthy lungs.

Features of left ventricle longitudinal strain in children from one to five years old, born with low, very low, and extremely low body weight

Purpose. The study assessed left ventricle longitudinal strain of the endocardial, middle, and epicardial layers in children from one to five years old, born with low, very low, and extremely low body weight.Material and methods. The study was performed in 204 children aged from one to five years; of these, 53 children were prematurely born late in pregnancy, 103 children were born very preterm, and 48 children were born healthy and full-term. The left ventricle longitudinal strain of the endocardial, middle, and epicardial layers was assessed off-line using the Speckle Tracking Imaging-2D Strain technology.Results. Disturbance of the transmural gradient strain of left ventricle wall were detected in 11.32% of prematurely born late in pregnancy children and in 16.5% of very preterm children. A decrease of left ventricle segments strain was registered in 33.96% of children prematurely born late in pregnancy and in 18.44% very preterm children. In children of the same age, born healthy and full-term, transmural wall gradient disturbances and decrease of strain in left ventricle segments were not observed. In children prematurely born late in pregnancy, the disturbance of the transmural strain gradient of left ventricle and the decrease of strain in left ventricle segments are not associated with left ventricle remodeling.Conclusion. The development of the cardiovascular system in children of early and preschool age, born prematurely with low, very low, and extremely low body weight, is characterized by disturbances in the transmural strain gradient of left ventricle wall, due to the processes of postnatal growth and development of the child’s heart, which requires monitoring on an outpatient basis in polyclinic in childhood — by a pediatric cardiologist and a pediatrician, and in adulthood — by a cardiologist and therapist.

Comparison of the Clinical Characteristics of Infants with Punctate White Matter Lesions and/or Cystic Lesions

BACKGROUND

We aimed to investigate the differences in the clinical characteristics of preterm infants with punctate white matter lesions (PWMLs) and those with cystic periventricular leukomalacia (cPVL) using term-equivalent age magnetic resonance imaging.

METHODS

We conducted a retrospective case-control study to explore the clinical characteristics of infants (< 35 weeks gestation, born between 2007 and 2017 in a single Level III perinatal center) with PWML, cPVL or with PWML plus cPVL and compared them with those of gestational-age-matched controls.

RESULTS

Among 602 infants, 29, 5, and 4 were assigned to the PWML group, cPVL group, and PWML plus cPVL group (PWML-cPVL group), respectively. Compared to the control group (n = 87), the PWML group had higher birth weights (p = 0.04), rates of histological chorioamnionitis (p = 0.04), vaginal delivery (p = 0.008), and early heart contraction failure (within 72 hours after birth) (p = 0.003). The cPVL group had lower umbilical blood gas base excess (p = 0.01), higher rate of late-onset circulatory collapse (p = 0.008), and higher hydrocortisone requirements (p = 0.03) than the control group (n = 15). The PWML-cPVL group had a higher rate of intraventricular hemorrhage (p = 0.03) than the control group (n = 12). In the multivariate logistic regression analysis, vaginal delivery (odds ratio [OR] = 3.5; 95% confidence interval [CI] = 1.37-9.40; p = 0.009), higher birth weight (per 1 g) (OR = 1.001; 95% CI = 1.0001-1.002; p = 0.03), and early heart contraction failure (OR = 5.4; 95% CI = 1.84-16.8; p = 0.002), were independent risk factors for PWML.

CONCLUSION

Clinical characteristics of infants with PWML compared with gestational-age-matched controls differed from those with cPVL or PWML plus cPVL, as PWML were not related to severe disruption of hemodynamics.

The use of milrinone in neonates with persistent pulmonary hypertension of the newborn - a randomised controlled trial pilot study (MINT 1)

OBJECTIVE

To assess the impact of milrinone administration on time spent on nitric oxide (iNO) in infants with acute pulmonary hypertension (aPH). We hypothesized that intravenous milrinone used in conjunction with iNO would reduce the time on iNO therapy and the time spent on invasive ventilation in infants ≥34 weeks gestation with a diagnosis of aPH. We aimed to assess the practicality of instituting the protocol and contributing to a sample size calculation for a definitive multicentre study.

STUDY DESIGN

This was a multicentre, randomized, double-blind, two arm pilot study, with a balanced (1:1) allocation. Infants with a gestation ≥34 weeks and a birth weight ≥2000 grams aPH, an oxygenation index of ≥10, and commenced on iNO were eligible. Participants on iNO were assigned to either a milrinone infusion (intervention) or a normal saline infusion (placebo) for up to 35 h. The primary outcome was time on iNO and feasibility of conducting the protocol.

RESULTS

The trial was terminated early after 4 years of enrollment due to poor recruitment. Four infants were allocated to the intervention arm and 5 to the placebo arm. The groups were well matched for baseline variables. No differences were seen in any of the primary or secondary outcomes.

CONCLUSION

Conducting an interventional trial in the setting of acute pulmonary hypertension in infants is not feasible using our current approach. Future studies in this area require alternative trial design to improve recruitment as this topic remains understudied in the neonatal field.

TRIAL REGISTRATION

www.isrctn.com ; ISRCTN:12949496; EudraCT Number:2014-002988-16.

The effects of early combined training on the physical development of preterm infants with different gestational ages

Objective

To investigate the effects of early combined training on the physical development of preterm infants of different gestational ages.

Methods

A total of 144 preterm infants from our hospital's neonatal intensive care unit (NICU) between 2019 and 2020 were selected as the research participants and randomly divided into an intervention group (77 cases) and a control group (67 cases). The physical development and catch-up growth satisfaction rate of preterm infants in the intervention and control groups were compared at 40 weeks, 3 months, 6 months and 12 months of corrected age.

Results

At 40 weeks of gestational age and corrected 3 months of gestational age, the physical growth indexes of the intervention group were higher than those of the control group, with a statistical difference (P < 0.05). At the corrected age of 12 months, the body weight and length of preterm infants in the <29 weeks intervention group were still higher than those in the control group (P < 0.05). The body weight of preterm infants in the 29-32 weeks and 32-34 weeks intervention groups was higher than in the control group (P < 0.05). There was no statistical difference between the intervention and control groups in the 34-37 weeks category (P > 0.05). The catch-up growth satisfaction rates of all the physical growth indexes in the intervention group were higher than those of the control group at the corrected 3 months for all the gestational ages (P < 0.05). While those indexes in the three >29 weeks intervention groups were higher than those in the <29 weeks intervention group at the corrected age of 12 months (P < 0.05).

Conclusion

Early combined training can promote the early catch-up growth of preterm infants, especially in the early gestational age groups (<34 weeks), and the catch-up growth promotion can last for 12 months. The older the gestational age, the sooner catch-up growth satisfaction will occur.

Non-invasive cardiac output monitoring before and after baby extubation - A feasibility study (NICOMBabe study)

BACKGROUND

Mechanical ventilation induces changes in intrapleural, intrathoracic and intra-abdominal pressure. These changes have various implications on cardiac output (CO).

AIMS

The aim of this study was to determine the feasibility of measuring changes in CO after elective extubation in neonates using the principle of transthoracic bioreactance (TBR).

STUDY DESIGN

This was a prospective observational cohort study in a level III neonatal centre. CO, stroke volume (SV) and heart rate were measured continuously for 2 h before and 2 h after elective extubation by TBR.

SUBJECTS

Neonates undergoing elective extubation were eligible for enrolment.

OUTCOME MEASURES

The primary outcome of the study was change in CO post elective extubation.

RESULTS

Ten neonates were enrolled, seven (70 %) had a statistically significant decrease in CO after extubation, three (30 %) infants had a statistically significant increase in CO after extubation. Changes in CO were primarily driven by changes in SV and the pattern of change was related to patent ductus arteriosus (PDA) status prior to extubation.

CONCLUSION

Extubation significantly influences CO in neonatal patients and the pattern of change appears to be related to PDA status.

Prematurity and Pulmonary Vein Stenosis: The Role of Parenchymal Lung Disease and Pulmonary Vascular Disease

Pulmonary vein stenosis (PVS) has emerged as a critical problem in premature infants with persistent respiratory diseases, particularly bronchopulmonary dysplasia (BPD). As a parenchymal lung disease, BPD also influences vascular development with associated pulmonary hypertension recognized as an important comorbidity of both BPD and PVS. PVS is commonly detected later in infancy, suggesting additional postnatal factors that contribute to disease development, progression, and severity. The same processes that result in BPD, some of which are inflammatory-mediated, may also contribute to the postnatal development of PVS. Although both PVS and BPD are recognized as diseases of inflammation, the link between them is less well-described. In this review, we explore the relationship between parenchymal lung diseases, BPD, and PVS, with a specific focus on the epidemiology, clinical presentation, risk factors, and plausible biological mechanisms in premature infants. We offer an algorithm for early detection and prevention and provide suggestions for research priorities.

Hemodynamic Quality Improvement Bundle to Reduce the Use of Inotropes in Extreme Preterm Neonates

BACKGROUND

We evaluated the effect of the quality improvement (QI) bundle on the rate of inotrope use and associated morbidities.

METHODS

We included inborn preterm neonates born at < 29 weeks admitted to level III NICU. We implemented a QI bundle focusing on the first 72 h from birth which included delayed cord clamping, avoidance of routine echocardiography, the addition of clinical criteria to the definition of hypotension, factoring iatrogenic causes of hypotension, and standardization of respiratory management. The rate of inotropes use was compared before and after implementing the care bundle. Incidence of cystic periventricular leukomalacia (cPVL) was used as a balancing measure.

RESULTS

QI bundle implementation was associated with significant reduction in overall use of inotropes (24 vs 7%, p < 0.001), dopamine (18 vs 5%, p < 0.001), and dobutamine (17 vs 4%, p < 0.001). Rate of acute brain injury decreased significantly: acute brain injury of any grade (34 vs 20%, p < 0.001) and severe brain injury (15 vs 6%, p < 0.001). There was no difference in the incidence of cPVL (0.8 vs 1.4%, p = 0.66). Associations remained significant after adjusting for confounding factors.

CONCLUSIONS

A quality improvement bundled approach resulted in a reduction in inotropes use and associated brain morbidities in premature babies.

Cerebral near-infrared spectroscopy monitoring (NIRS) in children and adults: a systematic review with meta-analysis

BACKGROUND

Cerebral oxygenation monitoring utilising near-infrared spectroscopy (NIRS) is increasingly used to guide interventions in clinical care. The objective of this systematic review with meta-analysis and Trial Sequential Analysis is to evaluate the effects of clinical care with access to cerebral NIRS monitoring in children and adults versus care without.

METHODS

This review conforms to PRISMA guidelines and was registered in PROSPERO (CRD42020202986). Methods are outlined in our protocol (doi: 10.1186/s13643-021-01660-2).

RESULTS

Twenty-five randomised clinical trials were included (2606 participants). All trials were at a high risk of bias. Two trials assessed the effects of NIRS during neonatal intensive care, 13 during cardiac surgery, 9 during non-cardiac surgery and 1 during neurocritical care. Meta-analyses showed no significant difference for all-cause mortality (RR 0.75, 95% CI 0.51-1.10; 1489 participants; I2 = 0; 11 trials; very low certainty of evidence); moderate or severe, persistent cognitive or neurological deficit (RR 0.74, 95% CI 0.42-1.32; 1135 participants; I2 = 39.6; 9 trials; very low certainty of evidence); and serious adverse events (RR 0.82; 95% CI 0.67-1.01; 2132 participants; I2 = 68.4; 17 trials; very low certainty of evidence).

CONCLUSION

The evidence on the effects of clinical care with access to cerebral NIRS monitoring is very uncertain.

IMPACT

The evidence of the effects of cerebral NIRS versus no NIRS monitoring are very uncertain for mortality, neuroprotection, and serious adverse events. Additional trials to obtain sufficient information size, focusing on lowering bias risk, are required. The first attempt to systematically review randomised clinical trials with meta-analysis to evaluate the effects of cerebral NIRS monitoring by pooling data across various clinical settings. Despite pooling data across clinical settings, study interpretation was not substantially impacted by heterogeneity. We have insufficient evidence to support or reject the clinical use of cerebral NIRS monitoring.

Cardiorespiratory management of infants born at 22 weeks' gestation: The Iowa approach

The approach to clinical care of infants born at 22 weeks' gestation must be consistent and well-designed if optimal results are to be expected. Publications from several international centers have demonstrated that, although there may be variance in aspects of care in this vulnerable population, treatment should be neither random nor inconsistent. In designing a standardized approach, careful attention should be paid to the unique anatomy, physiology, and biochemistry of this vulnerable patient population. Emerging evidence, suggesting a link between cardiopulmonary health and longer-term sequela, highlights the importance of understanding the relationship between cardiorespiratory illnesses of the 22-week infant, treatments provided, and subsequent cardiopulmonary development. In this review we will provide an overview to our approach to cardiopulmonary assessment and treatment, with a particular emphasis on the importance of early recognition of atypical phenotypes, timely interventions with evidence-based treatments, and longitudinal monitoring.

Baseline Values of Left Ventricular Systolic Function in Preterm Infants With Septic Shock: A Prospective Observational Study

BACKGROUND AND AIM

Guidelines recommended that cardiac index (CI) of term infants with septic shock should reach the target level of 3.3-6.0L/(min⋅m²). However, there are still no standard values for preterm infants with septic shock. Herein, we investigated the functional echocardiographic baseline values of left ventricular (LV) systolic functional parameters at the onset of septic shock in preterm infants and possible correlations between baseline values and poor outcomes.

MATERIALS AND METHODS

This was a prospective, observational, and longitudinal single-center study. Eligible infants were monitored for LV systolic functional parameters using functional echocardiography at the onset of septic shock. The primary study outcome was the difference in the baseline value of LV systolic functional parameters in preterm infants with septic shock with different gestational age (GA) and birth weight (BW). The secondary outcome was septic shock-associated death or severe brain injury (including grade 3-4 intraventricular hemorrhage or periventricular leukomalacia).

RESULTS

In total, 43 subjects met the criteria, with a median GA of 32^1/7 weeks and BW of 1800 grams. No difference was observed in baseline values of LV systolic functional parameters among infants with different GA and BW. Infants were assigned to good and poor outcomes groups based on septic shock-associated death or severe brain injury. Out of 43 infants, 29 (67.4%) had good outcomes vs. 14 (32.6%) with poor outcomes. Stroke index (SI) [18.2 (11.1, 18.9) mL/m² vs. 23.5 (18.9, 25.8) mL/m², p = 0.017] and cardiac index (CI)[2.7 (1.6, 3.5) L/(min⋅m²) vs. 3.4 (3.0, 4.8) L/(min⋅m²), p = 0.015] in infants with poor outcomes were significantly lower (P < 0.05). Receiver operating characteristic (ROC) curve analysis showed that the cut-off values of SI and CI for predicting poor outcomes in preterm infants with septic shock were 19.5 mL/m² (sensitivity, 73.9%; specificity, 81.8%) and 2.9L/(min⋅m²) (sensitivity, 78.3%; specificity, 72.7%), with area under the ROC curve (AUC) value of 0.755 and 0.759, respectively.

CONCLUSION

There were no differences in baseline LV systolic functional values among preterm infants with septic shock with different GA and BW. However, preterm infants with SI<19.5mL/m² and/or CI<2.9L/(min⋅m²) at the onset of septic shock were at high risk of having poor outcomes.

Management Practices During Perinatal Respiratory Transition of Very Premature Infants

The present review considers some controversial management practices during extremely premature perinatal transition. We focus on perinatal prevention and treatment of respiratory distress syndrome (RDS) in immature infants. New concerns regarding antenatal corticosteroid management have been raised. Many fetuses are only exposed to potential adverse effects of the drug. Hence, the formulation and the dosage may need to be modified. Another challenge is to increase the fraction of the high-risk fetuses that benefit from the drug and to minimize the harmful effects of the drug. On the other hand, boosting anti-inflammatory and anti-microbial properties of surfactant requires further attention. Techniques of prophylactic surfactant administration to extremely immature infants at birth may be further refined. Also, new findings suggest that prophylactic treatment of patent ductus arteriosus (PDA) of a high-risk population rather than later selective closure of PDA may be preferred. The TREOCAPA trial (Prophylactic treatment of the ductus arteriosus in preterm infants by acetaminophen) evaluates, whether early intravenous paracetamol decreases the serious cardiorespiratory consequences following extremely premature birth. Lastly, is inhaled nitric oxide (iNO) used in excess? According to current evidence, iNO treatment of uncomplicated RDS is not indicated. Considerably less than 10% of all very premature infants are affected by early persistence of pulmonary hypertension (PPHN). According to observational studies, effective ventilation combined with early iNO treatment are effective in management of this previously fatal disease. PPHN is associated with prolonged rupture of fetal membranes and birth asphyxia. The lipopolysaccharide (LPS)-induced immunotolerance and hypoxia-reperfusion-induced oxidant stress may inactivate NO-synthetases in pulmonary arterioles and terminal airways. Prospective trials on iNO in the management of PPHN are indicated. Other pulmonary vasodilators may be considered as comparison drugs or adjunctive drugs. The multidisciplinary challenge is to understand the regulation of pregnancy duration and the factors participating the onset of extremely premature preterm deliveries and respiratory adaptation. Basic research aims to identify deficiencies in maternal and fetal tissues that predispose to very preterm births and deteriorate the respiratory adaptation of immature infants. Better understanding on causes and prevention of extremely preterm births would eventually provide effective antenatal and neonatal management practices required for the intact survival.

Reference Values for Point-of-Care Echocardiographic Measurements of Preterm Infants in China

BACKGROUND

Few studies have examined the reference value of the left ventricular structure and function in preterm infants. This study was designed to establish a point-of-care echocardiographic reference range of left ventricular structure and function based on different gestational age, weight, and body surface area (BSA) for preterm infants within 7 days after birth.

METHODS

We retrospectively studied 489 patients with traditional echocardiographic data of left ventricular (LV) M-mode: LV end diastolic dimensions (LVED), LV end systolic dimension (LVES), end-diastolic interventricular septal thickness (IVSd), end diastolic LV posterior wall thickness (LVPWd), left atrial (LA) and aortic root (AO) diameters, and index of LA/AO, LV ejection fraction (LVEF), LV fractional shortening (LVFS), and pulsed wave Doppler: aortic valve flow rate (AV), peak mitral valve flow rate E(MV-E), peak mitral valve flow rate A(MV-A), and MV-E/A. The LV dimensions and the maximum blood flow velocities of the aortic valves and mitral valves according to gestational age, birth weight, and body surface area (BSA) are presented in percentiles tables. Percentile curves of aforesaid four cardiac measurements (LVED, LA diameter (LAD), MV-E, MV-E/A) using the R language Generalized Additive Models for Location, Scale and Shape (GAMLSS) method were developed according to different gestational ages and weights.

RESULTS

Measurements of all cardiac dimensions and Doppler maximum velocities of AV, MV-E, and MV-E/A showed a correlation with gestational age, weight, and BSA. LVED, LAD, MV-E, and MV-E/A showed a trend of increasing values with gestational age and weight on the percentile curves.

CONCLUSION

The percentile tables and graphs of these point-of-care echocardiographic data can provide reliable reference data for Chinese neonates. Normative values are recommended as a source of reference data for the identification of potentially abnormal echocardiography.

Vasoactive medications in extremely low gestational age neonates during the first postnatal week

OBJECTIVE

The management of early hypotension in extremely low gestational age neonates (ELGANs) varies greatly between centers. The objective of this study was to provide updated data on the use of vasoactive medications in ELGANs during the first postnatal week.

STUDY DESIGN

We identified ELGANs (22-27 weeks gestational age) cared for at Pediatrix neonatal intensive care units from 2009 to 2018. We evaluated the frequency of exposure to vasoactive medications by gestational age, and compared use of vasoactive medications between two epochs (2009-2013 and 2014-2018).

RESULTS

A total of 10,070/34,234 (29%) ELGANs received ≥1 vasoactive medication. Dopamine was the most frequently used vasoactive medication. The majority (83%) of treated ELGANs initiated therapy on postnatal days 0-1. Overall use of vasoactive medications was slightly lower in 2014-2018 than 2009-2013 (28 vs 31%, p < 0.001).

CONCLUSION

A substantial proportion of ELGANs were exposed to vasoactive medications during the first postnatal week.

Maximum vasoactive-inotropic score and mortality in extremely premature, extremely low birth weight infants

OBJECTIVE

To determine the relationship between maximum vasoactive-inotropic (VIS^max) and mortality in extremely premature (<29 weeks completed gestation), extremely low birth weight (ELBW, <1000 g) infants.

STUDY DESIGN

Single center, retrospective, and observational cohort study.

RESULTS

We identified 436 ELBW, <29 week, inborn infants cared for during the study period. Compared to infants with VIS^max of 0, the frequency of mortality based on VIS^max ranged from 3.3-fold to 46.1-fold. VIS^max > 30 was associated with universal mortality. Multivariable modeling that included gestational age, birth weight, and VIS^max revealed significant utility to predict mortality with negative predictive value of 87.0% and positive predictive value of 84.8% [adjusted AUROC: 0.90, (0.86-0.94)] among patients that received vasoactive-inotropic treatment.

CONCLUSION

VIS^max is an objective measure of hemodynamic/cardiovascular support that was directly associated with mortality in extremely premature ELBW infants. The VIS^max represents an important step towards neonatal precision medicine and risk stratification of extremely premature ELBW infants.

End-organ saturations correlate with aortic blood flow estimates by echocardiography in the extremely premature newborn - an observational cohort study

BACKGROUND

Near-infrared spectroscopy (NIRS) measures of cerebral saturation (Csat) and renal saturation (Rsat) in extreme premature newborns may be affected by systemic blood flow fluctuations. Despite increasing clinical use of NIRS to monitor tissue saturation in the premature infant, validation of NIRS measures as a correlate of blood flow is still needed. We compared echocardiography (ECHO) derived markers of ascending aorta (AscAo) and descending aorta (DesAo) blood flow with NIRS measurements obtained during the ECHO.

METHODS

Newborns < 29 weeks' gestation (2013-2017) underwent routine NIRS monitoring. Csat, Rsat and systemic saturation at the time of ECHO were retrospectively analyzed and compared with Doppler markers of aortic flow. Renal and cerebral fractional tissue oxygen extraction (rFTOE and cFTOE, respectively) were calculated. Mixed effects models evaluated the association between NIRS and Doppler markers.

RESULTS

Forty-nine neonates with 75 Csat-ECHO and 62 Rsat-ECHO observations were studied. Mean post-menstrual age was 28.3 ± 3.8 weeks during the ECHO. Preductal measures including AscAo velocity time integral (VTI) and AscAo output were correlated with Csat or cFTOE, while postductal measures including DesAo VTI, DesAo peak systolic velocity, and estimated DesAo output were more closely correlated with Rsat or rFTOE.

CONCLUSIONS

NIRS measures are associated with aortic blood flow measurements by ECHO in the extremely premature population. NIRS is a tool to consider when following end organ perfusion in the preterm infant.

Evaluation of urine output, lactate levels and lactate clearance in the transitional period in very low birth weight preterm infants

OBJECTIVE

To assess the association between urine output (UO), arterial lactate levels (LL) and lactate clearance with haemodynamic instability and death in very low birth weight (VLBW) preterm in the transitional period.

STUDY DESIGN

Retrospective cohort study with VLBW newborns born in 2016 and 2017, excluding those with malformations and without data. We evaluated 254 preterm infants with a total of 482 lactate levels measured in the first 72 h. Areas under the curve (AUC) were calculated for receiver-operator characteristics (ROC) curves of UO and LL (alone and combined) and of lactate clearance for prediction of haemodynamic instability and death.

RESULTS

All AUC were below 0.80. Sensitivity and specificity were also not very good. Although patients with poor outcomes had lactate levels higher than those with good outcomes, discrimination was poor.

CONCLUSION

UO and LL and lactate clearance were not good predictors of haemodynamic instability or death within 10 days of life. What is Known • It is already established that blood pressure is not a good marker for haemodynamic stability in the preterm infant. • Others clinical parameters, albeit are largely used, are not fully reliable as well. What is New • In our study we tried to determine the sensibility and specificity of urine output and arterial lactate and also the lactate clearance. • All AUC were below 0.80. Sensitivity and specificity were also not very good. Although patients with poor outcomes had lactate levels higher than those with good outcomes, discrimination was poor.

Simulation in Neonatal Echocardiography

There is a growing interest in neonatologists to train in echocardiography. Recommendations for training have been published by medical societies and working groups, but concerns exist on their feasibility in the face of limited resources. Simulators are increasingly used for training in medicine, including echocardiography. They have the potential to help overcome the shortage of training opportunities. We describe the currently available 2 echocardiography simulators designed for neonatology. Both systems are based on real 3-dimensional echocardiographic data and use an electromagnetic tracking system. Although limited data exist proving their effectiveness, deduction from other disciplines support this assumption.

Updates on Management for Acute and Chronic Phenotypes of Neonatal Pulmonary Hypertension

Neonatal pulmonary hypertension is a heterogeneous disease in term and preterm neonates. It is characterized by persistent increase of pulmonary artery pressures after birth (acute) or an increase in pulmonary artery pressures after approximately 4 weeks of age (chronic); both phenotypes result in exposure of the right ventricle to sustained high afterload. In-depth clinical assessment plus echocardiographic measures evaluating pulmonary blood flow, pulmonary vascular resistance, pulmonary capillary wedge pressure, and myocardial contractility are needed to determine the cause and provide individualized targeted therapies. This article summarizes the causes, risk factors, hemodynamic assessment, and management of neonatal pulmonary hypertension.

Clinical Trials in Hemodynamic Support: Past, Present, and Future

Managing low blood flow states in the preterm population remains a challenge in neonatal clinical care. The heterogeneity of the trials to date and the relatively low number of infants enrolled, in addition to a desire to oversimplify the underlying pathophysiology, have contributed to an inability to draw meaningful conclusions to direct clinical care. This article reviews the current literature on this topic in the preterm population and outlines the challenges that have been encountered in performing such trials. Alternative studies are proposed, based on the lessons learned over the past number of years.

Intervention and Outcome for Neonatal Hypotension

Many observational studies have shown that infants with blood pressures (BPs) that are in the lower range for their gestational age tend to have increased complications such as an increased rate of significant intraventricular hemorrhage and adverse long-term outcome. This relationship does not prove causation nor should it create an indication for treatment. However, many continue to intervene with medication for low BP on the assumption that an increase in BP will result in improved outcome. Only adequately powered prospective randomized controlled trials can answer the question of whether individual treatments of low BP are beneficial.

Machine Learning to Support Hemodynamic Intervention in the Neonatal Intensive Care Unit

Hemodynamic support in neonatal intensive care is directed at maintaining cardiovascular wellbeing. At present, monitoring of vital signs plays an essential role in augmenting care in a reactive manner. By applying machine learning techniques, a model can be trained to learn patterns in time series data, allowing the detection of adverse outcomes before they become clinically apparent. In this review we provide an overview of the different machine learning techniques that have been used to develop models in hemodynamic care for newborn infants. We focus on their potential benefits, research pitfalls, and challenges related to their implementation in clinical care.

Non-invasive Cardiac Output Monitoring in Neonates

Circulatory monitoring is currently limited to heart rate and blood pressure assessment in the majority of neonatal units globally. Non-invasive cardiac output monitoring (NiCO) in term and preterm neonates is increasing, where it has the potential to enhance our understanding and management of overall circulatory status. In this narrative review, we summarized 33 studies including almost 2,000 term and preterm neonates. The majority of studies evaluated interchangeability with echocardiography. Studies were performed in various clinical settings including the delivery room, patent ductus arteriosus assessment, patient positioning, red blood cell transfusion, and therapeutic hypothermia for hypoxic ischemic encephalopathy. This review presents an overview of NiCO in neonatal care, focusing on technical and practical aspects as well as current available evidence. We discuss potential goals for future research.

Regional tissue oxygenation monitoring in the neonatal intensive care unit: evidence for clinical strategies and future directions

Near-infrared spectroscopy (NIRS)-based monitoring of regional tissue oxygenation (rSO₂) is becoming more commonplace in the neonatal intensive care unit (NICU). While increasing evidence supports rSO₂ monitoring, actual standards for applying this noninvasive bedside technique continue to evolve. This review highlights the current strengths and pitfalls surrounding practical NIRS-based monitoring in the neonatal population. The physiologic background of rSO₂ monitoring is discussed, with attention to understanding oxygen delivery/consumption mismatch and its effects on tissue oxygen extraction. The bedside utility of both cerebral and peripheral rSO₂ monitoring in the NICU is then explored from two perspectives: (1) disease/event-specific "responsive" monitoring and (2) "routine," continuous monitoring. Recent evidence incorporating both monitoring approaches is summarized with emphasis on practical applicability in the NICU. Finally, a future paradigm for a broad-based NIRS monitoring strategy is presented, with attention towards improving personalization of neonatal care and ultimately enhancing long-term outcomes.

NT-proBNP as an Early Marker of Diastolic Ventricular Dysfunction in Very-Low-Birth-Weight Infants

The objective is to examine the correlation between plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) and tissue Doppler imaging (TDI) echocardiographic parameters in the first 28 days of life in very-low-birth-weight infants (VLBWI). VLBWI admitted to the Neonatal Intensive Care Unit (NICU) at Hospital Puerta del Mar, Spain, from January 2015 to January 2017 were prospectively enrolled. Weekly determination of plasma NT-proBNP (pg/mL), and echocardiograms were done during the first 28 days of life. 101 preterm infants with a mean GA of 28.85 weeks (± 1.85 SD) and mean birth weight of 1152 g (± 247.4 SD) were included. A total of 483 echocardiograms and 139 NT-proBNP determinations were performed. We found a negative correlation between plasma NT-proBNP levels and diastolic velocities: mitral A' (ρ = - 0.15, p = 0.04), mitral E' (ρ = - 0.17, p = 0.02), tricuspid A' (ρ = - 0.20, p = 0.006), tricuspid E' (ρ = - 0.24, p = 0.0009). In the first 24 h of life, NT-proBNP levels were strongly correlated with mitral A' and E' velocities in patients with no patent ductus arteriosus (PDA) (ρ = - 0.75, p = 0.04). In preterm patients, elevated NT-proBNP levels are related to worse diastolic myocardial function. In the first 24 h, this correlation is much stronger in the absence of PDA.

Persistence of right ventricular dysfunction and altered morphometry in asymptomatic preterm Infants through one year of age: Cardiac phenotype of prematurity

INTRODUCTION

Prematurity impacts myocardial development and may determine long-term outcomes. The objective of this study was to test the hypothesis that preterm neonates develop right ventricle dysfunction and adaptive remodelling by 32 weeks post-menstrual age that persists through 1 year corrected age.

MATERIALS AND METHODS

A subset of 80 preterm infants (born <29 weeks) was selected retrospectively from a prospectively enrolled cohort and measures of right ventricle systolic function and morphology by two-dimensional echocardiography were assessed at 32 weeks post-menstrual age and at 1 year of corrected age. Comparisons were made to 50 term infants at 1 month and 1 year of age. Sub-analyses were performed in preterm-born infants with bronchopulmonary dysplasia and/or pulmonary hypertension.

RESULT

In both term and preterm infants, right ventricle function and morphology increased over the first year (p < 0.01). The magnitudes of right ventricle function measures were lower in preterm-born infants at each time period (p < 0.01 for all) and right ventricle morphology indices were wider in all preterm infants by 1 year corrected age, irrespective of lung disease. Measures of a) right ventricle function were further decreased and b) morphology increased through 1 year in preterm infants with bronchopulmonary dysplasia and/or pulmonary hypertension (p < 0.01).

CONCLUSION

Preterm infants exhibit abnormal right ventricle performance with remodelling at 32 weeks post-menstrual age that persists through 1 year corrected age, suggesting a less developed intrinsic myocardial function response following preterm birth. The development of bronchopulmonary dysplasia and pulmonary hypertension leave a further negative impact on right ventricle mechanics over the first year of age.

Deliveries at extreme prematurity: outcomes, approaches, institutional variation, and uncertainty

PURPOSE OF REVIEW

Medical decision making and practices surrounding extremely premature birth remains challenging for parents and care providers alike. Recently, concerns have been raised regarding wide practice variation, selection bias, and the limitations of outcomes data in this population. The purpose of this review is to summarize the recent literature relevant to deliveries at extreme prematurity with a focus on outcomes, approaches, and institutional variation.

RECENT FINDINGS

Newer data suggest that evidence-based clinical guidelines and protocols for both pregnant women and infants at extreme prematurity are emerging and may improve care and outcomes at lower gestational ages. It has also been recently shown that wide practice variation, selection bias, and methodological limitations of outcomes data reporting with respect to deliveries at extreme prematurity exist.

SUMMARY

Counseling at extreme prematurity should prioritize eliciting parental values and preferences with the goal of personalized shared decision-making. Providers should recognize limitations in counseling families at extreme prematurity, including selection bias, institutional variation, outcomes inaccuracies, prognostic uncertainty, and implicit biases. Standardized reporting of perinatal outcomes should be developed to help alleviate current outcomes misrepresentations and improve counseling at extreme prematurity. Education for providers in advanced communication skills is needed when counseling at extreme prematurity.

Comprehensive Evaluation of Right Heart Performance and Pulmonary Hemodynamics in Neonatal Pulmonary Hypertension : Evaluation of cardiopulmonary performance in neonatal pulmonary hypertension

PURPOSE OF REVIEW

Pulmonary hypertension is characterized by an elevation of pulmonary artery pressures and prolonged exposure of the right ventricle to high afterload that collectively contribute to morbidity and mortality in both the term and preterm infants. This review summarizes the pathogenesis, etiologies, and hemodynamic profiles of the conditions that result in pulmonary hypertension in neonates. We explore the application of echocardiographic techniques for the assessment of right ventricular performance and pulmonary hemodynamics that enhance and guide the diagnosis and management strategies in neonates.

RECENT FINDINGS

Clinical assessments based on the determinants of mean pulmonary artery pressures (pulmonary vascular resistance, pulmonary blood flow, and pulmonary capillary wedge pressure) provide a physiologic approach in determining the acute and chronic etiologies of pulmonary hypertension in neonates. In addition, advances in neonatal echocardiography now afford the capability to obtain quantitative information that often precedes the qualitative information acquired by conventional methods and also provide sensitive markers of right ventricle performance for prognostic information based on the determinants of mean pulmonary artery pressures. Neonatal pulmonary hypertension represents a physiologic spectrum that accounts for the variance in clinical presentation and response to therapies. Physiology-based approaches to etiological identification, coupled with the emerging echocardiographic methods for the assessment of pulmonary hypertension in neonates will likely help to identify cardiovascular compromise earlier, guide therapeutic intervention, monitor therapeutic effectiveness, and improve overall outcome.

Left ventricular diastolic function influences right ventricular - Pulmonary vascular coupling in premature infants

INTRODUCTION

Reduced left ventricular (LV) diastolic function can exert significant load to the right ventricle (RV) that can affect RV-pulmonary vasculature (PV) coupling. RV-PV can be assessed with the RV length-force relationship (tricuspid annular plane systolic excursion [TAPSE] to pulmonary artery acceleration time [PAAT] ratio). We aimed to determine the association between LV diastolic function measured using tissue Doppler imaging (TDI) and TAPSE/PAAT.

METHODS

A study of premature infants <29 weeks gestation. TAPSE/PAAT, LV e' and a' waves were measured on Day 1 following birth. Correlation between diastolic indices and TAPSE/PAAT was performed. The independent effect of LV diastolic function and TAPSE/PAAT was assessed using linear regression.

RESULTS

One hundred and sixty-two infants with a mean ± SD gestation & birthweight of 26.6 ± 1.5 weeks & 938 ± 241 g. There was a significant positive correlation between LV e' (r = 0.44, p < 0.01)/LV a' (r = 0.44, p < 0.01) and TAPSE/PAAT. This relationship remained significant when adjusting for important confounders (all p < 0.01). Infants with LV a' values in the lowest quartile had lower TAPSE values (4.2 ± 1.2 vs. 5.1 ± 1.1 mm, p < 0.01) without a difference in PAAT (41 ± 8 vs. 41 ± 10 ms, p = 0.97).

CONCLUSIONS

We observed a direct correlation between LV diastolic function and RV-PV coupling in the first day of age, highlighting the importance ventricular interdependence in premature infants. TAPSE/PAAT, as the index of the RV-PV interaction may be further explored for its potential to assess RV reserve under stress with preterm infants in health and disease.

Discrepancy between invasive and non-invasive blood pressure readings in extremely preterm infants in the first four weeks of life

Background

The agreement between invasive and non-invasive blood pressure (BP) readings in the first days of life of preterm infants is contentiously debated.

Objective

To compare mean, systolic and diastolic invasive (IBP) and non-invasive BP (NBP) readings obtained during routine care in the first four weeks of life of extremely preterm infants.

Methods

We extracted pairs of IBP and NBP readings obtained from preterm infants born below 28 weeks of gestation from the local database. After exclusion of erroneous measurements, we investigated the repeated measures correlation and analyzed the agreement (bias) and precision adjusted for multiple measurements per individual.

Results

Among 335 pairs of IBP and NBP readings obtained from 128 patients, we found correlation coefficients >0.65 for mean, systolic and diastolic BP values. The bias for mean BP readings was -0.4 mmHg (SD 6.1), for systolic BP readings 6.2 mmHg (SD 8.1), and for diastolic BP readings -4.3 mmHg (SD 6.5). Overestimation of systolic IBP and underestimation of diastolic IBP by the non-invasive measurement were found both in the group with gestational age from 23 to 25.9 weeks and in the group with gestational age from 26 to 27.9 weeks. Systolic NBP readings tended to exceed invasive readings in the range <50 mmHg (bias 9.9 mmHg) whereas diastolic NBP readings were lower than invasive values particularly in the range >30 mmHg (bias -5.5 mmHg).

Conclusion

The disagreement between invasive and non-invasive BP readings in infants extends to the first four weeks of life. Biases differ for mean, systolic and diastolic BP values. Our observation implies that they may depend on the range of the blood pressure. Awareness of these biases and preemptive concomitant use of IBP and NPB readings may contribute to reducing over- or under-treatment.

Early diastolic dysfunction and respiratory morbidity in premature infants: an observational study

OBJECTIVE

To test if diastolic dysfunction measured on day one of age is associated with the need for invasive ventilation in preterm infants.

STUDY DESIGN

We conducted a retrospective observational tissue Doppler echocardiographic study over the first 12 h of age for infants born <32 weeks who were invasively ventilated, and infants on continuous positive pressure ventilation (CPAP).

RESULTS

One hundred and eighty-three infants were included (27 ± 2 weeks and 999 ± 296 g). Invasively ventilated infants [(n = 96 (53%)] had lower left ventricular (LV) e' (3.4 ± 1.0 vs. 4.1 ± 1.5 cm/s, p < 0.01) and lower LV ea' ratio (0.8 ± 0.2 vs. 1.0 ± 0.4, p < 0.01), even after adjusting for common neonatal confounders (LV e' adjusted OR 0.62, 95% CI 0.45 - 0.87, p < 0.01; LV ea' adjusted OR 0.14, 95% CI 0.03-0.68, p = 0.01).

CONCLUSION

LV diastolic dysfunction is independently associated with a higher risk for invasive ventilation on day one of age.

Circulatory Insufficiency and Hypotension Related to the Ductus Arteriosus in Neonates

The biological role of the ductus arteriosus (DA) in neonates varies from an innocent bystander role during normal postnatal transition, to a supportive role when there is compromise to either systemic or pulmonary blood flow, to a pathological state in the presence of hemodynamically significant systemic to pulmonary shunts, as occurs in low birth weight infants. Among a wide array of clinical manifestations arising due to the ductal entity, systemic circulatory insufficiency and hypotension are of significant concern as they are particularly challenging to manage. An understanding of the physiologic interplay between the DA and the circulatory system is the key to developing appropriate targeted therapeutic strategies. In this review, we discuss the relationship of systemic hypotension to the DA, emphasizing the importance of critical thinking and a precise individual approach to intensive care support. We particularly focus on the variable states of hypotension arising directly due to a hemodynamically significant DA or seen in the period following successful surgical ligation. In addition, we explore the mechanistic contributions of the ductus to circulatory insufficiency that may manifest during the transitional period, states of maladapted transition (such as acute pulmonary hypertension of the newborn), and congenital heart disease (both ductal dependent and non-ductal dependent lesions). Understanding the dynamic modulator role of the ductus according to the ambient physiology enables a more precise approach to management. We review the pathophysiology, clinical manifestations, diagnosis, monitoring, and therapeutic intervention for the spectrum of DA-related circulatory compromise.

Monitoring Circulation During Transition in Extreme Low Gestational Age Newborns: What's on the Horizon?

Echocardiography and near-infrared spectroscopy have significantly changed our view on hemodynamic transition of the extreme preterm infant. Instead of focusing on maintaining an arbitrary target value of blood pressure, we aim for circulatory well-being by a comprehensive holistic assessment of markers of cardiovascular instability. Most of these clinical and biochemical indices are influenced by transition itself and remain poor discriminators to identify patients with a potential need for therapeutic intervention. At the same time, the evolution in data capturing and storage has led to a change in our approach to monitor vital parameters. Continuous trend monitoring has become more and more relevant. By using signal extraction methods, changes in trends over time can be quantified. In this review, we will discuss the impact of these innovations on the current monitoring practices and explore some of the potential benefits these techniques may have in improving real-time detection of extreme low birth weight infants at risk for morbidity related to impaired hemodynamic transition.