Transitional circulation and hemodynamic monitoring in newborn infants.

Transitional circulation is normally transient after birth but can vary markedly between infants. It is actually in a state of transition between fetal (in utero) and neonatal (postnatal) circulation. In the absence of definitive clinical trials, information from applied physiological studies can be used to facilitate clinical decision making in the presence of hemodynamic compromise. This review summarizes the peculiar physiological features of the circulation as it transitions from one phenotype into another in term and preterm infants. The common causes of hemodynamic compromise during transition, intact umbilical cord resuscitation, and advanced hemodynamic monitoring are discussed. IMPACT: Transitional circulation can vary markedly between infants. There are alterations in preload, contractility, and afterload during the transition of circulation after birth in term and preterm infants. Hemodynamic monitoring tools and technology during neonatal transition and utilization of bedside echocardiography during the neonatal transition are increasingly recognized. Understanding the cardiovascular physiology of transition can help clinicians in making better decisions while managing infants with hemodynamic compromise. The objective assessment of cardio-respiratory transition and understanding of physiology in normal and disease states have the potential of improving short- and long-term health outcomes.

Effects of inhaled nitric oxide (iNO) in pulmonary hypertension secondary to arteriovenous malformations: a retrospective cohort study from the European iNO registry.

This study aims to assess the effects of inhaled nitric oxide (iNO) on oxygenation in the management of pulmonary hypertension (PH) secondary to arteriovenous malformations (AVMs) in neonates. This is a matched retrospective cohort study from January 1, 2013, to December 31, 2017. The European inhaled nitric oxide registry from 43 neonatal and pediatric ICUs in 13 countries across Europe was used to extract data. The target population was neonates treated with iNO for the management of PH. The cases (PH secondary to AVMs treated with iNO) were matched (1:4 ratio) to controls (PH without AVMs treated with iNO). The main outcome measure was the absolute change of oxygenation index (OI) from baseline to 60 min after starting iNO in cases and controls. The primary outcome of our study was that the mean absolute change in OI from baseline to after 60 min was higher among cases 10.7 (14), than in controls 6 (22.5), and was not statistically different between the groups. The secondary outcome variable - death before discharge - was found to be significantly higher in cases (55%) than in controls (8%). All the other variables for secondary outcome measures remained statistically insignificant.   Conclusion: Infants with PH secondary to AVMs treated with iNO did not respond differently compared to those presented with PH without AVMs treated with iNO. Right ventricular dysfunction on echocardiography was higher in cases than controls (cases: 66.7% and controls: 28.6%) but was not statistically significant. What is Known: • Arterioenous malformation (AVM) is a well-known cause of persistent pulmonary hypertension in newborns. Inhaled nitric oxide (iNO) is most commonly used as first-line therapy for pulmonary hypertension in newborns. • Around 40-50% of vein of Galen malformations (VOGMs) are found to have congestive heart failure in the neonatal period. What is New: • Neonates may present with an isolated PH of the newborn as the main feature of the VOGMs. A large proportion of cases with AVMs have been associated with right ventricular cardiac dysfunction.  • Results from one of the largest database registries in the world for iNO have been used to answer our research question.

"Current concepts in assisted mechanical ventilation in the neonate" - Part 2: Understanding various modes of mechanical ventilation and recommendations for individualized disease-based approach in neonates.

Mechanical ventilation is a lifesaving intervention in critically ill preterm and term neonates. However, it has the potential to cause significant damage to the lungs resulting in long-term complications. Understanding the pathophysiological process and having a good grasp of the basic concepts of conventional and high-frequency ventilation is essential for any medical or allied healthcare practitioner involved in the neonates' respiratory management. This review aims to describe the various types and modes of ventilation usually available in neonatal units. It also describes recommendations of an individualized disease-based approach to mechanical ventilation strategies implemented in the authors' institutions.

Procedural Interventions and Stabilization Times During Interfacility Neonatal Transport.

OBJECTIVE: Transport teams perform multiple procedural interventions during the stabilization of critically ill neonates. The setting of this study was a national cohort of interfacility neonatal transports from nontertiary centers. METHODS: A retrospective cohort study of neonatal transports having interventional procedures using the Canadian Neonatal Transport Network database during 2014 to 2016. Demographics and procedures associated with stabilization times ≤ 120 versus > 120 minutes were analyzed. Predictors of stabilization time were evaluated using multivariable logistic regression analysis. RESULTS: Among 3,350 neonatal transports analyzed, the 3 most frequently performed procedures were peripheral intravenous insertion, arterial blood gas sampling, and endotracheal tube insertion, with success rates of 85.2%, 89.1%, and 95.3%, respectively. The frequency of procedures varied across gestational age subgroups, and success rates were lower for umbilical arterial catheter insertions. After adjustment for confounders, more invasive procedures and a higher number of interventions were associated with longer stabilization times. CONCLUSION: The type and frequency of procedures performed had a significant impact on stabilization time. Any procedures that are nonessential for stabilization at the nontertiary center, such as umbilical arterial catheter insertion, could be minimized to promote timely admission to tertiary centers. The demonstrated variations in procedural success among teams provide useful information for benchmarking and promote the sharing of training practices.

"Current concepts of mechanical ventilation in neonates" - Part 1: Basics.

Mechanical ventilation is potentially live saving in neonatal patients with respiratory failure. The main purpose of mechanical ventilation is to ensure adequate gas exchange, including delivery of adequate oxygenation and enough ventilation for excretion of CO2. The possibility to measure and deliver small flows and tidal volumes have allowed to develop very sophisticated modes of assisted mechanical ventilation for the most immature neonates, such as volume targeted ventilation, which is used more and more by many clinicians. Use of mechanical ventilation requires a basic understanding of respiratory physiology and pathophysiology of the disease leading to respiratory failure. Understanding pulmonary mechanics, elastic and resistive forces (compliance and resistance), and its influence on the inspiratory and expiratory time constant, and the mechanisms of gas exchange are necessary to choose the best mode of ventilation and adequate ventilator settings to minimize lung injury. Considering the pathophysiology of the disease allows a physiology-based approach and application of these concepts in daily practice for decision making regarding the use of modes and settings of mechanical ventilation, with the ultimate aim of providing adequate gas exchange and minimising lung injury.