The association of cumulative vasoactive drugs and neurodevelopmental outcomes in preterm Infants <29 weeks gestation

OBJECTIVE

To assess the effect of cardiovascular medications on the neurodevelopment of preterm infants, as measured by calculated cumulative time of vasoactive-inotropic score (VISct).

METHODS

A retrospective study was conducted on preterm infants who developed significant hypotension defined as a mean BP more than 2SDs below the mean for GA and received treatment with duration > 6 hours for each hypotensive episode, we calculated the vasoactive inotropic score (VIS) and cumulative exposure to cardiovascular medications over time (VISct). The composite Bayley III was reported from the high-risk follow-up clinic for the surviving infants between 18 to 21 months corrected age.

RESULTS

VISct was significantly higher in infants with abnormal neurodevelopment. Cognitive Bayley was the most affected component with median (IQR) VISct 882.5(249,2047) versus 309(143,471) (p-value 0.012), followed by language function with VISct 786(261,1563.5), versus 343(106.75,473.75) (p-value 0.016) when those with Bayley III <85 were compared with those with normal Bayley IIIs.

CONCLUSION

High VISct scores may have negative effect on cognitive and language neurodevelopmental outcomes.

A vasoactive inotropic score predicts the severity of compromised systemic circulation and mortality in preterm infants

OBJECTIVE

To validate the vasoactive inotropic score as a predictor of the severity of compromised systemic circulation and mortality in preterm infants.

METHODS

A retrospective study was conducted on preterm infants with Compromised systemic circulation [hypotension±lactic acidosis±oliguria] who received a cardiovascular support, we calculated the vasoactive inotropic score (VIS) and cumulative exposure to cardiovascular medications over time (VISct). Receiver operator curve was constructed to predict the primary outcome which was death & refractory hypotension.

RESULTS

VIS had an area under the curve of 0.73 (95% CI 0.85-0.98, p <  0.001). A VIS cut off of 25 has sensitivity and specificity of 66% and 92%, and positive and negative predictive values of 78.5% and 83%, respectively.

CONCLUSION

High VIS predicts the severity of Compromised systemic circulation and mortality rate in preterm infants.

Titration of inspired oxygen in preterm infants with hypoxemic respiratory failure using near-infrared spectroscopy and pulse oximetry: A new approach

BACKGROUND

Titration of inspired oxygen is a challenge in preterm infants with hypoxemic respiratory failure (HRF). Monitoring of brain oxygen by near-infrared spectroscopy (NIRS) has been proven to minimize the burden of hyperoxia and hypoxemia; with a better understanding of cerebral autoregulation, integrating NIRS and pulse oximetry for titrating inspired oxygen in preterm infants is a novel approach.

METHODS

We studied the impact of integrated monitoring of oxygen saturation by pulse oximetry (SpO₂ ) and cerebral regional tissue oxygen (crRTO) by NIRS during a stepwise oxygen reduction test (ORT) on reducing oxygen requirement in preterm infants with HRF. The correlation between SpO₂ with crRTO, and fractional oxygen extraction (FOE) was assessed, concordance levels (r > 0.5) were determined during the assessment period and were considered as a sign of impaired autoregulation. The primary outcome was the achievement of significantly lower FiO₂ at 72 h after the start of the integrated monitoring.

RESULTS

A total of 38 preterm infants were included, 27 had normal cerebral autoregulation (CAR) (Group 1) in whom SpO₂ was poorly correlating with crRTO with (r < 0.5) and had a significantly greater percentage of reduction below baseline in FiO₂ (mean: 34%). Eleven infants had impaired CAR (Group 2) with SpO₂ significantly correlating with crRTO (r > 0.5) and had a linear trend of FOE inverse to SpO₂ and crRTO; this was considered as an arterial saturation dependent oxygen delivery (SadDO₂ ).

CONCLUSION

Integrated monitoring of preterm infants by SpO₂ and crRTO was associated with easier weaning of oxygen with less burden of both hyperoxia and hypoxemia.

Lung ultrasound predicts histological lung injury in a neonatal model of acute respiratory distress syndrome

RATIONALE

Point-of-care ultrasound (POCUS) is used to evaluate pulmonary edema in adults with acute respiratory distress syndrome (ARDS). Its use has not been validated in neonatal models.

OBJECTIVES

We compared an in vivo lung ultrasound score against clinical and histological markers of acute lung injury, in a neonatal animal model, hypothesizing that POCUS would sensitively diagnose early acute lung injury in neonates and discern its severity.

METHODS

Fifteen anesthetized, ventilated 3-day-old neonatal piglets were divided into controls, moderate lung injury, or severe lung injury by graded treatment with oleic acid. Degree of lung injury was quantified at baseline, immediately after oleic acid administration, and 1 hour after the evolution of acute lung injury, by blood gases, ventilation parameters and calculated oxygenation deficit; hemodynamic indices by echocardiography, and lung ultrasound obtained in an 8-region grid of anterior and posterior zones, semi-quantitatively analyzed by a blinded observer. Lungs were inflation-fixed postmortem at last mean airway pressure, for histological assessment.

RESULTS

Acute lung injury manifested in oleic acid-treated groups as dose-dependent capillary leak causing intravascular depletion and cardiac failure, hypoxemia with increasing intrapulmonary shunt fraction, decreased lung compliance, and resistance. Ultrasound scores of anterior regions distinguished moderate from severe injury; scores in posterior regions reached maximum values immediately after lung injury. POCUS score correlated with calculated intrapulmonary shunt fraction (R²  = .65) and with histological injury score (R²  = .61), P < .01.

CONCLUSION

We conclude that POCUS may be valuable in neonates for early quantification of acute lung injury or ARDS; and that nondependent ultrasound regions clearly distinguish severity of pulmonary edema.

Pre-symptomatic targeted treatment of patent ductus arteriosus in preterm newborns: A systematic review and meta-analysis

BACKGROUND

A clinically significant patent ductus arteriosus (PDA) is associated with significant morbidity and mortality in premature newborns. Symptomatic PDAs are often treated with prostaglandin synthesis inhibitors (PSI), but controversy remains if PSIs should also be used to manage early, asymptomatic PDAs.

OBJECTIVE

To systematically identify, critically appraise, and evaluate the efficacy and safety of pharmacological management of pre-symptomatic PDA in preterm newborns after confirmed patency by echocardiography.

STUDY DESIGN

Systematic review and meta-analysis.

SEARCH METHODS

We searched MEDLINE (Ovid), EMBASE (Ovid), Cochrane Central Register of Controlled Trials (Wiley), from date of inception to February 2017. Supplemental searching was performed in Scopus and Web of Science to identify additional relevant citations. We also searched conference proceedings, reference lists of relevant articles and the WHO International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared the use of indomethacin or ibuprofen to placebo for treatment of pre-symptomatic PDA in preterm newborns (<32 weeks gestational age and <1500gms).

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials, assessed risk of bias and extracted trial-level data. Outcomes are reported as risk ratios from random-effects models. Absolute risk reduction (ARR) is additionally reported for significant outcomes.We included seven trials (466 newborns). Targeted medical treatment did not significantly reduce mortality rates (RR 0.85, 95% CI 0.50 to 1.43; ARR -2.38%, 95% CI -8.04% to 3.29%; I2 0% 6 studies; 442 newborns), but it did significantly reduce the overall incidence of developing symptomatic PDA (RR 0.39, 95% CI 0.21 to 0.73; ARR -34.3%, 95% CI -50.8% to -17.8%; I2 0%; 3 studies; 97 newborns) compared to placebo. Other efficacy or safety outcomes were not significantly different.

CONCLUSIONS

Targeted medical treatment of pre-symptomatic PDA decreases the incidence of developing symptomatic PDA, but not neonatal mortality. Further studies are essential to confirm these results.

Targeted Neonatal Echocardiography-Guided Therapy in Vein of Galen Aneurysmal Malformation: A Report of Two Cases with a Review of Physiology and Approach to Management

Vein of Galen malformation results in predictable changes in physiology which exist on a continuum. Severe pulmonary hypertension may present as hypoxemia; however, excessive reduction in pulmonary vascular resistance may precipitate progressive pulmonary overcirculation and impaired systemic blood flow. Right ventricular performance and the patency and direction of the ductus arteriosus may play a crucial role in postductal organ perfusion. Physiological stabilization may be complex and variable over time. The utilization of targeted neonatal echocardiography to guide treatment decisions may improve the ability to provide therapy tailored to the specific disease pathophysiology and monitor serially as conditions change. An enhanced approach to physiological stabilization may reduce the risk of unexpected decompensation and allow for thoughtful, controlled endovascular embolization in appropriate candidates.

Effect of vasopressin on a porcine model of persistent pulmonary hypertension of the newborn

BACKGROUND

Persistent pulmonary hypertension of the newborn (PPHN) is due to a failure of pulmonary vascular relaxation. Vasopressin, a systemic vasoconstrictor acting on smooth muscle AVPR1a receptors, is used in treatment of PPHN. We sought to determine acute effects of vasopressin infusion on pulmonary hemodynamics in a large animal model of hypoxic PPHN.

METHODS

PPHN was induced in 6 newborn piglets by 72 h normobaric hypoxia (FiO2 = 0.10); controls were 7 age-matched 3-day-old piglets. Animals were anesthetized and ventilated with central venous and arterial lines, and after stabilization, randomized using a crossover design to normoxic or hypoxic ventilation, then 30 min infusion of 0.0012 U/kg/min vasopressin, followed by 45 min vasopressin washout period. Echocardiographic parameters and oxygen consumption were measured before and after vasopressin. Relaxation to vasopressin was tested in isolated PPHN and control pulmonary arteries by isometric myography. Expression of AVPR1a receptor mRNA was quantified in arterial and myocardial tissues.

RESULTS

Vasopressin did not alleviate hypoxia-responsiveness of PPHN pulmonary circuit. There were no significant differences in pulmonary hypertension, cardiac function indices, or oxygenation indices after vasopressin infusion. Vasopressin did not dilate control or PPHN pulmonary arteries, and AVPR1 was minimally expressed.

CONCLUSIONS

Vasopressin does not have a direct pulmonary vasodilator effect in PPHN, within the timeframe studied.

The Impact of Hypoxemia on the Development of Retinopathy of Prematurity in Infants Less Than 29 Weeks of Gestation

OBJECTIVE

To study the impact of cumulative exposure to hypoxemia on the development of retinopathy of prematurity (ROP) in preterm infants less than 29 weeks' gestation.

STUDY DESIGN

This is a retrospective analysis of the effect of cumulative exposure to hypoxemia during the first 10 weeks of life in preterm infants <29 weeks' gestation. Cumulative time spent at various levels of oxygen saturation was calculated by converting the daily percentage of time to minutes per day. Cumulative exposure to hypoxemia (cT_<80 or oxygen saturation <80%) was calculated weekly and compared between outcomes. The primary outcome was the development of ROP requiring treatment.

RESULTS

Cumulative hypoxemia exposure was significantly associated with ROP requiring treatment. When adjusted for other neonatal morbidities, only gestation was consistently associated with ROP requiring treatment.

CONCLUSION

Cumulative exposure to hypoxemia in the first few weeks was not associated with ROP or treatment of ROP after adjustment for confounders.

Lung Ultrasound as a New Technique for Diagnosis of Neonatal Respiratory Diseases

Point-of-care ultrasound in the NICU is becoming more commonplace and is now used for a number of indications. Over the past ten years, the use of ultrasound as an alternative to a chest x-ray for the diagnosis of neonatal lung disease has been explored, and protocols were developed to refine the interpretation of ultrasound images in neonatal lung disease. The purpose of this column is to briefly explain the physics of ultrasound and describe the application of ultrasound to neonatal lung assessment.

Cardiac Air Embolism in Neonates: A Hemodynamic Perspective

Cardiac air embolism should be suspected in any neonate with acute unexplained cardiovascular collapse or worsening oxygenation. We present here five cases that presented with the above symptoms. A comprehensive evaluation including targeted neonatal echocardiography and near-infrared spectroscopy helped confirm the diagnosis and assess the hemodynamic state. Management was supportive including left lateral positioning, chest compressions, and cardiovascular medications to treat pulmonary hypertension and systemic hypotension.

Patent Ductus Arteriosus in Preterm Infants, Part 1: Understanding the Pathophysiologic Link Between the Patent Ductus Arteriosus and Clinical Complications

The clinical guidelines for treating patent ductus arteriosus (PDA) have significantly evolved over the last decades from treating any ductal shunt to more conservative management where only the hemodynamically significant patent ductus arteriosus (HSPDA) is treated. This shift has resulted largely from a lack of evidence from randomized controlled trials supporting a relationship between treating a PDA and improving long-term neonatal outcomes. However, there are many unresolved issues. There is no consensus on the precise definition of HSPDA requiring treatment or a clear understanding of when to treat HSPDA. Moreover, the current evidence shows worsening of the long-term neurodevelopmental outcome for infants undergoing surgical PDA ligation.<br/> The presence of physiologic variability among preterm infants, and the presence of different compensatory mechanisms may make it difficult to establish a link between pathophysiology and long-term outcomes. That is, the physiologic variability cannot be simply assessed by randomly assigning infants into two arms of a study. Relying on research from animal and human studies, this article explains the link between the pathophysiology of a PDA and neonatal outcomes.

The Impact of Integrated Evaluation of Hemodynamics on Management of Preterm Infants with Late-Onset Compromised Systemic Circulation

Objectives To study the impact of integrated evaluation of hemodynamics (IEH), using targeted neonatal echocardiography (TNE), cerebral regional tissue oxygenation (crRTO), and fractional oxygen extraction (FOE), using near-infrared spectroscopy (NIRS) on the management of infants with late-onset compromised systemic circulation (LCSC), and evaluation of the hemodynamic characteristics. Study Design Retrospective cohort study comparing infants with LCSC who underwent IEH (April 2014 to May 2016) with an earlier EPOCH who did not undergo IEH (January 2012 to March 2014). The primary outcome was the time to recovery. Results Total 43 infants were included; 18 infants underwent IEH with a median (IQR) 2 (1-3) assessments per infant. The time to recovery was shorter in IEH group with a median (IQR) 28 hours (15-62) compared with non-IEH group 96 hours (30-160). Autoregulation was compromised in 50%, and systemic vascular resistance (SVR) was low in 67%. Conclusion IEH was associated with shorter time to recovery in infants with LCSC.

Integrated Evaluation of Neonatal Hemodynamics, Part 2: Systematic Bedside Assessment

Intact hemodynamics results when there is adequate oxygen uptake by the respiratory system, normal cardiac output, sufficient oxygen-carrying capacity of blood, and intact autoregulatory mechanisms to maintain enough oxygenation for normal end-organ function. The current routine monitoring of cardiovascular dynamics in sick preterm and term infants has been based on incomplete evaluation and relies on nonspecific and sometimes misleading clinical markers such as blood pressure. A thorough understanding of perinatal and neonatal cardiovascular, respiratory, oxygen, and other specific end-organ physiology is also mandatory for proper targeted interpretation.

Integrated Evaluation of Neonatal Hemodynamics Program Optimizing Organ Perfusion and Performance in Critically Ill Neonates, Part 1: Understanding Physiology of Neonatal Hemodynamics

Integrated evaluation of neonatal hemodynamics is the integration of information obtained by echocardiography, clinical evaluation, and biochemical markers, in addition to the clinical information obtained from noninvasive and invasive monitoring of blood pressure and arterial and tissue oxygenation, leading to the formulation of a medical recommendation. This review will focus on the physiology of cardiovascular dynamics and oxygen delivery.

The impact of integrated evaluation of hemodynamics using targeted neonatal echocardiography with indices of tissue oxygenation: a new approach

OBJECTIVE

To study the impact of integrated evaluation of hemodynamics (IEH) using targeted neonatal echocardiography, together with regional tissue oxygenation, fractional oxygen extraction using near-infrared spectroscopy on the management of infants with compromised hemodynamics.

STUDY DESIGN

Retrospective cohort comparison of two groups of infants with compromised hemodynamics. EPOCH 1: did not undergo IEH (January 2012 to March 2014); EPOCH 2: underwent IEH (April 2014 to December 2015). The primary outcome was the time to recovery.

RESULTS

In all, 340 infants were included; 158 underwent IEH with a median (IQR) of 2 (1 to 3) evaluations per infant. Reasons for assessment included PDA (60%), compromised systemic circulation (14%) and clinically suspected pulmonary hypertension (22%). The time to recovery was shorter in IEH group in patients with compromised systemic circulation median (IQR), 32 h (24 to 63) compared with none IEH group 71 h (36 to 96), pulmonary hypertension 63 h (14.2 to 102) in IEH group compared with 68 h (24 to 240) in none IEH group, there were fewer PDA-related complications in preterm infants with PDA in IEH group.

CONCLUSION

IEH was associated with shorter time to clinical recovery in infants with compromised hemodynamics.

A Patent Ductus Arteriosus Severity Score Predicts Chronic Lung Disease or Death before Discharge

OBJECTIVES

To test the hypothesis that a patent ductus arteriosus (PDA) severity score (PDAsc) incorporating markers of pulmonary overcirculation and left ventricular (LV) diastolic function can predict chronic lung disease or death before discharge (CLD/death).

STUDY DESIGN

A multicenter prospective observational study was conducted for infants <29 weeks gestation. An echocardiogram was carried out on day 2 to measure PDA diameter and maximum flow velocity, LV output, diastolic flow in the descending aorta and celiac trunk, and variables of LV function using tissue Doppler imaging. Predictors of CLD/death were identified using logistic regression methods. A PDAsc was created and a receiver operating characteristic curve was constructed to assess its ability to predict CLD/death.

RESULTS

We studied 141 infants at a mean (SD) gestation and birthweight of 26 (1.4) weeks and 952 (235) g, respectively. Five variables were identified that were independently associated with CLD/death (gestation at birth, PDA diameter, maximum flow velocity, LV output, and LV a' wave). The PDAsc had a range from 0 (low risk) to 13 (high risk). Infants who developed CLD/death had a higher score than those who did not (7.3 [1.8] vs 3.8 [2.0], P < .001). PDAsc had an area under the curve of 0.92 (95% CI 0.86-0.97, P < .001) for the ability to predict CLD/death. A PDAsc cut-off of 5 has sensitivity and specificity of 92% and 87%, and positive and negative predictive values of 92% and 82%, respectively.

CONCLUSIONS

A PDAsc on day 2 can predict the later occurrence of CLD/death further highlighting the association between PDA significance and morbidity.