Low Superior Vena Cava Research Articles

Superior Vena Cava Flow in Preterm Infants and Neonatal Outcomes: A Systematic Review.

Superior vena cava (SVC) flow has been considered a surrogate marker of systemic blood flow in neonates. We conducted a systematic review to evaluate the association between low SVC flow recorded during the early neonatal period and neonatal outcomes. We searched the following databases (until December 9, 2020; updated October 21, 2022): PROSPERO, OVID Medline, OVID EMBASE, Cochrane Library (CDSR and Central), Proquest Dissertations and Theses Global, and SCOPUS using controlled vocabulary and key words representing the concepts "superior vena cava" and "flow" and "neonate." Results were exported to COVIDENCE review management software. The search retrieved 593 records after the removal of duplicates, of which 11 studies (nine cohorts) met the inclusion criteria. The majority of the studies included infants born at <30 weeks of gestation. The included studies were assessed as high risk of bias in terms of the incomparability of the study groups, with infants in the low SVC flow group noted to be more immature than those in the normal SVC flow group or subjected to different cointerventions. We did not conduct meta-analyses in view of the significant clinical heterogeneity noted in the included studies. We found little evidence to suggest that SVC flow in the early neonatal period is an independent predictor for adverse clinical outcomes in preterm infants. Included studies were assessed at high risk of bias. We conclude that SVC flow interpretation for prognostication or for making treatment decisions should be restricted to the research setting for now. We highlight the need for strengthened methods in future research studies. KEY POINTS: · We studied whether low SVC flow in the early neonatal period is a marker for adverse outcomes in preterm infants.. · There is insufficient evidence to conclude that low SVC flow is a valid predictor of adverse outcomes.. · There is insufficient evidence to conclude that SVC flow-directed hemodynamic management improves clinical outcomes..

A novel echocardiography method to assess upper body systemic blood flow in preterm infants and comparison with superior vena cava flow measurement

To evaluate feasibility, reproducibility, and prognostic value of a new echocardiographic method to assess systemic arterial blood flow directed to the upper part of the body (UBAF, upper body arterial flow) alternative to superior vena cava flow (SVCF) measurement. We performed echocardiographic evaluations in 106 infants in the first 2 days of life to obtain SVCF, left ventricle output (LVO), UBAF, and standard parameters of patent ductus arteriosus (PDA) significance. UBAF was calculated by subtracting from LVO the aortic arch blood flow measured immediately distally to the origin of the left subclavian artery. Main outcome measures: UBAF and SVCF agreement was assessed by Bland–Altman analysis in terms of bias, limits of agreement and repeatability index. The Intraclass Correlation Coefficient was used to measure the strength of inter-rater agreement. The agreement between UBAF and SVCF was high. The Concordance Correlation Coefficient (CCC) was 0.7434. (CCC 0.7434, 95% C.I. [0.656, 0.8111]). There was a good absolute agreement between the two raters ICC = 0.747; p value < 0.0001; 95%CI [0.601; 0.845]. Adjusting for confounding factors (BW, GA, PDA) included in the model, there was a statistically significant relationship between UBAF and SVCF.Conclusion: UBAF showed a strong agreement with the SCVF with a better reproducibility. Our data support UBAF as a potentially useful marker of cerebral perfusion in the evaluation of preterm infants.What is Known:• Low SVC (superior vena cava) flow in the neonatal period has been associated with periventricular haemorrhage and unfavourable long-term neurodevelopmental outcome.• Ultrasound measurement of flow in SVC shows relatively high inter-operator variability.What is New:• Our study highlights how much overlap there is between upper-body arterial flow (UBAF) measurement and SCV flow measurement. UBAF is easier to perform and has a strong correlation with better reproducibility.• UBAF may replace measurement of cava flow as a method for haemodynamic monitoring of unstable preterm and asphyxiated infants.

Randomised trial of dobutamine versus placebo for low superior vena cava flow in preterm infants: Long-term neurodevelopmental outcome.

Although circulatory impairment during the transitional circulation associates morbidity and mortality, its treatment remains controversial. In a pilot trial on circulatory impairment defined as low superior vena cava (SVC) flow, dobutamine (Db) versus placebo (PL) showed a trend towards improved short-term outcomes. The purpose of this study was to report on the long-term outcome of the infants who were observed for SVC flow patterns. Among the 126 infants <31 weeks of gestation prospectively scanned from birth, 28 presented low SVC flow within the first 24 h after birth and received Db (n=16) or PL (n=12). Follow-up of survivors included motor assessment and Bayley Scales II or III at 2 years, and the Reynolds Intellectual Assessment Scale at 6 years. Neurodevelopmental impairment (NDI) was defined as: cerebral palsy (Gross Motor Function Classification System ≥ level 2), or a cognitive function score < -2 standard deviations; or moderate or severe hearing or visual impairment. Db group, PL group and normal-flow group were compared. Eighteen infants died (Db: 5; PL: 2; normal flow group: 11, P=0.1). Follow-up in survivors was accomplished in 80% and 55% of the cohort at 2 years and 6 years, respectively. No significant difference in the combined outcome (mortality or NDI) was found between the groups (42% Db, 36% PL, 30% normal flow group). This exploratory analysis did not show any differences in the long-term outcome of infants according to SVC flow patterns or its treatment early after birth.

Superior vena cava flow: Role, assessment and controversies in the management of perinatal perfusion

The superior vena cava (SVC) is a large vein responsible for the venous return of blood from structures located superior to the diaphragm. The flow in the SVC can be assessed with Doppler ultrasound and can be used as a proxy for cerebral perfusion. Early clinical research studies showed that low SVC flow, particularly if for a prolonged period, was associated with short term morbidity such as intraventricular hemorrhage, mortality, and poorer neurodevelopmental outcomes. However, these findings have not been consistently reported in more recent studies, and the role of SVC flow in early management and as a predictor of poor long-term neurodevelopment has been questioned. This paper provides an overview of SVC assessment, the expected range of findings, and reviews the role of SVC flow as a diagnostic and monitoring tool for the assessment of perinatal perfusion.

Low preoperative superior vena cava blood flow predicts bidirectional cavopulmonary shunt failure

BackgroundIn this study we sought to determine whether preoperative superior vena cava (SVC) blood flow measured using cardiac magnetic resonance (CMR) predicts physiology and clinical outcome after bidirectional cavopulmonary shunt (BCPS). MethodsThe retrospective single-center study included 65 (2012-2017) patients who underwent BCPS. Preoperative CMR imaging, echocardiography, catheterization, and clinical outcomes were reviewed. SVC flow was measured using phase contrast CMR. The Kaplan-Meier method and Cox regression was used for BCPS takedown-free survival and predictor analyses. ResultsThe absolute and indexed SVC flow was 0.5 (interquartile range [IQR], 0.4-0.7) L/min and 1.7 (IQR, 1.4-2.0) L/min/mm2 respectively, which was comparable with the SVC blood flow volume previously measured. The median age and body weight at BCPS was 6.5 (IQR, 5.5-8.5) months and 6.9 (IQR, 6.0-7.7) kg. After follow-up, at a median of 17.1 (IQR, 7.9-41.3) months, 14 patients (21.5%) underwent the Fontan completion and 40 (61.5%) with BCPS physiology were waiting for the Fontan completion. The 11 remaining patients (16.9%), included those who underwent takedown (n = 7; 10.8%) or died with a BCPS (n = 4; 6.2%). Severe hypoxia was the leading cause of mortality, directly accounting for two-thirds of deaths (66.6%; 6/9). The BCPS takedown-free survival was 96.8% at 6 months, and 79.9% at 3 years. Preoperative SVC blood flow was significantly positively correlated with early post-BCPS arterial saturation (P = .00). The multivariable analysis showed SVC flow was the only factor associated with BCPS failure (hazard ratio, 0.186; P = .04) among the predictors related to the pre-BCPS anatomy and physiology. ConclusionsSVC blood flow might be as critically important as pulmonary artery anatomic and physiologic parameters in the evaluation of BCPS candidacy in the single-ventricle population.

Validity of Biomarkers of Early Circulatory Impairment to Predict Outcome: A Retrospective Analysis.

Objectives: The definition of circulatory impairment in the premature infant is controversial. Current research suggests overdiagnosis and overtreatment. We aimed to analyse which biomarkers move clinicians to initiate cardiovascular treatment (CVT). The prognostic capacity for adverse outcome (death and/or moderate-severe brain damage by cranial ultrasound at term equivalent) of these biomarkers was evaluated.Study Design: Retrospective data analysis from preterm infants enrolled in a placebo-controlled trial on dobutamine for low superior vena cava (SVC) flow, who showed normal SVC flow within the first 24 h (not randomized). Five positive biomarkers were considered: MABP < gestational age (GA)-1 mmHg; MABP < GA-5 mmHg; lactate > 4 mmol/L; BE < −9 mmol/L; SVC flow <51 ml/kg/min.Results: Ninety eight infants formed the study cohort. Thirty six received CVT (2–95 h). Logistic regression models adjusted for gestational age showed a positive association between CVT and the risk of death or moderate-severe abnormal cranial ultrasound at term equivalent [(OR 5.2, 95%CI: 1.8–15.1) p = 0.002]. MABP < GA-1 mmHg and lactate > 4 mmol/L were the most prevalent biomarkers at start of treatment. Low BE, high serum lactate and low SVC flow at first echocardiography showed a trend toward being associated with adverse outcome, although not statistically significant.Conclusions: Low blood pressure and high lactate are the most prevalent biomarkers used for CVT prescription. Lactic acidosis and low SVC flow early after birth showed a trend toward being associated with adverse outcome. These findings support using a combination of biomarkers for inclusion in a placebo-controlled trial on CVT during transitional circulation.

Associations of measures of systemic blood flow used in a randomized trial of delayed cord clamping in preterm infants.

To determine associations of low superior vena cava (SVC) flow (≤55 ml/kg/min) and low right ventricular output (RVO) (≤150 ml/kg/min) in preterm infants. An observational study in infants <30 weeks gestation randomized to receive immediate (<10 s) or delayed cord clamping (DCC) (≥60 s). The study enrolled 265 infants with a mean (SD) gestation 28 (2) weeks. Eighty-six (33%) infants had low SVC flow and 81 (31%) infants had low RVO. In multivariate analysis, low SVC flow was associated with gestation; low RVO was associated with DCC, gender and 5-minute Apgar; whereas mean RVO was negatively associated with both FiO2 and mean airway pressure (MAP) at 9 h and 24 h. Low SVC flow was associated with ductus arteriosus (DA) treatment. Infants with low RVO had higher mortality on univariate analysis, but this was not significant after adjusting for gestation. SVC flow was associated with gestation, whilst RVO was associated with placental transfusion, gender, condition at birth, and early respiratory adaptation. Compared to infants with normal values, more infants with low SVC flow were treated for DA, but infants with low RVO had no significant difference in mortality or morbidity.

RELATIONSHIPS BETWEEN NEAR-INFRARED SPECTROSCOPY, PREDUCTAL PERFUSION INDEX AND CARDIAC OUTPUTS IN EXTREMELY PRETERM INFANTS IN THE FIRST 72 HOURS OF LIFE

Abstract BACKGROUND Assessment of hemodynamics during the transitional period in preterm infants is challenging. OBJECTIVES We aimed to describe the relationship between cerebral regional tissue oxygenation saturation (CrSO2), preductal perfusion index (PI), echocardiographic and clinical parameters in extremely preterm infants in their first 72 hours of life. DESIGN/METHODS This single center prospective observational study was conducted in the level 3 neonatal intensive care unit of Sainte-Justine Hospital between July 2015 and May 2016. Twenty newborns born at &lt;28 weeks of gestation were continuously monitored with CrSO2 and preductal PI as well as cardiac outputs measured at 6, 24, 48 and 72 hours of life. Data were assessed for normality and Pearson correlation statistics were performed. Serial data were tested using a one-way ANOVA with repeated measures and Bonferroni adjustment. The level of significance was set to 0.05 RESULTS Median gestational age and birth weight were 25.0 weeks (24–26) and 750 g (655–920) respectively. Table 1 describes the measures over the 72 hours of the study period. CrSO2 and preductal PI were weakly correlated with mean blood pressure, PaCO2, lactates and haemoglobin. Fifteen patients had at least one episode of low left and/or right ventricular output (RVO) measured and showed strong correlation between CrSO2 and superior vena cava (SVC) flow at H6 (r=0.74) and H24 (r=0.86) and between PI and RVO at H6 (r=0.68) and H24 (r=0.92). Five patients had low SVC flowat H6 and showed strong correlation between PI and RVO (r=0.98). CONCLUSION CrSO2 and preductal PI were weakly correlated with clinical parameters in the preterm infants. However, CrSO2 and PI showed stronger correlation with RVO and SVC flow during low cardiac output states.

Accuracy of Intravenous Electrocardiography Confirmation of Peripherally Inserted Central Catheter for Parenteral Nutrition.

Parenteral nutrition (PN) is a life-saving therapy for patients with intestinal failure. Safe delivery of hyperosmotic solution requires a central venous catheter (CVC) with tip in the lower superior vena cava (SVC) or at the SVC-right atrium (RA) junction. To reduce cost and delay in use of CVC, new techniques such as intravascular electrocardiogram (ECG) are being used for tip confirmation in place of chest x-ray (CXR). The present study assessed for accuracy of ECG confirmation in home PN (HPN). Records for all patients consulted for HPN from December 17, 2014, to June 16, 2015, were reviewed for patient demographics, diagnosis leading to HPN initiation, and ECG and CXR confirmation. CXRs were subsequently reviewed by a radiologist to reassess location of the CVC tip and identify those that should be adjusted. Seventy-three patients were eligible, and after assessment for research authorization and postplacement CXR, 17 patients (30% male) with an age of 54 ± 14 years were reviewed. In all patients, postplacement intravascular ECG reading stated tip in the SVC. However, based on CXR, the location of the catheter tip was satisfactory (low SVC or SVC-RA junction) in 10 of 17 patients (59%). Due to the high osmolality of PN, CVC tip location is of paramount importance. After radiology review of CXR, we noted that 7 of 17 (41%) peripherally inserted central catheter lines were in an unsatisfactory position despite ECG confirmation. With current data available, intravenous ECG confirmation should not be used as the sole source of tip confirmation in patients receiving HPN.

New developments in cerebral blood flow autoregulation analysis in preterm infants: a mechanistic approach.

Impaired autoregulation capacity implies that changes in cerebral perfusion follow changes in blood pressure; however, no analytical method has explored such a signal causality relationship in infants. We sought to develop a method to assess cerebral autoregulation from a mechanistic point of view and explored the predictive capacity of the method to classify infants at risk for adverse outcomes. The partial directed coherence (PDC) method, which considers synchronicity and directionality of signal dependence across frequencies, was used to analyze the relationship between spontaneous changes in mean arterial pressure (MAP) and the cerebral tissue oxygenation index (TOI). PDCMAP>>TOI indicated that changes in TOI were induced by MAP changes, and PDCTOI>>MAP indicated the opposite. The PDCMAP>>TOI and PDCTOI>>MAP values differed. PDCMAP>>TOI adjusted by gestational age predicted low superior vena cava flow (≤41 ml/kg per min), with an area under the receiver operating characteristic curve of 0.72 (95% CI: 0.63-0.81; P < 0.001), whereas PDCTOI>>MAP did not. The adjusted pPDCMAP>>TOI (the average value per patient) predicted severe intracranial hemorrhage and mortality. PDCMAP>>TOI allows for a noninvasive physiological interpretation of the pressure autoregulation process in neonates. PDCMAP>>TOI is a good classifier for infants at risk of brain hypoperfusion and adverse outcomes.

Randomized, Placebo-Controlled Trial of Dobutamine for Low Superior Vena Cava Flow in Infants

To gather information for a future confirmatory trial of dobutamine (DB) for circulatory impairment (ie, low superior vena cava [SVC] flow). A total of 127 infants born at < 31 weeks gestational age were serially scanned from birth to 96 hours after birth. The infants were randomly assigned to 2 groups and were treated with DB (stepwise dose increase, 5-10-15-20 μg/kg/min) or placebo if they had an SVC flow < 41 mL/kg/min within the first 24 hours after birth. The primary outcome measures were the achievement and maintenance of an SVC flow ≥ 41 mL/kg/min. Secondary outcome measures were the short-term evolution of clinical and biochemical variables, near-infrared spectroscopy, cranial Doppler ultrasound, and clinical outcomes. SVC flow increased throughout the first 96 hours for the entire cohort. All of the randomized infants (n = 28) except 2 achieved and maintained an SVC flow ≥ 41 mL/kg/min after intervention; however, the infants treated with DB (n = 16) showed a higher heart rate and improved base excess compared with those treated with placebo (n = 12). Low SVC flow was associated with low gestational age (P = .02) and poor condition at birth (P = .02). Low SVC flow significantly increased the risk of severe ischemic events (OR, 13; 95% CI, 2.4-69.2; P < .01). This exploratory trial demonstrates a tendency toward improved short-term clinical and biochemical perfusion variable outcomes in infants with low SVC flow treated with DB. ClinicalTrials.gov (NCT01605279) and the European Clinical Trials Database (EurodraCT 2009-010901-35).

Prior Innominate Vein Occlusion Does Not Preclude Successful Bidirectional Superior Cavopulmonary Connection

Low superior vena cava (SVC) blood flow has recently been identified as a marker for bidirectional superior cavopulmonary connection (SCPC) failure and death. Prior innominate vein occlusion is considered a significant anatomic risk factor for SCPC failure. We therefore evaluated the outcomes of infants who underwent SCPC with known upper-body venous obstruction. Between February 1995 and June 2014, SCPC was carried out in 8 patients who had either a single SVC with known prior occlusion of the innominate vein (n = 6) or bilateral SVCs without a bridging vein with occlusion of one SVC (n = 2). The cause of the occlusion was an indwelling catheter in 5 patients. These patients were compared with 8 patients with normal upper-body venous drainage who underwent SCPC. Patients were evaluated for preoperative risk factors (including SVC size, pulmonary artery size, Nakata index, pulmonary vascular resistance), operative factors, and clinical outcomes to determine the impact of prior upper-body venous occlusion on SCPC failure or death. There were no significant differences in preoperative risk factors between the two groups, except for a significantly lower Nakata index in the study group with a trend toward smaller pulmonary artery branch size. There were no SCPC takedowns or mortalities. There was no significant difference in postoperative length of stay (median of 7 days [range, 5 to 32 days] versus 5 days [range, 4 to 32 days]; p = 0.17. Study patients had a lower mean systemic oxygen saturation at discharge, 81% versus 85% (p = 0.05). In the study group, at a median follow-up of 42 months, 3 patients underwent successful Fontan completion and 5 are still awaiting Fontan completion. Although patients with prior upper-body venous obstruction may have lower systemic oxygen saturations at hospital discharge, they do not demonstrate an increased SCPC failure or mortality rate. Innominate vein occlusion or its equivalent in patients with bilateral SVCs should not preclude the performance of SCPC. Physiologic rather than anatomic evaluation of preoperative systemic venous return may be more useful to predict outcome after SCPC.

PS-101 New Developments In Autoregulation (ar) Analysis: Assessment Of Causality

<h3>Background</h3> Cerebral AR is a complex, developmentally regulated process still not well characterised in neonates. A number of factors interact with the smooth muscle cells regulating cerebral arterial tone and perfusion. Various analytical methods have been applied to explore AR¹. Although in this multifactorial process the assessment of synchronicity and causality is crucial, yet it has not been established. <h3>Objective</h3> To analyse the temporal causality between two biological signals in the frequency-domain by quantifying the influence of each signal to the other across the frequencies. To assess the predictive capacity of the method to classify infants at risk for adverse neonatal outcome. <h3>Methods</h3> Partial directed coherence (PDC)² and spectral coherence (COH) methods were used to analyse the relationship between spontaneous changes in mean arterial blood pressure (MABP) and near-infrared cerebral oximetry (TOI). PDC_MABP»TOI indicated that changes in TOI were induced by MABP changes and PDC_TOI»MABP,the opposite. <h3>Results</h3> PDC_MABP»TOI and PDC_TOI»MABPvalues differed. PDC_MABP»TOI and COH predicted low superior vena cava (SVC) flow (≤41 ml/kg per min) with an area under the ROC curve of 0.68 (95% CI: 0.63–0.77; p &lt; 0.001) and 0.60 (95% CI: 0.51–0.70; p &lt; 0.05), respectively; whereas PDC_TOI»MABP did not (p &lt; 0.248). The pPDC_MABP»TOI and pCOH were calculated as the averaged value per patient. pPDC_MABP»TOI but not pCOH predicted mortality. <h3>Conclusions</h3> PDC_MABP»TOIis a good classifier for infants at risk of brain hypoperfusion and adverse outcome. PDC_MABP»TOIallows a non-invasive physiological interpretation of the pressure-AR process in neonates. <h3>References</h3> Riera J <i>et al</i>. 2014 (submitted) Baccalá L, Sameshima K. <i>Biol_Cyber</i> 2001.

PS-102 Relationship Between Carotid Blood Flow, Cardiac Output And Blood Pressure In Extremely Preterm Infants

<h3>Background and aims</h3> Cardiovascular problems, including low flow and hypotension are common in extremely preterm infants. Low cerebral blood flow is associated with poor long-term outcome (1). Right common carotid artery flow (RCCAF) provides a reproducible non-invasive measure of blood flow to the brain, but there are no studies of RCCAF in extremely preterm infants. We wanted to investigate the relationship between RCCAF, cardiac output (CO) and BP in this group. <h3>Methods</h3> We studied 30 infants born &lt;29 weeks gestation. RCCAF and CO using Doppler ultrasound was measured on day 1 and 3 of life. RCCAF and CO was measured using established methods. Mean arterial BP was measured at the time of recording the RCCAF. Non-parametric statistics were used for analysis (SPSS v22). Ethics committee approval (Reference 12/LO/1553) and written parental consent obtained. <h3>Results</h3> Median (range) gestation and birth weight was 26 (23–28) weeks and 775 (515–1470) grams respectively. There were no statistically significant correlations between RCCAF, BP or CO in this cohort on day 1 or day 3 of life. <h3>Conclusions</h3> RCCAF increased between day 1 and day 3 of life in extremely preterm infants, which reflects improved CO. We found no significant relationship between RCCAF, BP and CO in our babies. Values in this cohort were lower than previously reported in more stable infants, particularly on day 1. <h3>Reference</h3> Seri I. Low superior vena cava flow during the first postnatal day and neurodevelopment in preterm infants. <i>J Pediatr</i> 2004

New Time-Frequency Method for Cerebral Autoregulation in Newborns: Predictive Capacity for Clinical Outcomes

To describe an alternative analysis in the frequency-domain of the temporal relationship between 2 biological signals and evaluate the method's predictive capacity for classifying infants at risk for an adverse outcome. We studied 54 infants (mean gestational age 27 weeks) with invasive mean arterial blood pressure monitoring. The bivariate autoregressive spectral coherence (BiAR-COH) method and the spectral coherence methods were used to analyze the relationship between spontaneous changes in mean arterial blood pressure and the near-infrared tissue oxygenation index. The mean postnatal age at the beginning and end of the autoregulation study was 6.0 (3.0) and 29.0 (7.5) hours, respectively. The BiAR-COH was superior to the spectral coherence in predicting low superior vena cava (SVC) flow (≤ 41 mL/kg per minute), with an area under the receiver operating characteristic curve of 0.84 (95% CI, 0.77-0.90; P < .001). The BiAR-COH threshold for identifying low SVC flow was 0.577, with 0.8 sensitivity and 0.76 specificity. After adjusting for the repeated measures effect (multiple epochs) in a given patient, the averaged BiAR-COH per patient and averaged COH per patient were calculated as the average value per patient. The pBiAR-COH (but not the pCOH) was associated with intraventricular hemorrhage grades 3 and 4 and predicted mortality. The BiAR-COH classifier identifies low SVC flow infants who are at risk for brain hypoperfusion. The BiAR-COH is superior to frequency domain methods in predicting adverse outcomes in infants.

Evaluation of the Sherlock 3CG Tip Confirmation System on peripherally inserted central catheter malposition rates.

Peripherally inserted central catheters are often positioned blindly in the central circulation, and this may result in high malposition rates, especially in critically ill patients. Recently, a new technology has been introduced (Sherlock 3CG Tip Positioning System) that uses an electro-magnetic system to guide positioning in the superior vena cava, and then intra-cavity ECG to guide positioning at the cavo-atrial junction. In this observational study, we investigated how the Sherlock 3CG Tip Positioning System would affect peripherally inserted central catheter malposition rates, defined using a post-insertion chest radiograph, in critically ill patients. A total of 239 catheters positioned using the Sherlock 3CG Tip Positioning System were analysed. When an adequate position was defined as low superior vena cava or cavo-atrial junction, 134 catheters (56.1%; 95% CI 50-62%) were malpositioned. When an adequate position was defined as mid/low superior vena cava, cavo-atrial junction or high right atrium (≤2cm from cavo-atrial junction), 49 (20.5%; 95% CI 16-26%) catheters were malpositioned. These malposition rates are significantly lower than our own historical data, which used a 'blind' anthropometric technique to guide peripherally inserted central catheter insertion.

Timing of cord clamping in very preterm infants: more evidence is needed

In December 2012, the American College of Obstetricians and Gynecologists published a Committee Opinion entitled "Timing of umbilical cord clamping after birth." It stated that "evidence exists to support delayed cord clamping in preterm infants, when feasible. The single most important benefit for preterm infants is the possibility for a nearly 50% reduction in IVH." However, the Committee Opinion added that the ideal timing of umbilical cord clamping has yet to be determined and recommended that large clinical trials be conducted in the most preterm infants. Published randomized controlled trials include <200 infants of <30 weeks' gestation, with assessments of neurodevelopmental outcome in less than one-half of the children. This is a major gap in the evidence. Without reliable data from randomized controlled trials that optimally include childhood follow-up evaluations, we will not know whether delayed cord clamping may do more overall harm than good. Ongoing trials of delayed cord clamping plan to report childhood outcomes in >2000 additional very preterm infants. Current recommendations may need to change when these results become available. Greater international collaboration could accelerate resolution of whether this promising intervention will improve disability-free survival in about 1 million infants who will be born very preterm globally each year.

Perfusion index in newborn infants: a noninvasive tool for neonatal monitoring

To review the utility of perfusion index (PI) in the evaluation of neonatal clinical conditions. Twenty-five manuscripts were reviewed. PI provides information about haemodynamic stability, illness severity, early neonatal respiratory outcome, low superior vena cava flow and subclinical chorioamnionitis. PI is a valuable tool to assess the newborn's health condition and could become a standardised measure in clinical evaluation. Different study designs are necessary to provide further validation to this method.

The relationship between BNP, NTproBNP and echocardiographic measurements of systemic blood flow in very preterm infants

Preterm infants are at risk of circulatory compromise following birth. Functional neonatal echocardiography including superior vena cava (SVC) flow is increasingly used in neonatal medicine, and low SVC flow has been associated with adverse outcome. However, echocardiography is not readily available in many neonatal units and B-type natriuretic peptides (BNPs) may be useful in guiding further cardiovascular assessment. This study investigated the relationship between BNP, N-terminal pro-BNP (NTproBNP) and echocardiographic measurements of systemic blood flow in very preterm infants. This is a prospective observational study. Sixty preterm infants <32 weeks gestational age were included after the treating neonatologist had requested an echocardiogram for suspected cardiovascular compromise. BNP and NTproBNP were sampled just before the echocardiogram. Echocardiographic examination included fractional shortening (FS), SVC flow, left and right ventricular output (LVO and RVO). Statistical analysis included simple linear regression of BNP and NTproBNP with echocardiographic measures and multiple regression including potential confounding variables. Mean (s.d.) gestational age at birth was 27(5) (2(1)) weeks, median (interquartile range, IQR) birth weight was 995 (845 to 1175) grams. Neither BNP nor NTproBNP correlated with SVC flow (BNP 95% confidence interval (CI) -0.0014 to 0.013, P=0.12; NTproBNP 95% CI -0.00069 to 0.01, P=0.085); LVO (BNP 95% CI -0.00078 to 0.0072, P=0.11; NTproBNP 95% CI -0.0034 to 0.0034, P=0.99); RVO (BNP 95% CI -0.00066 to 0.0058, P=0.12; NTproBNP 95% CI -0.0012 to 0.0044, P=0.25); or FS (BNP 95% CI -0.053 to 0.051, P=0.96; NTproBNP 95% CI -0.061 to 0.019, P=0.3). Multivariate linear regression did not significantly alter results. In this cohort of very preterm infants, BNP and NTproBNP did not correlate with echocardiographic measurements of systemic blood flow within the first 72 h of life.

Cerebral tissue oxygenation index, cardiac output and superior vena cava flow in infants with birth weight less than 1250 grams in the first 48 hours of life

BackgroundNear-infrared spectroscopy is a non-invasive method of assessing cerebral oxygenation. Functional echocardiography is increasingly used by neonatologists in the assessment of cardiovascular function. AimsTo correlate cerebral tissue oxygenation index (cTOI) and cardiac output in infants less than 1250g at 6, 12, 24 and 48hours of age. Study designA prospective observational study. SubjectsNewborns with birth weight<1250g. Outcome measuresSerial assessments of superior vena cava (SVC) flow, right and left ventricular outputs, ductus arteriosus and cTOI were performed at 6, 12, 24 and 48hours of age. Clinical parameters, including mean blood pressure, mean airway pressure, blood gas parameters and oxygen saturations were recorded. Results22 neonates were enrolled following parental consent. The mean birth weight was 851g (SD±201), mean gestational age was 25.9weeks (SD±1.7). Mean SVC flow at 6hours of age was 56.8ml/kg/min and increased to 68.6ml/kg/min at 48hours of age. 9 infants (41%) had at least one measurement of low SVC flow (<41ml/kg/min) in the first 48hours. Mean cTOI was 65.2% at 6hours of age, 63.9% at 12hours of age, 68.8% at 24hours of age and 67.2% at 48hours of age. Cerebral fractional tissue oxygen extraction values were highest at 12hours (0.31±0.09). There was no correlation between SVC flow and cTOI values. ConclusionSVC flow, left and right ventricular output increased during first 48hours of life. cTOI decreased at 12hours of age with a concomitant increase in fractionated oxygen extraction. These changes reflect transitional changes in both cardiac and cerebral hemodynamics in extremely low gestational age newborns during the first 48hours.