Assessing fluid responsiveness with ultrasound in the neonatal intensive care setting: the mini-fluid challenge.

The mini-fluid challenge (MFC) can guide individualised fluid therapy and prevent fluid overload and associated morbidity in adult intensive care patients. This ultrasound test is based on the Frank-Starling principles to assess dynamic fluid responsiveness, but limited MFC data exists for newborns. This brief report describes the feasibility of the MFC in 12 preterm infants with late onset sepsis and 5 newborns with other pathophysiology. Apical views were used to determine the changes in left ventricular stroke volume before and after a 3 ml/kg fluid bolus was given over 5 min. Four out of the 17 infants were fluid responsive, defined as a post-bolus increase in stroke volume of 15% or more.  Conclusion: The MFC was feasible and followed the physiological principles of stroke volume and extravascular lung water changes and 24% were fluid responsive. The MFC could enable future studies to examine whether adding fluid responsiveness to guide fluid therapy in newborns can reduce the risk of fluid overload. What is Known: • Fluid overload is associated with morbidity and mortality. • The mini-fluid challenge (MFC) provides a personalised approach to fluid therapy. What is New: • The MFC is feasible in newborns. • The MFC followed the physiological principles of stroke volume and extravascular lung water changes.

Mortality in the neonatal intensive care setting: Do benchmarks tell the whole story?

AIM: Australian neonatal mortality data are collected and shared within collaborative networks. Individual unit outcomes are benchmarked between units and presented in quarterly or yearly reports. Low mortality is commonly interpreted as optimal performance. However, current collected data do not differentiate between death due to severe illness and death following treatment limitation. This study aims to explore the physiological condition immediately before death, and the proportion of deaths attributed to treatment limitation. METHODS: This retrospective single centre study of 100 consecutive deaths classified the physiological condition 12 h prior to death as stable or unstable using a clinical illness score based upon pH, oxygen saturation index, medications and blood product use. Documented discussions regarding expected outcomes and goals of management were reviewed for agreed upon treatment limitations and analysed against physiological stability. RESULTS: Causes of death were sepsis (n = 24), congenital anomalies (n = 20), extreme prematurity (n = 19), hypoxic ischaemic encephalopathy (n = 18), intraventricular haemorrhage (n = 11) and other (n = 8). Forty-eight infants were physiologically stable at 12 h before death. In infants classified as physiologically stable, 90% of deaths were in a scenario where palliative care was discussed and intensive care treatment was ceased. These deaths accounted for 43% of total mortality in our unit. CONCLUSION: A large portion of mortality in our unit could be attributed to treatment limitations in physiologically stable infants with high risk of neurodevelopmental impairment. Our study emphasises the need to consider the physiological status around time of death for optimal benchmarking of mortality between neonatal units.

Echocardiography algorithms to assess high left atrial pressure and grade diastolic function in preterm infants.

BACKGROUND: Relaxation, restoring forces, myocardial stiffness and atrial function determine left ventricular (LV) diastolic function. This study aims to provide a comprehensive assessment of diastolic function in preterm infants using conventional echocardiography and speckle tracking imaging and determine the diagnostic accuracy of various algorithms to detect high left atrial pressure (LAP). METHODS: Preterm infants received an echocardiogram 1 week after birth and diastolic reference values were derived from the outer percentiles of stable preterm infants. Impaired relaxation, LV stiffness and high LAP were defined by using algorithms where at least half of the parameters were outside the normal range. Diastolic function was graded using the 2016 American Society of Echocardiography algorithm and expanded with the EA ratio and left atrial strain. The diagnostic accuracy of various algorithms to detect high LAP was determined with sensitivity analysis. RESULTS: We studied 146 infants (59 stable) with a mean of 27(1) weeks gestation. Impaired relaxation, LV stiffness and high LAP were found in 8%, 7%, and 14% of infants. The patent ductus arteriosus was a contributing factor to high LAP and LV stiffness, not impaired relaxation. Diagnostic accuracy improved from 90% to 96% and sensitivity from 40% to 90% by adding left atrial strain to the 2016 algorithm. CONCLUSION: Various grades of diastolic dysfunction could be appreciated in preterm infants using a multi-parameter approach. Adding left atrial strain improved sensitivity to detect infants with high LAP.

Clinical and haemodynamic characteristics of preterm infants with early onset sepsis.

AIM: Early onset sepsis (EOS) in preterm infants is associated with high morbidity and mortality. Improved characterisation of the haemodynamic presentation of EOS could lead to more effective and targeted treatments. METHODS: We performed a retrospective observational study of preterm infants ≤32 week' gestation with EOS between 2010 and 2020 and gathered clinical, haemodynamic and echocardiographic data. RESULTS: Of the 2198 admitted infants, 27 infants (median gestational age 28 weeks, median birthweight 1174 g) developed EOS with predominantly gram-negative pathogens and the overall mortality rate was 33.3%. Besides hypotension, clinical signs were non-specific, and over half of infants were normotensive in the first 72 h of life. Those with hypotension received more fluid resuscitation, inotropic support and had a higher mortality compared to the normotensive infants. Cardiac ultrasound was available in 18 infants and commonly revealed higher as expected cardiac output, pulmonary hypertension and diastolic dysfunction. CONCLUSION: Preterm infants with EOS had a high mortality rate, especially when they progressed from sepsis to septic shock. Echocardiography revealed a normal haemodynamic pattern, or one suggestive of vasodilatation and warm shock physiology. Targeting this pathophysiology earlier might improve outcomes.

A Randomized Placebo-Controlled Pilot Trial of Early Targeted Nonsteroidal Anti-Inflammatory Drugs in Preterm Infants with a Patent Ductus Arteriosus.

OBJECTIVE: To establish the feasibility of a future large randomized trial to compare early treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) while awaiting spontaneous patent ductus arteriosus (PDA) closure. STUDY DESIGN: Preterm infants at <29 weeks of gestation with a PDA diameter >1.5 mm and <72 hours after birth were randomized to NSAIDs vs placebo. No open-label NSAID treatment was allowed in either arm, but all infants with PDA volume load received supportive management, including optimization of airway pressure, careful fluid management, and diuretics as needed. The pilot outcomes were recruitment rate and incidence of open-label treatment. Secondary clinical outcomes included chronic lung disease or death, the planned primary outcome for a future large trial. RESULTS: Overall, 54% of the approached parents consented to participate in the study. The median recruitment rate was 3 infants per month, and a total of 72 infants were randomized. One patient in each arm received open-label treatment. PDA closure rates were 74% for the NSAIDs arm vs 30% for the placebo arm, but this was not associated with significant changes in clinical outcomes. CONCLUSIONS: This pilot trial showed that recruitment of more than one-half of eligible infants with a low incidence of open-label treatment is feasible. PDA closure rates and clinical outcomes were similar to those reported in previous PDA trials.

Opioids for newborn infants receiving mechanical ventilation.

BACKGROUND: Mechanical ventilation is a potentially painful and discomforting intervention that is widely used in neonatal intensive care. Newborn infants demonstrate increased sensitivity to pain, which may affect clinical and neurodevelopmental outcomes. The use of drugs that reduce pain might be important in improving survival and neurodevelopmental outcomes. OBJECTIVES: To determine the benefits and harms of opioid analgesics for neonates (term or preterm) receiving mechanical ventilation compared to placebo or no drug, other opioids, or other analgesics or sedatives. SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 9), in the Cochrane Library; MEDLINE via PubMed (1966 to 29 September 2020); Embase (1980 to 29 September 2020); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 29 September 2020). We searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. SELECTION CRITERIA: We included randomised and quasi-randomised controlled trials comparing opioids to placebo or no drug, to other opioids, or to other analgesics or sedatives in newborn infants on mechanical ventilation. We excluded cross-over trials. We included term (≥ 37 weeks' gestational age) and preterm (< 37 weeks' gestational age) newborn infants on mechanical ventilation. We included any duration of drug treatment and any dosage given continuously or as bolus; we excluded studies that gave opioids to ventilated infants for procedures. DATA COLLECTION AND ANALYSIS: For each of the included trials, we independently extracted data (e.g. number of participants, birth weight, gestational age, types of opioids) using Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria and assessed the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). We evaluated treatment effects using a fixed-effect model with risk ratio (RR) for categorical data and mean difference (MD) for continuous data. We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: We included 23 studies (enrolling 2023 infants) published between 1992 and 2019. Fifteen studies (1632 infants) compared the use of morphine or fentanyl versus placebo or no intervention. Four studies included both term and preterm infants, and one study only term infants; all other studies included only preterm infants, with five studies including only very preterm infants. We are uncertain whether opioids have an effect on the Premature Infant Pain Profile (PIPP) Scale in the first 12 hours after infusion (MD -5.74, 95% confidence interval (CI) -6.88 to -4.59; 50 participants, 2 studies) and between 12 and 48 hours after infusion (MD -0.98, 95% CI -1.35 to -0.61; 963 participants, 3 studies) because of limitations in study design, high heterogeneity (inconsistency), and imprecision of estimates (very low-certainty evidence - GRADE). The use of morphine or fentanyl probably has little or no effect in reducing duration of mechanical ventilation (MD 0.23 days, 95% CI -0.38 to 0.83; 1259 participants, 7 studies; moderate-certainty evidence because of unclear risk of bias in most studies) and neonatal mortality (RR 1.12, 95% CI 0.80 to 1.55; 1189 participants, 5 studies; moderate-certainty evidence because of imprecision of estimates). We are uncertain whether opioids have an effect on neurodevelopmental outcomes at 18 to 24 months (RR 2.00, 95% CI 0.39 to 10.29; 78 participants, 1 study; very low-certainty evidence because of serious imprecision of the estimates and indirectness). Limited data were available for the other comparisons (i.e. two studies (54 infants) on morphine versus midazolam, three (222 infants) on morphine versus fentanyl, and one each on morphine versus diamorphine (88 infants), morphine versus remifentanil (20 infants), fentanyl versus sufentanil (20 infants), and fentanyl versus remifentanil (24 infants)). For these comparisons, no meta-analysis was conducted because outcomes were reported by one study. AUTHORS' CONCLUSIONS: We are uncertain whether opioids have an effect on pain and neurodevelopmental outcomes at 18 to 24 months; the use of morphine or fentanyl probably has little or no effect in reducing the duration of mechanical ventilation and neonatal mortality. Data on the other comparisons planned in this review (opioids versus analgesics; opioids versus other opioids) are extremely limited and do not allow any conclusions. In the absence of firm evidence to support a routine policy, opioids should be used selectively - based on clinical judgement and evaluation of pain indicators - although pain measurement in newborns has limitations.

Progression from sepsis to septic shock and time to treatments in preterm infants with late-onset sepsis.

AIM: Late-onset sepsis (LOS) in preterm infants can progress rapidly from minimal clinical signs and symptoms to septic shock which is associated with high mortality. The aim of this study was to describe the progression from sepsis to septic shock and evaluate our management performance with emphasis on time to treatments. METHODS: This was a retrospective observational study including preterm infants ≤32 weeks gestation with LOS and septic shock defined as the requirement of fluids and vasopressors. Physiological changes and time to first diagnostics and treatments were determined from the point of first appearance of clinical signs and symptoms of sepsis (TONSET ). RESULTS: During the 10-year observational period, 279 infants developed LOS and 25 (8.9%) progressed to septic shock. The median (interquartile range) time from TONSET to blood culture, administering antibiotics, fluid bolus and vasopressors was 8.4 (4.8-12.2), 9.2 (5.6-12.4), 14.6 (9.5-34.5) and 22.0 (14.6-44.7) h, respectively. Hypotension and raised lactate were prominent physiological changes in the progression to septic shock. Fluid bolus and vasopressors were administered when blood pressure was 20 and 41% below to what was normal before the infant became unwell. Vasopressors significantly increased blood pressure and heart rate. Mortality rate was 40% with no difference in time to treatments between survivors and non-survivors. CONCLUSION: Clinical recognition of the onset of sepsis in preterm infants remains difficult and contributes to delay of treatment. Once recognised, early administration of antibiotics, fluid bolus and vasopressors should be prioritised.

Delayed versus Immediate Cord Clamping in Preterm Infants.

BACKGROUND: The preferred timing of umbilical-cord clamping in preterm infants is unclear. METHODS: We randomly assigned fetuses from women who were expected to deliver before 30 weeks of gestation to either immediate clamping of the umbilical cord (≤10 seconds after delivery) or delayed clamping (≥60 seconds after delivery). The primary composite outcome was death or major morbidity (defined as severe brain injury on postnatal ultrasonography, severe retinopathy of prematurity, necrotizing enterocolitis, or late-onset sepsis) by 36 weeks of postmenstrual age. Analyses were performed on an intention-to-treat basis, accounting for multiple births. RESULTS: Of 1634 fetuses that underwent randomization, 1566 were born alive before 30 weeks of gestation; of these, 782 were assigned to immediate cord clamping and 784 to delayed cord clamping. The median time between delivery and cord clamping was 5 seconds and 60 seconds in the respective groups. Complete data on the primary outcome were available for 1497 infants (95.6%). There was no significant difference in the incidence of the primary outcome between infants assigned to delayed clamping (37.0%) and those assigned to immediate clamping (37.2%) (relative risk, 1.00; 95% confidence interval, 0.88 to 1.13; P=0.96). The mortality was 6.4% in the delayed-clamping group and 9.0% in the immediate-clamping group (P=0.03 in unadjusted analyses; P=0.39 after post hoc adjustment for multiple secondary outcomes). There were no significant differences between the two groups in the incidences of chronic lung disease or other major morbidities. CONCLUSIONS: Among preterm infants, delayed cord clamping did not result in a lower incidence of the combined outcome of death or major morbidity at 36 weeks of gestation than immediate cord clamping. (Funded by the Australian National Health and Medical Research Council [NHMRC] and the NHMRC Clinical Trials Centre; APTS Australian and New Zealand Clinical Trials Registry number, ACTRN12610000633088 .).

Dilated hypertrophy: a distinct pattern of cardiac remodeling in preterm infants.

BACKGROUND: Young adults born preterm have remodeled hearts, i.e., altered cardiac shape and size with impaired cardiac function. At present, the natural history and pattern of prematurity related cardiac remodeling are not clearly established. The aim of this study was to compare the left ventricle (LV) geometry and function of preterm infants at 36 weeks postmenstrual age (PMA) with gestation matched newborn infants. METHODS: LV end diastolic volume index (LV EDVI), LV mass index (LVMI), relative wall thickness (RWT), and sphericity index (SI) were prospectively obtained with echocardiography. LV geometry was classified according to the Gaasch method. LV function was assessed by determining ejection fraction (EF), longitudinal strain (LS), mitral annulus systolic motion (s'), and estimated LV filling pressure (E/e'). RESULTS: Eighty-three preterm infants between 23 and 29 weeks gestation, and 40 infants of 36 weeks gestation at birth were analysed. LV EDVI, LVMI, SI, LS, s', and E/e' were higher in preterm group while RWT and EF were comparable between groups. LV showed normal geometry in 55.4%, physiological enlargement in 23% and dilated hypertrophy in 21.6% preterm infants. CONCLUSION: At 36 week, preterm infants have significantly dilated, hypertrophied, and more spherical LV with impaired diastolic function compared with PMA matched newborn infants.

Left ventricular ejection fraction using manual and semi-automated biplane method of discs in very preterm infants.

BACKGROUND: Biplane left ventricular ejection fraction (LVEF) is a valuable echocardiographic parameter for assessment of LV systolic pump efficiency in adults and children, but not often reported in preterm infants. The primary aim of this study was to longitudinally measure biplane LVEF in very preterm infants during the neonatal intensive care period. Secondary aim was to compare manual and semi-automatic determination of LVEF for agreement and variability. METHODS: Stable preterm infants less than 30 weeks gestation were scanned on day 3, day 28, and at 36 weeks postmenstrual age. The LV endocardium was traced manually and semi-automatically using integrated speckle tracking software in apical 4-chamber and apical 3-chamber images to obtain end-diastolic volume and end-systolic volume, and calculate LVEF. Agreement between methods and variability within and between observers was determined using an interclass correlation coefficient (ICC) and Bland-Altman analysis. RESULTS: Sixty-six preterm infants with a mean birth weight of 1100 (239) g were analyzed. The average manual biplane LVEF was 58 (3)%, 59 (3)%, and 55 (4)% at the three respective time points. Manual LVEF showed good agreement with semi-automatic LVEF (ICC 0.76) with a small bias of -1.5 (3.0)%. Interobserver variability of LVEF improved with semi-automatic tracing of the LV endocardial border (ICC manual 0.68 vs semi-automatic 0.80). CONCLUSION: Left ventricular systolic pump efficiency in preterm infants remains stable during the neonatal intensive care period. Semi-automatic biplane LVEF has less interobserver variability and can be used interchangeably with manual biplane LVEF.

Time to positive blood culture in early onset neonatal sepsis: A retrospective clinical study and review of the literature.

AIM: Neonatal early onset sepsis (EOS) is a low-incidence, high-risk disease which has prompted significant overtreatment with antibiotics for the standard duration of 48 h. The aims of this study were to determine whether blood cultures collected from term and late preterm neonates for EOS would return a positive result for pathogenic bacteria within 24 h and to review the literature to supplement the results. METHODS: This is a retrospective observational study of time to positive blood culture in the BACTEC culture system from neonates ≥34 weeks in a single referral centre between 1999 and 2018. A literature review was conducted through PubMed, MEDLINE and Embase using search terms of 'neonatal sepsis' AND 'blood culture'. Studies were included if they reported time to positive blood culture in EOS. RESULTS: Forty positive cultures were included in this report, with 39 (98%) showing bacterial growth within 24 h. One culture, obtained after commencement of antibiotics, became positive at 3 days. Sixteen papers were included in our literature review and six presented data for an EOS cohort; a median of 96.5% of pathogenic EOS blood cultures become positive within 24 h. CONCLUSIONS: All pathogenic blood cultures collected pre-therapy from neonates ≥34 weeks suspected of EOS returned a positive result within 24 h of incubation. Similar studies have found that 92-100% of cultures are positive by 24 h. This data could contribute to re-evaluation of the current standard duration of antibiotic use in term and late preterm neonates with suspected EOS.

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

OBJECTIVE: 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. DESIGN/METHODS: An observational study in infants <30 weeks gestation randomized to receive immediate (<10 s) or delayed cord clamping (DCC) (≥60 s). RESULTS: 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. CONCLUSIONS: 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.

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

A correction to this paper has been published and can be accessed via a link at the top of the paper.

Left ventricular vortex formation in preterm infants assessed by blood speckle imaging.

BACKGROUND: A vortex is a rotational fluid structure formed by shearing of fluid layers. It forms during diastole in the left ventricle (LV) and helps redirect flow to the LV outflow tract for ejection, optimizing energy conservation. The aim of this study was to demonstrate the feasibility of detecting and analyzing LV vortices using a new ultrasound technique known as blood speckle imaging (BSI). METHODS: Conventional and BSI parameters were acquired in preterm infants referred for echocardiography. BSI feasibility and reliability were explored using highest frequency settings and optimized Nyquist limits. Vortex area was determined by tracing the outer vortex ring at maximum area. Peak vortex formation time (PVFT) was determined at time of maximum vortex area relative to the R-wave, and vortex duration from frame-by-frame analysis of first appearance to vortex degradation. RESULTS: Left ventricle vortices were detected in 49 of the 50 preterm infants (weight 500-2020 g) with excellent intra- and inter-observer reliability. Mean vortex area indexed to LV area was 0.19 (0.08). Peak vortex formation time was at 87 (7)% of the cardiac cycle, and vortex duration lasted 13 (4)% of the cardiac cycle. Vortex area correlated positively with LV length, end-diastolic dimension, end-diastolic volume, mitral annular (R +0.42, +0.50, +0.47, +0.50, all P < 0.01), and transmitral Vti (R +0.37, P < 0.01). PVFT correlated negatively with E, EA, and Ee' (R -0.42, -0.47, -0.47, all P < 0.01). CONCLUSION: Left ventricle vortex formation can be analyzed with two-dimensional BSI and has the potential to complement existing parameters of cardiac health.

Left Ventricular Diastolic Dysfunction and Diastolic Heart Failure in Preterm Infants.

Diastolic dysfunction is primarily an echocardiographic diagnosis. Its clinical counterpart is diastolic heart failure, where the heart has difficulty to fill at normal pressure and the patient develops signs of pulmonary edema. Although diastolic dysfunction is common in adults, limited information is available in preterm infants. The aim of this study is to explore left ventricular diastolic dysfunction and diastolic heart failure in preterm infants and describe clinical manifestations in this population. This is a retrospective observational study in preterm infants < 30 weeks' gestation who received an echocardiography in the first 4 weeks after birth. Diastolic dysfunction was graded using a population-specific adapted version of the adult recommendations for the evaluation of left ventricular diastolic function by echocardiography. Left ventricular diastolic dysfunction was absent, indeterminate, and definite in 82%, 14%, and 4% of the 168 echocardiograms analyzed, and is associated with increased respiratory signs and respiratory deterioration at 48 h before echocardiogram. In seven infants, diastolic heart failure was diagnosed with both ultrasound and clinical signs. The cumulative risk of diastolic dysfunction increased with the increasing postnatal age and a patent ductus arteriosus. Evidence of left ventricular diastolic dysfunction on echocardiography is relatively common in preterm infants, while the left ventricular diastolic heart failure is less frequent. Prolonged exposure to volume load was the most common cause.

Preterm Infant Outcomes after Randomization to Initial Resuscitation with FiO2 0.21 or 1.0.

OBJECTIVE: To determine rates of death or neurodevelopmental impairment (NDI) at 2 years corrected age (primary outcome) in children <32 weeks' gestation randomized to initial resuscitation with a fraction of inspired oxygen (FiO2) value of 0.21 or 1.0. STUDY DESIGN: Blinded assessments were conducted at 2-3 years corrected age with the Bayley Scales of Infant and Toddler Development, Third Edition or the Ages and Stages Questionnaire by intention to treat. RESULTS: Of the 290 children enrolled, 40 could not be contacted and 10 failed to attend appointments. Among the 240 children for whom outcomes at age 2 years were available, 1 child had a lethal congenital anomaly, 1 child had consent for follow-up withdrawn, and 23 children died. The primary outcome, which was available in 238 (82%) of those randomized, occurred in 47 of the 117 (40%) children assigned to initial FiO2 0.21 and in 38 of the 121 (31%) assigned to initial FiO2 1.0 (OR, 1.47; 95% CI, 0.86-2.5; P = .16). No difference in NDI was found in 215 survivors randomized to FiO2 0.21 vs 1.0 (OR, 1.26; 95% CI, 0.70-2.28; P = .11). In post hoc exploratory analyses in the whole cohort, children with a 5-minute blood oxygen saturation (SpO2) <80% were more likely to die or to have NDI (OR, 1.85; 95% CI, 1.07-3.2; P = .03). CONCLUSIONS: Initial resuscitation of infants <32 weeks' gestation with initial FiO2 0.21 had no significant effect on death or NDI compared with initial FiO2 1.0. Further evaluation of optimum initial FiO2, including SpO2 targeting, in a large randomized controlled trial is needed. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Network Registry ACTRN 12610001059055 and the National Malaysian Research Registry NMRR-07-685-957.

A comparison between Philips and Tomtec for left ventricular deformation and volume measurements in neonatal intensive care patients.

BACKGROUND: Two-dimensional speckle tracking echocardiography is an emerging technique for analyzing cardiac function in newborns. Strain is a highly reliable and reproducible parameter, and reference values have been established for term and preterm newborns. Its implementation into clinical practice has been slow, partly due to lack of inter-vendor consistency. Our aim was to compare recent versions of Philips and Tomtec speckle tracking software for deformation and semiautomated volume and area measurements in neonatal intensive care patients. METHODS AND RESULTS: Longitudinal and circumferential deformation and cavity dimensions (volume, area) were determined off line from apical and short-axis images in 50 consecutive newborns with a median birthweight of 760 g (range 460-3200 g). Absolute mean endocardial global longitudinal strain measurements were similar between vendors, but with wide limits of agreement (Philips -18.9 [2.1]%, Tomtec -18.6 [2.5]%, bias -0.3 [1.7]%, and limits of agreement -3.6%-3.1%). Longitudinal strain rate and circumferential measurements showed poor correlation. All volume and area measurements correlated well between the vendors, but with significant bias. CONCLUSION: Global longitudinal strain measurements compared well between vendors but wide limits of agreement, suggesting that longitudinal measurements are preferred using similar hardware and software.

Left atrium function and deformation in very preterm infants with and without volume load.

BACKGROUND: Left atrium (LA) function can be assessed by volumetric measurements, conventional and tissue Doppler, and more recently, deformation imaging using two-dimensional speckle tracking echocardiography (2DSTE). 2DSTE allows for measurement of volume and deformation and can quantify the contribution of the reservoir, conduit, and contraction phase. A common cause for LA dysfunction in very preterm infants is volume overload with a patent ductus arteriosus (PDA). The aim of this study was to explore the feasibility and reliability of LA 2DSTE in preterm infants, and describe LA function with and without PDA volume load. METHODS: We prospectively recruited preterm infants <30 weeks of gestation referred for assessment of a possible PDA. A cardiac ultrasound was performed at day 3 and in week 4 of life and analyzed using conventional techniques and 2DSTE. RESULTS: Forty-eight infants (32 with PDA) were included. LA 2DSTE analysis was feasible in 96% of measurements with good reliability of strain and volume parameters. Strain rate was less reliable. Poorer LA contraction and reservoir function was associated with larger LA volume index, higher inflow over the mitral valve at early diastole, higher EA ratio, and higher Ee' ratio. Poorer conduit function was associated with higher Ee' ratio. A larger PDA diameter was found to be an independent contributor to deteriorating LA contraction and reservoir function. CONCLUSION: LA 2DSTE analysis is feasible in preterm infants and provides detailed information on atrium mechanics. Further studies are needed to explore the clinical value of these new parameters in this population.