Shape of Pulmonary Artery Doppler Flow Profile and Right Ventricular Hemodynamics in Neonates.

OBJECTIVES: To characterize pulmonary artery Doppler flow profile (PAFP) patterns among infants receiving care in neonatal intensive care units and to examine the association of PAFP patterns with pulmonary and right ventricular (RV) hemodynamics. STUDY DESIGN: This is a retrospective study at 2 tertiary intensive care units over 4 years that included neonates who demonstrated a complete tricuspid regurgitation envelope on targeted neonatal echocardiography. Separate personnel reviewed TNEs to characterize PAFP patterns, divide cohort into PAFP groups, and measure quantitative indices of RV hemodynamics (RV systolic pressure, pulmonary artery acceleration time and its ratio with RV ejection time, tricuspid annular plane systolic excursion, and RV output), for intergroup comparisons. RESULTS: We evaluated TNEs from 186 neonates with median gestational age of 28.5 weeks (IQR, 25.9-35.9 weeks). Four distinct PAFP patterns were identified (A) near-isosceles triangle (22%), (B) right-angled triangle (29%), (C) notching (40%), and (D) low peak velocity (<0.4 m/s; 9%). Groups A-C demonstrated a stepwise worsening in all indices of PH, whereas pattern D was associated with lower tricuspid annular plane systolic excursion and RV output. Using common definitions of pulmonary hypertension (PH), pattern A performed best to rule out PH (sensitivity range, 81%-90%) and pattern C for diagnosing PH (specificity range, 63%-78%). CONCLUSIONS: Inspection of PAFP is a simple bedside echocardiography measure that provides clinically meaningful information on underlying RV hemodynamics and may aid in screening and monitoring of patients for PH in intensive care units.

Impact of Early Hemodynamic Screening on Extremely Preterm Outcomes in a High-Performance Center.

Rationale: Increasing survival of extremely preterm infants with a stable rate of severe intraventricular hemorrhage represents a growing health risk for neonates. Objectives: To evaluate the role of early hemodynamic screening (HS) on the risk of death or severe intraventricular hemorrhage. Methods: All eligible patients 22-26+6 weeks' gestation born and/or admitted <24 hours postnatal age were included. As compared with standard neonatal care for control subjects (January 2010-December 2017), patients admitted in the second epoch (October 2018-April 2022) were exposed to HS using targeted neonatal echocardiography at 12-18 hours. Measurements and Main Results: A primary composite outcome of death or severe intraventricular hemorrhage was decided a priori using a 10% reduction in baseline rate to calculate sample size. A total of 423 control subjects and 191 screening patients were recruited with a mean gestation and birth weight of 24.7 ± 1.5 weeks and 699 ± 191 g, respectively. Infants born at 22-23 weeks represented 41% (n = 78) of the HS epoch versus 32% (n = 137) of the control subjects (P = 0.004). An increase in perinatal optimization (e.g., antepartum steroids) but with a decline in maternal health (e.g., increased obesity) was seen in the HS versus control epoch. A reduction in the primary outcome and each of severe intraventricular hemorrhage, death, death in the first postnatal week, necrotizing enterocolitis, and severe bronchopulmonary dysplasia was seen in the screening era. After adjustment for perinatal confounders and time, screening was independently associated with survival free of severe intraventricular hemorrhage (OR 2.09, 95% CI [1.19, 3.66]). Conclusions: Early HS and physiology-guided care may be an avenue to further improve neonatal outcomes; further evaluation is warranted.

Anomalous origin of the right coronary artery from the pulmonary artery (ARCAPA): Echocardiographic diagnosis in a critically ill newborn.

ARCAPA echocardiographic diagnosis. A network of small multiple coronary vessels, a systo-diastolic jet of flow into the pulmonary artery and a retrograde inverted «blue¼ flow into the RCA are the key signs. CT-scan confirms the diagnosis .

Echocardiographic evaluation of left atrial volume and comparative analysis to left atrial to aortic root ratio in premature neonates and infants with patent ductus arteriosus.

PURPOSE: Left atrium to aortic root ratio (LA/Ao) is an echocardiographic marker of hemodynamically significant patent ductus arteriosus (PDA). Since 2-dimensional measurement of the ratio is geometrically limited, left atrial volume (LAV) which has 3-dimensional characteristics was investigated. The aim of this study was to determine a correlation between LA/Ao ratio and LAV as well as holodiastolic flow reversal in preterm neonates with and without a PDA. METHODS: A retrospective evaluation of neonates with and without PDA was performed. Targeted neonatal echocardiography evaluation of LA/Ao and LAV was measured from parasternal long-axis view and the apical 4 and 2-chamber views, respectively. Univariate and linear regression analysis were performed. RESULTS: 200 patients were included of whom 158 (79.0%) had a PDA shunt. The median gestational age at the time of echo was 27.4 weeks (IQR: 25.7-29.4 weeks). The median LA/Ao ratio was 1.51 (IQR: 1.26-1.83) and median LAV indexed to weight was  .91 mL/kg (IQR: .65-1.18 mL/kg). There was a significant correlation between LA/Ao and LAV indexed to weight in the PDA group (r2 = .080, p = .0003). LA/Ao ratio and LAV indexed to weight differed significantly between those with diastolic flow reversal versus no-flow reversal (LA/Ao, p = .003; LAV, p = .001). CONCLUSIONS: This study demonstrated a significant correlation between LA/Ao and LAV in preterm infants with PDA, with greater magnitude of discordance for LAV. The power of LAV versus LA/Ao in monitoring hemodynamically significant PDA requires prospective evaluation.

Assessment of Myocardial Function in Infants of Mothers with Gestational Diabetes Mellitus Using Deformation Imaging over the First Year of Age.

OBJECTIVE: To assess serial myocardial performance and pulmonary vascular resistance (PVR) in infants of mothers with gestational diabetes mellitus (GDM) over the first year of life. STUDY DESIGN: This was a prospective, observational study. Echocardiography was performed at birth, 6 months, and 1 year of age. Pulmonary artery acceleration time and left ventricular (LV) eccentricity index provided surrogate measurements of PVR. Biventricular function was assessed by tissue Doppler imaging and deformation analysis. RESULTS: Fifty infants of mothers with GDM were compared with 50 controls with no difference in gestation (38.9 ± 0.8 weeks vs 39.3 ± 0.9 weeks; P = .05) or birthweight (3.55 ± 0.49 kg vs 3.56 ± 0.41 kg; P = .95). At 1 year of age, the pulmonary artery acceleration time was lower (70 ± 11 vs 79 ± 10; P = .01) in the GDM group. LV global longitudinal strain (24.7 ± 1.9 vs 28.8 ± 1.8 %; P < .01), LV systolic strain rate (1.8 ± 0.2 vs 2.1 ± 0.3 1/s; P < .01), and RV free wall strain (31.1 ± 4.8 vs 34.6 ± 3.9 %; P < .01) were lower in the GDM cohort at 1 year of age (all P values adjusted for gestation, mode of delivery, and maternal body mass index). CONCLUSIONS: Our findings demonstrate higher indices of PVR and lower biventricular function in infants of mothers with GDM compared with controls at each time point assessed in this study over the first year of life.

Growth of targeted neonatal echocardiography in Chinese neonatal intensive care units: gaps in practice and training.

To evaluate clinical practice, neonatologists' attitudes, and the extent of training and accreditation regarding targeted neonatal echocardiography (TnEcho) among Chinese neonatologists. A web-based questionnaire was emailed to 331 neonatologists across China who completed training in subspecialty neonatology. The survey covered various aspects of TnEcho, including the characteristics of clinical practice, attitudes towards its usefulness, and perceived barriers to implementation and training methods. Survey response rate was 68.0% (225/331). Seventy-nine (35.1%) respondents stated that TnEcho was utilized in their NICUs. Most respondents reported the use of echocardiography to evaluate hemodynamic significance of the patent ductus arteriosus (PDA, 94.9%). The eyeballing technique was most used to evaluate left (82.3%) and right (77.2%) ventricular function. Most respondents (87.3-96.2%) positively valued the role of TnEcho in providing timely and longitudinal hemodynamic information to guide cardiovascular care. Access to TnEcho was more likely in centers with on-site pediatric cardiology service (p = .003), larger bed capacity (p = .004), or level IV status (p = .003). Lack of experienced practitioners with echocardiography expertise (88.9%) and accredited training programs (85.8%) was perceived to be the major barrier to implementation. Of concern, most practitioners with TnEcho skills received training in an informal manner through workshops (60.8%) or self-directed learning (54.4%). Conclusions: The use of TnEcho for longitudinal evaluation of infants with hemodynamic instability is growing within Chinese NICUs. There is an urgent need to develop standardized training programs and accreditation for TnEcho which are adapted to the Chinese context.

Outcomes of patent foramen ovale greater than 3 mm at birth in extremely low birthweight infants.

BACKGROUND: Foramen ovale (FO) is an obligate fetal shunt that typically resolves after birth, although patency throughout life is not uncommon. The natural history of patent FO (PFO) is known in term infants, but less is known about its course in extremely preterm infants. We describe the echocardiographic changes in FO size from birth to discharge in extremely low birth weight (ELBW) infants in this retrospective study. METHODS: Cohort was divided based on size of FO at birth. Size of FO at discharge was measured and evaluated relative to postnatal weight gain. Demographics and clinical outcomes were compared between the two groups. RESULTS: Of the 54 ELBW infants, 50 were born with FO less than 3 mm in diameter (small), and 4 were born with FO greater than 3 mm (large). Of small defects, the majority (44/50, 88%) did not increase in size with weight gain, and minority (6/50, 12%) increased in size, and three of these 6 patients, FO grew to be slightly larger than 3 mm. In contrast, all large defects (4 of 4, 100%) nearly doubled in size with postnatal growth. These 4 ELBW infants with enlargement of FO had a flap valve evident on echocardiogram obtained prior to discharge, and subsequently closed on outpatient follow-up echocardiograms, although time to resolution was variable (6 months - 3 years). One infant had presumptive resolution because of the presence of flap valve. CONCLUSION: No maternal or neonatal demographic characteristics were predictive of FO enlargement, although, demonstrable flap valve on discharge echocardiogram correlated with resolution of FO on outpatient follow-up echocardiogram. Therefore, based on our data, we recommend that ELBW infants born with large FO should have echocardiographic re-evaluation of the atrial septal opening prior to discharge, to specify the presence of a flap valve or lack thereof, which is an important detail that can help a neonatologist determine the need for outpatient cardiac follow-up.

Management of neonatal pulmonary hypertension-a survey of neonatal intensive care units in India.

BACKGROUND: Persistent pulmonary hypertension of the newborn (PPHN) is a common neonatal condition associated with significant morbidity and mortality. First-line diagnostic and treatment options such as echocardiography and inhaled nitric oxide (iNO) are not routinely available in resource limited settings and alternative treatment modalities need to be utilized. This study was conducted to assess current diagnostic and management strategies used for PPHN in Indian neonatal intensive care units (NICUs). METHODS: A questionnaire in multiple choice question format was sent to practising neonatologists in India via an online survey tool between July to August 2021. Information pertaining to demographic data, diagnostic criteria and management strategies of PPHN was requested. The responses were collated and information processed. RESULTS: There were 118 respondent NICUs (response rate 74%). The majority of neonatal units (65%) admitted an average of 1-3 patients of PPHN per month. Targeted neonatal echocardiography (TnECHO) was practised in 80% of the units. Most common management strategies being followed were pulmonary vasodilators (88.1%), inotropes (85.6%), conventional ventilation (68.6%) and high frequency ventilation (59.3%). The most preferred pulmonary vasodilator was sildenafil (79%) and inotropic agent was milrinone (32%). Only 25% of respondents reported use of iNO. None of the participating units used extracorporeal membrane oxygenation. CONCLUSION: We found wide variability in management practices of PPHN across Indian NICUs. Non-selective pulmonary vasodilators are more widely used than iNO. There is an urgent need for structured TnECHO training programs and evidence based national guidelines for standardized management of PPHN as per availability of resources in India. Additional research on low cost alternative therapies to iNO in Indian settings might be helpful.

Normal values for superior vena cava flow in preterm neonates using a new echocardiographic approach.

OBJECTIVE: Recently, a novel approach to imaging Superior Vena Cava (SVC) flow has been presented, showing better repeatability and better agreement with MRI-derived SVC flow measures. The objective was to establish normal values of SVC flow with the novel approach in the first 48 h of life. STUDY DESIGN: This was a prospective, observational study. All infants with gestational age (GA) less than 31 weeks were eligible. Echocardiographic evaluation was performed at 5, 12, 24, 48 h of postnatal life. A subgroup of uncomplicated infants was studied to define a normal range for SVC flow. RESULTS: Forty-five infants were enrolled. We estimated normative values in a subgroup of 31 uncomplicated infants. The median SVC flow significantly increases from 83 ml/kg/min at 5 h of life to 153 ml/kg/min at 48 h (p < .001). CONCLUSION: Using the novel approach we derived normal values of SVC flow in a cohort of uncomplicated preterm population at high risk for developing IVH.

Physiology of Low Blood Pressure During the First Day After Birth Among Extremely Preterm Neonates.

OBJECTIVE: To investigate the circulatory physiology of hypotension during the first day after birth among stable extremely preterm neonates. STUDY DESIGN: Case-control study of neonates born at ≤276/7 weeks gestational age with hypotension, defined as mean blood pressure in mmHg less than gestational age in weeks for at least 1 hour during the first 24 hours after birth, who underwent comprehensive echocardiography assessment before commencement of cardiovascular drugs. Neonates with hypotension (n = 14) were matched by gestational age and intensity of respiratory support with normotensive neonates (n = 27) who underwent serial echocardiography during the first day after birth, and relatively contemporaneous echocardiography assessments were used for comparison. RESULTS: Neonates with hypotension had a higher frequency of patent ductus arteriosus ≥1.5 mm (71% vs 15%; P < .001) and ductal size (median diameter, 1.6 mm [IQR, 1.4-2.1] vs 1.0 mm [IQR, 0-1.3]; P = .002), higher echocardiography indices of left ventricular systolic function (mean shortening fraction, 34 ± 7% vs 26 ± 4%; P < .001; mean longitudinal strain, -16 ± 5% vs -14 ± 3%; P = .04; and mean velocity of circumferential fiber shortening, 1.24 ± 0.35 circ/s vs 1.01 ± 0.28 circ/s; P = .03), lower estimates of left ventricular afterload (mean end-systolic wall stress, 20 ± 7 g/cm2 vs 30 ± 9 g/cm2; P < .001 and mean arterial elastance, 43 ± 19 mmHg/mL vs 60 ± 22 mmHg/mL; P = .01), without significant difference in stress-velocity index z-score (-0.42 ± 1.60 vs -0.88 ± 1.30; P = .33). Neonates with hypotension had higher rates of any degree of intraventricular hemorrhage (71% vs 22%; P = .006). CONCLUSIONS: Low blood pressure in otherwise well extremely low gestational age neonates was associated with low systemic afterload and larger patent ductus arteriosus, but not left ventricular dysfunction.

Perioperative management of arteriovenous malformation guided by integrated evaluation of hemodynamics.

We aimed to demonstrate the value of monitoring infants with arteriovenous malformation (AVM) during endovascular embolization with integrated evaluation of hemodynamics (IEH) and guiding decisions according to the underlying pathophysiology. This is a retrospective analysis of the perioperative hemodynamics data for 2 complex cases of AVM transferred to Khaula Hospital in Oman for interventional management. We described the value of novel physiological insights gained from comprehensive IEH and provided a systematic approach to the perioperative management. Postoperative targeted neonatal echo (TNE) was used to guide the weaning of the cardiovascular medications within 24 h. Both cases showed significant right ventricle (RV) volume overload before surgery. Narrowing of the pulse pressure (PP) during or after endovascular embolization was used as a marker of compromised systemic blood flow in real time followed by an assessment by TNE to guide the appropriate therapy.Conclusion: Integrated evaluation of hemodynamics is helpful to guide perioperative physiologic-based management of AVM. What is Known: • The preoperative management of hemodynamic compromise due to AVM has been described in many articles. • Perioperative management of AVM and related hemodynamics is a challenge to the intensive care team. What is New: • Integrated evaluation of hemodynamics is a comprehensive assessment and helpful in understanding the underlying physiologic changes during intervention with AVM. • This integrated evaluation can lead to physiologic-based medical recommendation with subsequent improvement.

The evolution of cardiac point of care ultrasound for the neonatologist.

Cardiac point of care ultrasound (POCUS) is increasingly being utilized in neonatal intensive care units to provide information in real time to aid clinical decision making. While training programs and scope of practice have been well defined for other specialties, such as adult critical care and emergency medicine, there is a lack of structure for neonatal cardiac POCUS. A more comprehensive and advanced hemodynamic evaluation by a neonatologist has previously published its own clinical guidelines and specific rigorous training programs have been established to achieve competency in neonatal hemodynamics. However, it is becoming increasingly evident that access and training for basic cardiac assessment by ultrasound enhances bedside clinical care for specific indications. Recently, expert consensus POCUS guidelines for use in neonatal and pediatric intensive care endorsed by the European Society of Pediatric and Neonatal Intensive Care (ESPNIC) have been published to guide the clinicians in using POCUS for specific indications, though the line between cardiac POCUS and advanced hemodynamic evaluation remains somewhat fluid.Conclusion: This article is focused on neonatal cardiac POCUS and its evolution, value, and limitations in the modern neonatal clinical practice. Cardiac POCUS can provide physiological and hemodynamic information in making clinical decisions while dealing with neonatal emergencies. However, it should be applied only for the specific indications and should be performed by a clinician trained in cardiac POCUS. There is an urgent need of developing cardiac POCUS curriculum and certification to support a widespread and safe use in neonates. What is Known: • International training guidelines and curriculum have been published for neonatologist-performed echocardiography (NPE) or targeted neonatal echocardiography (TNE). • International evidence-based guidelines for use of point of care ultrasound (POCUS) in neonates and children have been recently published. What is New: • Cardiac POCUS is increasingly being incorporated in neonatal practice for emergency situations. However, one must be aware of its specific indications and limitations, especially for the neonatal clinical practice. • Cardiac POCUS and NPE/TNE are continuum of cardiac imaging with different indications and training requirements.

Assessment of superior vena cava flow and cardiac output in different patterns of patent ductus arteriosus shunt.

BACKGROUND: Despite the widespread use of superior vena cava (SVC) flow as a marker of systemic blood flow from the upper body, no previous studies have systematically evaluated the correlation between SVC flow and other echocardiography measures of systemic blood flow in the context of different patterns of patent ductus arteriosus (PDA) shunt direction METHODS: A retrospective cohort study of preterm infants (< 30 weeks, < 21 days of life) who underwent comprehensive targeted neonatal echocardiography (TnECHO) was performed. Patients were categorized as follows: (i) Hemodynamically significant left-to-right shunt; (ii): Bidirectional shunt; (iii) No PDA or insignificant shunt. SVC flow, as measured by two distinct methods, was compared to left and right ventricular outputs (LVO and RVO). Intra- and inter-observer reliability testing was performed RESULTS: In total, 45 patients were included (15 in each group) with a median [IQR] weight of 720 [539, 917] grams at the time of assessment. SVC dimensions and flow measurements were not different between the groups, although patients with left-to-right shunt had higher LVO/RVO ratio. SVC flow, as estimated using the modified method, had a strong correlation with LVO (r = .63, p = 0.012) and RVO (r = .635, p = 0.011) in patients with no PDA. Inter- and intra-observer reliability were both stronger for LVO and RVO when compared to SVC flow measurements CONCLUSION: SVC flow was comparable across all three groups irrespective of higher LVO and LVO/RVO ratio in patients with left-to-right shunts. This may reflect poor measurement reliability or compensation for left-to-right ductal shunt by increased LVO to maintain systemic perfusion.

Relationship of Patent Ductus Arteriosus Echocardiographic Markers With Descending Aorta Diastolic Flow.

OBJECTIVES: To characterize the relationship of echocardiographic markers of left heart overload and flow in peripheral major end-organ vessels (eg, celiac artery) with the presence of reversed holodiastolic flow in the descending aorta, considered a surrogate marker of an increased transductal shunt volume, in preterm patients with a patent ductus arteriosus (PDA). METHODS: This work was a retrospective study of data from echocardiography performed to investigate the hemodynamic significance of a PDA in preterm patients. We studied differences in echocardiographic markers of the PDA shunt volume according to patterns of flow in the postductal descending aorta (no PDA, PDA with antegrade diastolic flow, and PDA with reversed diastolic flow). The strength of the association between each echocardiographic marker and the presence of aortic holodiastolic flow reversal was investigated. RESULTS: We studied 137 patients with a median (interquartile range) birth weight of 850 (694-1030) g and a median gestational age of 25 (24-27) weeks. Among patients with a PDA (113), those with diastolic flow reversal in the descending aorta (44) presented had increased echocardiographic markers representative of the shunt volume (increased left ventricular output, left atrial-to-aortic ratio, pulmonary vein D wave, and shorter isovolumic relaxation time) compared to those with aortic antegrade diastolic flow. A positive, albeit weak, correlation between diastolic flow reversal and shunt volume echocardiographic markers was found. Abnormal diastolic flow in the celiac artery had the strongest correlation (R2  = 0.24). CONCLUSIONS: In preterm patients with a PDA, echocardiographic markers of the shunt volume were more abnormal in patients with reversed diastolic flow in the descending aorta. These data support the assumption that variance in these markers are related to the shunt volume, which needs consideration when adjudicating hemodynamic significance.

Targeted neonatal echocardiography-guided therapy pre-embolisation for congenital hepatic vascular malformation: inhaled nitric oxide to prevent paradoxical embolisation to the systemic circulation.

Arteriovenous malformations may present with significant haemodynamic compromise in the neonatal period, typically with high output cardiac failure that may be accompanied by hypoxia and right ventricular dysfunction. Targeted neonatal echocardiography performed by trained neonatologists provides an enhanced physiology-based approach that can guide treatment and minimise complications. We present a case of a large hepatic vascular malformation whose therapy was guided by targeted neonatal echocardiography to prevent paradoxical embolisation of procedural glue to the systemic circulation.

Use of sildenafil in an infant with persistent pulmonary hypertension secondary to lung and renal hypoplasia - a case report.

BACKGROUND: Premature preterm rupture of membranes (PPROM) is reported to be associated with high rates of neonatal mortality and morbidity. Sildenafil has been used in infants with persistent pulmonary hypertension of newborn (PPHN) due to congenital diaphragmatic hernia (CDH) and bronchopulmonary dysplasia (BPD). Recently, Sildenafil has been evaluated as an alternative or adjunctive pulmonary vasodilator. This case report illustrates the use of early sildenafil for PPHN and right ventricular dysfunction in an unusual setting of lung and renal hypoplasia. CASE PRESENTATION: A male infant was born at 37 weeks with a birth weight of 2840 g. Rupture of membranes developed at approximately 24 weeks of gestational age (GA). Bilateral small kidneys (< 2 standard deviations below average) were detected on ultrasound (US) examination at 30 weeks of gestation. The baby developed pneumothorax and pulmonary hypertensive crisis towards the end of the first day. An echocardiogram showed a dilated right ventricle, moderate right ventricular systolic dysfunction, hypoplastic pulmonary arteries and a large patent ductus arteriosus with bidirectional flow. The patient was sedated, paralyzed, and inhaled nitric oxide was administered to decrease the pulmonary resistance. In anticipation of persistent pulmonary hypertension due to the hypoplastic lungs and small calibre of pulmonary arteries, sildenafil was started on day of life (DOL) 5 at a dosage of 0.25 mg/kg/dose Q8H and gradually increased to 2 mg/kg/dose Q8H on DOL 9. The patient was finally extubated on DOL 7 and weaned off of non-invasive respiratory support on DOL 26. Sildenafil was gradually weaned beginning on DOL 21 and discontinued on DOL 48. Repeat echocardiogram assessment at 3 months showed complete resolution of PHT and right ventricular dilatation. CONCLUSIONS: We describe the early use of sildenafil in treating pulmonary hypertension associated with lung and renal hypoplasia in a non-CDH patient. Following this treatment the patient made a full recovery from right ventricular dysfunction.

Clinical and echocardiography predictors of response to inhaled nitric oxide in hypoxic preterm neonates.

AIM: To evaluate the clinical and echocardiography modulators of treatment response in hypoxemic preterm infants exposed to inhaled nitric oxide (iNO). METHODS: In this multicentre retrospective study, clinical parameters, including oxygenation, ventilation and haemodynamics, were collected for preterm infants <36 weeks gestation before and 2 h after initiation of iNO for acute hypoxemia. Comprehensive echocardiography, performed near the time iNO initiation, was analysed by experts blind to the clinical course. Multiple logistic regression analysis was used to identify factors associated with iNO response as defined by a reduction in the fraction of inspired oxygen by >0.20. RESULTS: A total of 213 infants met eligibility criteria, of which 73 had echocardiography data available and formed the study cohort. Response to iNO was demonstrated in 56% of patients. Younger post-natal age (odds ratio (OR) 0.94; 95% confidence interval (CI) 0.89, 0.99) and the presence of pulmonary hypertension (PH) (OR 4.47; 95% CI 1.23-11.9) were independently predictive of iNO response regardless of gestational age. Among neonates <72 h old with documented PH, iNO response was seen in 82%. The onset of a new diagnosis of severe (grade III/IV) intraventricular haemorrhage (IVH) after iNO treatment was seen in 6 of 40 patients <28 weeks' gestational age, with a greater frequency in responders (32 vs. 0%, P = 0.02). CONCLUSIONS: Positive response to iNO is greatest in the first 3 days of life and in patients with echo-confirmed PH, independent of gestational age. The association between critical illness, iNO administration and IVH in extremely premature infants may merit prospective delineation.

Relationship of Patent Ductus Arteriosus Size to Echocardiographic Markers of Shunt Volume.

OBJECTIVE: To define the technique of estimating ductal diameter (DD) that best correlates with echocardiographic markers of transductal shunt volume in preterm infants >7 days old with persistent patent ductus arteriosus (PDA). STUDY DESIGN: We conducted a retrospective study of 104 neonates born at <30 weeks gestation that had targeted neonatal echocardiography evaluation of PDA performed between 7 and 30 days. We used univariate analysis to determine the association of echocardiographic markers of shunt volume with ductal size definitions: DD, DD indexed to weight, and DD indexed to left pulmonary artery diameter. RESULTS: Two hundred echocardiograms were reviewed from 104 patients with a median gestational age of 25.4 weeks (range, 25-26.3 weeks) and a median birth weight of 810 g (range, 740-920 g). We found a weak correlation of each method of PDA size definition with individual echocardiographic markers of transductal shunt volume, of which nonindexed DD demonstrated the best correlation. The best correlation was found with markers of systemic hypoperfusion, such as diastolic flow reversal in the descending aorta (R2 = 0.24) and celiac artery (R2 = 0.21). Markers of pulmonary overcirculation, such as left ventricular end-diastolic diameter (R2 = 0.19) and left ventricular output (R2 = 0.17), showed fair correlation with nonindexed DD. CONCLUSION: In preterm infants >7 days old with PDA, nonindexed DD demonstrated weak correlations with individual echocardiographic markers of shunt volume. These data highlight the need for comprehensive echocardiographic evaluation in addition to diameter measurements to provide a better understanding of the hemodynamic consequences of PDA.

Incidental Findings on Routine Targeted Neonatal Echocardiography Performed in Preterm Neonates Younger Than 29 Weeks' Gestation.

OBJECTIVES: The aim of this study was to quantify the rate of incidental findings identified on elective research echocardiography performed on neonates younger than 29 weeks' gestation. METHODS: We conducted a retrospective study of echocardiographic examinations performed within the first 24 hours of age on neonates younger than 29 weeks' gestation over a 3-year period for research purposes. Incidental echocardiographic findings and pertinent clinical data were recorded. RESULTS: Echocardiographic examinations performed on 145 neonates were retrospectively reviewed. Forty-three neonates (30%) had a total of 54 unexpected findings (37%). Most comprised malpositioned umbilical venous catheters, where the tip was located in the left atrium. The remainder of the conditions identified included unsuspected congenital heart disease, liver hematomas, and unexpected pulmonary hypertension. CONCLUSIONS: There is a high rate of incidental findings identified on screening echocardiograms. Routine targeted neonatal echocardiographic screening of preterm neonates may be warranted to identify the considerable likelihood of asymptomatic findings.