Diagnosis of patent ductus arteriosus in the preterm newborn

The Possible Protective Role of Bilirubin on Oxidative Stress Related Morbidity in Preterm Infants

To evaluate the effect of bilirubin levels in the first week of life on the frequency of oxidative-stress related morbidity. We included all preterm infants with a gestational age less than 32 weeks. The mean total serum bilirubin of the first week of life was measured and compared between infants with and without oxidative stress related morbidity. A total of 116 preterm infants were included. Univariate analysis showed that mean ± SD TSB levels were statistically significantly lower in infants with chronic lung disease (95 ± 31.4micromole/l vs 119 ± 31micromole/l, p = 0.019), necrotizing enterocolitis (94.4 ± 29micromole/l vs 118 ± 31micromole/l p = 0.044) and patent ductus arteriosus (104 ± 33micromole/l vs 120 ± 30micromole/l p = 0.018). However, when adjusted for gestational age, there were no longer statistically significant differences observed. Elevated bilirubin levels in the first week of life are not protective against the oxidative stress related morbidity in very preterm infants.

A Novel Patent Ductus Arteriosus Severity Score to Predict Clinical Outcomes in Premature Neonates

Background: Patent Ductus Arteriosus (PDA) in premature neonates has been associated with comorbidities including chronic lung disease (CLD), and death. However, the treatment of PDA remains controversial. There have been several echocardiographic variables previously used to determine the hemodynamic significance of PDA but their utility in early prediction of clinical outcomes is not well studied. Objective: The objective of our study was to evaluate the use of a severity scoring system incorporating markers of systemic under perfusion, pulmonary over perfusion and left ventricular (LV) function in predicting clinical outcomes in premature neonates. Methods: It is a single center prospective observational study involving newborns < 32 weeks’ gestation. An echocardiogram was done within seven days of life to measure variables previously known to predict severity of shunting in PDA including pulmonary perfusion index (PPI). Predictors of CLD/death were identified using multivariate logistic regression. A severity score was derived and its ability to predict clinical outcomes was tested using a receiver operating characteristic curve. Results: We studied 98 infants with a mean (SD) gestation of 28.9 ± 1.91 weeks and birth weight of 1228.06 ± 318.94 g, respectively. We identified five echocardiographic variables along with gestational age that was independently associated with the outcome variable (PPI, LV output, Superior Mesenteric Artery [SMA] Velocity Time Integral [VTI], Peak diastolic flow velocity in Pulmonary Vein [PV Vd], and reversal of flow in diastole in descending aorta [DFR]). The range of severity score was 0 (low risk) to 12 (high risk). A higher score was associated with the primary outcome variable of CLD/death (7.5 [1.2] vs. 3.6 [1.5], p < 0.001). Our severity score had an area under the curve of 0.97 (95% CI 0.93−0.99, p < 0.001) for predicting CLD/death. Conclusion: Our new PDA severity score of 5.5 has a sensitivity and specificity of 94% and 93%, and positive and negative predictive values of 94% and 93%, respectively.

Visual Perception, Fine Motor, and Visual-Motor Skills in Very Preterm and Term-Born Children before School Entry-Observational Cohort Study

Very preterm children (<32 weeks gestation at birth; VP) are at risk of developmental difficulties. Specific functional difficulties and delays in visual perception, fine motor, and visual-motor skills have received little research attention, although they are critical for daily life and school readiness. Our aim was to assess these skills in a contemporary cohort of 60 VP and 60 matched term-born children before school entry. We administered the Movement Assessment Battery for Children (M-ABC-2) and the Developmental Test of Visual Perception (DTVP-2). Linear and logistic regressions were run to test group differences in performance and rates of developmental delay in visual perception, fine motor, and visual-motor skills. Very preterm children had lower scores than term-born children in visual perception (β = -0.25; p = 0.006), fine motor (β = -0.44; p < 0.001), and visual-motor tasks (β = -0.46; p < 0.001). The rate of developmental delay (<-1 SD) was higher among VP in visual perception (odds ratio (OR) = 3.4; 95% confidence interval (CI 1.1-10.6)), fine motor (OR = 6.2 (2.4-16.0)), and visual-motor skills (OR = 13.4 (4.1-43.9)) than in term-born controls. VP children are at increased risk for clinically relevant developmental delays in visual perception, fine motor, and visual-motor skills. Following up VP children until preschool age may facilitate early identification and timely intervention.

Voice and Exercise Related Respiratory Symptoms in Extremely Preterm Born Children After Neonatal Patent Ductus Arteriosus

Objective: To investigate voice characteristics and exercise related respiratory symptoms in extremely preterm born 11-year-old children, focusing particularly on associations with management of a patent ductus arteriosus (PDA). Study design: Prospective follow-up of all children born in Norway during 1999-2000 at gestational age <28 weeks or with birthweight <1,000 g. Neonatal data were obtained prospectively on custom-made registration forms completed by neonatologists. Voice characteristics and exercise related respiratory symptoms were obtained at 11 years by parental questionnaires. Result: Questionnaires were returned for 228/372 (61%) eligible children, of whom 137 had no history of PDA. PDA had been noted in 91 participants, of whom 36 had been treated conservatively, 21 with indomethacin, and 34 with surgery. Compared to the children treated with indomethacin or conservatively, the odds ratio (95% confidence interval) for the surgically treated children were 3.4 (1.3; 9.2) for having breathing problems during exercise, 16.9 (2.0; 143.0) for having a hoarse voice, 4.7 (1.3; 16.7) for a voice that breaks when shouting, 4.6 (1.1; 19.1) for a voice that disturbs singing, and 3.7 (1.1; 12.3) for problems shouting or speaking loudly. The significance of surgery per se was uncertain since the duration of mechanical ventilation was associated with the same outcomes. Conclusion: Extremely preterm born children with a neonatal history of PDA surgery had more problems with voice and breathing during exercise in mid-childhood than those whose PDA had been handled otherwise. The study underlines the causal heterogeneity of exercise related respiratory symptoms in preterm born children.

The effect of patent ductus arteriosus on pre-ductal and post-ductal perfusion index in preterm neonates

OBJECTIVE

The ductus arteriosus is a blood vessel that connects the pulmonary artery to the descending aorta during fetal life and generally undergoes spontaneous closure shortly after birth. In premature neonates it often fails to close (patent ductus arteriosus-PDA), which can result in diversion of a significant part of the left-ventricular cardiac output to the pulmonary circulation. This left-to-right shunt may result in significant increase of pulmonary blood flow and decrease of systemic perfusion (hemodynamically significant PDA-hsPDA), which may lead to severe neonatal morbidity. The study objective was to find the relationship between hsPDA and perfusion index (PI), a photoplethysmographic parameter related to systemic perfusion.

APPROACH

PI measures the relative systolic increase in tissue light absorption due to the systolic increase in the tissue blood volume. PI has been found to be directly related to tissue perfusion and is therefore expected to be affected by hsPDA.

MAIN RESULTS

PI was found to be higher in preterm neonates with hsPDA after first week of life, in comparison to those with closed DA, despite the lower systemic perfusion, probably due to reverse flow during diastole.

SIGNIFICANCE

In our study, perfusion index increased despite the lower systemic perfusion, indicating that in neonates with hsPDA, perfusion index is not necessarily a measure of perfusion. Nevertheless, PI can be used as a screening tool for suspicious PDA, in order to select a relatively small group of neonates for a more definitive examination by echocardiography, which is not suitable for universal screening.

Hemodynamic Effects on Systemic Blood Flow and Ductal Shunting Flow after Loading Dose of Intravenous Caffeine in Preterm Infants according to the Patency of Ductus Arteriosus

BACKGROUND

In preterm infants, caffeine citrate is used to stimulate breathing before they are weaned from mechanical ventilation and to reduce the frequency of apnea. In recent studies, effects of caffeine on the cardiovascular system have been emphasized in preterm infants with patent ductus arteriosus (PDA).

METHODS

This study aimed to assess the short-term hemodynamic effects on systemic blood flow and ductal shunting flow after loading standard doses of intravenous caffeine in preterm infants. Echocardiographic studies were performed by a single investigator, before and at 1 hour and 4 hours after an intravenous infusion of a loading dose as 20 mg/kg caffeine citrate for 30 minutes.

RESULTS

In 25 preterm infants with PDA, left ventricular output decreased progressively during 4 hours after caffeine loading. Superior vena cava (SVC) flow decreased and ductal shunting flow increased at 1 hour and then recovered at 4-hour to baseline values. A diameter of PDA significantly decreased only at 4-hour after caffeine loading. There were no significant changes of these hemodynamic parameters in 29 preterm infants without PDA.

CONCLUSION

In preterm infants with PDA, a standard intravenous loading dose of 20 mg/kg caffeine citrate was associated with increasing ductal shunting flow and decreasing SVC flow (as a surrogate for systemic blood flow) 1 hour after caffeine loading, however, these hemodynamic parameters recovered at 4 hours according to partial constriction of the ductus arteriosus. Close monitoring of hemodynamic changes would be needed to observe the risk for pulmonary over-circulation or systemic hypo-perfusion due to transient increasing ductal shunting flow during caffeine loading in preterm infants with PDA.

Unilateral vocal cord paralysis after surgical closure of a patent ductus arteriosus in extremely preterm infants

AIM

Left vocal cord paralysis (LVCP) is variably reported post ligation of patent ductus arteriosus (PDA). Our objective was to determine the incidence of LVCP and identify predictive factors and associated morbidities in preterm infants post PDA ligation.

METHODS

This is a retrospective cohort study of infants less than 29 weeks gestational age from 2006 to 2014 who underwent PDA ligation. Infants with laryngeal symptoms underwent flexible fibreoptic nasopharyngolaryngoscopy to evaluate vocal cord function. We compared short- and long-term morbidities among infants with and without symptomatic LVCP.

RESULTS

A total of 35 infants underwent PDA ligation in the study period, of which 11 infants (31%) developed symptomatic LVCP. Dysphonia was the presenting symptom in all neonates with LVCP and stridor was present in 46% (5/11) of them. The median (interquartile range) gestation (25 weeks (24-27) vs. 25 weeks (23-28)), birthweight (810 g (550-1180) vs. 825 g (550-1220)) and age at surgery (19 days (9-27) vs. 20 (5-69)) were similar in infants with and without LVCP, respectively. Infants with LVCP took significantly longer to reach suck feeds (128 vs. 90 days, P = <0.001), stayed longer in hospital (119 vs. 95 days, P = 0.01) and were more likely to go home on oxygen (73 vs. 27%; P = 0.024). Neurodevelopmental outcomes were similar in the two groups.

CONCLUSIONS

LVCP was noted in 31% of infants post PDA ligation and was associated with prolonged hospital stay, a longer time to reach suck feeds and a need for home oxygen. No predictive factors for development of LVCP were identified.

Enteral paracetamol or Intravenous Indomethacin for Closure of Patent Ductus Arteriosus in Preterm Neonates: A Randomized Controlled Trial

OBJECTIVE

To compare the efficacy of enteral paracetamol and intravenous indomethacin for closure of patent ductus arteriosus (PDA) in preterm neonates.

DESIGN

Randomized controlled trial.

SETTING

Level III neonatal intensive care unit.

PARTICIPANTS

77 preterm neonates with birth weight ?1500 g and PDA size ?1.5 mm, with left to right ductal flow with left atrium to aortic root ratio >1.5:1; diagnosed by 2D-Echo within first 48 hours of life.

INTERVENTION

Paracetamol drops through the infant feeding tube (15 mg/kg/dose 6 hourly for 7 days) or intravenous indomethacin (0.2 mg/kg/dose once daily for 3 days).

OUTCOME MEASURES

Primary: PDA closure rate assessed by echocardiography. Secondary: need for surgical closure of PDA, renal impairment, gastrointestinal bleed, necrotising enterocolitis, hepatotoxicity, pulmonary hemorrhage, sepsis, hypothermia, retinopathy of prematurity, intraventricular hemorrhage, bronchopulmonary dysplasia and mortality.

RESULTS

PDA closure rate was 100% (36/36) in enteral paracetamol group as compared to 94.6% (35/37) in intravenous indomethacin group (P=0.13). The secondary outcomes were also similar between the two groups. There was no occurrence of hepatotoxicity.

CONCLUSIONS

Enteral paracetamol is safe but not superior to intravenous indomethacin in the treatment of PDA in preterm neonates.

Chest shielding for prevention of a haemodynamically significant patent ductus arteriosus in preterm infants receiving phototherapy

BACKGROUND

Patent ductus arteriosus (PDA) is associated with mortality and morbidity in preterm infants. Phototherapy is a common treatment for jaundice in preterm infants. However, phototherapy has been associated with failure of closure of the ductus arteriosus in preterm infants.

OBJECTIVES

To determine if chest shielding of preterm infants receiving phototherapy reduces the incidence of clinically and/or haemodynamically significant PDA and reduces morbidity secondary to PDA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library; 2015, Issue 3), MEDLINE, EMBASE, CINAHL, previous reviews, cross-references, abstracts, proceedings of scientific meetings, and trial registries through March 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster-RCTs, or quasi-RCTs of chest shielding during phototherapy compared to sham shielding or no shielding for the prevention of a haemodynamically or clinically significant PDA in preterm infants.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed studies for eligibility and quality and extracted data. We defined a clinically significant PDA as the presence of a PDA with clinical signs of an effect on organ function attributable to the ductus arteriosus. We defined a haemodynamically significant PDA as clinical and/or echocardiographic signs of a significant ductus arteriosus effect on blood flow.

MAIN RESULTS

We included two small trials enrolling very preterm infants (Rosenfeld 1986; Travadi 2006). We assessed both as at high risk of bias. No study reported clinically significant PDA, defined as the presence of a PDA with clinical symptoms or signs attributable to the effect of a ductus arteriosus on organ function. Rosenfeld 1986 reported a non-significant reduction in haemodynamically significant PDA with left atrial to aortic root ratio greater than 1.2 (risk ratio (RR) 0.23, 95% confidence interval (CI) 0.05 to 1.01; 74 infants) but a statistically significant risk difference (RD -0.18, 95% CI -0.34 to -0.03; number needed to treat for an additional beneficial outcome (NNTB) 5, 95% CI 3 to 33). Rosenfeld 1986 reported a significant reduction in PDA detected by murmur (RR 0.50, 95% CI 0.29 to 0.88; RD -0.30, 95% CI -0.52 to -0.08; NNTB 3, 95% CI 2 to 12; 74 infants). Rosenfeld 1986 reported a significant reduction in treatment with indomethacin (RR 0.12, 95% CI 0.02 to 0.88; RD -0.21, 95% CI -0.35 to -0.06; NNTB 5, 95% CI 3 to 17; 74 infants), and only one infant had a ductal ligation in the no-shield group. There were no other significant outcomes, including mortality to discharge or 28 days, days in oxygen, days on mechanical ventilation, days in hospital, intraventricular haemorrhage, retinopathy of prematurity, or exchange transfusion.

AUTHORS' CONCLUSIONS

The available evidence is very low quality and insufficient to assess the safety or efficacy of chest shield during phototherapy for prevention of PDA in preterm infants. Further trials of chest shielding are warranted, particularly in settings where infants are not receiving prophylactic or early echocardiographic targeted cyclo-oxygenase inhibitors for PDA.

Perfusion Index in Preterm Infants during the First 3 Days of Life: Reference Values and Relation with Clinical Variables

BACKGROUND

The perfusion index (PI) derived from pulse oximetry readings represents the ratio of pulsatile (arterial blood) and nonpulsatile contributors to infrared light absorption. PI has been shown to correlate with cardiac performance. In theory, PI is readily available on every pulse oximeter; therefore, no additional sensors or infant handling are required. Currently, reference values are lacking in (preterm) neonates and the association with common clinical conditions is unclear.

OBJECTIVES

To establish reference values for the PI in premature infants and at the same time determine the influence of common clinical conditions.

METHODS

PI was prospectively monitored on the lower limb for 72 h in 311 neonates born with a gestational age <32 weeks between January 2011 and December 2013. Longitudinal mixed-effects modeling was used. Linear, quadratic, and cubic models were explored. Main effects and interactions were investigated.

RESULTS

A squared model (0-24 h) followed by a linear model (24-72 h) provided the best fit of the data. PI was lowest around 12-18 h after birth and showed a steady increase thereafter. PI was positively related with female gender, gestational age, and pulse pressure. Negative associations were found with SIMV/HFOV ventilation, dopamine administration, mean arterial blood pressure, and arterial oxygen saturation. Although more complex, the general association with a patent ductus arteriosus was positive.

CONCLUSION

PI varied according to several clinical conditions. The association with common clinical factors suggests that PI might be used for monitoring neonatal hemodynamics and possibly as an additional guidance for interventions.

Recovery of vocal fold immobility following isolated patent ductus arteriosus ligation

OBJECTIVE

Identify laryngoscopic and functional outcomes of infants with vocal fold immobility (VFI) following patent ductus arteriosus (PDA) ligation and identify predictors of recovery.

METHODS

Retrospective review of patients with VFI following PDA ligation from 2001 to 2012 at a single institution. Inclusion criteria were: (1) PDA ligation as only cardiac surgical procedure; (2) left VFI documented by laryngoscopy; (3) minimum follow up 120 days, with at least 2 laryngoscopies performed. Resolution of VFI was determined at follow-up laryngoscopy. Univariate logistic regression models were used to identify variables associated with VFI recovery.

RESULTS

66 subjects were included with median follow up of 3.0 (± 2.1) years. The mean gestational age was 24.5 ± 1.4 weeks, mean birth weight 673 ± 167 g, and mean age at procedure was 18.6 ± 14.3 days. Patients presented with respiratory symptoms (39%), dysphonia (78%) and dysphagia (55%). Resolution of VFI was observed in 2/66 (3%) patients. Recovery was documented at 20 days and 11 months respectively. Respiratory symptoms, dysphagia, and dysphonia persisted at last follow up in 11%, 47%, and 20% of patients.

CONCLUSIONS

VFI associated with ligation of the ductus arteriosus has a low rate of recovery. Clinical symptoms frequently persist, and as such regular follow-up by otolaryngologists to mitigate morbidity is indicated.

Novel treatment criteria for persistent ductus arteriosus in neonates

BACKGROUND

The indications for ductus arteriosus ligation in very-low-birth-weight infants (VLBWIs) with persistent ductus arteriosus (PDA) are unclear. Increased left ventricular end-diastolic dimension (LVDd) is commonly found in patients with PDA. Here, the enlargement of LVDd in term and preterm neonates without congenital heart disease was estimated by two-dimensional echocardiography.

METHODS

The value of the measured LVDd was divided by the normal LVDd as an index (LVDd ratio) to compare 30 patients who underwent PDA ligation with 30 patients treated with indomethacin and 30 patients who did not undergo radical therapy.

RESULTS

An LVDd ratio between 122% and 197% (mean, 142%) was considered to be an indication for the ligation procedure. The proportion of patients exceeding 130% in the LVDd ratio was 87% (26/30) in those patients who underwent ligation. Catecholamines and/or vasodilators were required in 83% patients for the treatment of low ejection fraction or hypertension after operations, suggesting that patients had been in preload and/or afterload remodeling failure during the operation. The percentage of patients with less than 115% in the LVDd ratio was 90% in the non-radical-therapy patients. The LVDd ratios of 130% and 115% were regarded as cut-off values for surgical ligation and indomethacin treatment.

CONCLUSION

The LVDd ratio is a useful measure to determine the treatment of VLBWIs with PDA.

NT-proBNP Levels Improve the Ability of Predicting a Hemodynamically Significant Patent Ductus Arteriosus in Very Low-Birth-Weight Infants

Purpose:

A hemodynamically significant Patent ductus arteriosus (HsPDA) in premature infants is known to be associated with significant morbidity. Recently brain natriuretic peptides and superior mesenteric artery (SMA)-resistive indices have been used to effectively diagnose HsPDA.

Objective:

To assess the sensitivity and specificity of N-terminal proBNP (NT-proBNP) in predicting an HsPDA diagnosed by clinical and echocardiographic criteria including pulsatility index (PI) of SMA.

Materials and Methods:

All preterm neonates <1500 g were evaluated with echocardiograms and NT-proBNP levels on the 3^rd to 5^th day of life and then every week until the echo showed either a closed PDA or non-HsPDA.

Results:

Sixty-nine babies with mean gestational age of 27 weeks were included in the study. NT-proBNP levels were significantly higher in the HsPDA group (n=22) with a mean±SEM of 24420±3190 compared to 3072±332 in the non-HsPDA group (n=47) (P<0.001). NT-pro BNP level of 5900 pg/ml had 96% sensitivity and 90% specificity of predicting HsPDA.

Conclusions:

With frequently changing hemodynamics in low-birth weight infants, including NT-proBNP and PI of SMA improve the ability of assessing the effects of a HsPDA and will help timing of intervention.

The Aristotle score predicts mortality after surgery of patent ductus arteriosus in preterm infants

BACKGROUND

Outcomes after surgical ligation of patent ductus arteriosus (PDA) in preterm infants are often complicated by prematurity associated comorbidities. The Aristotle comprehensive complexity score (ACCS) has been proposed as a useful tool for complexity adjustment in the analysis of outcome after congenital heart surgery. The aims of this study were to define preoperative risk factors for mortality and to demonstrate the usefulness of ACCS to predict mortality after surgical ligation of PDA in the preterm.

METHODS

Included were 49 preterm babies (≤35 weeks of gestation) who had surgical ligation of PDA between May 2009 and July 2012. Median gestational age was 27.6 weeks (range, 23 to 35 weeks) and median birth weight was 1,040 g (range, 520 to 2,280 g). Median age at operation was 15 days (range, 4 to 44 days) and median weight was 1,120 g (range, 400 to 2,880 g). Initial oral ibuprofen was ineffective in 24 patients and contraindicated in 25. All surgical ligations were done at bedside in the neonatal intensive care unit. Preoperative clinical and laboratory profiles were reviewed and ACCS was derived.

RESULTS

Eight of 49 patients (16.3%) died at a median of 14 days (range, 2 to 73 days) after PDA ligation. Patients who had contraindications for oral ibuprofen (odds ratio [OR] 8.94; p=0.049), coagulopathy (OR 12.13; p=0.025), renal dysfunction (OR 28.88; p=0.003), intraventricular hemorrhage greater than grade II or seizure (OR 34.00; p=0.002), and ACCS points (OR 29.594; p<0.05) were significantly associated with an increased risk for mortality. Among the risk factors, ACCS showed the largest area under curve (0.991) by receiver-operating characteristic curve analysis. Optimal cutoff value of ACCS for mortality were 15 or greater, with sensitivity of 87.5%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 97.6%.

CONCLUSIONS

The ACCS, especially for procedure-independent complexity factors, is a useful tool to predict mortality after ligation of PDA in preterm infants.

Intrauterine inflammation alters cardiopulmonary and cerebral haemodynamics at birth in preterm lambs

Intrauterine inflammation is associated with preterm birth and poor long-term cardiopulmonary outcomes. We aimed to determine the effect of intrauterine inflammation on the cardiopulmonary and cerebral haemodynamic transition at birth, and the response to subsequent haemodynamic challenge. Fetal instrumentation was performed at ∼112 days gestation (term is 147 days) for measurement of cardiopulmonary and cerebral haemodynamics. At 118 days, inflammation was induced by intra-amniotic administration of lipopolysaccharide (LPS; n = 7); controls (n = 5) received intra-amniotic saline. At 125 days lambs were delivered and mechanically ventilated. Arterial blood gases, pulmonary and systemic arterial blood pressures and flows were measured during the perinatal period. At 10 min a haemodynamic challenge was administered by increasing positive end-expiratory pressure. During the first 10 min after birth, LPS-exposed lambs had higher pulmonary vascular resistance and lower pulmonary blood flow and left ventricular output than controls. Carotid arterial blood flow was higher in LPS-exposed lambs than controls between 3 and 7 min after delivery, and cerebral oxygen delivery was higher at 5 min. During the haemodynamic challenge, pulmonary blood flow and left ventricular output were reduced in controls but not in LPS-exposed lambs; a transient reduction in brachiocephalic arterial pressure occurred in LPS-exposed lambs but not in controls. Intrauterine inflammation altered the cardiopulmonary and cerebral haemodynamic transition at birth and reduced the cardiopulmonary response to a haemodynamic challenge after birth. The transient reduction in brachiocephalic arterial pressure suggests intrauterine inflammation may alter cerebrovascular control following an increase in positive end-expiratory pressure.

Functional echocardiography in staging for ductal disease severity : role in predicting outcomes

Equipoise persists as to the issue of assigning haemodynamic and clinical significance to a patent ductus arteriosus (PDA). The objective was to ascertain whether echocardiographic scoring of a PDA correlates with outcomes. Unit electronic data base was accessed to identify infants less than 32 weeks' gestation who received ibuprofen for medical closure of the PDA during the period June 2010-June 2012. Echocardiographic score was assigned on the day of therapy and the infants were prospectively followed up to ascertain the occurrence of chronic lung disease (CLD). Logistic regression analysis was used to estimate the association between composite score and occurrence of CLD. Fifty-two infants were identified out of which 27 (52 %) subsequently developed CLD. Echocardiographic parameters were of a significantly higher magnitude in infants who later developed CLD. The median composite score (inter-quartile range) was also significantly higher in this group 26 (24-26) vs. 19 (17-20), p < 0.001). Higher composite scores were associated with increased risk of developing CLD; for every one point increase in composite score, the odds of CLD increased by 78 % (odds ratio (95 % CI): 1.78 (1.35-2.34); p < 0.001).

CONCLUSIONS

Infants with a high composite score, assigned according to the staging criteria at the time of treatment, were noted to have a higher incidence of subsequent CLD. Whether disease stratification can be the basis of further RCT's needs prospective evaluation.

B-type natriuretic Peptide assay for the diagnosis and prognosis of patent ductus arteriosus in preterm infants

BACKGROUND AND OBJECTIVES

Patent ductus arteriosus (PDA) is a significant cause of morbidity and mortality in preterm infants. Measurement of plasma B-type natriuretic peptide (BNP) has been reported to be a useful bedside screening tool for the presence of hemodynamically significant PDA (hsPDA) in neonates. This study was conducted to investigate the usefulness of a BNP assay as a biochemical marker for the diagnosis of hsPDA and predictive biomarker of the response to indomethacin in preterm infants.

SUBJECTS AND METHODS

Preterm infants born at <37 weeks' gestational age were prospectively enrolled within 24 hours of birth. Plasma BNP levels were measured on days 1, 4, and 7. Significant PDA was diagnosed by large ductal flow with left to right shunt on color Doppler echocardiography, along with clinical features of PDA. Following that, hsPDA was treated with indomethacin.

RESULTS

A total of 28 preterm infants were prospectively enrolled in this study. Seven infants with PDA had higher on day 4 plasma BNP values (median 654.68 pg/mL; range 428.29-1280.00) compared to the control group (median 124.52 pg/mL; range 37.21-290.49). The area under the receiver operator characteristic curve for the detection of hsPDA was high: 0.998 (95% confidence interval: 0.995-1.002). The cutoff of BNP concentration for the diagnosis of hsPDA was determined to be 412 pg/mL (sensitivity: 100%; specificity: 95%).

CONCLUSION

B-type natriuretic peptide can be a useful biomarker for the screening and diagnosis of PDA in preterm infants. Serial BNP measurements are valuable for assessing the clinical course and indomethacin responsiveness of PDA.

Variation in the diagnosis and management of patent ductus arteriosus in premature infants

OBJECTIVES

To determine variations in neonatology practice regarding the diagnosis and management of patent ductus arteriosus (PDA) in premature infants.

DESIGN

Standardized telephone interview of preferences and practices.

SUBJECTS

Canadian neonatologists in active clinical practice.

RESULTS

Of 136 eligible Canadian neonatologists, 100 respondents (74%) estimated the proportion of infants with suspected PDA who have echocardiography to be a median of 80% (range 0% to 100%), with considerable variation both within and between centres. Only two centres had written guidelines. More recent medical school graduates were significantly more likely to use echocardiography. Increased use of echocardiography was also significantly related to increased availability. Fluid restriction and indomethacin was used as initial therapy by 89% of respondents, with the indomethacin dose standardized for 83%; surgical ligation was used when indomethacin therapy was contraindicated or had failed. Personal guidelines directed decisions regarding therapy for the majority of neonatologists.

CONCLUSIONS

Among Canadian neonatologists, there is considerable variation regarding practices related to the diagnosis and management of PDA in premature infants. This variation may potentially affect the cost effectiveness of care for these patients.

Patent ductus arteriosus in the preterm infant: a survey of clinical practices in French neonatal intensive care units

Patent ductus arteriosus (PDA) is one of the most common problems in the care of premature infants, especially the extremely premature. There is no real consensus regarding the diagnostic criteria or treatment of a hemodynamically significant PDA. Its diagnosis, assessment, and treatment still remain challenges. Therefore, we investigated clinical practices in French tertiary neonatology centers regarding the management of PDA to compare their similarities and differences. We sent a questionnaire by email to the PDA specialist in every French tertiary neonatal intensive care unit. It contained 27 items regarding the unit's structure, method of diagnosing PDA, and treatment choices. The completed questionnaire were returned via email and analyzed blindly. The questionnaire response rate was 87.5%, which allowed us to draw some conclusions regarding French clinical practices in the care of neonates with PDA. Although the diagnostic criteria are quite similar, the therapeutic practices are rather different across neonatal care units. We highlight the great variability in French clinical practices when it comes to treating PDA and underscore the necessity for harmonization of these practices, which could be achieved using multicenter, randomized studies to identify the advantages of one approach compared with another.

Neonatologist-performed functional echocardiography in the neonatal intensive care unit

The use of point-of-care functional ultrasound to assess cardiovascular function is gaining interest in the neonatal intensive care unit (NICU). The modality has been in use in adult intensive care units for some time and has often guided management. Clinical signs such as heart rate, blood pressure, and capillary refill time, which physicians traditionally have relied upon, provide limited insight into the adequacy of systemic blood flow and organ perfusion. Enhanced cardiovascular imaging and hemodynamic evaluation offers novel insights regarding the contribution of the ductus arteriosus, myocardial performance and pulmonary hemodynamics to ongoing clinical instability. In addition, it allows more accurate delineation of the nature of the underlying disease process and facilitates the evaluation of response to therapeutic intervention. This review examines the potential clinical role of ultrasound methods in the NICU; specifically, its applications in different disease states, and how the technology may be introduced safely in the NICU.

Long-term morbidities associated with vocal cord paralysis after surgical closure of a patent ductus arteriosus in extremely low birth weight infants

OBJECTIVE

Determine associations between left vocal cord paralysis (LVCP) and poor respiratory, feeding and/or developmental outcomes in extremely low birth weight (ELBW) infants following surgical closure of a patent ductus arteriosus (PDA).

STUDY DESIGN

ELBW infants who underwent PDA ligation between January 2004 and December 2006 were identified. We compared infants with and without LVCP following ligation to determine relationships between LVCP and respiratory morbidities, feeding and growth difficulties and neurodevelopmental impairment at 18 to 22-month follow-up. Student's t-test, Fisher's exact test and multivariable regression analyses were used to determine associations.

RESULT

In all, 60 ELBW infants with a mean gestational age of 25 weeks and mean birth weight of 725 g had a PDA surgically closed. Twenty-two of 55 survivors (40%) were diagnosed with LVCP post-operatively. Infants with LVCP were significantly more likely to develop bronchopulmonary dysplasia (82 vs 39%, P=0.002), reactive airway disease (86 vs 33%, P<0.0001), or need for gastrostomy tube (63 vs 6%, P<0.0001).

CONCLUSION

LVCP as a complication of surgical ductal ligation in ELBW infants is associated with persistent respiratory and feeding problems. Direct laryngoscopy should be considered for all infants who experience persistent respiratory and/or feeding difficulties following PDA ligation.

Role of echocardiography on the evaluation of patent ductus arteriosus in newborns

The echocardiogram is the preferred procedure in confirming the diagnosis and characterizing PDA. Doppler echocardiography proved more efficient than clinical examination in grading PDA and becomes essential in the evaluation of clinically significant ductal shunting. Four patterns of PDA shunt can be identified using pulsed Doppler echocardiography: pulmonary hypertension, growing pattern, pulsatile pattern, closing pattern. In this review we confirm that echocardiography can provide a reasonable as well as accurate prediction of the development of later clinically significant PDA by a combination of variables that are easy to measure and compare.

B-type natriuretic peptide to predict ductus intervention in infants <28 weeks

Patent ductus arteriosus (PDA) is frequent in neonates with gestational age of less than 28 wk. Clinical and echocardiographic signs define hemodynamic significance of PDA, but do not reveal the need for PDA intervention in the first days of life. B-type natriuretic peptide (BNP) has been proposed as a screening tool for PDA in preterm infants. To determine whether BNP can predict the need for PDA intervention, plasma BNP was measured by chemiluminescence immunoassay in 67 preterm infants <28 wk (median 26) on the second day of life in a prospective blinded study. PDA intervention was based on specified clinical and echocardiographic findings. Twenty-four patients (intervention group) received treatment for PDA and 43 patients (controls) remained without intervention. BNP concentrations were higher in the intervention (median 1069 pg/mL) than in the control group (247 pg/mL, p < 0.001). BNP correlated positively with ductal size (R = 0.46, p < 0.001) and atrial/aortic root ratio (R = 0.54, p < 0.001). In conclusion, plasma BNP proved to be a good predictor for ductus intervention (area under the curve: 0.86) with the best cutoff at 550 pg/mL on the second day of life in ventilated infants less than 28 wk gestation (sensitivity: 83%; specificity: 86%).

Patent ductus arteriosus ligation in neonates: preoperative predictors of poor postoperative outcomes

PURPOSE

The purpose of this study was to identify preoperative predictors of adverse outcomes in infants undergoing surgical ligation of patent ductus arteriosus (PDA).

METHODS

Charts of all neonates who underwent PDA ligation at Texas Children's Hospital (Houston, TX) between 2001 and 2006 were retrospectively reviewed with specific attention to preoperative clinical characteristics, echocardiographic details, operative morbidity, and postoperative outcomes. Infants with other cardiac anomalies or right-to-left or bidirectional PDA shunt were excluded.

RESULTS

Eighty-two neonates were included (mean gestational age, 27 weeks; mean birth weight, 1000 g). There were no intraoperative complications. Preoperative symptoms related to respiratory insufficiency, hypotension, apnea, and pulmonary edema improved after ligation (P < .001). Birth weight, age at ligation, and indomethacin use did not correlate with postoperative outcome; however, lower gestational age, lower blood pressure, and lower shunt peak velocity predicted longer time to extubation by multiple analysis techniques (P < .0001). Linear regression (controlling for gestation, birth weight, and mean arterial pressure) showed inverse correlation between peak velocity and postoperative days on the ventilator (95% confidence interval, 47.18 to -12.25; P = .001).

CONCLUSION

The PDA ligation can be accomplished safely; however, some neonates have prolonged recovery. Lower gestational age and low peak velocity (<2.6 m/s) at the PDA shunt correlate with lengthened ventilator requirement after surgery.

Management of the neonate with patent ductus arteriosus

Care of the preterm infant with a suspected or confirmed diagnosis of patent ductus arteriosus (PDA) is a frequent challenge for the neonatal nurse. Management of term infants with cardiac lesions dependent upon a PDA can be even more challenging. It is vital for neonatal nurses to understand the normal cardiovascular and pulmonary changes that occur at birth so they can anticipate pathological processes influencing the clinical course of an infant with a PDA. In addition, knowledge of current and effective treatment approaches is essential to providing optimal care for these vulnerable infants, as well as in guiding their parents. The purpose of this article is to review current information about PDA, including physiology, pathophysiology, pharmacological approaches, surgical considerations, complications and outcomes, parental support, and areas for future research.

Surgical closure of patent ductus arteriosus reduces the cerebral tissue oxygenation index in preterm infants: a near-infrared spectroscopy and Doppler study

BACKGROUND

The aim of this study was to investigate the effects of patent ductus arteriosus (PDA) ligature on cerebral oxygen saturation, cerebral blood volume (CBV) and cerebral blood flow velocity by means of near-infrared spectroscopy (NIRS) and transcranial Doppler simultaneous examinations.

METHODS

This is an observational study considering 16 babies of gestational age 24-34 weeks diagnosed with PDA who underwent surgical ligation. The cerebral oxygen saturation, CBV and blood gases values were obtained 35 min before ligation, so also around the 14th and 27th min after the clip's insertion.

RESULTS

Cerebral oxygen saturation, measured as tissue oxygenation index (TOI), decreased significantly after PDA ligation from a basal value of 61.1 (3.8) before surgery to 56.6 (3.3) and 55.8 (2.6)%, for the 14th and 27th min, respectively (P<0.04). CBV before and after clipping was unvaried. A negative correlation was found between DeltapH and DeltaCBV after ligation (R=0.52, P=0.03), whilst a positive correlation was found between DeltaCBV and DeltaP(aCO2) (R=0.62, P=0.009). pH increased at the 27th min post-ligation.

CONCLUSIONS

NIRS is a tool for obtaining information on cerebral oxygen saturation and CBV changes during surgical PDA ligation at the bedside. A fall in TOI suggests an increased oxygen extraction during PDA surgery. The lack of increase in DeltaCBV or in diastolic flow velocity show that the PDA before the clipping did not limit cerebral blood flow, the drop in TOI suggests increased oxygen consumption over the clip and the need for accurate monitoring of oxygen utilization after the surgical treatment.

Longitudinal changes of brain-type natriuretic peptide in preterm neonates

OBJECTIVE

To determine age-related concentrations of brain-type natriuretic peptide in preterm infants using bedside Triage brain-type natriuretic peptide test and correlate it to the presence or absence of the patent ductus arteriosus and ventilatory support.

METHODS

Serum brain-type natriuretic peptide levels were measured in infants who were born at <32 weeks' gestation from birth to 2 months of age. Serial echocardiograms were performed, until closure of the patent ductus arteriosus, or until discharge. Brain-type natriuretic peptide levels were correlated to the day of life, gestational age, presence or absence of the patent ductus arteriosus, and the degree of ventilatory support. Nineteen preterm infants (gestational age: 24-31 weeks; birth weight: 645-1670 g) were enrolled prospectively during the first 2 weeks of life. Serum brain-type natriuretic peptide levels (pg/mL) were determined in 177 blood samples, and 87 paired echocardiograms were performed.

RESULTS

Significant negative correlation was found between brain-type natriuretic peptide levels and the day of life and remained significant when the patients were stratified by gestational age (< or =28 weeks and >28 weeks). Higher brain-type natriuretic peptide levels correlated with increasing grade of the patent ductus arteriosus. Significant differences in brain-type natriuretic peptide levels were seen with increasing ventilatory support. Comparisons between the size of patent ductus arteriosus and the degree of ventilatory support to brain-type natriuretic peptide levels revealed that the size of the patent ductus arteriosus was the major determinant of both brain-type natriuretic peptide levels and the degree of ventilatory support.

CONCLUSIONS

Similar to term infants, brain-type natriuretic peptide levels of preterm infants are related to the chronological age and decline during the first month of life. Rapid bedside Triage brain-type natriuretic peptide is a potentially valuable and practical assay in determining the hemodynamic changes in preterm infants.

Severity of the ductal shunt: a comparison of different markers

BACKGROUND

When the ductus arteriosus (DA) is patent, the ductal shunt is proportional to the ratio of left ventricular output (LVO) to systemic blood flow. Systemic blood flow can be estimated by measuring flow in the superior vena cava (SVC).

OBJECTIVE

To re-evaluate the accuracy of standard echocardiographic markers of patent ductus arteriosus (PDA) using LVO/SVC flow ratio.

METHODS

Prospective study. Preterm infants of 24-30 weeks gestational age and postnatal age less than 48 hours. The following echocardiographic criteria were measured: left atrial to aortic root ratio (LA/Ao); DA diameter by B mode and colour Doppler; mean and end diastolic flow velocity of the left pulmonary artery (LPA); LVO; SVC flow.

RESULTS

Twenty three preterm infants were enrolled (median gestational age 28 weeks (range 24-30), median birth weight 840 g (500-1440)). The DA was closed in eight (mean (SD) LVO/SVC 2.4 (0.3)) and open in 15 (mean (SD) LVO/SVC 4.5 (0.6)). An LA/Ao ratio > or =1.4, a DA diameter > or =1.4 mm/kg, and a mean and end diastolic flow velocity of LPA respectively > or =0.42 and > or =0.20 m/s identified an LVO/SVC > or =4 with a sensitivity and a specificity above 90%.

CONCLUSION

This study indicates that LA/Ao ratio, DA diameter, and mean and end diastolic flow velocity of the LPA are accurate markers of PDA. These standard echocardiographic variables are easy to measure and need less skill and resources than direct measurements of ductal shunt.

Postural adjustments in preterm infants at 4 and 6 months post-term during voluntary reaching in supine position

Gradually it is getting clear that motor development - in particular balance control - in so-called "low-risk" preterm infants often differs from that in full-term infants. However, little is known on the etiology and pathophysiology of these problems. The aim of this study was to evaluate postural behavior during reaching by means of kinetic and kinematic measurements. Preterm infants (n = 32) without cerebral palsy were investigated longitudinally at the corrected ages of 4 and 6 mo. Thirteen age-matched full-term infants served as controls. Cognitive and motor development were assessed by means of the quality of General Movements (GMs) at 4 mo and Bayley scales at 6 and 12 mo. The infants were lying supine on a forceplate reaching for a toy and the kinetics of the total body's Center of Pressure (COP) was measured in cranial-caudal and medial-lateral direction. The analysis focused on COP displacement, Vmax and oscillatory changes of the COP displacement during reaching. The kinematic analysis of reaching focused on movement units, Vmax and a compound kinematic variable reflecting the quality of reaching. The results showed that preterm infants showed a remarkable "still" postural behavior, which differed significantly from the mobile COP behavior of the full-term infants. More "still" postural behavior at 6 mo was associated with a better quality of reaching movements and with normal GMs at 4 mo. We concluded that "still" postural behavior is an adequate postural strategy of preterm infants. But it might be that this postural behavior is an indicator of later dysfunction.

Treatment of patent ductus arteriosus

Patent ductus arteriosus (PDA) continues to be one of the most common problems found in premature infants. The incidence is inversely related to gestation, but may be reduced by use of antenatal steroids, lower volume fluid regimen and judicious use of phototherapy. However, there continues to be controversy as to the appropriate indications for treatment, varying from prophylaxis on the basis of gestation to treatment only when a PDA is demonstrably significant. The situation is further complicated by differing diagnostic criteria for ductal patency or significance. Prophylactic treatment is likely to result in up to 64% of babies being treated unnecessarily. Early treatment of significant or symptomatic PDA depends upon accurate diagnosis. PDA closure can then be achieved using medical means, with surgery reserved for patients in whom this fails or in whom there are contra-indications. However, the optimum timing for intervention remains unknown.

Kinematic quality of reaching movements in preterm infants

Many preterm infants may experience so-called minor developmental disorders; however, in general, the problems in motor behavior are not detected until school age. To introduce therapies aimed at the prevention of these problems, we need to increase our knowledge of motor function and dysfunction at early age. The present study focused on the organization of reaching movements in full-term and preterm infants without cerebral palsy. The reaching behavior of premature infants (n = 63) was assessed longitudinally at the corrected ages of 4 and 6 mo. Clinical assessments were made at 6 and 12 mo of age. On the basis of the infant's morbidity during the early stay in the neonatal intensive care unit, the preterm infants were allocated into a high-risk and a low-risk group. Results from a previous study in full-term infants (n = 13) were included. Kinematics of reaching movements in supine position were measured, and the analysis focused on movement velocity and movement units. A compound parameter of kinematic variables was created, reflecting the quality of reaching movements. The present study showed that at the age of 4 mo, low-risk preterm infants showed more often optimal reaching behavior than full-term and preterm high-risk infants. This better reaching performance was related to a better general motor and behavioral development during the first year of life. At the age of 6 mo, the advantage of the low-risk group in reaching behavior had disappeared and a disadvantage in the form of nonoptimal reaching behavior of the high-risk group emerged.

Diastolic flow velocity of the left pulmonary artery of patent ductus arteriosus in preterm infants

BACKGROUND

The usefulness of diastolic pulmonary flow velocity determined by echocardiography in the assessment of symptomatic patent ductus arteriosus (sPDA) in preterm infants has not been confirmed.

METHODS

Echocardiography was performed daily in infants ranging from 23 to 31 gestational weeks of age, and diastolic flow velocity of the left pulmonary artery (DFLPA) was measured. The DFLPA data before indomethacin administration for sPDA were compared with data obtained after indomethacin administration. The normal range of DFLPA was also determined from serial measurements performed in infants who did not develop sPDA during the first 7 days of life. Then, this range was compared with data from infants who did develop sPDA during this time.

RESULTS

In infants who underwent indomethacin treatment, DFLPA increased with the development of sPDA and decreased when the symptoms of sPDA disappeared. On the basis of results from serial DFLPA measurement, the sensitivity and specificity of DFLPA for assessing sPDA was found to be 0.82 and 0.83, respectively.

CONCLUSIONS

Measurement of DFLPA by echocardiography is a useful method for assessing sPDA in preterm infants.

The persistently patent arterial duct in the premature infant

The presence of a persistently patent arterial duct is common in premature neonates and may be associated with high morbidity. Early accurate diagnosis, assessment of the significance of the left to right shunt and prompt treatment are required to improve the outcome in this infant population.

A preliminary study of the application of the transductal velocity ratio for assessing persistent ductus arteriosus

OBJECTIVE

To compare the transductal velocity ratio (TVR) of the persistent ductus arteriosus (PDA) with other echocardiographic criteria for haemodynamic significance of a PDA.

METHODS

This was a prospective study (from January 1997 to August 1998) in the nurseries of the Royal Women's Hospital, Melbourne. Infants with a clinically suspected PDA were eligible and included if the echocardiogram showed a PDA with a structurally normal heart and the TVR had been measured. The PDA was assessed for evidence of left heart dilatation, the presence of reverse or absent diastolic flow in the descending aorta, the pattern of Doppler flow velocity waveform in the ductus arteriosus, and subjective assessment of ductal diameter on the real time image. The peak systolic velocity (PSV) was obtained from the pulmonary and aortic ends of the PDA, and the TVR calculated by dividing the PSV at the pulmonary end by the PSV at the aortic end.

RESULTS

Forty two infants had 59 echocardiographs with their TVR calculated. Mean (SD) birth weight was 1008 (362) g. Mean (SD) gestational age at birth was 27.4 (2.2) weeks with a mean (SD) corrected gestational age of 28.7 (2.7) weeks. The mean TVR was decreased in those infants with a high left atrial diameter/aortic diameter (LA/Ao) ratio (1.9 v 2.8, p = 0.0032) or reverse/absent diastolic flow in the descending aorta (2.1 v 3.0, p = 0.02). This difference was greater if those two criteria were combined (1.7 v 3.4, p = 0.0027). The mean TVR was decreased in infants with a wide open duct seen on two dimensional imaging (1.5 v 3.0, p < 0.0001) or pulsatile flow seen on pulsed Doppler in the PDA (1.9 v 3.4, p = 0.0001). The LA/Ao and left ventricle internal diameter/aortic diameter (LVIDd/Ao) ratios were higher in the group with a TVR < 1.8 than in the other two groups; these differences were statistically significant.

CONCLUSIONS

The TVR as a measure of the degree of constriction of a PDA is associated with other echocardiographic criteria for a haemodynamically significant PDA. A low TVR (signifying a poorly constricted duct) is associated with echocardiographic features of a significant left to right shunt, and vice versa. Further research is required to determine the usefulness of the TVR in predicting closure or likely continuing patency of a PDA and the need for treatment.

Intra-arterial blood pressure reference ranges, death and morbidity in very low birthweight infants during the first seven days of life

OBJECTIVES

We aimed to: (1) assess the association of average, low, high and variable mean blood pressure (mbp) on death and the common morbidities of very low birthweight infants, and in doing so, (2) to derive representative reference ranges for mbp in very low birthweight infants.

STUDY DESIGN

This five year retrospective study assessed 1 min computer recordings of intra-arterial mbp in 232 very low birthweight infants over the first 7 days of life in a tertiary NICU. Four measures of mbp were assessed: average, variability, maximum (per time period), and percentage of time with a mean blood pressure less than the infant's gestation. Correlation was made with death and the development of intraventricular haemorrhage (IVH), periventricular leukomalacia (PVL) and retinopathy of prematurity (ROP).

RESULTS

The mbp increased with increasing birthweight and postnatal age (though with a slight decrease on days 6 and 7). Birthweight, gestation and colloid support (adjusted for birthweight and gestation) were the only factors significantly associated with mbp. IVH was predominantly associated with a low and variable mbp on the day IVH was noted or the day before. PVL and ROP were not associated with blood pressure.

CONCLUSIONS

These reference ranges include more infants and data than previously published and relate mbp in this cohort to morbidity and mortality. They could assist clinicians in judging appropriate mbp for birthweight.

Capillary refilling time and hemodynamics in neonates: a Doppler echocardiographic evaluation

OBJECTIVE

To evaluate the correlation of the capillary refilling time measured in neonates with the hemodynamic parameters obtained by Doppler echocardiography.

DESIGN

Prospective study.

SETTING

Neonatal intensive care unit (ICU) in a university hospital.

PATIENTS

Neonates without congenital cardiac disease admitted to the neonatal ICU (n = 100).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The clinical parameters obtained were: heart rate; blood pressure; mean airway pressure; cutaneous temperature; and capillary refilling time. The echocardiographic data included the measurement of aortic diameter, left atrial diameter, and shortening fraction. Pulsed-Doppler echocardiography was used to measure flow velocity values in the ascending aorta, in the pulmonary artery trunk, and in the patent ductus arteriosus. Cardiac index was calculated secondarily from the volumetric equation, including measured flow velocity in the ascending aorta, aortic diameter, and body weight. Shunt severity at this level was measured by analysis of the descending aortic flow. Thereafter, three groups were defined for analysis: group 1 with obliterated ductus arteriosus; group 2 with patent ductus arteriosus without a retrograde flow in the subdiaphragmatic aorta; and group 3 with patent ductus arteriosus and a retrograde flow in the subdiaphragmatic aorta. There was no correlation between the capillary refilling time and the following parameters: shortening fraction; mean airway pressure; body weight; left atrial diameter/ aortic diameter ratio; blood pressure; and heart rate. In group 1, the capillary refilling time was significantly linked to cardiac index (r2 = .54, p < .001). A lower correlation coefficient between capillary refilling time and cardiac index was found in groups 2 (r2 =.31, p < .001) and 3 (r2 =.41, p < .001).

CONCLUSION

The capillary refilling time was significantly linked to cardiac index in neonates.

Pulmonary artery pressure: early predictor of chronic lung disease in preterm infants

AIM

To determine if pulmonary artery pressure (PAP) in ventilated preterm infants is independently associated with the development of chronic lung disease (CLD) and whether early assessment has any prognostic value.

METHODS

Two cohorts (development n = 55; and validation n = 28) of preterm infants were studied at 24 hours of age. PAP was assessed non-invasively using its inverse correlation with the corrected acceleration time to right ventricular ejection time ratio (AT:RVET(c)), calculated from the pulmonary artery Doppler waveform. Clinical and respiratory variables were also collected. Using logistic regression analysis to identify factors independently associated with CLD, a prognostic score was developed to predict CLD. The ability of the score to predict CLD was described using receiver operating characteristic (ROC) curves.

RESULTS

Birthweight, inspired oxygen concentration, and AT:RVET(c) were independently predictive of CLD. The area under the ROC curve was 0.96 for the development and 0.89 for the validation cohort. Exclusion of AT:RVET(c) resulted in a reduction to 0.88 and 0.73, respectively.

CONCLUSION

PAP is independently associated with CLD. An early assessment of PAP using AT:RVET(c) may permit the early prediction of CLD as part of a multifactorial scoring system.

Bisferiens peaks in the radial artery pressure wave during patent ductus arteriosus in newborn infants: relationship with ascending aortic flow

Previously, we found evidence that bisferiens peaks in the radial artery pressure wave in the newborn infant may suggest the presence of a left-to-right shunt through a patent ductus arteriosus (PDA). The purpose of the present study was to analyze the origin of this pulsus bisferiens. Starting from the assumption that the radial artery pressure wave form is similar to the aortic pressure wave form, as described previously, we attempted to explain the bisferiens peaks on the basis of echocardiographically obtained ascending aortic flow. We studied 11 preterm mechanically ventilated infants with a left-to-right shunt through a PDA and 7 without. Aortic volume flow was established echocardiographically, and radial artery blood pressure measurement was performed with a high fidelity cathetermanometer system. Ascending aortic peak flow during PDA was significantly higher in the case of PDA, compared with the case without PDA. An augmented peak flow with an abrupt decline after the high peak in PDA, resulting in a sharp pressure peak with a steep decline after the peak, was thought to explain the first sharp peak of pulsus bisferiens. An abrupt decline of flow after peak flow is thought to be due to the fast runoff of blood through the ductus. According to the pulsatile pressure dynamics theories, which state that pressure wave forms consist of forward and backward wave forms, the second peak of the pulsus bisferiens can be explained by the return of the reflected (backward) wave form when the forward wave form has already considerably decreased. We conclude that the bisferiens peaks found in PDA result from a combination of large stroke volume (augmented first peak) and large runoff (quick decline of the forward wave) before the return of the reflected wave.

Factors affecting the neonatal response to artificial surfactant

OBJECTIVE

To define the individual neonatal response to the artificial surfactant, Exosurf, and factors that may influence the response.

METHODOLOGY

Eighty-two consecutive, preterm neonates with respiratory distress syndrome, who received Exosurf at < 12 h of age were studied. Their response was categorized from the graphical change in the oxygenation index with postnatal age, for 12 h after each of two doses of surfactant and assessed independently by two observers. Clinical factors were analysed for their effect on the four pre-defined categories of response, namely: none; mild; good: relapsed; and good: sustained.

RESULTS

Within the first 12 h, 11% of the neonatas showed no response, 5% a mild response and 84% a good response, but 34% relapsed. By 24 h, 6% still showed no response (all died), 11% showed a mild response and 83% a good response, of whom half relapsed. At 24 h, no response was significantly associated with low gestational age and asphyxia, mild response with less severe lung disease. According to the response there was a gradation in the risk of death during the first week.

CONCLUSIONS

The response to Exosurf can be individually and reproducibly categorized and demonstrated that 83% of neonates had a good response but half relapsed. No response was associated with extreme prematurity and asphyxia.

Cost-effectiveness of echocardiography for evaluation of children with murmurs

Echocardiography is widely accepted as an accurate diagnostic test to evaluate heart murmurs in children, however its costs, and the ubiquity of murmurs in children, discourage its universal application. The purpose of this article is to identify some clinical circumstances in which the cost of echocardiography is justified for the evaluation of heart murmurs in infants and children. Eight common clinical problems were selected in which a heart murmur is present and a diagnosis is called for. Effectiveness of echocardiography and less costly clinical diagnostic methods in these settings were compared. In some circumstances, echocardiography is worth the cost, because clinical evaluation is unacceptably insensitive to important disease (the premature infant with a murmur which might represent a patent ductus arteriosus, the infant with a dysmorphic syndrome and a murmur). In others, the expert clinical examination is highly accurate (the asymptomatic child with a heart murmur) and is preferred over the echocardiogram as the initial diagnostic approach on the grounds of cost. When the expert clinical examination suggests minor structural heart disease, a continuum of echocardiographic cost-effectiveness relative to the expert clinical examination exists between these extremes depending on the working diagnosis. A threshold has not yet been defined at any point on this continuum above which the public will demand the greater diagnostic detail available echocardiographically, and below which the public will refuse to accept its greater cost. Quantitative formal cost-effectiveness analysis of echocardiography for evaluation of heart murmur in infants and children is not yet feasible because the benefits of echocardiography are indirect, dependent upon the as yet unmeasured benefits of correct management of congenital heart defects. To go beyond simple comparison of efficacy of echocardiography with less costly methods, further work is required in outcomes research in congenital heart disease.