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ABSTRACT: Background: Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism. Objectives: To describe adrenal function in premature infants undergoing PDA ligation and to investigate its association with pre- and postoperative clinical and echocardiography-derived indices of disease severity. Methods: A retrospective cohort study was conducted over a 2-year period on infants who underwent PDA ligation and had preoperative adrenocorticotropic hormone (ACTH) stimulation. All infants were screened by echocardiography for low LVO at 1 h after surgery and treated with intravenous milrinone if LVO <200 ml/kg/min. The primary outcome evaluated was low LVO at 1 h after surgery. Secondary outcomes included hypotension and oxygenation and ventilation failure occurring within 24 h. Results: A total of 35 infants at a median gestation of 25.4 (24.5-26.4) weeks and weight at birth of 700 (600-810) g were included. Baseline median cortisol measured preoperatively was 202 (137-403) nmol/l. Following the ACTH stimulation test, 3 infants had cortisol ≤500 nmol/l while 15 had ≤750 nmol/l. There was no association seen between any cortisol value and low LVO postoperatively. Post-ACTH cortisol ≤750 nmol/l was significantly associated with hypotension (p = 0.03) and oxygenation (p = 0.04) and ventilation (p = 0.008) failure. Receiver-operator characteristic curve showed a high predictive value of post-ACTH cortisol for all clinical outcomes. Conclusions: Post-ACTH cortisol (≤750 nmol/l) may be associated with clinical indices of postoperative cardiorespiratory instability. Relative adrenal insufficiency may play a role in the etiology of post-PDA ligation hemodynamic and respiratory instability.
Neonatology 04/2013; 104(1):28-33. · 2.66 Impact Factor
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ABSTRACT: Non-invasive cardiac output monitoring is a potentially useful clinical tool in the neonatal setting. Our aim was to evaluate a new method of non-invasive continuous cardiac output (CO) measurement (NICOM™) based on the principle of bioreactance in neonates.
In this prospective observational study, 10 neonates underwent 97 paired NICOM and echocardiography (echo) assessments of left ventricular output (LVO). For each neonate, NICOM measurements of left ventricular stroke volume (SV) and LVO over a 2- to 4-hour period were correlated with blinded, simultaneous, discrete echo measurements of SV and LVO. The precision and accuracy of the NICOM monitor relative to echo during periods of steady state were assessed.
The infants' median birth weight was 2.72 kg (IQR 1.56-3.23 kg, range 1.44-4.00) and their median gestation was 37 weeks (IQR 31-40 weeks, range 31-41). Median NICOM SV and LVO readings were consistently lower than echo (2.6 ml [IQR 1.4-3.2, range 0.6-5.3] vs. 3.5 ml [IQR 2.1-4.4, range 1.1-6.8], and 400 ml/min [IQR 233-476] vs. 559 ml/min [IQR 386-652], p < 0.001). The NICOM LVO readings were lower than the echo readings by a mean of 153 ± 56 ml/kg. NICOM consistently under-read LVO by 31 ± 8%, and this systematic difference was constant across the range of LVOs obtained. There was a strong correlation between NICOM and echo measurements of LVO (r = 0.95, p < 0.001).
Non-invasive cardiac output monitoring is feasible in neonates. Further validation studies in neonatal animal experimental models and human neonates need to be conducted before routine clinical use.
Neonatology 04/2012; 102(1):61-7. · 2.66 Impact Factor
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ABSTRACT: The use of plain radiographs in assessing the correct position of peripherally inserted central catheter (PICC) line tips is not always accurate. Ultrasound may be a better modality in detecting tip position and aid in line manipulation. We assessed the accuracy of plain radiographs in determining PICC line tip position compared with using targeted neonatal echocardiography (TnECHO) in a tertiary neonatal intensive care unit. Following PICC insertion, tip position was confirmed using TnECHO after the first radiograph. A 2 × 2 table was constructed to compare the two modalities' ability to detect line position. A total of 22 infants were included in the study with a gestation of 26.5 weeks (25.4 to 28.8) and birth weight of 833 g (710 to 1930). Concordance between radiographs and TnECHO for PICC line tip position occurred in 13 infants (59%). Sensitivity of radiographs in determining malposition was 64% with a specificity of 55%. Three infants were incorrectly identified to have deep lines and two infants were incorrectly identified to have short lines. In nine infants (41%), a second radiograph was avoided following line manipulation using TnECHO. TnECHO is a useful tool in identifying tip position, performing real-time manipulation, and minimizing exposure to further radiographs.
American Journal of Perinatology 11/2011; 29(2):101-6. · 1.32 Impact Factor
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ABSTRACT: To investigate the value of targeted neonatal echocardiography (TnECHO) in predicting cardiorespiratory instability after patent ductus arteriosus (PDA) ligation, and to evaluate the impact of TnECHO-directed care.
We reviewed serial echocardiography evaluations of 62 preterm infants after PDA ligation to investigate the relationship between indices of myocardial performance and postoperative cardiorespiratory instability. A predictive model was developed based on TnECHO criteria, with targeted initiation of intravenous milrinone. A comparative evaluation was performed between matched infants in the previous era (epoch 1; n=25) and current era (epoch 2; n=27) of TnECHO-guided treatment.
Left ventricular output <200 mL/kg/min at 1 hour after PDA ligation was a sensitive predictor of systemic hypotension and the need for inotropes, and was used for initiation of i.v. milrinone infusion in epoch 2. Infants treated with milrinone had a lower incidence of ventilation failure (15% vs 48%; P=.02) and less need for inotropes (19% vs 56%; P=.01), and showed a trend toward improved oxygenation (P=.08).
TnECHO facilitates early detection of infants at greatest risk for subsequent cardiorespiratory deterioration. Administration of milrinone to neonates with low cardiac output may lead to improved postoperative stability.
The Journal of pediatrics 11/2011; 160(4):584-589.e1. · 4.02 Impact Factor
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Case Reports 01/2009; 2009:bcr2006106625.
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ABSTRACT: The use of natriuretic peptides in the neonatal population is emerging. B-type Natriuretic Peptide (BNP) and N-terminal-Pro-BNP (NTpBNP) are used in the adult population to assess myocardial function and volume loading. Their role in prognosis following cardiac surgery has also been identified. In preterm infants NTpBNP is becoming increasingly recognised as a potential screening tool for patent ductus arteriosus (PDA), and a marker for myocardial performance. In addition, NTpBNP may provide prognostic information in preterm infants and term infants with congenital diaphragmatic hernia (CDH). In this paper, the role of NTpBNP in the preterm population will be discussed.
International Journal of Pediatrics 01/2009; 2009:175216.
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ABSTRACT: Determining the significance of a patent ductus arteriosus (PDA) remains difficult in preterm neonates and current echocardiographic markers give little information about ductal steal. We hypothesized that the relationship between celiac artery flow (CAF) and left ventricular output (LVO) in the presence of a PDA may determine haemodynamic significance.
To examine CAF to LVO ratio (CAF:LVO) in the presence and the absence of a PDA in preterm neonates, and to compare CAF:LVO to current echocardiographic markers of a significant PDA.
This was a prospective observational study of neonates <1,500 g. Echocardiography was performed at 12 h and day 3. PDA, LVO and CAF were measured by echocardiography. The infants were divided into those who developed a significant PDA (PDA >1.4 mm and left atrial to aortic ratio >1.5 on day 3) and controls. A further assessment was carried out following successful PDA treatment with ibuprofen or surgical ligation.
A total of 33 infants were enrolled. 19 infants had a PDA (median gestation 27 weeks, birth weight 915 g), and 14 controls (gestation 28.7 weeks, birth weight 1,110 g). At 12 h, there was no difference in CAF, LVO or CAF:LVO. On day 3, there was a significant difference in CAF:LVO between PDA versus control groups. CAF:LVO significantly correlated with conventional markers of ductal significance. A CAF:LVO value of 0.10 had a sensitivity of 93% and a specificity of 78% for the presence of a significant PDA. Following successful PDA treatment CAF:LVO returned to levels similar to controls.
CAF:LVO may be used to determine which PDA warrants treatment and serve as a marker of treatment success. Trials are needed to correlate CAF:LVO with outcome and the impact of basing PDA treatment on this ratio.
Neonatology 02/2008; 93(3):206-12. · 2.66 Impact Factor
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ABSTRACT: B-type natriuretic peptide (BNP) and N-terminal-pro-BNP (NTpBNP) have a major role in screening and diagnosis of cardiac disease and monitoring of the treatment response in children and adults. This review discusses the evidence underpinning the potential benefits of these natriuretic peptides in neonatology. They may serve as a useful adjunct to echocardiography in the diagnosis of patent ductus arteriosus and its response to treatment and the diagnosis of persistent pulmonary hypertension of the newborn. However, more work is needed to explore the possible roles of BNP/NTpBNP in the management of sepsis and monitoring of cardiac performance in neonates.
Archives of Disease in Childhood - Fetal and Neonatal Edition 08/2007; 92(4):F320-4. · 3.05 Impact Factor
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Archives of Disease in Childhood - Fetal and Neonatal Edition 04/2007; 92(2):F134. · 3.05 Impact Factor
