Early prediction of a significant patent ductus arteriosus in infants <32 weeks gestational age.

BACKGROUND: The optimal thresholds for identification of preterm infants at greatest risk for adverse sequelae related to patent ductus arteriosus have not been well delineated. Our aim was to determine hemodynamic parameters in the first 24 hours using continuous non-invasive vital and structural measurements to predict which infants required PDA treatment in our institution. METHODS: Retrospective secondary analysis of data from infants born 23 to 32 weeks gestational age with cardiac output and stroke volume via electrical cardiometry, cerebral tissue oximetry measurements, mean arterial blood pressure (BP), heart rate, and oxygen saturation and functional echocardiography results at 12 hours of life were recorded when available (93 percent of subjects). RESULTS: A total of 292 infants, of which 55 (26±2 weeks, 862±268 grams) were treated for PDA. Treated infants demonstrated increased left ventricular output (p < 0.001) and lower mean BP (p = 0.010). The optimal area under the receiver operating characteristic curve (AUC) for predicting PDA treatment in our all gestations cohort is a mean BP at 15 hours of life of <33 mm Hg (AUC = 0.854, p < 0.001, 95% CI 0.792, 0.916). For infants <28 weeks a mean BP at 13 hours of life of <33 mm Hg (AUC = 0.741, p < 0.050, 95% CI 0.642, 0.839). CONCLUSIONS: In our cohort increased left ventricular output and lower mean BP predicted a clinically significant PDA requiring treatment.

Hemodynamic effects of sodium bicarbonate administration.

OBJECTIVE: To describe the hemodynamic changes that occur with sodium bicarbonate (NaHCO3) administration in premature neonates. STUDY DESIGN: This retrospective study included premature neonates 23 to 31+6 weeks of gestational age who underwent continuous cardiac and cerebral monitoring as participants in prospective trials at our institution, and who received NaHCO3 infused over 30 min in the first 24 h of life. Blood pressure (BP), heart rate, cardiac output (CO), SpO2 and cerebral oximetry (StO2) were captured every 2 s. A baseline was established for all continuous data and averaged over the 10 min before NaHCO3 administration. Baseline was compared with measurements over 10 min epochs until 80 min after administration. Arterial blood gases before and within 1 h of administration were also compared. Significance was set at P<0.05. RESULTS: A total of 36 subjects received NaHCO3 (1.3±0.3 mEq kg-1) in the first 24 h (14±8.5 h) of life. NaHCO3 administration increased pH (7.23 vs 7.28, P<0.01) and decreased base deficit (-8.9 vs -6.8, P<0.01) and PaCO2 (45 vs 43 mm Hg, P<0.05). There was a transient but significant (P<0.05) decrease in systemic BP coinciding with an increase in cerebral oxygenation without an increase in oxygen extraction. CO did not change. CONCLUSION: Early postnatal NaHCO3 administration does not acutely improve CO but does cause transient fluctuations in cerebral and cardiovascular hemodynamics in extremely premature infants.

Placental transfusion: a review.

Recently there have been a number of studies and presentations on the importance of providing a placental transfusion to the newborn. Early cord clamping is an avoidable, unphysiologic intervention that prevents the natural process of placental transfusion. However, placental transfusion, although simple in concept, is affected by multiple factors, is not always straightforward to implement, and can be performed using different methods, making this basic procedure important to discuss. Here, we review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking and cut-umbilical cord milking, and the evidence in term and preterm newborns supporting this practice. We will also review several factors that influence placental transfusion, and discuss perceived risks versus benefits of this procedure. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution.

The use of electrical cardiometry for continuous cardiac output monitoring in preterm neonates: a validation study.

BACKGROUND: Electrical cardiometry (EC) is a continuous noninvasive method for measuring cardiac output (CO), but there are limited data on premature infants. We evaluated the utility of EC monitoring by comparing the results obtained using EC to measurements of CO and systemic blood flow using echocardiography (ECHO). METHODS: In this prospective observational study, 40 preterm neonates underwent 108-paired EC and ECHO measurements. RESULTS: There were correlations between EC-CO and left ventricular output (LVO, p < 0.005) and right ventricular output (RVO, p < 0.005) but not with superior vena cava (r = 0.093, p = 0.177). Both RVO and LVO correlated with EC with and without a hemodynamically significant ductus arteriosus (p = 0.001 and 0.008, respectively). The level of agreement was decreased in infants ventilated by high-frequency oscillation ventilators (HFOV). The bias in HFOV was also positive compared with the negative biases found in other modes of ventilation. CONCLUSION: Given the correlation of EC with LVO, RVO, and lack of confounding effects of the ductus, our results suggest that EC has promise for trending CO in the preterm infant. However, given the limitations with mode of ventilation and the lack of correlation at low LVO values, further study is needed before this technology can be for routine use.

Oliguria during hydrocortisone dosage wean in very low birth weight infants.

BACKGROUND: Intravenous hydrocortisone (HC) is often used in very low birth weight infants (VLBW) but can be complicated by oliguria when discontinued or tapered. OBJECTIVES: To determine which factors were associated with oliguria during HC taper. METHODS: We reviewed all VLBW infants who received initial doses of HC ≥ 1 mg/kg/d. The initial dose and duration of HC, and the incidence of oliguria (urine output [UO] < 2 mL/kg/h) during HC taper, were recorded. In those with oliguria, we recorded the change in UO (mL/kg/h), blood pressure, and creatinine. RESULTS: The mean initial HC dose was 2.8 ± 1 mg/kg/d, and the mean total duration of HC therapy was 23 ± 25 days. Oliguria occurred in 24% (13/54) of treated infants. These infants were exposed to higher and longer duration of the initial HC dose than infants without oliguria. Oliguria was predicted by the initial HC dose (odds ratio [OR] 5.8, 95% confidence interval [CI] 1.3-25.8, p = 0.02) and by the number of days at initial dose (OR 1.7, 95%CI 1.1-2.7, p = 0.03). CONCLUSIONS: Oliguria during HC dosage weaning was associated with higher initial HC exposure.

A randomized controlled trial of ultrasound-guided peripherally inserted central catheters compared with standard radiograph in neonates.

OBJECTIVE: The placement of a peripherally inserted central catheter (PICC) routinely incorporates tip position confirmation using standard radiographs. In this study, we sought to determine whether real-time ultrasound (RTUS) could be used to place a PICC in a shorter time period, with fewer manipulations and fewer radiographs than the use of radiographs to determine accurate placement. STUDY DESIGN: This was a prospective, randomized, trial of infants who required PICC placement. Catheters were placed using either standard radiograph, with blinded evaluation of the catheters using RTUS or with RTUS guidance, with input on catheter tip location. The number of radiographs required to confirm proper positioning, duration of the procedure and manipulations of the lines were recorded for both groups. Final confirmation of PICC placement was by radiographs in both groups. RESULT: A total of 64 patients were enrolled in the study, with 16 failed PICC attempts. Of the 48 remaining infants, 28 were in the standard placement group and 20 were in the RTUS-guided group. The mean ± s.d. gestational ages and weight at time of placement were 30 ± 4 weeks and 1229 ± 485 g, respectively. The RTUS use significantly decreased the time of line placement by 30 min (P=0.034), and decreased the median number of manipulations (0 vs 1, P=0.032) and radiographs (1 vs 2 P=0.001) taken to place the catheters. Early identification of the PICC by RTUS was possible in all cases and would have saved an additional 38 min if radiographs were not required. CONCLUSION: In the hands of ultrasound (US)-experienced neonatologists, RTUS-guided PICC placement reduces catheter insertion duration, and is associated with fewer manipulations and radiographs when compared with conventional placement.

Changes in hemodynamics after rescue surfactant administration.

OBJECTIVE: To evaluate the hemodynamic changes occurring after rescue surfactant dosing in relation to the clinical respiratory response in preterm infants with respiratory distress syndrome. STUDY DESIGN: We studied 20 infants who received surfactant (poractant alfa) after failing continuous positive airway pressure (CPAP) beyond 2 h of life. Consecutive echocardiograms were performed before the surfactant dose, 10 min after and 1 h after the surfactant dose. Superior vena cava flow, right ventricular output, atrial and patent ductus arteriosus diameter and direction of shunting were measured. A surfactant responder (SR) was defined as an infant whose inspired fraction of oxygen was reduced to air (0.21) by 3 h after surfactant administration. A surfactant non-responder (SNR) was defined as an infant who remained on more than 0.21 at 3 h postsurfactant administration. Concurrent physiological parameters (heart rate, transcutaneous CO2, mean arterial blood pressure, mean airway pressure) were also recorded. Subject characteristics were compared relative to noted hemodynamic effects. RESULTS: Of the 20 infants enrolled in the study, 12 were SR. These infants received surfactant earlier and had increased measures of systemic blood flow after receipt of surfactant compared with baseline. SNR did not have changes in systemic blood flow from baseline after surfactant dosing. There was no change in ductal shunting or atrial shunting between the two groups. CONCLUSIONS: A good clinical response to rescue surfactant is seen in infants who received surfactant earlier and is associated with increase in systemic blood flow. Timing of rescue surfactant administration needs to be further evaluated in larger prospective studies.

Altered transitional circulation in infants of diabetic mothers with strict antenatal obstetric management: a functional echocardiography study.

OBJECTIVE: Infants born to diabetic mothers (IDMs) even with good glycemic control are at risk for neonatal morbidity. Many of these problems occur during neonatal transition. We assessed (i) systemic and pulmonary blood flow in IDMs compared with controls and (ii) directional blood flow changes within fetal shunts during the first few days of life. STUDY DESIGN: In this prospective observational cohort study, we evaluated right (RVO) and left ventricular output, superior vena cava flow, atrial and ductal shunts, and tricuspid regurgitation in 32 IDMs and 18 controls using serial echocardiography after birth and 48 h of life in both groups and at 24 and 72 h in IDMs only. RESULT: IDMs had lower RVO after birth and 48 h of life. IDMs also had less left to right atrial shunt and more right to left ductal shunt after birth compared with controls. In all, 15 of the 32 IDMs were admitted to the neonatal intensive care unit and 11 had respiratory symptoms. CONCLUSION: Persistence of fetal shunts and decreased RVO in IDMs suggest that even those with good gestational control have impaired transitional hemodynamics.