Risk Factors of Chylothorax After Congenital Heart Surgery in Infants: A Single-Centre Retrospective Study.

Background: Studies of chylothorax after congenital heart disease in infants are rare. Chylothorax has a higher incidence in infancy, but its risk factors are not well understood. Objective: The purpose of this study is to investigate the risk factors of chylothorax after congenital heart surgery in infants. Methods: This retrospective study included 176 infants who underwent congenital heart disease surgery at the Guangdong Cardiovascular Institute, China, between 2016 and 2020. According to the occurrence of chylothorax, the patients were divided into a control group (n = 88) and a case group (n = 88). Univariate and multivariate logistic regression were performed to analyse the incidence and influencing factors of chylothorax after congenital heart surgery in infants. Results: Between 2016 and 2020, the annual incidence rate fluctuated between 1.55% and 3.17%, and the total incidence of chylothorax was 2.02%. Multivariate logistic regression analysis showed that postoperative albumin (p = 0.041; odds ratio [OR] = 0.095), preoperative mechanical ventilation (p = 0.001; OR = 1.053) and preterm birth (p = 0.002; OR = 5.783) were risk factors for postoperative chylothorax in infants with congenital heart disease. Conclusion: The total incidence of chylothorax was 2.02% and the annual incidence rate fluctuated between 1.55% and 3.17% between 2016 and 2020. Premature infants, longer preoperative mechanical ventilation and lower albumin after congenital heart surgery may be risk factors for chylothorax. In addition, infants with chylothorax are inclined to be infected, need more respiratory support, use a chest drainage tube for longer and remain longer in hospital.

The clinical value of ultrasonic cardiac output monitor in very-low birth-weight and extremely-low-birth-weight infants undergoing PDA ligation.

BACKGROUND: Cardiorespiratory instability occurs very often in very-low-birth-weight (VLBW) and extremely-low-birth-weight (ELBW) infants undergoing patent ductus arteriosus (PDA) ligation during the early postoperative period. This study aimed to investigate ultrasonic cardiac output monitor (USCOM) as a bedside tool by evaluating the hemodynamic changes in preterm infants following PDA ligation and assessing factors that may influence these changes. METHODS: This was a single-center prospective observational study at a third-level neonatal intensive care unit. A total of 33 infants, including 21 VLBW and 12 ELBW infants, were involved. Hemodynamic measurements were performed in these infants using a USCOM preoperatively as well as 0-1 h, 8-10 h, and 24 h postoperatively. RESULTS: The PDA ligation was associated with reductions of the left ventricular cardiac output (LVCO) (P < 0.001), cardiac index (P < 0.001), flow time corrected (FTC) (P < 0.001), Smith-Madigan inotropy index (SMII) (P < 0.001), oxygen delivery (DO2) (P < 0.001), and oxygen delivery index (DO2I) (P < 0.001) and an increase of the systemic vascular resistance index (SVRI) (P < 0.001) at 0-1 h, 8-10 h, and 24 h post-ligation compared with the respective preoperative values. Compared with the respective values at 0-1 h post-ligation, there was no significant difference in the CI, SMII, or FTC at 8-10 h and 24 h post-ligation. However, the SVRI decreased at 8-10 h and 24 h post-ligation. Moreover, the DO2I increased at 8-10 h and 24 h post-ligation, and the LVCO and DO2 increased at 24 h post-ligation. CONCLUSION: Our study confirmed that the hemodynamic changes measured by the USCOM were similar to those measured by echocardiography in previous reports. Thus, USCOM is a useful and convenient bedside tool for assessing hemodynamic changes to guide the use of fluids, inotropic agents, and vasopressors and help modify the post-ligation course, and they may be a surrogate for repeated echocardiography during the early post-ligation period in preterm infants or a preliminary screening method.

Measurement of inotropy and systemic oxygen delivery in term, low- and very-low-birth-weight neonates using the Ultrasonic Cardiac Output Monitor (USCOM).

Background The aim of this study was to assess the normal values of the Smith-Madigan inotropy index (SMII) and oxygen delivery index (DO2I) in low-birth-weight (LBW) and very-low-birth-weight (VLBW) newborns on the first 3 days of life, and to identify how different degrees of maturity influence cardiovascular alterations during the transitional period compared with term neonates. Methods Twenty-eight VLBW newborns, 46 LBW newborns and 50 normal full-term newborns admitted to our department were studied. Hemodynamics of the left heart were measured in all neonates over the first 3 days using the Ultrasonic Cardiac Output Monitor (USCOM). This was combined with hemoglobin concentration and pulse oximetry to calculate DO2I. Blood pressure was combined with the hemodynamic measures and hemoglobin concentration to calculate SMII. Results SMII showed statistically significant differences among the three groups (VLBW 0.48 ± 0.11; LBW 0.54 ± 0.13; term 0.69 ± 0.17 W/m2 P < 0.001), which was in line with the following myocardial parameters: stroke volume index (SVI) and cardiac index (CI) (P < 0.001 and <0.001). For systemic oxygen delivery (DO2) parameters, significant differences were found for DO2I (P < 0.001) while hemoglobin concentration and pulse oximetry demonstrated no significant differences. In the VLBW group, SMII and DO2I showed no significant change over the 3 days. Conclusion Normal inotropy and systemic DO2I values in VLBW neonates over the first 3 days of life were assessed. SMII and DO2I were significantly lower in VLBW neonates during the first 72 h of life. With increasing birth weight, higher myocardial inotropy and DO2 were found. The addition of USCOM examination to standard neonatal echocardiography may provide further important information regarding cardiac function.

[Clinical study of neonatal cardiac output measurement methods].

OBJECTIVE: To assess agreement between the ultrasonic cardiac output monitor (USCOM) and conventional echocardiography (ECHO) in the measurement of cardiac output in newborn infants, investigate the accuracy and clinical utility of the USCOM in healthy neonates. To explore a more convenient, faster, more accurate hemodynamic monitoring method, for improving the outcome of the critically ill neonates. METHOD: From October 1(st), 2011 to March 31(st), 2012, a total of 49 infants were included, 20 were term infants, 29 were preterm infants. Cardiac outputs were measured by both ultrasonic cardiac output monitor and echocardiography in all the infants, 60 times measurements were done in both the term infants the preterm infants. The cardiac output of the left and right ventricles, heart rate, diameter and velocity time integral of the aortic valve and pulmonary artery valve of each infant were recorded. The consistency of two methods was analyzed as described by Bland-Altman. RESULT: Term the term infant group includea 20 term infants, 11 were male and 9 were female, the mean gestational age were (38.1 ± 0.56) weeks, mean age were (2 ± 1) days, mean weight were (3.2 ± 0.29) kg, mean Apgar score were 10. The mean left ventricular output measured by Echo was (242.3 ± 38.9) ml/(kg·min), measured by USCOM was (211.7 ± 38.5) ml/(kg·min); The mean right ventricular output measured by ECHO was (318.9 ± 47.0) ml/(kg·min), measured by USCOM was (340.7 ± 76) ml/(kg·min). Agreement between Echo and USCOM for left ventricular output (LVO) was (bias, ± limits of agreement, mean % error): (30.6 ± 51.1) ml/(kg·min), 21%, and for right ventricular output (RVO): (-21.8 ± 105) ml/(kg·min), 33.2%. The diameter of the aortic valve and pulmonary artery valve measured by conventional echocardiography were significantly larger than that estimated by ultrasonic cardiac output monitor (P < 0.001). The velocity time integral of the pulmonary artery valve measured by ultrasonic cardiac output monitor were significantly larger than measured by conventional echocardiography (P < 0.001). The heart rate, velocity time integral of the aortic valve measured by two methods had no significant differences (P > 0.05). The preterm neonates group included 29 preterm infants, 18 were male and 11 were female, the mean gestational age were (32.6 ± 2.8) weeks, mean age were (2 ± 1) days, mean weight were (1.88 ± 0.57) kg. All the infants were diagnosis as preterm infant, low birth weight. The mean left ventricular output measured by ECHO was (259.8 ± 70) ml/(kg·min), measured by USCOM was (235.6 ± 61.8) ml/(kg·min), the mean right ventricular output measured by ECHO was (318.9 ± 47.0) ml/(kg·min), measured by USCOM was (340.7 ± 76) ml/(kg·min). Agreement between Echo and USCOM for left ventricular output (LVO) was (bias, ± limits of agreement, mean % error): (24.1 ± 71.2) ml/(kg·min), 27.4%, and for right ventricular output (RVO): (-29.5 ± 192.9) ml/(kg·min), 51.8%. The diameter of the aortic valve and pulmonary artery valve measured by conventional echocardiography were significantly larger than estimated by ultrasonic cardiac output monitor (P < 0.001). The velocity time integral of the pulmonary artery valve measured by USCOM were significantly larger than that measured by conventional echocardiography (P < 0.001). The heart rate, velocity time integral of the aortic valve measured by two methods had no significant differences (P > 0.05). CONCLUSION: Agreement between USCOM and conventional ECHO in the LVO measurement is acceptable, both in the term group and the preterm group. LVO measurement measured by USCOM is recommended. The accuracy and clinical utility of the USCOM in neonates is acceptable. USCOM is a convenient, fast and accurate hemodynamic monitoring method in neonates. While the agreement between USCOM and conventional ECHO in the RVO measurement is poor, especially in the preterm group, the results of the RVO cannot be considered interchangeable in the two methods.

Measurement of systemic oxygen delivery and inotropy in healthy term neonates with the Ultrasonic Cardiac Output Monitor (USCOM).

INTRODUCTION: The aim of this study was to assess the normal values for Smith-Madigan inotropy (SMI), Smith-Madigan inotropy index (SMII), oxygen delivery (DO2) and oxygen delivery index DO2I in healthy term neonates on the first day of life and during circulatory adaptation over the first three days of life. METHODS: Hemodynamics of the left heart were measured non-invasively in 71 normal full-term neonates over the first three days using the Ultrasonic Cardiac Output Monitor (USCOM). This was combined with hemoglobin concentration from umbilical cord blood and pulse oximetry to calculate DO2 and DO2I. Blood pressure was measured using automated oscillometry and combined with the hemodynamic measures and hemoglobin concentration using the Smith-Madigan method to calculate inotropy (SMI) and inotropy index (SMII). RESULTS: SMI and SMII showed no significant change during the study period, ranging from 154 to 168 mW and 694 to 731 mW/m(2). Mean (SD) DO2 and DO2I showed a significant fall over three days from 131 (63) ml/min and 596 (278) ml/m(2)/min to 118 (46) ml/min and 517 (173) ml/m(2)/min (p<0.01 and <0.001 respectively) with a corresponding decrease in cardiac output from 758 (143) ml/min to 658 (131) ml/min, (p=0.002). There was no significant change in stroke volume, heart rate, SMI or SMII within the first day. DO2 and DO2I showed small but significant decreases within the first day from 153 (46) ml/min and 699 (174) ml/min/m(2) to 129 (36) ml/min and 609 (141) ml/min/m(2) (p=0.017 and 0.048 respectively). CONCLUSIONS: Normal inotropy of the left heart and systemic DO2 values in healthy full-term neonates over the first three days of life were assessed using the USCOM. Subjects showed stable myocardial contractility over the first three days with decreasing DO2 and DO2I in line with the decrease in cardiac output (CO). DO2 and DO2I showed small but significant reductions during the first 24 h. USCOM proved to be a feasible and convenient non-invasive bedside tool to assess inotropy and oxygen delivery in neonates.