Mechanical support of the functionally single ventricle.
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Biomedical subjects
Publications and source records attributed to Chitra Ravishankar.
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OBJECTIVE: Although extracorporeal membrane oxygenation (ECMO) is an acceptable strategy for children with refractory cardiac dysfunction after cardiac surgery, its role after stage I reconstruction for hypoplastic left heart syndrome and its variants is controversial. Our objective is to describe the outcome of "nonelective" ECMO after stage I reconstruction. DESIGN: Retrospective case series. SETTING: Pediatric cardiac intensive care unit. PATIENTS: Infants placed on ECMO after stage I reconstruction from January 1998 to May 2005. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Of the 382 infants who underwent stage I reconstruction during the study period, 36 (9.4%) required ECMO in the postoperative period. There were 22 infants with hypoplastic left heart syndrome. Indications for ECMO included inability to separate from cardiopulmonary bypass in 14 and cardiac arrest in 22. Fourteen infants (38.8%) survived to hospital discharge. Nonsurvivors had longer cardiopulmonary bypass time (150.1 +/- 70.0 mins vs. 103.9 +/- 30.0 mins, p =. 01). 9/14 infants (64%) supported with ECMO> than 24 hrs after stage I reconstruction survived while only 5/22 infants (22%) requiring ECMO< 24 hrs of stage I reconstruction survived (p =. 02). Of note, all five infants diagnosed with an acute shunt thrombosis were early survivors. Mean duration of ECMO was 50.1 +/- 12.5 hrs for survivors and 125.2 +/- 25.0 for nonsurvivors (p =. 01). 7/14 early survivors are alive at a median follow-up of 20 months (2-78 months). CONCLUSIONS: In our experience, ECMO after stage I reconstruction can be life saving in about a third of infants with otherwise fatal conditions. It is particularly useful in potentially reversible conditions such as acute shunt thrombosis and transient depression of ventricular function.
We present a case of multiple arrhythmias in a 3-year-old child who was presented to the emergency department with emesis. Initial vital signs were significant for a heart rate from 40 to 60 beats per minute with stable blood pressure. An electrocardiogram showed complete atrioventricular block with a junctional escape rhythm of 40 to 55 bpm that subsequently progressed to atrial flutter/fibrillation and then to a junctional escape rhythm. She was given intravenous atropine, resulting in acceleration of the junctional rhythm. Sinus rhythm resumed with a prolonged PR interval a few hours later with normalization of the electrocardiogram the following day. Routine laboratory tests, toxicology screens, and tests for other cardiac medications in the home were negative. However, at 20 hours after presentation, her digoxin level was 2.9 ng/mL. Parents denied that the child had access to any digoxin-containing substances. This case illustrates that digoxin toxicity can manifest with multiple arrhythmias and that recognition of this can be very difficult, especially when there is no witness to ingestion. Clinicians should be suspicious for digoxin toxicity when a child presents with persistent emesis, altered level of consciousness, and bradyarrhythmias with or without hemodynamic instability.
BACKGROUND: Recent reports advocate that a right ventricular to pulmonary artery (RV-PA) conduit improves outcome after the stage I reconstruction. METHODS: We retrospectively compared the outcomes of all neonates who underwent a stage I reconstruction between January 1, 2002, and October 1, 2004, with use of the RV-PA conduit and modified Blalock-Taussig shunt (mBTS) interspersed over this time period. RESULTS: In all, 149 infants underwent a stage I reconstruction (95 mBTS, 54 RV-PA) for hypoplastic left heart syndrome (HLHS) or variants. There was a preference for the RV-PA conduit in patients with aortic atresia (mBTS 30% versus RV-PA 67%, p < 0.01). There was no difference in surgical mortality (mBTS 14% versus RV-PA 17%, p = 0.67), time to extubation (mBTS 4.5 +/- 4.8 days versus RV-PA 3.9 +/- 3.5 days, p = 0.47), or length of hospital stay (mBTS 25 +/- 29 days versus RV-PA 21 +/- 23 days, p = 0.52). There was an increased incidence of shunt reinterventions in the patients with the RV-PA conduit (mBTS 17% versus RV-PA 32%, p = 0.04). Patients with RV-PA conduit returned earlier for stage II reconstruction (mBTS 6.5 +/- 2.5 months versus RV-PA 5.6 +/- 1.7 months, p = 0.05). There was no difference in overall mortality (mBTS 32% versus RV-PA 30%, p = 0.45) with a median duration of follow-up of 18 +/- 8 months. CONCLUSIONS: Comparing shunt strategies (mBTS versus RV-PA) over the same time period, we found no difference in outcome. These data support the need for a larger prospective, randomized trial.
BACKGROUND: Mixed venous saturation (S & OV0456;o2) is an important measurement that helps guide the care of critically ill patients. Invasive S & OV0456;o2 assessment in infants and children is often avoided because of the inherent risks. A noninvasive tissue saturation (S to 2) monitor has recently been developed that uses near-infrared spectroscopy to measure oxyhemoglobin saturation in muscle. In adult and animal studies, S to 2 correlated with oxygen delivery and S & OV0456;o2. There has been no evaluation in pediatric patients. OBJECTIVE: To evaluate tissue saturation as a noninvasive measure of mixed venous saturation in children. DESIGN: A prospective observational study. SETTING: Catheterization laboratory in a tertiary care children's medical center. PATIENTS: We studied 98 children (49 without intracardiac mixing and 49 with intracardiac mixing) <or=12 yrs of age who underwent cardiac catheterization. Under general anesthesia, we compared S to 2 measured over the deltoid muscle with superior vena cava saturation in both groups and S to 2 with pulmonary artery saturation in patients without intracardiac mixing. Paired measurements were analyzed for bias, precision, and correlation via Bland-Altman plot and linear regression. RESULTS: No meaningful correlation was found between S to 2 and superior vena cava saturation or pulmonary artery saturation. Bland-Altman analyses of S to 2 with superior vena cava saturation yielded bias values of -6.67 +/- 37.33% in patients with intracardiac mixing and -0.82 +/- 41.31% in patients without mixing. Bland-Altman analysis of S to 2 with pulmonary artery saturation yielded a bias of 3.61 +/- 41.32% in patients without mixing. Differences between noninvasive and invasive measurements were greatest in smaller children. CONCLUSION: Noninvasive tissue saturation over the deltoid does not correlate with S & OV0456;o2 in children. It is possible that more precise probe spacing, coupled with optimal muscle-mass location, could result in more accurate measures in future investigations.
OBJECTIVE: To determine whether postnatal vitamin A therapy increased ductal closure rate in premature infants. STUDY DESIGN: This was a prospective, double-blind, placebo-controlled trial. Subjects (n=40) were recruited on day of life 1. Inclusion criteria were premature neonates weighing 500 to 1500 g with an indwelling umbilical line. Vitamin A was administered intramuscularly on days 1, 3, and 7. Blood vitamin A and retinol binding protein levels were obtained on days 1 and 3. Echocardiography was performed on days 1, 3, 7, and 14. Failure of ductal closure was defined as the presence of a moderate to large patent ductus arteriosus on day 14, indomethacin therapy, or surgical ligation. RESULTS: Comparison between the treatment and placebo groups revealed no differences in gestational age, weight, or oxygenation index. Vitamin A and retinol binding protein levels did not differ between the groups at entry but increased significantly after vitamin A treatment. Failure of ductal closure occurred in 22 of 40 babies without any difference between the groups (12/22 vs 10/18, P=NS). Four infants required surgical ligation, all in the treatment group (P=.04). Clinical outcome did not vary between groups. CONCLUSION: Postnatal vitamin A therapy did not improve ductal closure rates in premature infants.
The field of cardiac intensive care is rapidly evolving with nearly simultaneous advances in surgical techniques and adjunctive therapies, respiratory care, intensive care technology and monitoring, pharmacologic research and development, and computing and electronics. The focus of care has now shifted toward reducing morbidity and improving "quality of life" while the survival of infants and children with congenital heart defects, including those with univentricular hearts has dramatically improved during the last three decades. Despite these advances, there remains a predictable fall in cardiac output after cardiopulmonary bypass. This article focuses on early identification and aggressive treatment of the low cardiac output syndrome peculiar to these patients. The authors also briefly review the recent advances in the treatment of pulmonary hypertension, mechanical support, and neurologic surveillance after cardiac surgery.
A five-month old male with a single ventricle palliated with a bidirectional cavopulmonary anastomosis developed severe respiratory insufficiency from respiratory syncytial virus (RSV) pneumonitis. He was successfully rescued with extracorporeal membrane oxygenation (ECMO) therapy and recovered with minimal morbidity.