Analysis of haemodynamics surrounding blood transfusions after the arterial switch operation: a pilot study utilising real-time telemetry high-frequency data capture.

BACKGROUND: Packed red blood cell transfusions occur frequently after congenital heart surgery to augment haemodynamics, with limited understanding of efficacy. The goal of this study was to analyse the hemodynamic response to packed red blood cell transfusions in a single cohort, as "proof-of-concept" utilising high-frequency data capture of real-time telemetry monitoring. METHODS: Retrospective review of patients after the arterial switch operation receiving packed red blood cell transfusions from 15 July 2020 to 15 July 2021. Hemodynamic parameters were collected from a high-frequency data capture system (SickbayTM) continuously recording vital signs from bedside monitors and analysed in 5-minute intervals up to 6 hours before, 4 hours during, and 6 hours after packed red blood cell transfusions-up to 57,600 vital signs per packed red blood cell transfusions. Variables related to oxygen balance included blood gas co-oximetry, lactate levels, near-infrared spectroscopy, and ventilator settings. Analgesic, sedative, and vasoactive infusions were also collected. RESULTS: Six patients, at 8.5[IQR:5-22] days old and weighing 3.1[IQR:2.8-3.2]kg, received transfusions following the arterial switch operation. There were 10 packed red blood cell transfusions administered with a median dose of 10[IQR:10-15]mL/kg over 169[IQR:110-190]min; at median post-operative hour 36[IQR:10-40]. Significant increases in systolic and mean arterial blood pressures by 5-12.5% at 3 hours after packed red blood cell transfusions were observed, while renal near-infrared spectroscopy increased by 6.2% post-transfusion. No significant changes in ventilation, vasoactive support, or laboratory values related to oxygen balance were observed. CONCLUSIONS: Packed red blood cell transfusions given after the arterial switch operation increased arterial blood pressure by 5-12.5% for 3 hours and renal near-infrared spectroscopy by 6.2%. High-frequency data capture systems can be leveraged to provide novel insights into the hemodynamic response to commonly used therapies such as packed red blood cell transfusions after paediatric cardiac surgery.

Arrhythmias Requiring ECMO in Infants Without Structural Congenital Heart Disease.

Arrhythmias account for 55 per 100,000 patient evaluations in pediatric emergency departments. Most arrhythmias in children are amenable to medical management or cardioversion. Rarely, arrhythmias lead to significant hemodynamic instability requiring extracorporeal membrane oxygenation (ECMO) support. This study seeks to evaluate children under 1 year of age with a structurally normal heart requiring ECMO for an arrhythmia. This is a retrospective review of the Extracorporeal Life Support Organization Registry. All patients less than 1 year of age between 2009 and 2019 with a diagnosis of arrhythmia and without a diagnosis of structural heart malformation were included. Demographics, clinical characteristics, and outcomes were assessed with descriptive statistics and univariate and multivariable analyses. A total of 140 eligible patients were identified from the dataset. The most common arrhythmia was supraventricular tachycardia (SVT) in 70 (50%) patients. ECMO complications occurred in 106 (76.3%) patients and survival to discharge was achieved in 120 (85.7%) patients. In-hospital mortality was associated with neuromuscular blockade prior to ECMO [aOR 10.0 (95% CI 2.95-41.56), p < 0.001], neurologic ECMO complication [aOR 28.1 (95% CI 6.6-155.1), p < 0.001], and race with white race being protective [aOR 0.13, (95% CI 0.02-0.21), p = 0.002]. Similar survival and complication rates were found in subgroup analysis of SVT arrhythmias alone. Arrhythmias necessitating ECMO support in infants without structural congenital heart disease is a rare occurrence. However, survival to hospital discharge is favorable at greater than 85%. Given the favorable survival, earlier and more aggressive utilization of ECMO may result in improved outcomes.

Standard CPR versus interposed abdominal compression CPR in shunted single ventricle patients: comparison using a lumped parameter mathematical model.

INTRODUCTION: Cardiopulmonary resuscitation (CPR) in the shunted single-ventricle population is associated with poor outcomes. Interposed abdominal compression-cardiopulmonary resuscitation, or IAC-CPR, is an adjunct to standard CPR in which pressure is applied to the abdomen during the recoil phase of chest compressions. METHODS: A lumped parameter model that represents heart chambers and blood vessels as resistors and capacitors was used to simulate blood flow in both Blalock-Taussig-Thomas and Sano circulations. For standard CPR, a prescribed external pressure waveform was applied to the heart chambers and great vessels to simulate chest compressions. IAC-CPR was modelled by adding phasic compression pressure to the abdominal aorta. Differential equations for the model were solved by a Runge-Kutta method. RESULTS: In the Blalock-Taussig-Thomas model, mean pulmonary blood flow during IAC-CPR was 30% higher than during standard CPR; cardiac output increased 21%, diastolic blood pressure 16%, systolic blood pressure 8%, coronary perfusion pressure 17%, and coronary blood flow 17%. In the Sano model, pulmonary blood flow during IAC-CPR increased 150%, whereas cardiac output was improved by 13%, diastolic blood pressure 18%, systolic blood pressure 8%, coronary perfusion pressure 15%, and coronary blood flow 14%. CONCLUSIONS: In this model, IAC-CPR confers significant advantage over standard CPR with respect to pulmonary blood flow, cardiac output, blood pressure, coronary perfusion pressure, and coronary blood flow. These results support the notion that single-ventricle paediatric patients may benefit from adjunctive resuscitation techniques, and underscores the need for an in-vivo trial of IAC-CPR in children.

Training Pathways in Pediatric Cardiac Intensive Care: Proceedings From the 10th International Conference of the Pediatric Cardiac Intensive Care Society.

The increase in pediatric cardiac surgical procedures and establishment of the practice of pediatric cardiac intensive care has created the need for physicians with advanced and specialized knowledge and training. Current training pathways to become a pediatric cardiac intensivist have a great deal of variability and have unique strengths and weaknesses with influences from critical care, cardiology, neonatology, anesthesiology, and cardiac surgery. Such variability has created much confusion among trainees looking to pursue a career in our specialized field. This is a report with perspectives from the most common advanced fellowship training pathways taken to become a pediatric cardiac intensivist as well as various related topics including scholarship, qualifications, and credentialing.

Sodium bicarbonate use during in-hospital pediatric pulseless cardiac arrest - a report from the American Heart Association Get With The Guidelines(®)-Resuscitation.

BACKGROUND: Despite limited recommendations for using sodium bicarbonate (SB) during cardiopulmonary resuscitation (CPR), we hypothesized that SB continues to be used frequently during pediatric in-hospital cardiac arrest (IHCA) and that its use varies by hospital-specific, patient-specific, and event-specific characteristics. METHODS: We analyzed 3719 pediatric (<18 years) index pulseless CPR events from the American Heart Association Get With The Guidelines-Resuscitation database from 1/2000 to 9/2010. RESULTS: SB was used in 2536 (68%) of 3719 CPR events. Incidence of SB use between 2000 and 2005 vs. 2006 and 2010 was 71.1% vs. 66.2% (P=0.002). The primary outcome was survival to discharge. Secondary outcomes included 24-h survival and neurologic outcome. Multivariable logistic regression analyzed the association between SB use and outcomes. SB had increased use an ICU location, metabolic/electrolyte disturbance, prolonged CPR, pVT/VF, and concurrently with other pharmacologic interventions. Adjusting for confounding factors, SB use was associated with decreased 24-h survival (aOR 0.83, 95% CI: 0.69, 0.99) and decreased survival to discharge (aOR 0.80; 95% CI: 0.65, 0.97). Inclusion of metabolic/electrolyte abnormalities, hyperkalemia, and toxicologic abnormalities only (n=674), SB use was not associated with worse outcomes or unfavorable neurologic outcome. CONCLUSIONS: SB is used frequently during pediatric pulseless IHCA, yet there is a significant trend toward less routine use over the last decade. Because SB is more likely to be used in an ICU, with prolonged CPR, and concurrently with other pharmacologic interventions; its use during CPR may be associated with poor prognosis due to an association with "last ditch" efforts of resuscitation rather than causation.

Use of the cardioprotectants thymosin ß4 and dexrazoxane during congenital heart surgery: proposal for a randomized, double-blind, clinical trial.

Neonates and infants undergoing heart surgery with cardioplegic arrest experience both inflammation and myocardial ischemia-reperfusion (IR) injury. These processes provoke myocardial apoptosis and oxygen-free radical formation that result in cardiac injury and dysfunction. Thymosin ß4 (Tß4) is a naturally occurring peptide that has cardioprotective and antiapoptotic effects. Similarly, dexrazoxane provides cardioprotection by reduction of toxic reactive oxygen species (ROS) and suppression of apoptosis. We propose a pilot pharmacokinetic/safety trial of Tß4 and dexrazoxane in children less than one year of age, followed by a randomized, double-blind, clinical trial of Tß4 or dexrazoxane versus placebo during congenital heart surgery. We will evaluate postoperative time to resolution of organ failure, development of low cardiac output syndrome, length of cardiac ICU and hospital stays, and echocardiographic indices of cardiac dysfunction. Results could establish the clinical utility of Tß4 and/or dexrazoxane in ameliorating ischemia-reperfusion injury during congenital heart surgery.

Effect of low-dose naloxone infusion on fentanyl requirements in critically ill children.

OBJECTIVE: Sedating critically ill patients often involves prolonged opioid infusions causing opioid tolerance. Naloxone has been hypothesized to limit opioid tolerance by decreasing adenylate cyclase/cyclic adenosine monophosphate activation. The study purpose was to investigate the effect of low-dose naloxone on the maximum cumulative daily fentanyl dose in critically ill children. METHODS: We conducted a double-blinded, randomized, placebo-control trial from December 2002 through July 2004 in a university PICU. We enrolled 82 children age 1 day to 18 years requiring mechanical ventilation and fentanyl infusions anticipated to last for >4 days were eligible for enrollment. Those receiving additional oral analgesia or sedation, having a history of drug dependence or withdrawal, or having significant neurologic, renal, or hepatic disease were excluded. In addition to fentanyl infusions, patients received low-dose naloxone or placebo infusions. Medications were adjusted using the Modified Motor Activity Assessment Scale. Withdrawal was monitored using the Modified Narcotic Withdrawal Scale. Intervention was a low-dose naloxone infusion (0.25 microg/kg per hour) and the main outcome variable was the maximum cumulative daily fentanyl dose (micrograms per kilogram per day). RESULTS: There was no difference in the maximum cumulative daily fentanyl dose between patients treated with naloxone (N = 37) or those receiving placebo (N = 35). Adjustment for the starting fentanyl dose also failed to reveal group differences. Total fentanyl dose received throughout the study in the naloxone group (360 microg/kg) versus placebo (223 microg/kg) was not statistically different. Placebo patients trended toward fewer rescue midazolam boluses (10.7 vs 17.8), lower total midazolam dose (11.6 mg/kg vs 23.9 mg/kg), and fewer rescue fentanyl boluses (18.5 vs 23.9). CONCLUSIONS: We conclude that administration of low-dose naloxone (0.25 microg/kg per hour) does not decrease fentanyl requirements in critically ill, mechanically ventilated children.

Respiratory syncytial viral infection in an infant with unrepaired anomalous left coronary artery from the pulmonary artery.

Abnormal origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare coronary anomaly in children that requires necessary and urgent repair. We report a child who was hospitalized with respiratory failure due respiratory syncytial viral (RSV) infection and was subsequently diagnosed with ALCAPA. Aggressive treatment for RSV included synagis and nebulized ribavirin prior to surgical repair. After waiting 4 weeks for the RSV infection to resolve, she underwent successful left coronary artery reimplantation on hospital day 27 and has regained normal left ventricular size and function.

The extracardiac lateral tunnel Fontan, constructed with bovine pericardium: comparison with the extracardiac conduit Fontan.

BACKGROUND: The Fontan procedure performed with an extracardiac conduit (ECC) has gained wide acceptance as an alternative to the intracardiac lateral tunnel because it avoids placement of extensive atrial suture lines and use of prosthetic material in the systemic circulation. The extracardiac lateral tunnel (ELT) is a modification of the Fontan procedure which uses pericardium and the external surface of the atrium to create a conduit from the inferior vena cava to the pulmonary artery. This surgery theoretically avoids disruption of intra-atrial conduction by eschewing endocardial suturing while maintaining conduit growth potential and the ability to easily create a fenestration to the systemic circulation. METHODS: We retrospectively analyzed the short-term outcome of 96 consecutive patients who underwent an extracardiac Fontan procedure. An ELT using bovine pericardium was performed in 59 patients, whereas 37 patients received a traditional ECC. RESULTS: The 2 groups were similar with respect to age (P = .96), body surface area (P = .54), number of preoperative Fontan risk factors (P = .43), and ventricular morphology (P = .72). There were no significant differences in the following outcome variables between the ELT and the traditional ECC: length of hospitalization (P = .73), duration of chest tube drainage (P = .48), abnormal rhythm at time of discharge (P = .27), and mortality (P = .63). CONCLUSIONS: The ELT Fontan can be performed with a low risk of mortality and complications. The results are equivalent to the traditional ECC procedure. The theoretical advantages of the procedure suggest that it should be considered a useful modification of Fontan surgery.

Fresh whole blood versus reconstituted blood for pump priming in heart surgery in infants.

BACKGROUND: In an attempt to reduce the coagulopathic and inflammatory responses seen after cardiopulmonary bypass, the use of fresh whole blood during heart operations has become the standard of care for neonates and infants at many institutions. We compared the use of fresh whole blood with the use of a combination of packed red cells and fresh-frozen plasma (reconstituted blood) for priming of the cardiopulmonary bypass circuit. METHODS: We conducted a single-center, randomized, double-blind, controlled trial involving children less than one year of age who underwent open-heart surgery. Patients were assigned to receive either fresh whole blood that had been collected not more than 48 hours previously (96 patients) or reconstituted blood (104 patients) for bypass-circuit priming. Clinical outcomes and serologic measures of systemic inflammation and myocardial injury were compared between the groups. RESULTS: The group that received reconstituted blood had a shorter stay in the intensive care unit than the group that received fresh whole blood (70.5 hours vs. 97.0 hours, P=0.04). The group that received reconstituted blood also had a smaller cumulative fluid balance at 48 hours (-6.9 ml per kilogram of body weight vs. 28.8 ml per kilogram, P=0.003). Early postoperative chest-tube output, blood-product transfusion requirements, and levels of serum mediators of inflammation and cardiac troponin I were similar in the two groups. CONCLUSIONS: The use of fresh whole blood for cardiopulmonary bypass priming has no advantage over the use of a combination of packed red cells and fresh-frozen plasma during surgery for congenital heart disease. Moreover, circuit priming with fresh whole blood is associated with an increased length of stay in the intensive care unit and increased perioperative fluid overload.

Pediatric cardiac intensivists: are enough being trained?

OBJECTIVE: To determine both the number of cardiac intensivists being trained by member institutions of the Pediatric Cardiac Intensive Care Society and the perceived need for these professionals. DESIGN: Web-based survey of pediatric cardiac intensive care unit program directors. RESULTS: A total of 54 directors completed the survey (41% response rate). Twelve pediatric cardiac critical care fellowship positions are offered each year among the responding Pediatric Cardiac Intensive Care Society institutions in the United States and Canada-only six of the 12 positions were filled in the academic year 2002-2003. Cardiac intensivist recruitment was ongoing at 25 of the programs surveyed (46%). An additional 45 cardiac intensivists will be sought during the next 1-3 yrs and 36 during the subsequent 3- to 5-yr period. CONCLUSIONS: There is a discrepancy between the current and growing need for trained pediatric cardiac intensivists and the graduation rate of these professionals from teaching programs.

Myocardial inflammatory activation in children with congenital heart disease.

OBJECTIVE: In several cardiac-related diseases, there is a strong association between systemic endotoxemia, myocardial cytokine production, and cardiac failure. Because pre- and postoperative endotoxemia recently was reported in children with congenital heart disease, we sought direct evidence of myocardial inflammatory activation in a cohort of children undergoing congenital heart surgery on cardiopulmonary bypass. Inflammatory activation was prospectively defined as the presence of nuclear factor-kappaB nuclear translocation in myocardial tissue samples. DESIGN: Prospective observational study. SETTING: Tertiary care pediatric intensive care unit. PATIENTS: Fifteen children with congenital heart disease undergoing operative repair on cardiopulmonary bypass. INTERVENTIONS: All patients underwent operative repair of congenital heart disease on cardiopulmonary bypass and had plasma samples obtained for endotoxin and tumor necrosis factor-alpha, both pre- and postoperatively. Myocardial tissue samples were obtained intraoperatively, both before and during cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: Elevated plasma endotoxin concentrations were documented in all 15 patients during the study period. In 12 patients, plasma endotoxin was elevated before cardiopulmonary bypass. The median preoperative tumor necrosis factor-alpha concentration was 16.4 pg/mL, which is higher than concentrations reported in adults with New York Heart Association class III congestive heart failure. Examination of myocardial tissue samples revealed nuclear factor-kappaB nuclear translocation (predominantly p50/p65 heterodimers) in nine of 15 patients (60%). Four of these nine patients had nuclear factor-kappaB nuclear translocation before initiation of cardiopulmonary bypass, with p50/p50 homodimers present in two of the four. CONCLUSIONS: These data provide the first evidence of nuclear factor-kappaB activation in children with congenital heart disease and the first evidence of myocardial nuclear factor-kappaB translocation in human hearts before explant for transplantation. Furthermore, these data suggest that, similar to adults with advanced congestive heart failure, the myocardial inflammatory cascade may contribute to the pathophysiology of congenital heart disease in infants and children.

Fenestration improves clinical outcome of the fontan procedure: a prospective, randomized study.

BACKGROUND: The Fontan procedure is the definitive operation for palliation of complex congenital heart disease with single-ventricle physiology. Fenestration of the Fontan circuit allows for shunting of deoxygenated blood to the systemic circulation. This procedure improved the clinical outcomes of patients who are at high risk for poor Fontan results. However, it is controversial whether fenestration is beneficial for standard-risk patients. METHODS AND RESULTS: This prospective, randomized trial evaluated the clinical utility of fenestration in patients with standard preoperative risk profiles for Fontan surgery. Forty-nine consecutive patients were assigned to undergo either a fenestrated (25 patients) or nonfenestrated (24 patients) Fontan procedure. The fenestrated and nonfenestrated groups were comparable with respect to age (P=0.944), body surface area (P=0.250), number of preoperative risk factors for poor outcome (P=0.681), cardiopulmonary bypass time (P=0.302), number of patients who required aortic cross-clamping (P=0.240), preoperative oxygen saturation (P=0.101), and number of patients with dominant left ventricular morphology (P=0.534). Patients in the fenestrated group had 55% less total chest tube drainage (P=0.036), 41% shorter total hospitalization (P=0.018), and 67% fewer additional procedures in the postoperative period (P=0.006) than those in the nonfenestrated group. CONCLUSIONS: Baffle fenestration performed at the time of Fontan surgery improves short-term outcome in standard-risk patients by decreasing pleural drainage, hospital length of stay, and need for additional postoperative procedures.