Lisa Wise-Faberowski

Anesthesia and the Developing Brain: Relevance to the Pediatric Cardiac Surgery

Anesthetic neurotoxicity has been a hot topic in anesthesia for the past decade. It is of special interest to pediatric anesthesiologists. A subgroup of children potentially at greater risk for anesthetic neurotoxicity, based on a prolonged anesthetic exposure early in development, are those children receiving anesthesia for surgical repair of congenital heart disease. These children have a known risk of neurologic deficit after cardiopulmonary bypass for surgical repair of congenital heart disease. Yet, the type of anesthesia used has not been considered as a potential etiology for their neurologic deficits. These children not only receive prolonged anesthetic exposure during surgical repair, but also receive repeated anesthetic exposures during a critical period of brain development. Their propensity to abnormal brain development, as a result of congenital heart disease, may modify their risk of anesthetic neurotoxicity. This review article provides an overview of anesthetic neurotoxicity from the perspective of a pediatric cardiac anesthesiologist and provides insight into basic science and clinical investigations as it relates to this unique group of children who have been studied over several decades for their risk of neurologic injury.

Anesthesia during surgical repair for congenital heart disease and the developing brain: neurotoxic or neuroprotective?

Every year, approximately 10 000 children require anesthesia for congenital heart surgery during their first year of life (1,2). Advances in surgical techniques, cardiopulmonary bypass, anesthesia, and intensive care management have dramatically improved long-term survival in these children and have therefore focused attention on quality of life and neurocognitive outcomes (3–6). As the numbers of survivors increase and surgical procedures become more complex, there is a growing concern about the risk of abnormal neurologic outcome. The neurodevelopmental outcome of these children is quite variable: many are totally normal, while 20–50% of these children have neurologic impairment and developmental disabilities (7,8). The etiology of neurologic impairment in these children has been studied and is multifactorial: brain immaturity (9–11), timing of surgery in cyanotic infants (12), prolonged low brain regional oxygen saturation (13), prolonged

Programmatic Approach to Management of Tetralogy of Fallot With Major Aortopulmonary Collateral Arteries: A 15-Year Experience With 458 Patients

Background— Tetralogy of Fallot with major aortopulmonary collateral arteries is a complex and heterogeneous condition. Our institutional approach to this lesion emphasizes early complete repair with the incorporation of all lung segments and extensive lobar and segmental pulmonary artery reconstruction. Methods and Results— We reviewed all patients who underwent surgical intervention for tetralogy of Fallot and major aortopulmonary collateral arteries at Lucile Packard Children’s Hospital Stanford (LPCHS) since November 2001. A total of 458 patients underwent surgery, 291 (64%) of whom underwent their initial procedure at LPCHS. Patients were followed for a median of 2.7 years (mean 4.3 years) after the first LPCHS surgery, with an estimated survival of 85% at 5 years after first surgical intervention. Factors associated with worse survival included first LPCHS surgery type other than complete repair and Alagille syndrome. Of the overall cohort, 402 patients achieved complete unifocalization and repair, either as a single-stage procedure (n=186), after initial palliation at our center (n=74), or after surgery elsewhere followed by repair/revision at LPCHS (n=142). The median right ventricle:aortic pressure ratio after repair was 0.35. Estimated survival after repair was 92.5% at 10 years and was shorter in patients with chromosomal anomalies, older age, a greater number of collaterals unifocalized, and higher postrepair right ventricle pressure. Conclusions— Using an approach that emphasizes early complete unifocalization and repair with incorporation of all pulmonary vascular supply, we have achieved excellent results in patients with both native and previously operated tetralogy of Fallot and major aortopulmonary collateral arteries.

Complete Atrioventricular Septal Defects

Complete atrioventricular septal defect (CAVSD) refers to a complex malformation of the atrial and ventricular septum and is defined by an abnormal embryological development of the endocardial cushions in the atrioventricular canal resulting in maldevelopment of the atrial–ventricular valves [1]. CAVSD represents around 3% of congenital cardiac defects and it is a frequent anomaly in the context of autosomic trisomic anomalies, particularly in patients with Down’s syndrome (trisomy 21) and Edward’s syndrome (Trisomy 18). Fifty percent of atrioventricular septal defects are diagnosed in patients with Down’s syndrome and 30% of these have a CAVSD [2].

Acute and sustained isoflurane neuroprotection: The effect of culture age and duration of oxygen and glucose deprivation

Objectives: Organotypic hippocampal slice (OHS) cultures provide the opportunity to dissect factors influencing volatile anaesthetic neuroprotective efficacy. It was hypothesized that three conditions—OHS culture age, oxygen glucose deprivation (OGD) duration and day of evaluation for cell death after OGD—influence isofluranes ability to provide acute and sustained protection against OGD-induced cell death. Methods: OHS were prepared from PND 9–11 rat pups and maintained in vitro for 0.5, 1, 2 or 3 weeks. The slices were exposed to OGD for 0, 10, 30, 60 or 90 minutes with or without 1.5% isoflurane. Sytox staining was used to determine the amount of cell death on post-OGD days 1, 3 and 7 and was compared to the amount of cell death in culture–age matched controls (no OGD). Results: The duration of OGD necessary to produce cell death was inversely related to culture age. All culture ages showed evidence of both acute and sustained neuroprotection, but the magnitude of protection depended on OHS culture age, duration of OGD and post-OGD day of evaluation. In 1 and 2-week old slices early isoflurane neuroprotection was best observed with 90 minutes OGD and late isoflurane protection was best observed with 10 minutes OGD. Conclusions: In OHS, acute and sustained isoflurane neuroprotection in OGD-induced cell death is dependent on the conditions being studied.

Bronchoscopy in children with tetralogy of fallot, pulmonary atresia, and major aortopulmonary collaterals

Children with Tetralogy of Fallot, Pulmonary Atresia, and Major Aortopulmonary Collaterals (TOF/PA/MAPCAs) undergoing unifocalization surgery are at risk for developing more postoperative respiratory complications than children undergoing other types of congenital heart surgery. Bronchoscopy is used in the perioperative period for diagnostic and therapeutic purposes. In this study, we describe bronchoscopic findings and identify factors associated with selection for bronchoscopy.

Management of high-risk reentry sternotomy in an infant for repair of a giant pseudoaneurysm of the right ventricular outflow tract.

Improved survival from congenital heart disease has led to an increasing need for complex reoperation by reentrant sternotomy. Peripheral cannulation and initiation of cardiopulmonary bypass prior to sternotomy to avoid the risk of cardiac injury and massive hemorrhage is an option in adults and larger children, but femoral vessel size precludes this strategy in infants. We describe the management of a high-risk reentry sternotomy in an infant for repair of a giant pseudoaneurysm after prior homograft repair of tetralogy of Fallot, using surgical dissection for suprasternal cannulation of the innominate artery and subxyphoid cannulation of the inferior vena cava.

Patent Ductus Arteriosus

The ductus arteriosus is a normal and vital fetal structure that arises from the left sixth aortic arch. It connects the main pulmonary artery to the descending thoracic aorta just distal and opposite to the origin of the left subclavian artery (Fig. 14.1). The pulmonary end usually tapers and is narrower than the aortic end.

Pulmonary reinterventions after complete unifocalization and repair in infants and young children with tetralogy of Fallot with major aortopulmonary collaterals

Background: Our institutional approach to tetralogy of Fallot (TOF) with major aortopulmonary collaterals (MAPCAs) emphasizes unifocalization and augmentation of the reconstructed pulmonary arterial (PA) circulation and complete intracardiac repair in infancy, usually in a single procedure. This approach yields a high rate of complete repair with excellent survival and low right ventricular (RV) pressure. However, little is known about remodeling of the unifocalized and reconstructed pulmonary circulation or about reinterventions on the reconstructed PAs or the RV outflow tract conduit. Methods: We reviewed patients who underwent complete repair of TOF with MAPCAs at our center at <2 years of age, either as a single‐stage procedure or after previous procedures. Outcomes included freedom from conduit or PA intervention after repair, which were assessed by Cox regression and Kaplan–Meier analysis. Results: The study cohort included 272 patients. There were 6 early deaths and a median of follow‐up of 3.6 years after complete repair. Reinterventions on the pulmonary circulation were performed in 134 patients, including conduit interventions in 101 patients, branch PA interventions in 101, and closure of residual MAPCAs in 9. The first conduit reintervention consisted of surgical conduit replacement in 77 patients, transcatheter pulmonary valve replacement with a Melody valve in 14, and angioplasty or bare metal stenting in 10. Surgical PA reinterventions were performed in 46 patients and transcatheter reinterventions in 75 (both in 20). Most PA reinterventions involved a single lung, and most transcatheter reinterventions a single vessel. Freedom from conduit replacement or transcatheter pulmonary valve replacement was 70 ± 3% at 5 years and was shorter in patients with smaller initial conduit size. Freedom from any PA reintervention was 64 ± 3% at 5 years, with the greatest rate during the first year. On multivariable analysis, factors associated with longer freedom from any PA reintervention included lower postrepair RV:aortic pressure ratio and larger original conduit size. Conclusions: We were able to obtain follow‐up data for the majority of patients, which demonstrated freedom from PA reintervention for two thirds of patients. The time course of and risk factors for conduit reintervention in this cohort appeared similar to previously reported findings in patients who received RV‐PA conduits in early childhood for other anomalies. Relative to the severity of baseline pulmonary vascular anatomy in TOF with MAPCAs, reinterventions on the reconstructed PAs were uncommon after repair according to our approach, and major reinterventions were rare. Nevertheless, PA reinterventions are an important aspect of the overall management strategy.

Ebstein’s Disease

Ebstein’s disease is a congenital cardiac anomaly that occurs with an incidence of approximately 1–5 in every 20,000 live newborns, therefore representing 1% of congenital cardiac defects. It is the most common etiology for congenital tricuspid regurgitation in the neonatal period as well as later in life. The etiology of Ebstein’s anomaly is unknown, however, a number of environmental factors have been implicated, namely maternal exposure to varnishing substances and maternal use of benzodiazepines and lithium ingestion during the first trimester of pregnancy.