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From the *Departments of Pediatrics and Anesthesiology, Baylor College of Medicine, Houston, Texas, and University of North Carolina School of Medicine, Chapel Hill, North Carolina.
Address correspondence and reprint requests to Nancy L. Glass, MD, MBA, FAAP, Professor of Pediatrics and Anesthesiology, Baylor College of Medicine and Texas Children's Hospital, 6621 Fannin Street, Suite A 300, MC 2-1495, Houston, TX 77030. Address e-mail to nglass{at}bcm.tmc.edu.
The Congenital Cardiac Anesthesia Society (CCAS) held its inaugural meeting in conjunction with the Pediatric Anesthesiology 2007 meeting in Phoenix, Arizona. Two previous meetings held in association with the Pediatric Cardiac Intensive Care Society meetings focused on Pediatric Cardiac Anesthesia. They were a resounding success and established the need and interest for the CCAS. In the future, the CCAS will alternate its annual meeting affiliation between the Winter Society for Pediatric Anesthesia/American Academy of Pediatrics-sponsored Pediatric Anesthesiology meetings and the Pediatric Cardiac Intensive Care Society meetings. This year's meeting began with Society President Dr. Dean Andropoulos welcoming nearly 250 participants. Dr. Andropoulos spoke about some of the new initiatives the society has planned. These include curriculum development for training in Pediatric Cardiac Anesthesia, an official affiliation with the journal Anesthesia & Analgesia, a newsletter for society members and the establishment of a CCAS Clinical Database.
Dr. James DiNardo moderated the first morning session on hypoplastic left heart syndrome. This began with an excellent presentation by Dr. Susan Nicholson on the long-term survival and neurodevelopmental outcome of children with hypoplastic left heart syndrome. Dr. Nicholson discussed the dramatic improvement in survival with contemporary survival rates of 77%–93%. She identified risk factors for poor outcomes and discussed some of the newer innovations that have contributed to improved survival after neonatal surgical interventions. Early referral, alternative techniques for providing pulmonary blood flow, the use of milrinone, and better monitoring were all mentioned. Although the survival for infants recovered from a stage-one repair is relatively good, there is still a 7%–15% interval mortality rate. Dr. Nicholson pointed out the need for closer monitoring of the stage-one survivors, especially those identified to be at increased risk. The presentation continued with a discussion of the neurodevelopmental outcome of survivors. Dr. Nicholson noted that preoperative issues such as associated cardiac lesions, certain genetic syndromes and preoperative limitations in cerebral blood flow may affect neurologic outcome. Postoperative events can also contribute significantly to neurodevelopmental morbidity.
Dr. George Hoffman spoke on the utility of near-infrared spectroscopy (NIRS) (INVOS Cerebral OximeterTM by Somanetics) for estimating cerebral and other somatic regional hemoglobin saturation. The NIRS monitor can be used as a way to trend regional perfusion and correlates best with tissue venous hemoglobin saturations. Dr. Hoffman cited studies that have correlated diminished neurologic outcome with low venous saturations. By placing oximetry probes over somatic sites such as the flank (kidney) as well as the forehead (brain), the clinician can monitor the relative adequacy of perfusion for each. He noted that inventions such as hypoventilation can increase the cerebral regional saturation while decreasing the rSVO2 at other somatic sites. Presumably, this is the result of a redistribution of blood flow, favoring the cerebral circulation. Dr. Hoffman emphasized that the final mixed venous saturation is the sum of the oxygen demand/ perfusion characteristics of many organ systems. The most appropriate therapy needs to consider these differences.
The final speaker for the first morning session was Dr. Andropoulos. He spoke about some of the strategies for neuroprotection in infants undergoing open heart surgery. He reviewed nine items that could contribute to an improved neurologic outcome: 1) Avoid or minimize deep hypothermia and circulatory arrest, 2) Favor antegrade cerebral perfusion over low flow cerebral perfusion, 3) Avoid low flow cardiopulmonary bypass (CPB), i.e., do not necessarily reduce CPB flow when the temperature is reduced, 4) Use pH-stat blood gas management when cooling the patient, 5) Target slightly higher hematocrits than previously used (range, 30%–35%) while on bypass, 6) Use NIRS monitoring, 7) Use inhaled anesthetics liberally for their neuroprotective effects, 8) Avoid hyperthermia, and 9) Consider the benefits of hypoxic preconditioning. Dr. Andropoulos finished by commenting on some exciting recent data that suggest pretreatment with high dose erythropoietin may be neuroprotective in the setting of hypoxic ischemic injury.
The next morning session, moderated by Dr. Chandra Ramamoorthy, focused on anatomy and arrhythmias. Dr. Norman Silverman spoke on the morphologic aspects of congenital heart disease, correlating it with transesophageal echocardiography (TEE) findings. Dr. Silverman reviewed many of the basic approaches to TEE imaging of children with congenital heart disease and described useful applications of the transgastric approach to image acquisition. Transgastric imaging allows assessment of aortic override in patients with Tetralogy of Fallot (TOF) and better alignment for Doppler flow estimates across the left ventricular outflow tract and its associated valve and great vessel. The transgastric short-axis view is an excellent way to assess regional left ventricular wall function. Dr. Silverman then reviewed the four chamber and various long- and short-axis esophageal views. Familiarity with these views will assist the clinician in assessing morphology of the heart chambers, valves, and great vessels, as well as the presence of functional abnormalities such as stenosis, regurgitation, residual shunting, and altered contractility.
Dr. Karen Booth spoke about diagnosis and management of intraoperative arrhythmias. She gave an excellent review of commonly encountered arrhythmias. Helpful hints on differentiating reentrant versus ectopic (autonomic) sources of tachycardias were presented. She emphasized the value of the echocardiography, direct inspection of the heart, and the atrial electrocardiogram in diagnosing many rhythm disturbances. Dr. Booth outlined treatment strategies for some arrhythmias and cautioned against the "knee-jerk" use of amiodarone. Pharmacologic as well as nonpharmacologic therapies were discussed.
The final morning session was moderated by Dr. Helen Holtby. The first speaker in this session was Dr. Robert Friesen. He started his talk by identifying the high-risk patient with pulmonary hypertension. The biggest "red flag" would appear to be patients with suprasystemic pulmonary artery pressures. He reviewed the pros and cons of various anesthetics in this patient population. His experience has led him to prefer a multidrug approach, preferring to use low doses of two or more drugs, rather than relying solely on heavier doses of a single drug. He also emphasized the need for careful airway management. Hypoxic and/or hypercarbic events may be poorly tolerated. Dr. Friesen finished by reviewing the pharmacologic treatment options for acute and chronic pulmonary hypertension. Nitric oxide, prostaglandins, phosphodiesterase inhibitors, endothelin receptor blockers, anticoagulation, and atrial septostomy were all mentioned.
Dr. Sharma Anshuman gave an interesting update on pediatric lung transplantation. He reviewed the epidemiology of patients listed for lung transplantation. He discussed the monitoring and anesthetic techniques used at his institution (St. Louis Children's Hospital). Many of these patients are chronically hypercarbic. Dr. Anshuman emphasized that the CO2 does not need to be normalized in the operating room. At his institution, all pediatric lung transplants are done on CPB. The postoperative course of lung transplant patients was also reviewed. Some do very well, but as Dr. Anshuman points out, complications are significant. Primary graft failure is the most common cause of early death. Bronchiolitis obliterans is the most common cause of death after the first year. Overall, the 5-yr survival rate is 50% and the 10-yr survival is about 30%. The need for strategies to reduced long-term morbidity and mortality was noted.
Dr. Helen Holtby then presented a case from her personal experience at the Hospital for Sick Children in Toronto. The case involved a 2-yr-old child with previously undiagnosed pulmonary hypertension, an incidental cervical arteriovenous malformation, and a recent history of syncope. He was scheduled for a magnetic resonance image scan of the head and heart. Despite Dr. Holtby's expertise and planning, the case went badly. An interesting discussion followed. The important issues discussed included the problems with caring for sick patients in remote locations, the ominous history of syncope, the hazards of long anesthetics (>3 h), and the need to differentiate a pulmonary hypertensive crisis with reactive pulmonary vasculature from primary right ventricular ischemia with relatively fixed pulmonary hypertension.
After lunch, Dr. Bruce Miller moderated a very informative Pro-Con session on aprotinin, followed by a problem-based learning discussion (PBLD). Dr. Paul Reynolds took the Pro side and Dr. Glyn Williams took the CON side with the title being "Aprotinin Should Routinely be Used in Infants and Children Undergoing Complex Open Heart Surgery." Between the two presenters, a very good (and collegial) review of the pharmacology of aprotinin and the controversies surrounding its use ensued. It became apparent that more data are needed to delineate which children are going to benefit most from aprotinin and when do the risks outweigh the potential benefits.
This session was concluded with an excellent PBLD presented by Drs. Emad Mossad and Suanne Daves. The title was "PBLD:16 year old Female, s/p TOF Repair for Laparoscopic Cholecystectomy." The case presentation was followed by a discussion of the implications of the type and timing of TOF repair. The residual defects and their significance were reviewed. Although the survival after TOF repair is generally very good, problems such as residual pulmonary insufficiency, persistent right ventricular outflow tract obstruction, and the presence of arrhythmias can lead to late morbidity and mortality. Patients having had a TOF repair should not be lost to follow-up by their cardiologists!
The day concluded with the presentation of two workshops. The first workshop, "Transesophageal Echocardiography in Children: An Interactive Session on Common Congenital Cardiac Defects" was presented by Dr. Wanda Miller-Hance. The other session, "Pacemakers: Everything You Always Wanted to Know but Were Afraid to Ask" was presented by Dr. Naomi J. Kertesz, cardiologist from Texas Children's Hospital. The presenters of the workshops did an excellent job going over some of the basics of pediatric TEE and pacemakers. Take-home messages? TEE takes practice and know-how. When dealing with pacemakers and implanted defibrillators, electrocautery can be your enemy, magnets can be unpredictable, and the cardiologist is your friend.
Footnotes
Accepted for publication June 11, 2007.
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