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From the *Duke University Medical Center, Mount Sinai Medical Center, University of Chicago, Children's Hospital of Michigan and Wayne State University, ¶Long Island College Hospital, ||Seattle Children's Hospital and 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 12th annual joint 2007 Winter meeting of the Society of Pediatric Anesthesia (SPA)/American Academy of Pediatrics (AAP) was held March 9–11 at the Pointe Hilton Resort at Squaw Peak in Phoenix.
Incoming SPA President Jayant K. Deshpande MD (Vanderbilt Children's, Nashville, TN) welcomed more than 600 meeting registrants. An enthusiastic invitation was extended to all SPA registrants to become active on SPA committees, after which he thanked SPA members for their donations and economic support of the SPA research fund, patient safety and education. Finally, he congratulated Dean B. Androupoulos, MD (TX Children's, Houston, TX) and Chandra Ramamoorthy, MBBS, FRCA (Stanford University, Stanford, CA) on the success of the first meeting of the Congenital Cardiac Anesthesia Society. Joseph P. Cravero, MD (Dartmouth Hitchcock, Lebanon, NH) was introduced as incoming Chairman of the AAP Section on Anesthesiology and Pain Medicine. Dr. Cravero reminded the SPA/AAP meeting registrants of the joint nature of the Winter meeting, and stated that it is imperative for SPA members to consider joining AAP, as our AAP section is the voice of anesthesia in AAP to influence pediatricians. Randall P. Flick, MD, MPH, FAAP (Mayo Clinic, Rochester, MN) Winter Meeting Program Chair, offered his greetings and provided clarifications to the program.
Aubrey Maze, MD (Phoenix, Children's, Phoenix, AZ) moderated an outstanding morning session on The Complex Pediatric Airway. Robert S. Holzmann, MD, FAAP (Children's Hospital, Boston, MA) spoke on Developmental Pathology of the Infant Airway. He created the analogy between architecture of a house and the embryology of the head and neck, underdevelopment or hypoplasia of building blocks leads to structural problems or anomalies with anesthetic implications. Defects focused on five pivotal topics: cranial vault and base, craniovertebral development, face, branchial apparatus, and larynx. Dr. Holzmann demonstrated examples of defects at each of these anatomic areas, emphasizing the spectrum of defects seen. Raanan Arens, MD (Children's Montefiore, Bronx, NY) spoke on Imaging the Obstructed Airway. The clinical presentation of obstructive sleep apnea (OSA) was illustrated to the audience by polysomnography; the etiology of OSA includes both anatomical and functional issues. Airway imaging methods include plain radiograph, cephalometry, endoscopy, acoustic reflection pharyngometry, computed tomography three-dimensional upper airway tomography, and magnetic resonance imaging (MRI). Although expensive, state-of-the-art processing software transforms a two-dimensional picture to a volumetric graphical reconstruction, which Dr. Arens illustrated showing video footage to delineate areas of obstruction. Airway architecture evaluation has been revolutionized with three-dimensional MRI airway reconstructions. The upper airway has been noted to be restricted in OSA to 60%–70% of its length with maximum restriction where the tonsils and adenoids overlap. MRI also offers dynamic imaging of the airway to evaluate airway collapsibility. Lastly, in vitro airway modeling techniques to study airway mechanics were described, including computational fluid dynamics (CFD) models and acrylic models, particularly useful in obesity research and effects of weight loss on airway size. Robin Cotton MD (Cincinnati Children's, Cincinnati, OH) lectured on Reconstructing the Airway. He stated that anesthesiologists rely on pediatric otolaryngologists to perform flexible laryngoscopy in the office in the airway evaluation algorithm, but also emphasized that (posterior to anterior) AP (or PA) and lateral neck films along with a thorough history and physical examination must not be omitted. The present innovative therapeutics include cricotracheal resection, flexible bronchoscopy, reflux evaluation, balloon dilation, slide tracheoplasty (useful for complete tracheal rings), pediatric voice assessment, and endoscopic procedures. He stressed that spontaneous ventilation is the ideal technique during airway assessment.
The second morning session Genetics and the Pediatric Anesthesiologist moderated by Joseph R. Tobin, MD, FAAP, FCCM (Wake Forest, Winston-Salem, NC), Evan Kharasch, MD (WA University, St. Louis, MS) discussed Pharmocogenetics in Pediatric Anesthesia. Pharmacogenetics has its roots in anesthesia as Werner Kalow historically identified atypical plasma cholinesterase. The functional hierarchy of single nucleotide polymorphisms was emphasized starting from 100,000 genes in the human genome at the bottom to only a few single nucleotide polymorphisms that occur that change clinical outcome at the top. Polymorphisms can affect enzymes for regulators, receptors or transporters. Thiopurine methyltransferase polymorphisms can result in 6-mercaptopurine toxicity. DNA polymorphisms have been identified encoding a number of cytochrome P450 enzymes, leading to variations in drug clearance. He discussed CYP2D6 P450 polymorphisms, important for metabolism of oral opioids such as codeine to morphine, and which may be compounded by ethnic differences that determine biological responsiveness to codeine and risk of toxicity. Also CYP3A P450 polymorphisms are important in metabolism of local anesthetics, but vary in clinical significance in terms of drug clearance (significant—tacrolimus, quinine, alprazolam versus midazolam, alfentanil, diltiazem). Opioid µ-receptor polymorphisms such as A188G are not thought to be clinically significant. Future challenges include genetic heterogeneity, phenotypic complexity, under-powered studies, and informed consent.
The third morning session Syndromes, Associations & Sequences was also moderated by Joseph R. Tobin, MD, FAAP, FCCM (Wake Forest, Winston-Salem, NC), Jennifer O'Flaherty, MD discussed When Sux Sucks—Adverse Reactions to Succinylcholine in Syndromic Patients. She described adverse drug reactions to succinylcholine since its introduction in 1951, including hyperkalemic cardiac arrest due to acetylcholine receptor upregulation, hyperkalemia due to anesthetic-induced rhabdomyolysis, and malignant hyperthermia. She discussed a number of conditions in which succinylcholine might have adverse outcomes, osteogenesis imperfecta, myotonic dystrophy, Long QT syndrome, the King-Denborough syndrome, and Central Core Disease. Victor C. Baum, MD (University of VA, Charlottesville, VA) discussed When Nitrous is No Laughing Matter. Nitrous oxide can exert deleterious effects after brief exposures, with onset of effects delayed over weeks. Patients with inborn errors of metabolism, including methionine synthase deficiency, homocystinuria, and methylmalonic academia, might be affected, as well as those with dietary deficiency of vitamin B12, such as in patients with phenylketonuria and breast-fed infants of vitamin B12-deficient mothers. The effects of nitrous oxide on the human fetus and infant remain unclear, although in immature animal models, nitrous oxide enhances low dose isoflurane-induced apoptotic neurodegeneration in the brain; in aging animals, neuropathic changes, including vacuolization, mitochondrial swelling, and neural cell death, are related to methionine synthase effects. The morning session concluded with Phil G. Morgan, MD (University Hospitals, Cleveland, OH) discussing When Propofol is Problematic. He reviewed the original presentation of propofol infusion syndrome (PIS) when use of high dose propofol (>4 mg/kg/h) for >48 hours resulted in the classic triad of bradycardia, lipidmia, and rhabdomyolysis; there are now recent case reports of lower doses (2.5 mg/kg/h) and/or shorter duration (<2 hours) resulting in PIS. He examined the physiology of PIS; the main idea is that propofol affects multiple "hits" in the electron transport chain (fatty acid entry, Complex I, II, III), but primarily at the entry of free fatty acids into the mitochondrial matrix. The concrete suggestions to minimize or prevent PIS included adjusting anesthetic dose using Bispectral Index monitoring, especially in those with Complex I disease mitochondrial defects; and using a dextrose-containing IV fluid to decrease fatty acid metabolism when using propofol.
The Friday afternoon session, moderated by Randall Flick, MD (Mayo Clinic, Rochester, MN) was devoted to issues of media coverage for high-profile cases. During the first segment of this session, William McIlvaine, MD (Childrens Hospital Los Angeles) discussed the provider perspective as part of an anesthesia team managing the separation of conjoined twins with media presence in the operating room. He highlighted the considerations as well as the effect of the media on the patient, family members, and operating room staff. Jennifer Gentile (NBC Today Show/Network Producer) provided the media perspective for the making of a good news story, elements of which include unusual or rare topics, the news of the day, popular or famous people, common problems, trends, and tear-jerkers. She concluded with five recommendations for interacting with the media, as follows: (1) be upfront on element, (2) deliver what you promise, (3) befriend the media, (4) do not ignore us, and (5) negotiate. Rounding out the panel on medicine and the media was Lee Aase (Manager, Media Relations, Mayo Clinic) who discussed the topic Meeting News Media Needs Without Compromising Care. He focused on the early setting of ground rules with regards to media coverage, the need for extensive planning by the medical teams, elements for success, and the various venues available for dissemination of the news story. Next it was time for Jeopardy! Myron Yaster, MD (Johns Hopkins Medical Center) moderated this educational and, at the same time, entertaining session. Co-moderators included Frederic Berry, MD (University of VA Health System), Aubry Maze, MD (Phoenix Children's Hospital), and David Polaner, MD (The Children's Hospital, Denver). The Jeopardy questions generated much audience participation and interesting discussions.
The Saturday morning session, sponsored by the AAP Section on Anesthesiology and Pain Medicine, began with oral presentations and awards for the best abstracts. The first place resident award was presented to Roland Brusseau, MD and colleagues from Children's Hospital, Boston. Dr. Brusseau's presentation was titled "Fetal and maternal plasma concentrations after intra-amniotic fentanyl administration in instrumented pregnant sheep." The authors investigated maternal and fetal fentanyl concentrations and clinical responses to three different intra-amniotic fluid doses of fentanyl (10, 25, and 100 mcg/kg fetal weight) in pregnant sheep. Plasma fentanyl levels were significantly higher in the fetus than the mother only at the highest dose tested. There were no differences in fetal pH or maternal vital signs and blood gases throughout the test period.
The second place resident award was presented to S.J. Gleich et al. from the Mayo Clinic, Rochester, for the abstract entitled "Incidence of perioperative cardiac arrest in pediatric patients undergoing cardiac surgery." The group studied 4242 children under 18-years-of-age from 1988 to 2005 who underwent surgery for repair of complex cardiac lesions at the Mayo Clinic. Cardiac arrest was defined as the need for chest compressions or inability to wean from bypass before transfer to the pediatric intensive care unit. The overall rate of cardiac arrest for all patients was 127/10,000 anesthetics, decreasing to 40/10,000 if inability to wean from bypass was excluded from analysis. The rates were highest in infants (284 and 58/10,000 respectively), consistent with previous noncardiac surgery studies.
The third place resident award was given to D. Singh et al. from Johns Hopkins University, for the abstract entitled "Identification of a high risk subset of POCA registrants: Potential impact on practice recommendations for successful resuscitation." The authors identified 28 cases of perioperative cardiac arrest at their institution and analyzed the cases by surgical procedure and underlying disease state(s). Two procedures resulted in the highest number of arrests: cardiac catheterization in young patients, and posterior spinal fusion in adolescents. The predominant mechanism of arrest in the cardiac catheterization patients was surgical in nature, typically perforation of myocardium or a great vessel, while the mechanism in posterior spinal fusion patients was hypovolemia. The authors reported that cardiopulmonary resuscitation in the prone position was ineffective because the Jackson spine table does not provide a flat surface under the torso for counter-pressure for chest compressions; turning the patient supine enhanced the efficacy of cardiopulmonary resuscitation.
The SPA Young Investigator Awards were given for the two best abstracts submitted by investigators in their first three years of practice. First place was awarded to S. Sadhasivam, MD et al. from Cincinnati Children's entitled "Real time assessment of perioperative child and adult behaviors and behavioral interactions." The purpose of this study was to asses the reliability of the newly developed Perioperative Adult Child Behavioral Interaction Scale (PACBIS)—a simple, video-based, real-time instrument, in assessing perioperative behaviors in children undergoing tonsillectomy and adenoidectomy. The long-term goal of the instrument was to find ways parents and health care providers could minimize perioperative anxiety in children. The PACBIS showed good interrater reliability, including >80% agreement in rating coping and distress behaviors in children, parents, anesthesiologists, and postanesthetic recovery nurses.
The second place young investigator award went to M.D. Twite et al. from The Children's Hospital, Denver for their presentation entitled "Exhaled nitric oxide levels are decreased in children with cyanotic congenital heart disease and correlate with the inflammatory response to cardiopulmonary bypass." Both cyanotic and acyanotic patients had a decrease in exhaled nitric oxide (eNO) at 30 minutes postcardiopulmonary bypass (CPB) and a return to baseline at 24 hours. At all times, values were lower in cyanotic patients. Blood levels of the systemic inflammatory response markers interleukin 6 and interleukin 10 increased at 30 minutes post-CPB and decreased at 24 hours. These changes correlated with changes in eNO. The authors hypothesized that chronically lower eNO levels in cyanotic patients may be due to underlying chronic inflammation triggered by hypoxemia. eNO changes correlate with inflammatory changes produced by CPB and may be due to an acute decrease in constitutive NO synthetase due to cellular dysfunction.
The AAP Advocacy Lecture was then given by Joan Y. Reede, MD, the Dean of Diversity and Community Partnership at Harvard University School of Medicine. Dr. Reede currently trains physicians to advise legislators on health care policy decisions. Her talk centered around poverty and its effect on the distribution of health care resources to disadvantaged children. Approximately 47 million Americans are currently uninsured. The poverty rate is increasing, especially in minorities, with ill effects on access to care, quality of care, education, etc. Dr. Reede stressed three principles: Equity, Professionalism, and Principles. The principles discussed were primacy of patient welfare, patient autonomy, and social justice (the distribution of services in a nondiscriminatory fashion). Her talk was thought-provoking and well received.
Finally, Dr. Lynda Means presented the AAP's Smith Award for outstanding lifetime service in pediatric anesthesia to Josephine "Pina" Templeton, MD, who joined the faculty at the Children's Hospital of Philadelphia in 1978 and retired in 1999. The audience congratulated and thanked Dr. Templeton for her contributions to our specialty.
Workshops and Refresher courses were offered both Friday and Saturday afternoons to provide updates on timely topics and to offer participants the chance to get hands-on experience with new techniques and unfamiliar equipment. As usual, these small group sessions provided opportunities for question and answer sessions, networking, and in-depth discussions. Newly expanded this year, the Problem-Based Learning Discussion sessions were held on both Saturday and Sunday mornings.
The Sunday morning session began with a lecture by guest speaker Dr. Peter Marhofer from Vienna, Austria, entitled "A New Horizon in Pediatric Anesthesia-Ultrasound." Dr. Marhofer began by describing the traditional nerve block techniques in children in terms of "pops and plops." Recent studies have shown that block quality improves and the incidence of complications is reduced with the use of ultrasound. Accurate needle position can be achieved and the distribution of local anesthetic confirmed under ultrasound guidance. Furthermore, the volume of local anesthetic can be reduced as well as the time to perform peripheral nerve blocks. Dr. Marhofer concluded that many of these purported advantages still require validation in clinical trials. The use of ultrasound guidance for peripheral nerve blocks in children is growing in popularity, as evidenced by the audience poll showing that a majority of respondents use ultrasound, alone or in combination with nerve stimulation, in their clinical practice.
Dr. Jerry Lerman then moderated a stimulating session entitled "New Drugs, Old Applications/Old Drugs, New Applications." Sugammadex, a modified cyclodextrin, is currently undergoing Phase III trials and is not yet approved for use. Dr. Wayne Nicholson updated the audience regarding this novel and exciting drug for reversal of neuromuscular blockade. It is particularly effective in reversing the action of rocuronium, but will also reverse blockade from vecuronium and, to a lesser extent, pancuronium. It has no effect on the benzylisoquinolines or depolarizing muscle relaxants. Numerous small studies were presented, all of which show the considerable promise of sugammadex. Even in the presence of profound neuromuscular blockade, rapid and complete reversal can be achieved. The steroidal rocuronium molecule is irreversibly encapsulated by the lipophilic core of the sugammadex molecule, rendering it unavailable for binding with the neuromuscular junction. No significant side effects or drug interactions have been identified. Phase IV trials results are eagerly anticipated.
Dr. R. Blaine Easley presented a comprehensive update regarding the potential applications of dexmedetomidine, a highly selective 
-2 adrenergic agonist. It is currently approved by the Food and Drug Administration for the sedation of tracheally intubated and ventilated adults in the intensive care unit, but not children. Numerous publications regarding its use in children were presented. Potential applications of this drug in pediatric anesthesia include: awake craniotomies, fiberoptic intubations, non-painful procedures (e.g., MRI), diagnostic procedures (e.g., bronchoscopy, colonoscopy), and mechanical ventilation. It may also prove effective in the reduction or treatment of emergence delirium and postoperative shivering. Further studies regarding metabolites, the effects of prolonged use, and drug pharmacology in infants, as well as in children with renal and/or hepatic impairment, are required.
The final session of the meeting, entitled "Ten Best Articles," was moderated again this year by Dr. Peter Davis. Dr. Harshard Gurnaney presented two articles concerning the use of ultrasound in regional anesthesia. In a study by Perlas et al., "The sensitivity of motor response to nerve stimulation and paresthesia for nerve localization as evaluated by ultrasound." Reg Anesth Pain Med 2006;31:445–50, 25% of adult patients had no motor response to nerve stimulation, despite ultrasound evidence of needle to nerve contact. This is concerning to our specialty, since most pediatric blocks are performed in anesthetized children using nerve stimulation alone, so that needle manipulation may lead to nerve damage.
The second article "Nerve puncture and apparent intraneural injection during ultrasound-guided axillary block does not invariably result in neurologic injury." Anesthesiology 2006;105:779–83 authored by P. Bigeleisen, evaluated the incidence of needle entry into the nerve while performing axillary blocks in adults using a paresthesia or "pop" technique. Intraneural injection was detected by concomitant ultrasonography in 22/26 patients. However, no patient had evidence of neurologic injury at six-month follow-up. This provocative article raises many questions regarding nerve injury after intraneuronal injection of local anesthetic.
The third article by G. Cuchiarro et al. "What postoperative outcomes matter to pediatric patients?" Anesth Analg 2006;102:1376–82 addressed the issue of assent, concluding that adolescents are capable of assigning value to a health condition (analgesia) and deciding on the trade-off (nausea) needed to achieve it.
Dr. Wanda Miller-Hance then presented three cardiac articles. The first, authored by Arnold et al. and titled "Avoiding transfusions in children undergoing cardiac surgery: A meta-analysis of randomized trials of aprotinin." Anesth Analg 2006;102:731–7, showed that aprotinin reduced the proportion of children who received blood transfusion during cardiac surgery with bypass by 33%. The authors concluded that further trials are warranted before aprotinin can be routinely recommended in this population.
In their article, "Modified and conventional ultrafiltration during pediatric cardiac surgery: clinical outcomes compared." J Thorac Cardiovasc Surg 2006;132:1291–8, Williams et al. showed no advantage in combining conventional and modified ultrafiltration in 60 infants undergoing biventricular repair. The authors concluded that the choice of ultrafiltration strategy may depend on the relative risks of each strategy.
The third article, "Transcatheter closure of perimembranous ventricular septal defects using the amplatzer membranous VSD occluder. Immediate and mid-term results of an international registry." Catheter Cardiovasc Interv 2006;68:620–8 by R. Holzer et al. described the successful deployment of this device in 93/100 patients, with complications in 29. They conclude that the device is safe and effective, though longer follow up is required before its widespread use.
Dr. Joel Gunter presented three technical articles, supplementing two with additional experimental work of his own. In the article "Preparation of the Drager primus anesthetic machine for malignant hyperthermia-susceptible patients." Can J Anesth 2006;53;885–90 Prinzhausen et al. showed that the Primus machine must be flushed for at least 70 minutes at a fresh gas flow of 10 L/min to reduce the volatile concentration to 5 ppm. In addition, high fresh gas flow must be maintained intraoperatively to prevent a rebound increase in anesthetic concentration. This recommendation is in stark contrast to the common practice of flushing anesthetic machines for 10–20 minutes before anesthetizing a malignant hyperthermia-susceptible patient.
Berens et al. showed rapid declines in regional oxygenation below the cross-clamp in neonates and infants <1 year undergoing aortic coarctation repair in their article "Near infrared spectroscopy monitoring during pediatric aortic coarctation repair." Paediatr Anaesth 2006;16:777–81. These changes were less evident in older children, possibly due to the development of more adequate collateral circulation.
The article by M. Lovich et al. "The delivery of drugs to patients by continuous IV infusion: modeling predicts potential dose fluctuations depending on flow rates and infusion system dead volume." Anesth Analg 2006;102:1147–53 was an important reminder of the complex interactions possible when multiple drug infusions are infused through infusion sets due to their associated dead-space. Readers are encouraged to read this article in its entirety. Dr. Gunter presented work of his own, which further illustrated the possible effects of these dose alterations. In particular, infants are at considerable risk due to their low weights and correspondingly small infusion volumes.
Dr. Davis concluded with his moderator's pick: A published study by R.P. Flick et al. "Perioperative cardiac arrests in children between 1988 and 2005 at a tertiary referral center: a study of 92,881 patients." Anesthesiology 2007;106:226–37 as well as a second study on the same subject from The Children's Hospital, Boston, which is still in press. Appropriately, Pediatric Anesthesiology 2007 closed with a lively discussion regarding these two studies and the definition of "anesthesia-related" cardiac arrest. Dr. Davis encouraged the audience to collaborate through the use of multicenter databases to help address some of the questions raised.
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Footnotes
Accepted for publication June 11, 2007.
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