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2001 Annual Meeting Review

This year's Society for Pediatric Anesthesia annual meeting was held in New Orleans. Although attendance was slightly down from past years, owing to the overall decline in attendance at the ASA following the tragic terrorist attack on the United States of September 11, there was still a relatively good turnout. The meeting was chaired by Frank Kern from Duke University School of Medicine.

The first session, moderated by Dr. Kern, was devoted to an examination of temperature regulation of pediatric patients in the perioperative period. Steven Frank (Johns Hopkins, Baltimore, MD) discussed the physiology of thermoregulation in children, the interactions between anesthetics and thermoregulation, and the efficacy of various techniques used for maintaining and increasing body temperature during anesthesia. Virtually all anesthetics (including regional anesthetic techniques) have negative effects on the ability to maintain body temperature, although the mechanisms by which the different classes of drugs do this vary. The result is a poikilothermic response, in which the body temperature declines passively towards the ambient temperature. Dr. Frank noted that there are numerous deleterious effects of hypothermia, including impairment of coagulation, decreased action of various enzyme systems, and increased metabolic demands. In order to maintain body temperature during surgery, one may employ either passive or active methods, but forced air warming (Bair HuggerÒ) is the most effective method. Other devices, such as circulating water mattresses, radiant heaters, counter-current fluid warmers (Hot LineÒ) are also effective, as are passive methods such as insulation and increasing environmental temp-erature, however they are less effective than forced air heating at increasing (rather than maintaining) body temperature.

Bruno Bissonnette (Hospital for Sick Children, Toronto) has been a prolific and pioneering investigator of thermoregulation and the effects of hypothermia in both the laboratory and the clinical arena. He discussed the potential beneficial effects of hypothermia for brain protection during periods of cerebral ischemia and low flow, such as cardiopulmonary bypass or cardiac arrest and asphyxia. The goal of therapeutic hypothermia is to reduce metabolic rate, glucose utilization and oxygen demands. Possible salutary mechanisms include reduction in excitotoxic responses and apoptosis, modulation of constitutive nitric oxide synthase (NOS) production and reduction of inducible NOS, and effects on edema and inflammatory responses. The differential temperature responses in the brain and body, especially in reaction to rewarming, were noted, and the potentially deleterious effects of rebound cerebral hyperthermia emphasized. Clinical data suggest that in some situations mild hypothermia might have cerebral protective effects, and that attempts at active rewarming following asphyxia may increase the risk of neurological injury.

The second pair of talks on this theme, in a session chaired by Steven Hall (Children's Memorial Hospital, Chicago) was on malignant hyperthermia (MH). Scott Schulman (Duke University Medical Center, Durham, NC) updated the audience on both the cellular physiology and the clinical presentation and course of MH. He also discussed current thinking on diagnosis, including the "variants" of MH, and treatment of an MH crisis. Barbara Brandom (Children's Hospital of Pittsburgh) spoke about the North American MH Registry and presented a series of cases that have been reported to the MH Hotline maintained by MHAUS. She used the case reports to illustrate the difficulty in making a definitive diagnosis of an MH crisis in many situations, specifically in differentiating these clinical episodes from other myopathic crises and events that may present with similar symptoms but may be distinct disease entities from MH. She discussed the current importance and utility of biopsy and contracture testing, especially as it impacts the ongoing development of genetically based tests for MH, and described the work of the Registry and the Hotline.

The afternoon sessions were both related to postoperative analgesia. In the two talks moderated by David Cohen (Children's Hospital of Philadelphia), organizational and logistical aspects of postoperative pain services were the focus of attention. Myron Yaster (Johns Hopkins) gave a presentation of the web-based teaching module that he and his colleagues have developed for credentialling and instructing non-anesthesiologists about pain management. He related how such an approach was the only feasible means of meeting the JCAHO requirements with both effectiveness and efficiency. The demonstration of the Internet interactive teaching program illustrated both the graphical and pedagogical sophistication that this initiative brought to bear on this difficult issue. He suggested that this approach has the potential to be effective for other similar hospital and JCAHO certification requirements. Steven Weisman (Children's Hospital of Wisconsin) described how the development of a system-wide initiative to improve awareness and quality of care for children in pain was instituted at his hospital, and how outcome measures were used to both demonstrate effectiveness as well as generate data to bolster fund raising and program development. He emphasized that the success of his program was predicated on the implementation of the program, dubbed "The Comfort Zone", across the entire hospital, and involving all strata of the hospital staff.

The final scientific session of the day was a debate on the balance of risks and benefits of regional anesthesia in children undergoing surgery with cardiopulmonary bypass, moderated by Allison Kinder Ross (Duke University Medical Center). The "pro" position was presented by Gregory Hammer (Lucille Salter Packer Children's Hospital at Stanford University Medical Center, Stanford, CA). Dr. Hammer, an enthusiastic proponent of regional anesthesia for cardiac surgery, discussed both the benefits of moderation of the stress response to bypass, including circulatory, metabolic, immunologic, and neuroendocrine effects, and clinical benefits, such as early extubation and improved analgesia with minimal effects on sensorium and respiratory function. He noted that high-dose opioid anesthesia has not been successful in ameliorating these undesirable responses to surgery and bypass, but that regional anesthesia has been shown to have a positive effect in this regard. He described the techniques used at Stanford, and discussed the safety issues, particularly concerning bleeding and neurologic injury. He concluded that the benefits outweigh the risks, when appropriate guidelines are followed, and advocated that regional anesthesia/analgesia be used for these cases. James Steven (Children's Hospital of Philadelphia) took the "con" position, and while acknowledging that regional anesthesia has well-demonstrated benefits, disputed that the concerns about safety have been adequately satisfied to justify the risks, particularly that of epidural hematoma. He pointed out that the purported benefits of regional anesthesia could be achieved with other safer techniques, and that the incidence of complications, which he estimated at between 3 and 5% from reports in the literature, appears to be too high to justify the use of regional techniques. Both speakers, as well as the audience, agreed that a well-designed multi-center study would be necessary to resolve the question with the current absence of definitive data.

The final address of the day was to have been delivered by Sten Lindahl (Karolinska Institute, Stockholm, Sweden). Dr. Lindahl, who is well known in the world of pediatric anesthesia and critical care as an investigator, clinician, and author, is also the Chairman of this year's Nobel Prize in Medicine Selection Committee. Unfortunately, the events of September 11 prevented him from traveling to the United States to speak about how the 100th Nobel Laureate in Medicine will be selected. In his place, Dr. Kern enlightened the audience about a topic of unfortunately great current importance and relevance- the use of biologic and chemical agents as weapons of terror.

The conference was well-received by the audience, who look forward to assembling again at the Spring joint meeting of the SPA and AAP Anesthesia Section in Miami Beach, FL.

David M. Polaner, MD, FAAP
The Children's Hospital
Denver, CO

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