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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.
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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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