Society for Pediatric Anesthesia 30th Annual Meeting Review

By Gee Mei Tan, MD
Children’s Hospital Colorado
and Sophie R. Pestieau, MD
Children's National Health System

The Society for Pediatric Anesthesia celebrated their 30th Annual Meeting, in the Windy City of Chicago, Illinois on Friday, October 21st, 2016. The meeting’s Program Chair, Christina Diaz, MD (Children's Hospital of Wisconsin) kicked off the day with a welcome message and an outline of the educational program. This one-day meeting included an excellent group of speakers who focused on three important topics with significant impact in pediatric anesthesia.  This article provides an in-depth review of the first and third sessions.

• Immunology, including how allergies and anaphylaxis affect our choice of anesthetics, as well as the impact of anesthesia on immunomodulation.
• Anesthetics performed outside the operating room, which not only covered photon and radiation therapy and the new cath lab consensus statement, but also dove into the role of the anesthesiologist vs. other specialists providing sedation services outside the OR. 
• The Pediatric Perioperative Surgical Home (PSH), how it fits into the Pediatric Anesthesia care model and how it can ultimately improve patient care.

The first session was moderated by Dolores B. Njoku, MD entitled “Immune System: Too Much Too Little”. One would think that this would have no relation with pain issues but the third speaker of the session, Juan P. Cata MD discussed Immunomodulation in the OR: Opioids/Regional/Transfusion.

Dr. Cata is an Assistant Professor of the Department of Anesthesiology and Perioperative Medicine and the Founder and Chair of Anesthesia and Surgical Oncology Research Group (ASORG) at MD Anderson Cancer Center, University of Texas. Therefore, the focus of his talk was on cancer and most of the literature he discussed was from the adult population.

He reminded us that natural killer cells (NKC) are part of our innate immunity and are important in cancer cell destruction. During the perioperative period, it has been shown that circulation of stress hormones (e.g. epinephrine and cortisol) and the inflammatory responses are increased significantly and this increase may last as long as postoperative day five. It is important to note that these responses decrease the function of natural killer cells which in turn would depress the immune system. This depression is seen in all surgeries and is directly related to the surgical insult. The good news is that beta blockers in their ability to modulate surgical stress may also be able to modulate natural killer cell function. In addition, the function of natural killer cells can also be modulated by opioids, volatile anesthetics, ketamine, local anesthetics and blood transfusions. There are studies to suggest that impact of surgical stress is perhaps more prominent than anesthetics or opioids in perioperative immune suppression.

Opioids have variable effects on the immune system. Multiple studies suggest that morphine depresses natural killer cell function more than tramadol or infusion of low doses of remifentanil. The effect of fentanyl is controversial as fentanyl administered in high doses has been shown to impair the function of the NKC during surgery while other studies have also shown that moderate doses of fentanyl increases the natural killer cell cytotoxicity, thus facilitating their action. There in lies the conundrum for anesthesiologists to find a perfectly balanced analgesic regimen that can minimize the deleterious effects of surgical stress and pain on the NKC cytotoxicity without facilitating them with, what appears to be, an agent and/or dose-dependent action of opioids.

There is very little evidence for or against the effects of volatile anesthetics on natural killer cell function. There are several studies suggesting that administering epidural anesthesia in healthy patients and patients with cancer was associated with increased natural killer cell function activity in the early postoperative period compared to general anesthesia. However, a meta-analysis of the effect on postoperative natural killer T lymphocyte function by Conrick-Martin et. al. in Journal of Clinical Anesthesia 2012 did not show a statistically significant advantage of neuraxial regional anesthesia compared to general anesthesia. However, the authors do acknowledge that the limitations of their analysis due to a small number of studies, and heterogeneity in the methods and encourage further investigations.

Transfusion related immunomodulation (TRIM) is a complication of blood transfusion that can lead to fatality. This is a multifactorial process which involves donor leukocytes, storage lesions and growth factors. There have been studies that show no difference in outcomes in critically ill pediatric patients when subjected to liberal or restrictive transfusion triggers. An American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) pediatrics analysis has also shown a relationship between perioperative blood transfusion and surgical site infection. Dr. Cata’s article, accepted for publication in Vox Sanguinis, failed to show any deleterious effect of perioperative blood transfusion and outcomes in children undergoing cytoreductive surgery with hyperthermic intraperitoneal chemoperfusion. However, he did state that his study may be underpowered. He ended the talk introducing the concept of pediatric patient blood management and the theory of three evils:

• EVIL 1 = Anemia is associated with poor oncological outcomes
• EVIL 2 = Transfusions are associated with poor oncological outcomes (in most tumors)
• EVIL 3 = Anemia and transfusion might be associated to poor surgical outcomes

The session on the Pediatric Perioperative Surgical Home (PSH) included presentations by Karen Thomson, MD (Children’s National Health System, Washington, DC), along with two other speakers. Dr. Thompson and the other speakers showed how the Perioperative Surgical Home (PSH) fits into the Pediatric Anesthesia care model and how it can ultimately improve patient care. PSH has been touted as a patient-centered, team-based approach that aims to improve the value of perioperative care. 

Dr. Thomson described in detail the enhanced recovery pathway for patients with adolescent idiopathic scoliosis put in place at her institution, a year and half ago. She emphasized that the creation of an evidence based clinical pathway begins with an in depth review of the literature. She then outlined the multiple steps in the implementation of a PSH model as well as strategies to optimize patient preparation and reduce variability in care.  These included a rigorous process mapping with various stakeholders (surgeons, anesthesiologists, nurses, physical therapists, etc.), and creation of teams for the four phases of peri-operative care of a spinal fusion patient in a PSH.

The four phases include: preoperative evaluation, intra-operative and post-operative surgical and pain management, as well as the post-operative follow-up. She also addressed strategies to assess economic impact i.e. cost savings (reduction in cost vs. hospital charges), which would lead to value added care model, since improved quality of healthcare, improved outcomes while decreasing cost, are the essential building blocks for provision of value added care. Finally, she concluded by sharing the success of the PSH for adolescent idiopathic scoliosis implemented at their institution, which led to lower perioperative transfusions, improved pain control, decreased use of opioids, and shorter length of hospital stay (from 5+ days to 3+ days). More information can be found in her article, Perioperative Surgical Home in Pediatric Settings: Preliminary Results, Anesth Analg 2016;123.

These presentations have important implications for us as pediatric anesthesiologists and pain providers and highlight our roles as perioperative physicians.