SPA Poster Presentation Review

Reviewed by: E Cudilo, MD and V Chidambaran, MD
Cincinnati Children’s Hospital, Cincinnati, OH

This year’s SPA-AAP Pediatric Anesthesiology meeting in Fort Lauderdale, Florida, included an impressive array of pediatric research. In case you missed it, or couldn’t make it to all the sessions, here is a synopsis of some the most-discussed presentations related to pain management.

First, here are some of the highlights from the Oral Presentation session moderated by Dr. Joseph Tobias (Nationwide Children’s Hospital) and Dr. Eugenie Heitmiller (Johns Hopkins Children’s Center).  There were three Resident Research Awards presented by the American Academy of Pediatrics (AAP) Section on Anesthesiology and Pain Medicine. First, Dr. Nathaniel Greene (Texas Children’s Hospital) presented research on the use of MRI diffusion tensor imaging. Based on their results, they recommend adjusting for post conceptual age to facilitate a better comparison of microstructural brain development in patients with various types of congenital heart disease who undergo corrective surgery within the first 30 days of life. Next, Dr. My Liu (C.S. Mott Children's Hospital) presented findings that a high body mass index in older children appears to be a risk factor for perioperative complications including adverse airway events and longer Post Anesthesia Care Unit (PACU) stays compared to the controls with normal body mass index. In the third presentation, Dr. Mike Wang (C.S. Mott Children's Hospital) presented the outcomes of a study looking at various weight estimation formulas in children. Their findings suggest that the Advanced Pediatric Life Support (APLS) formula [(2 x age in yr. + 8] for pediatric weight estimation remains accurate in normal body mass index children, but grossly underestimates the weight in overweight children, while the Luscombe formula [3 x age in yr. + 7] is better at predicting closer estimates of weight in the overweight pediatric population.

The resident awards were followed by the SPA Young Investigator Awards. The recipient of the first place award, Dr. Jagroop Mavi (Cincinnati Children’s Hospital), presented results of a genome-wide-association study in children undergoing tonsillectomy. Their findings show that genetic variants of fatty acid amide hydrolase (an important enzyme in the endocannabinoid pathway responsible for anandamide catabolism) predicts  postoperative respiratory depression, nausea and vomiting, and prolonged stay in the  PACU, secondary toopioid-related adverse effects despite receiving similar doses of perioperative morphine. Dr. Matthew Coghlan (The Hospital for Sick Children) received the second place award. He presented that morphine and isoflurane can induce misfolding of Phox2B (a protein that senses carbon dioxide levels and triggers breathing) and precipitate the development of Congenital Central Hypoventilation Syndrome disease phenotype that leads to a loss of carbon dioxide response and permanent brainstem dysfunction.

Now, moving on to the moderated Pain/Regional Poster Sessions, there were some common themes that emerged from the 24 selected posters, which must have resonated with the attendees because both poster sessions were very well-attended and full of animated discourse. The task of choosing just a few to highlight is monumental and likely to leave out many that equally deserve recognition.

Use of regional analgesia in children was a recurrent theme. Walker et al. (American Family Children's Hospital and University of Wisconsin, Madison) analyzed the use of peripheral nerve catheters in children by performing a review of the utilization and associated complications of 1307 cases from the Pediatric Regional Anesthesia Network (PRAN) database. They found no severe complications related to catheter use. The most common complication was catheter occlusion or accidental dislodgement  and they recommend focusing on improving techniques for securing the catheters. Similar conclusions regarding overall safety of continuous perineural catheters were presented by Ezziddin et.al. (Ann & Robert H. Lurie Children’s Hospital of Chicago) who interrogated their PRAN database with information regarding 557 catheter placements.

Continuing with the theme of regional analgesia in children, there were reports of successful use of paravertebral nerve catheters both in the inpatient and outpatient settings. Oliver et. al. (Yale-New Haven Children’s Hospital) described inpatient postoperative pain management utilizing two paravertebral nerve block catheters for a patient who had an anterior mediastinal mass resection via left thoracotomy, highlighting advantages over epidural catheters. Jones et. al. (Children’s Hospital of Pittsburgh of UPMC) described successful outpatient postoperative pain management via a continuous lumbar paravertebral nerve catheter with an On-Q Pump for a patient who had a left cleft alveolus repair with  allograft from the left iliac crest, resulting in superior outpatient analgesia, faster recovery, and increased satisfaction.

With all this discussion of regional anesthesia one may wonder “does it really make a difference”? Moore et.al. (Cincinnati Children’s Hospital) reviewed data from their electronic medical records of 149 pain service patients. The amount of perioperative opioids utilized by each patient who received regional analgesia was significantly less morphine, as calculated by converting the patients’ daily opioid use to a Morphine Equivalency Rate.

Chronic pain in adolescents is an important topic as highlighted through abstracts at this meeting. Cudilo et. al. (Cincinnati Children’s Hospital) through a combined prospective study on 78 adolescents with idiopathic scoliosis undergoing posterior spine fusion (PSF) followed by retrospective administration of questionnaires, found that approximately 50% of adolescents have chronic pain three months after surgery, the development of which can be predicted by higher immediate postoperative pain scores and level of anxiety in both child and parent.

Furthermore, the predictors for persistent pain one year after surgery were identified as surgical duration and anxiety of the child, with a correlation trend towards parental anxiety contributing to persistent pain. Lemanek et. al. (Nationwide Children’s Hospital) examined how pediatric chronic pain impacts the relationship between health-related quality of life (HRQoL) and functional disability from the parent perspective, through a retrospective study of 71 parents of 87 youth with various chronic pain conditions.

Another hot topic in pain medicine is pharmacogenetics and the impact of one’s genes on pain control and development of adverse side effects. Olbrecht et. al.  (Cincinnati Children’s Hospital) elucidated that variants of hepatic transport genes play a significant role in the pharmacokinetics of morphine and its metabolites in 228 children undergoing outpatient tonsillectomy. Caucasians (compared to African Americans) were found to have a higher frequency of the homozygous genotypes of OCT1 and ABCC3, which may explain their lower morphine clearance and higher incidence of adverse effects with morphine. From the same institution, Mavi et. al. provided data showing the risk of respiratory depression is affected by the µ opioid receptor gene OPRM1 A118G variant. The risk is reported to be 6-fold higher in patients with the AA genotype despite decreased morphine requirement, compared with the AG/GG genotype in 88 non-obese adolescents with idiopathic scoliosis who underwent spine fusion and received a morphine patient controlled analgesia for postoperative pain control.

Finally, there were over 215 non-moderated posters, ranging from case reports to research study reports. To mention a few, there was a case report of successful postoperative pain management utilizing liposomal bupivacaine for intercostal nerve blocks in an adolescent undergoing a pneumonectomy (Klinger et. al., Children’s National Medical Center). Additionally, retrospective data analysis of the use of perioperative gabapentinoids (gabapentin and pregabalin) in children with idiopathic scoliosis undergoing PSF was reported to reduce morphine consumption, facilitate early transition to oral pain medications and earlier ambulation; with no differences reported between the two gabapentinoids studied. (Lim et. al. and Choudhry et. al., Nemours Alfred I. duPont Hospital for Children).

These are just some of the selected highlights from more than 340 posters submitted and selected to be presented at the SPA-AAP Pediatric Anesthesiology 2014 meeting in Fort Lauderdale. One can hardly wait to see what the 28th Annual Meeting in New Orleans has in store! See everyone on Bourbon Street!