Featured Articles from September 2012

Event-Related Functional Magnetic Resonance Imaging of a Low Dose of Dexmedetomidine That Impairs Long-term Memory

In this study, healthy human volunteers viewed and rated 160 pictures during fMRI imaging while receiving either low-dose dexmedetomidine (target plasma concentration of 0.15 ng/ml) or placebo, and returned 4 days later for memory testing. The subjects that received dexmedetomidine were found to have impaired memory overall, but the memory effects were not different for emotionally arousing pictures (e.g. graphic war wound) vs. non-arousing pictures (e.g. cup). Imaging data revealed that dexmedetomidine primarily decreased cortical activity while increasing activity in the thalamus and posterior hippocampus. However, there was an area in the left hippocampus where placebo subjects had a larger subsequent memory effect compared to dexmedetomidine subjects. These results suggest that emotionally arousing content does not change the memory effects induced by dexmedetomidine, and that effects on a specific area of the hippocampus may play a role in dexmedetomidine-induced memory impairment.


Clinical Practice Guideline: Diagnosis and Management of Childhood Obstructive Sleep Apnea Syndrome

This revised American Academy of Pediatrics clinical practice guideline is intended for use by primary care clinicians and provides recommendations for the diagnosis and management of the obstructive sleep apnea syndrome (OSAS) in children and adolescents. It focuses on uncomplicated childhood OSAS associated with adenotonsillar hypertrophy (T&A) and/or obesity in an otherwise healthy child who is being treated in the primary care setting. It is accompanied by a technical report that can be found at http://www.ncbi.nlm.nih.gov/pubmed/22926176. From 1999–2010, 350 articles provided relevant data. Most articles were level II-IV. Highlights of the 8 recommendations include: (1) All children/adolescents should be screened for snoring. (2) Polysomnography (PSG) should be performed in children/adolescents with snoring and symptoms/signs of OSAS; if PSG is not available, then alternative diagnostic tests or referral to a specialist for more extensive evaluation may be considered. (3) T&A is recommended as the first-line treatment of patients with adenotonsillar hypertrophy. (4) Patients should be re-evaluated postoperatively to determine whether further treatment is required; (5) CPAP is recommended as treatment if T&A is not performed or if OSAS persists postoperatively. (6) Intranasal corticosteroids are an option for children with mild OSAS in whom T&A is contraindicated or for mild postoperative OSAS.


Society for Ambulatory Anesthesia Consensus Statement on Preoperative Selection of Adult Patients With Obstructive Sleep Apnea Scheduled for Ambulatory Surgery

The suitability of ambulatory surgery for a patient with obstructive sleep apnea (OSA) remains controversial because of concerns of increased perioperative complications including postdischarge death. A Society for Ambulatory Anesthesia task force on practice guidelines developed a consensus statement for the selection of patients with OSA scheduled for ambulatory surgery. A systematic review of the literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. There are 7 studies evaluating perioperative outcome in OSA patients undergoing ambulatory surgery and they are of limited quality.

Patients with a known diagnosis of OSA and optimized comorbid medical conditions can be considered for ambulatory surgery, if they are able to use a CPAP device in the postoperative period. Patients with a presumed diagnosis of OSA, based on screening tools such as the STOP-Bang questionnaire, and with optimized comorbid conditions, can be considered for ambulatory surgery, if postoperative pain can be managed predominantly with nonopioid analgesic techniques. On the other hand, OSA patients with nonoptimized comorbid medical conditions may not be good candidates for ambulatory surgery.