Functional Dissociation of θ Oscillations in the Frontal and Visual Cortices and Their Long-Range Network during Sustained Attention.

θ-Band (4-12 Hz) activities in the frontal cortex have been thought to be a key mechanism of sustained attention and goal-related behaviors, forming a phase-coherent network with task-related sensory cortices for integrated neuronal ensembles. However, recent visual task studies found that selective attention attenuates stimulus-related θ power in the visual cortex, suggesting a functional dissociation of cortical θ oscillations. To investigate this contradictory behavior of cortical θ, a visual Go/No-Go task was performed with electroencephalogram (EEG) recording in C57BL/6J mice. During the No-Go period, transient θ oscillations were observed in both the frontal and visual cortices, but θ oscillations of the two areas were prominent in different trial epochs. By separating trial epochs based on subjects' short-term performance, we found that frontal θ was prominent in good-performance epochs, while visual θ was prominent in bad-performance epochs, exhibiting a functional dissociation of cortical θ rhythms. Furthermore, the two θ rhythms also showed a heterogeneous pattern of phase-amplitude coupling with fast oscillations, reflecting their distinct architecture in underlying neuronal circuitry. Interestingly, in good-performance epochs, where visual θ was relatively weak, stronger fronto-visual long-range synchrony and shorter posterior-to-anterior temporal delay were found. These findings highlight a previously overlooked aspect of long-range synchrony between distinct oscillatory entities in the cerebral cortex and provide empirical evidence of a functional dissociation of cortical θ rhythms.

Outcomes Research in Vulnerable Pediatric Populations.

The Pediatric Anesthesia and Neurodevelopment Assessment (PANDA) study team held its biennial symposium in April 2018 to discuss issues on anesthetic neurotoxicity in the developing brain. One of the sessions invited speakers with different areas of expertise to discuss "Outcomes Research in Vulnerable Pediatric Populations." The vulnerable populations included neonates, children with congenital heart disease, children from low socioeconomic status, and children with incarcerated parents. Each speaker presented some of the ongoing research efforts in these groups as well as the challenges encountered in studying them.

Identification of perioperative pulmonary aspiration in children using quality assurance and hospital administrative billing data.

BACKGROUND: Perioperative aspiration is a rare but potentially devastating complication, occurring in 1-10 per 10 000 anesthetics based on studies of quality assurance databases. Quality assurance reporting is known to underestimate the incidence of adverse outcomes, but few large studies use supplementary data sources. This study aims to identify the incidence of and risk factors for perioperative aspiration in children using quality assurance data supplemented by administrative billing records, and to examine the utility of billing data as a supplementary data source. METHODS: Aspiration events for children receiving anesthesia at a tertiary care pediatric hospital between 2008 and 2014 were identified using (i) a perioperative quality assurance database and (ii) hospital administrative billing records with International Classification of Diseases, Ninth Revision Clinical Modification coded diagnoses of aspiration. Records were subject to review by pediatric anesthesiologists. Following identification of all aspiration events, the incidence of perioperative aspiration was calculated and risk factors were assessed. RESULTS: 47 272 anesthetic cases were evaluated over 7 years. The quality assurance database identified 20 cases of perioperative aspiration occurring in surgical inpatients, same-day admissions, and outpatients. Using hospital administrative data (which excludes outpatients with shorter than a 24-hour stay), 9 cases of perioperative aspiration were identified of which 6 had not been found through quality assurance data. Overall, International Classification of Diseases, Ninth Revision coding demonstrated a positive predictive value of 94.5% for any aspiration event; however, positive predictive value was <4% for perioperative aspiration. A total incidence of 5.5 perioperative aspirations per 10 000 (95% CI: 3.7-8.0 per 10 000) anesthetics was found. CONCLUSION: Quality assurance data offer an efficient way to measure the incidence of rare events, but may underestimate perioperative complications. International Classification of Diseases, Ninth Revision codes for aspiration used as a secondary data source were nonspecific for perioperative aspiration, but when combined with record review yielded a 30% increase in identified cases of aspiration over quality assurance data alone. The use of administrative data therefore holds potential for supplementing quality assurance studies of rare complications.

The tram track sign: a characteristic sonographic feature of polyethylene liner dissociation after total-hip arthroplasty.

OBJECTIVES: Polyethylene liner dissociation from an acetabular component is a complication of total-hip arthroplasty (THA) caused by slippage of the liner, which causes pain and requires a revision. The aim of this study was to evaluate sonographic features of liner dissociation and detect useful sonographic findings compared to conventional radiography and computed tomography (CT). METHODS: Among a total of 226 patients who underwent revision THA at our institution between September 2008 and June 2012, 10 patients (6 male and 4 female; mean age, 56.2 years) who showed severe narrowing of the superior joint space on the THA side and underwent sonography were retrospectively reviewed by evaluating radiographic, CT, and sonographic findings. In evaluation of the images, we put more emphasis on the "radiographic crescent sign," "CT crescent sign," and "sonographic tram track sign." RESULTS: At surgery, 7 patients showed liner dissociation, and 3 showed severe liner wear. On radiography, 8 of 10 patients (80%) had a correct diagnosis of the presence or absence of liner dissociation; on sonography, all 10 patients (100%) had a correct diagnosis. The sensitivity, specificity, and accuracy for diagnosis of liner dissociation by pelvic radiography and sonography were 100% (7 of 7), 33% (1 of 3), and 80% (8 of 10) and 100% (7 of 7), 100% (3 of 3), and 100% (10 of 10), respectively. CONCLUSIONS: Liner dissociation can be easily and well visualized by sonography, especially compared to pelvic radiography and CT. The sonographic tram track sign should be a very useful feature in the early diagnosis of liner dissociation.