Amygdala-mediated enhancement of memory for specific events depends on the hippocampus.

Emotional events are often remembered better than neutral events, a type of memory prioritization by affective salience that depends on the amygdala. Studies with rats have indicated that direct activation of the basolateral complex of the amygdala (BLA) can enhance memory for neutral events, and if the activation is brief and temporally targeted, can do so in a way that benefits memories for specific events. The essential targets of BLA activation in the case of event-specific memory enhancement were unknown, but the hippocampus was known to receive direct projections from the BLA and to support memory for events. In the present study, rats received counterbalanced infusions of either muscimol, a GABAA receptor agonist, or saline into the hippocampus prior to performing a novel object recognition memory task during which initial encounters with some of the objects were immediately followed by brief electrical stimulation to the BLA. When memory was tested 1day later in the saline condition, rats remembered these objects well but showed no memory for objects for which the initial encounter had not been followed by BLA stimulation. In contrast, no benefit to memory of BLA stimulation was observed in the muscimol condition. The results indicated that brief activation of the BLA can prioritize memories for events by enhancing memory for some object encounters but not others and that this benefit to memory depends on interactions between the amygdala and the hippocampus.

Prolonged Postoperative Mechanical Ventilation (PPMV) in children undergoing abdominal operations: An analysis of the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

BACKGROUND: Prolonged postoperative mechanical ventilation (PPMV) increases length of stay, hospitalization costs, and postoperative complications. Independent risk factors associated with PPMV are not well-known for children. METHOD: We identified children (<18 years) in the ACS NSQIP-P database who underwent a general surgical abdominal operation. We excluded children with preoperative ventilator dependence and mortality within 48 h of surgery. PPMV was defined as cumulative postoperative mechanical ventilation exceeding 72 h. A multivariable logistic regression model identified independent predictors of PPMV. RESULTS: We identified 108,392 children who underwent a general surgical abdominal operation in the ACS NSQIP-P database from 2012 to 2017. We randomly divided the population into a derivation cohort of 75,874(70%) and a validation cohort of 32,518(30%). In the derivation cohort, we identified PPMV in 1,643(2.2%). In the multivariable model, the strongest independent predictor of PPMV was neonatal age (OR:20.66; 95%CI:16.44-25.97). Other independent risk factors for PPMV were preoperative inotropic support (OR:10.56; 95%CI:7.56-14.77), an operative time longer than 150 min (OR:4.30; 95%CI:3.72-4.52), and an American Society of Anesthesiologists classification >3 (OR:12.16; 95%CI:10.75-13.75). CONCLUSION: Independent preoperative risk factors for PPMV in children undergoing a general surgical operation were neonatal age, preoperative ionotropic support, duration of operation, and ASA classification >3.

Improving ultrasound for appendicitis through standardized reporting of secondary signs.

OBJECTIVE: Our aim was to implement a standardized US report that included secondary signs of appendicitis (SS) to facilitate accurate diagnosis of appendicitis and decrease the use of computed tomography (CT) and admissions for observation. METHODS: A multidisciplinary team implemented a quality improvement (QI) intervention in the form of a standardized US report and provided stakeholders with monthly feedback. Outcomes including report compliance, CT use, and observation admissions were compared pretemplate and posttemplate. RESULTS: We identified 387 patients in the pretemplate period and 483 patients in the posttemplate period. In the posttemplate period, the reporting of SS increased from 5.4% to 79.5% (p<0.001). Despite lower rates of appendix visualization (43.9% to 32.7%, p<0.001) with US, overall CT use (8.5% vs 7.0%, p=0.41) and the negative appendectomy rate remained stable (1.0% vs 1.0%, p=1.0). CT utilization for patients with an equivocal ultrasound and SS present decreased (36.4% vs 8.9%, p=0.002) and admissions for observations decreased (21.5% vs 15.3%, p=0.02). Test characteristics of RLQ US for appendicitis also improved in the posttemplate period. CONCLUSION: A focused QI initiative led to high compliance rates of utilizing the standardized US report and resulted in lower CT use and fewer admissions for observation. Study of a Diagnostic Test Level of Evidence: 1.

Secondary signs may improve the diagnostic accuracy of equivocal ultrasounds for suspected appendicitis in children.

INTRODUCTION: Ultrasound (US) is the preferred imaging modality for evaluating appendicitis. Our purpose was to determine if including secondary signs (SS) improve diagnostic accuracy in equivocal US studies. METHODS: Retrospective review identified 825 children presenting with concern for appendicitis and with a right lower quadrant (RLQ) US. Regression models identified which SS were associated with appendicitis. Test characteristics were demonstrated. RESULTS: 530 patients (64%) had equivocal US reports. Of 114 (22%) patients with equivocal US undergoing CT, those with SS were more likely to have appendicitis (48.6% vs 14.6%, p<0.001). Of 172 (32%) patients with equivocal US admitted for observation, those with SS were more likely to have appendicitis (61.0% vs 33.6%, p<0.001). SS associated with appendicitis included fluid collection (adjusted odds ratio (OR) 13.3, 95% confidence interval (CI) 2.1-82.8), hyperemia (OR=2.0, 95%CI 1.5-95.5), free fluid (OR=9.8, 95%CI 3.8-25.4), and appendicolith (OR=7.9, 95%CI 1.7-37.2). Wall thickness, bowel peristalsis, and echogenic fat were not associated with appendicitis. Equivocal US that included hyperemia, a fluid collection, or an appendicolith had 96% specificity and 88% accuracy. CONCLUSION: Use of SS in RLQ US assists in the diagnostic accuracy of appendicitis. SS may guide clinicians and reduce unnecessary CT and admissions.

Event-specific enhancement of memory via brief electrical stimulation to the basolateral complex of the amygdala in rats.

The basolateral complex of the amygdala (BLA) modulates memory for emotional events, and direct activation of the BLA following a learning session can enhance subsequent memory. Yet optimal enhancement of episodic memory during emotional events would likely require that BLA activation occur close in time to the event and to be brief enough to target specific memories if some events are to be remembered better than others. In the present study, rats were given a novel object recognition memory task in which initial encounters with some of the objects were immediately followed by brief electrical stimulation of the BLA, and these objects were remembered better one day later as compared to objects for which the initial encounter was not followed by stimulation. The results indicated that BLA stimulation can enhance memory for individual events, a necessary ability for the BLA to modulate episodic memory effectively.