Efficacy of MedMyst: an Internet Teaching Tool for Middle School Microbiology

Can web-based technology be used to effectively introduce or reinforce aspects of microbiology to middle school students? This central hypothesis examines whether brief exposure to a web adventure format containing virtual lab experiments and computer games within an engaging story line can impact student learning. An episodic adventure series, MedMyst (http://medmyst.rice.edu), focuses on infectious diseases and the microbes that cause them. The website is not intended to replace classroom instruction, but rather to engage students in problem-solving activities not likely to be encountered elsewhere. It also provides scientists with a resource to introduce microbiology to adolescent audiences through outreach activities. In the online adventure, the player (student) enters a futuristic world in which he or she becomes a “Reconstructor,” a member of an elite team charged with preventing the spread of infectious disease. The series consists of three “missions,” each lasting approximately 30 to 40 minutes and designed to address a limited set of learning objectives. Middle school students participated in the creation of the characters and the stylized design through focus groups. Classroom teachers oversaw the alignment of the web adventure objectives with the National Science Content Standards. Scientists and clinicians reviewed the web adventure for content and accuracy. A field test involving over 700 students from nine different schools assessed the knowledge gains attributable to playing MedMyst. Gain scores from pretest to posttest indicated that middle school students retained important information by interacting with the online material for as little as 30 minutes per adventure; however, gains for high school students were less persuasive, perhaps indicating a different learning tool or content is required for this age audience

THREE ESSAYS ON EDUCATION POLICY

I combine novel data sources with quasi-experimental approaches and detailed knowledge of K-12 policy contexts to explore the causal effects of a range of policies on student cognitive and noncognitive outcomes and teacher labor supply. In Chapter 1, I use event-study and difference-in-differences approaches to estimate the effects of exposure to school active-shooter drills on measures of attendance and achievement. Attendance rates in academic quarters with shooter drills are 0.14-0.16 percentage points (pp) lower than in quarters without such drills. Proficiency rates among 3rd-5th graders exposed to shooter drills before reading and math tests are 0.40 pp lower than that of their counterparts exposed to pre-test fire drills; among 6th-8th graders, the drop is 0.50 pp in math and science. The negative effects of exposure to such drills appear to operate through distress or trauma and not merely disruptions to instructional time. In Chapter 2, I estimate the causal effect of older-age kindergarten enrollment on K-3 outcomes measured at high-frequency (i.e., 3 or 4 times per school year). My estimation strategy leverages a regression discontinuity approach and controls for measures of pre-kindergarten human capital. During kindergarten and first grade, teachers perceive older and younger kindergarten entrants similarly in their cooperativeness but older entrants as more skilled at working independently. Older kindergarteners enter school with further developed foundational literacy skills; however, by the end of both kindergarten and first grade, older entrants are similar to younger entrants in these skills. Finally, older kindergarten entrants are as likely as their younger counterparts to be identified with a disability throughout grades K-3. In Chapter 3, I explore teacher responsiveness to school-level sociodemographic changes resulting from a socioeconomic desegregation plan implemented in Wake County, North Carolina, during the 2000s. In years when schools undergo sociodemographic changes induced by this plan, teachers do not resign from their schools or apply to transfer to other schools at higher rates compared to years when these schools are unaffected by the plan. Teachers also take fewer sick days in the years when their schools are affected by the plan, and even fewer sick days the year after.Doctor of Philosoph

Determinants of hospital length of stay after thoracoabdominal aortic aneurysm repair

AbstractPurpose: Extended hospital length of stay (LOS) and consequent high costs are associated with thoracic and thoracoabdominal aortic aneurysm (TAAA) surgery. In this study, we examined factors that may influence LOS after TAAA repair. Methods: Five hundred forty thoracic and TAAA repairs were performed by one surgeon between 1990 and 1999. The data were analyzed with multiple linear regression with appropriate logarithmic transformation. The predictor variables included patient demographics, disease extent, severity indicators, intraoperative factors, and postoperative complications. Results: The median LOS was 15 days. Postoperative creatinine level of greater than 2.9 was the most important predictor of LOS, followed by spinal cord deficit, age, and pulmonary complication (all statistically significant with P <.05). A second model constrained to preoperative risk factors showed both age and complete diaphragmatic division to be associated with increased LOS. Preservation of the diaphragm led to reduced LOS by an average of 4 days. The adjunct cerebrospinal fluid drainage and distal aortic perfusion was associated with a decrease in LOS, although it did not reach statistical significance. Conclusion: Renal failure, spinal cord deficit, and pulmonary complication were the major determinants of LOS in patients for TAAA repair. This study shows that the preservation of diaphragmatic function and the use of the adjunct distal aortic perfusion and cerebrospinal fluid drainage may reduce hospital LOS. (J Vasc Surg 2002;35:648-53.

Blunt traumatic aortic injury: Initial experience with endovascular repair

ObjectivesEndovascular treatment of traumatic aortic injury (TAI) is an alternative to open repair (OR) in patients with blunt trauma. We report our initial experience after integration of endovascular repair using thoracic devices.MethodsA retrospective review of a prospectively collected institutional trauma registry was performed. Between September 2005 and November 2008, 71 patients with TAI presented to our institution. Based on imaging, TAIs were classified into grade 1-4 in severity. These included: grade 1, intimal tear; grade 2, intramural hematoma; grade 3, aortic pseudoaneurysm; and grade 4, free rupture. Initial management included resuscitation, blood pressure control, and treatment of associated injuries. After stabilization, all patients were considered for thoracic endovascular aortic repair (TEVAR) using a thoracic device. If contraindicated, candidates underwent OR. Outcome measures were mortality, stroke, paraplegia, intensive care unit (ICU), and hospital stay.ResultsThe mean age was 39.8 years, with 50 males. The mean injury severity score (ISS) was 42.6. Nineteen (27%) patients with a mean ISS of 60 died shortly after arrival prior to any vascular intervention. Ten (14%) patients with grade 1 injuries were managed medically. The remaining 42 (59%) patients with grade 2 and 3 injuries underwent repair. Median interval between admission and repair was 4.3 days (range, 0-109 days). Fifteen (21%) patients with a mean ISS of 34.4 underwent OR with no mortality, stroke, or paraplegia. Twenty-seven (38%) patients with a mean ISS of 36.7 underwent TEVAR with no mortality or paraplegia. One TEVAR patient suffered a perioperative stroke. Twenty-two patients had a TAG (W.L. Gore & Associates, Flagstaff, Ariz) device. Four patients had a Talent Thoracic (Medtronic Vascular, Santa Rosa, Calif), and 1 patient had an Excluder (W.L. Gore) device. The left subclavian artery was covered in 13 (48%) patients. Patients who underwent TEVAR were older than those who had OR (47.8 vs 31.1 years, P < .006). The aortic diameter proximal to the injury was larger in the TEVAR group (24.4 vs 19.6 mm, P < .0001). There was no difference in the mean ICU or hospital length of stay between the two groups. Mortality correlated with the ISS score (P < .0001). Median follow-up time was 19.4 months (range, 0-27). Only 56% of the TEVAR patients were fully compliant with their surveillance imaging protocol.ConclusionIn this initial experience, the results of TEVAR did not differ from OR. Long-term follow-up is required to determine the effectiveness of this treatment strategy. Adherence to follow-up imaging protocols is challenging in this patient population. Next generation devices will make TEVAR applicable to a wider range of patients

Update on blunt thoracic aortic injury: Fifteen-year single-institution experience

ObjectivesDespite improvements in the management of blunt thoracic aortic injury, mortality remains high. We report our experience with blunt thoracic aortic injury at a level 1 trauma center over the past 15 years.MethodsBetween January 1, 1997, and January 1, 2012, data on 338 patients who presented with suspected blunt thoracic aortic injury were entered into the University of Texas Medical School at Houston Trauma Center Registry. A total of 175 patients (52%) underwent thoracic aortic repair; 29 (17%) had open repair with aortic crossclamping, 77 (44%) had open repair with distal aortic perfusion, and 69 (39%) had thoracic endovascular aortic repair. Outcomes were determined, including early mortality, morbidity, length of stay, and late survival. Multiple logistic regression analysis was used to compute adjusted estimates for the effects of the operative technique.ResultsThe early mortality for all patients with blunt thoracic aortic injury was 41% (139/338). Early mortality was 17% (27/175) for operative aortic interventions, 4% (3/69) for thoracic endovascular aortic repairs, 31% (11/29) for open repairs with aortic crossclamping, and 14% (11/77) for open repairs with distal aortic perfusion. Survival for thoracic endovascular aortic repair at 1 year and 5 years was 92% and 87%, respectively. Survival for open repair at 1, 5, 10, and 15 years was 76%, 75%, 72%, and 68%, respectively.ConclusionsBlunt thoracic aortic injury remains associated with significant early mortality. Delayed selective management, when applied with open repair with distal aortic perfusion and the use of thoracic endovascular aortic repair, has been associated with improved early outcomes. The long-term durability of thoracic endovascular aortic repair is unknown, necessitating close radiographic follow-up

Postoperative renal function preservation with nonischemic femoral arterial cannulation for thoracoabdominal aortic repair.

BACKGROUND: Renal failure after thoracoabdominal aortic repair is a significant clinical problem. Distal aortic perfusion for organ and spinal cord protection requires cannulation of the left femoral artery. In 2006, we reported the finding that direct cannulation led to leg ischemia in some patients and was associated with increased renal failure. After this finding, we modified our perfusion technique to eliminate leg ischemia from cannulation. In this article, we present the effects of this change on postoperative renal function. METHODS: Between February 1991 and July 2008, we repaired 1464 thoracoabdominal aortic aneurysms. Distal aortic perfusion was used in 1088, and these were studied. Median patient age was 68 years, and 378 (35%) were women. In September 2006, we began to adopt a sidearm femoral cannulation technique that provides distal aortic perfusion while maintaining downstream flow to the leg. This was used in 167 patients (15%). We measured the joint effects of preoperative glomerular filtration rate (GFR) and cannulation technique on the highest postoperative creatinine level, postoperative renal failure, and death. Analysis was by multiple linear or logistic regression with interaction. RESULTS: The preoperative GFR was the strongest predictor of postoperative renal dysfunction and death. No significant main effects of sidearm cannulation were noted. For peak creatinine level and postoperative renal failure, however, strong interactions between preoperative GFR and sidearm cannulation were present, resulting in reductions of postoperative renal complications of 15% to 20% when GFR was \u3c60 mL\u3e/min/1.73 m(2). For normal GFR, the effect was negated or even reversed at very high levels of GFR. Mortality, although not significantly affected by sidearm cannulation, showed a similar trend to the renal outcomes. CONCLUSION: Use of sidearm cannulation is associated with a clinically important and highly statistically significant reduction in postoperative renal complications in patients with a low GFR. Reduced renal effect of skeletal muscle ischemia is the proposed mechanism. Effects among patients with good preoperative renal function are less clear. A randomized trial is needed

Cerebral monitoring with transcranial Doppler ultrasonography improves neurologic outcome during repairs of acute type A aortic dissection

ObjectiveNeurologic complications after repair of acute type A aortic dissection remain significant. The use of power M-mode transcranial Doppler monitoring to verify cerebral blood flow during these repairs might decrease cerebral ischemia by correcting malperfusion. The purpose of this study was to analyze the use of power M-mode transcranial Doppler monitoring during repairs of acute type A dissection with regard to neurologic outcome.MethodsWe performed a prospective study of patients undergoing repairs of acute type A aortic dissection. Repairs included profound hypothermic circulatory arrest and retrograde cerebral perfusion. Patients in whom transcranial Doppler monitoring was used to monitor cerebral blood flow and modify operative technique during repair (study group) were compared with those without monitoring and modification (control group).ResultsBetween September 2001 and October 2003, we repaired 56 cases of acute type A dissection. Power M-mode transcranial Doppler monitoring was used in 50% (28/56) of cases. Power M-mode transcranial Doppler monitoring altered operative cannulation and guided retrograde cerebral perfusion flow in 28.5% (8/28) and 78.6% (22/28) of cases, respectively. Two patients presented with preoperative stroke, one in each group. One operative death occurred in each group. In-hospital mortality and the occurrence of new stroke were not significantly different between the 2 groups. Temporary neurologic dysfunction occurred less often in the study group (14.8% [4/27] vs 51.8% [14/27], P = .008).ConclusionsIdentification of cerebral malperfusion requires cerebral monitoring. By ensuring cerebral blood flow by using power M-mode transcranial Doppler monitoring and correcting cerebral malperfusion by modifying operative technique, neurologic outcome was improved during repairs of acute type A aortic dissection

Outcomes after endovascular repair of arterial trauma

BackgroundEndovascular repair of peripheral arterial trauma using covered stent grafts is a minimally invasive alternative to open surgery in selected patients. Although the technical feasibility of endovascular repair has been established, there are a paucity of data regarding outcomes. The purpose of this study was to evaluate the short-term outcomes of endovascular repair in patients with peripheral arterial trauma.MethodsA review of a prospectively collected institutional trauma registry captured all patients with peripheral arterial injury who underwent endovascular repair from August 2004 to June 2012. Data collected included demographics, Injury Severity Score (ISS), mechanism, location and type of injury, imaging modality, intervention type, complications and reintervention, length of stay, and follow-up. Descriptive statistics were used for analysis.ResultsDuring the study period, we performed endovascular repair in 28 patients with peripheral arterial injuries. There were 20 male patients (71%) with a median age of 39 years (range, 13-88 years). The mean ISS was 17.2 (range, 9-41). The mechanism of injury was penetrating in 21 (75%) and blunt in seven (25%). The anatomic locations of the 28 arterial injuries were carotid (3 [11%]), subclavian (7 [25%]), axillary (6 [22%]), iliac (3 [11%]), and femoral/popliteal (9 [32%]). Findings consistent with injury on imaging included pseudoaneurysms (9 [32%]), extravasations (9 [32%]), occlusions (6 [22%]), and arteriovenous fistulas (4 [14%]). Technical success was achieved in all patients. The overall complication rate was 21%, with six patients requiring a secondary procedure. Two patients underwent a planned, elective conversion to open repair during the initial hospitalization. Four patients required conversion secondary to stent graft thrombosis. Three conversions were early (<30 days) and one was late (>30 days). The mean length of stay was 18.4 ± 22.9 days (range, 1-93 days), with a median follow-up of 13 months (range, 1-60 months). The overall limb salvage rate was 92% at 45 days and 79% at 93 days.ConclusionsThe present study outlines our early experience with endovascular repair of peripheral arterial injuries in a variety of anatomic locations. Overall complication rates are appreciable but can be effectively detected and managed with additional intervention. The inclusion of endovascular modalities in algorithms of trauma care holds considerable promise. The need to better define optimal algorithms for utilization and determine long-term outcomes of intervention requires significant additional study