Imaging Approach to the Diagnosis of Acute Appendicitis in a Group of Teaching Hospitals With 24/7 In-house Availability of Ultrasound Technologist: Effect of Timing of Request on Imaging Modality.

PURPOSE: The study sought determine effect of requisition timing on the initial-choice imaging modality in appendicitis evaluation. METHODS: This was an institutional review board-approved retrospective study, encompassing 3 University of Toronto teaching hospitals, offering 24/7 radiology coverage. All surgically proven appendicitis cases, from 2012-2014, were included and presurgical ultrasound (US) or computed tomography (CT) reports were analysed. Examinations were all requested by the emergency department, performed by the same technologists and reviewed or finalized by the same radiology group (residents fellows or attending). Two coverage categories, namely regular hours (8 am-5 pm, Monday-Friday) or after hours (5 pm-8 am, Monday-Friday and weekends) were compared. The percentage of the starting modality (US or CT), the rate of CT following an indeterminate US, and the sensitivity of each modality was compared between the 2 categories, utilising Mann-Whitney U and chi-square tests. RESULTS: Presurgical US or CT studies of 494 patients, from February 2012-August 2014, were evaluated. Regular-hours and after-hours coverage demonstrated 174 (89:85 women:men) and 320 (141:179 women:men; P < .04) patients. The average age, 37.9 ± 17.1 women versus 35.2 ± 13.7 men was not statistically different (P = .8). Regular hours included 89 of 174 (51.1%) of US-only examinations, 50 of 174 (29%) of CT-only examinations, and 35 of 174 (20%) of US examinations followed by CT examinations. After hours included 147 of 320 (46%) of US-only examinations, 147 of 320 (46%) of CT-only examinations, and 26 of 320 (8%) of US examinations followed by CT examinations (P < .001). The total diagnostic sensitivities for US and CT were 86% (81% regular hours, 90% after hours; P = .041) and 99.2% (100% regular hours, 99% after hours; P > .05), respectively. CONCLUSIONS: US was less utilised in acute appendicitis detection after hours, although its diagnostic sensitivity was better than regular-hours coverage.

Assessing the effect of patient screening and isolation on curtailing Clostridium difficile infection in hospital settings.

BACKGROUND: Patient screening at the time of hospital admission is not recommended as a routine practice, but may be an important strategy for containment of Clostridium difficile infection (CDI) in hospital settings. We sought to investigate the effect of patient screening in the presence of asymptomatic carriers and in the context of imperfect patient isolation. METHODS: We developed and parameterized a stochastic simulation model for the transmission dynamics of CDI in a hospital ward. RESULTS: We found that the transmission of CDI in the hospital, either through asymptomatic carriers or as a results of ineffective implementation of infection control practices, at the time of hospital admission. The results show that, for a sufficiently high reproduction number of CDI, the disease can persist within a hospital setting in the presence of in-ward transmission, even when there are no asymptomatically colonized patients at the time of hospital admission. CONCLUSIONS: Our findings have significant public health and clinical implications, especially in light of the emergence and community spread of hypervirulent CDI strains with enhanced transmission rates and toxin production. Rapid detection of colonized patients remains an important component of CDI control, especially in the context of asymptomatic transmission. Screening of in-hospital patients with potential exposure to colonized patients or contaminated environment and equipment can help reduce the rates of silent transmission of CDI through asymptomatic carriers.