Nationwide paediatric cohort study of a protective association between allergy and complicated appendicitis.

BACKGROUND: In a nationwide cohort the potentially protective association between allergy and complicated appendicitis was analysed, and the influence of seasonal antigens, antihistamine treatment, and timing of allergy onset assessed. METHODS: Some 1 112 571 children born between 2000 and 2010 were followed from birth until the end of 2014. A cross-sectional analysis of appendicitis cases, with comparison of allergic versus non-allergic children for absolute risk and odds of complicated appendicitis was first undertaken. This was followed by a longitudinal analysis of children with allergy and matched controls who had never had an allergy, for incidence rate and hazard of subsequent complicated or simple appendicitis. RESULTS: Of all children, 20.4 per cent developed allergy and 0.6 per cent had appendicitis during follow-up. Among children with appendicitis, complicated appendicitis was more common among non-allergic children (18.9 per cent, 948 of 5016) than allergic children (12.8 per cent, 173 of 1351) (P < 0.001), and allergic children had a lower adjusted odds of complicated appendicitis (adjusted odds ratio (OR) 0.80, 95 per cent c.i. 0.67 to 0.96; P = 0.021 ). The risk of complicated appendicitis among children with manifest allergy was reduced by one-third in the longitudinal analysis (incidence rate 0.13 versus 0.20 per 1000 person-years; hazard ratio (HR) 0.68, 95 per cent c.i. 0.58 to 0.81; P < 0.001), whereas the risk of simple appendicitis remained unchanged (incidence rate 0.91 versus 0.91; HR 1.00, 0.94 to 1.07; P = 0.932 ). Seasonal antigen exposure was a protective factor (adjusted OR 0.82, 0.71 to 0.94; P = 0.004) and ongoing antihistamine medication a risk factor (adjusted OR 2.28, 1.21 to 4.28; P = 0.012). CONCLUSION: Children with allergy have a lower risk of complicated appendicitis, but the same overall risk of simple appendicitis. Seasonal antigen exposure reduced, and antihistamine treatment increased, the risk of complicated disease.

Are the target exposure index and deviation index used efficiently?

INTRODUCTION: Exposure index (EI) is important to evaluate correct exposure in radiography and thus important for image quality. The purpose of this study was to evaluate whether the target exposure index (EIT) and deviation index (DI) were used efficiently. METHODS: Radiography departments in Iceland, using <10 years old equipment, were invited to participate. For each x-ray unit, admin users were asked about the use of EIT and data was gathered on EIT for five body parts (BP); lumbar spine, chest, hip, knee and hand. For each of the five BP, 100 examinations from the past year were selected randomly (or all, if < 100). The EI from one predefined view was recorded and the corresponding DI calculated. RESULTS: A total of ten x-ray units, from four manufacturers and located at eight departments, were included in the study. The departments involved are comprised of a university hospital, smaller hospitals, and miscellaneous private departments. Two departments (25%) had not set EIT, five (62.5%) used default values and only one had revised EIT values. In four departments (50%) radiographers favored "acceptable EI range" over DI. The mean EI was significantly different (p < 0.05) from the EIT in the majority of the five BP, in four out of the six departments that had defined EIT. In total 30% of images from all departments combined had DI outside the range of -3.0 < DI < +3.0. The standard deviation of DI was from 1.4 to 2.7. CONCLUSION: The study shows that the EIT and DI are not used efficiently, regardless of equipment vendor or department characteristics. IMPLICATIONS FOR PRACTICE: Current recommendations on targeting the mean DI of 0 need to be reinforced. Theoretical knowledge and training need to be improved.

Efficient use of automatic exposure control systems in computed tomography requires correct patient positioning.

BACKGROUND: Image quality and radiation dose to the patient are important factors in computed tomography (CT). To provide constant image quality, tube current modulation (TCM) performed by automatic exposure control (AEC) adjusts the tube current to the patient's size and shape. PURPOSE: To evaluate the effects of patient centering on tube current-time product (mAs) and image noise. MATERIAL AND METHODS: An oval-shaped acrylic phantom was scanned in various off-center positions, at 30-mm intervals within a 500-mm field of view, using three different CT scanners. Acquisition parameters were similar to routine abdomen examinations at each site. The mAs was recorded and noise measured in the images. The correlation of mAs and noise with position was calculated using Pearson correlation. RESULTS: In all three scanners, the mAs delivered by the AEC changed with y-position of the phantom (P<0.001), with correlation values of 0.98 for scanners A and B and -0.98 for scanner C. With x-position, mAs changes were 4.9% or less. As the phantom moved into the y-positions, compared with the iso-center, the mAs varied by up to +70%, -34%, and +56% in scanners A, B, and C, respectively. For scanners A and B, noise in two regions of interest in the lower part of the phantom decreased with elevation, with correlation factors from -0.95 to -0.86 (P<0.02). In the x-direction, significant noise relationships (P<0.005) were only seen in scanner A. CONCLUSION: This study demonstrates that patient centering markedly affects the efficacy of AEC function and that tube current changes vary between scanners. Tube position when acquiring the scout projection radiograph is decisive for the direction of the mAs change. Off-center patient positions cause errors in tube current modulation that can outweigh the dose reduction gained by AEC use, and image quality is affected.

International field test results of the Observable Indicators of Nursing Home Care Quality instrument.

Researchers at the University of Missouri-Columbia developed the Observable Indicators of Nursing Home Care Quality instrument to measure the dimensions of nursing home care quality during a brief on-site visit to a nursing home. The instrument has been translated for use in Iceland and used in Canada. Results of the validity and reliability studies using the instrument in 12 nursing homes in Reykjavik, in a large Veterans Home in Ontario with 14 units tested separately, and in 20 nursing homes in Missouri, are promising. High-content validity was observed in all countries, together with excellent inter-rater reliability and coefficient alpha. Test-retest reliabilities in Iceland and Missouri were good. Results of the international field test of the Observable Indicators of Nursing Home Care Quality instrument points to the usefulness of such an instrument in measuring nursing home care quality following a quick on-site observation in a nursing facility. The instrument should be used as a facility-wide assessment of quality, rather than for individual units within a facility. We strongly recommend its use by practising nurses in nursing homes to assess quality of care and guide efforts to improve care. We recommend its use by researchers and consumers and further testing of the use of the instrument with regulators.