BACKGROUND. There is growing realisation that human error contributes significantly to morbidity and mortality in modern healthcare. A number of taxonomies and classification systems have been developed in an attempt to categorise errors and quantify their impact. OBJECTIVES. To record and identify adverse events and errors as they impacted on acute trauma patients undergoing a computed tomography (CT) scan, and then quantify the effect this had on the individual patients. It is hoped that these data will provide evidence to develop error prevention programmes designed to reduce the incidence of human error. METHODS. The trauma database was interrogated for the period December 2012 - April 2017. All patients aged >18 years who underwent a CT scan for blunt trauma were included. All recorded morbidity for these patients was reviewed. RESULTS. During the period under review, a total of 1 566 patients required a CT scan at our institution following blunt trauma. Of these, 192 (12.3%, 134 male and 58 female) experienced an error related to the process of undergoing a CT scan. Of 755 patients who underwent a CT scan with intravenous contrast, detailed results were available for 312, and of these 46 (14.7%) had an acute deterioration in renal function. According to Chang's taxonomy, physical harm occurred as follows: grade I n=6, grade II n=62, grade III n=45, grade IV n=11, grade V n=27, grade VI n=21, grade VII n=15, grade VIII n=3 and grade IX n=2. Adverse events were performing an unnecessary scan (n=24), omitting an indicated scan (n=23), performing the scan incorrectly (n=8), scanning the wrong body part (n=7), equipment failure (n=18), omitting treatment following the scan (n=6), incorrect interpretation of the scan (n=65), deterioration during the scan (n=6) and others (n=35). The setting for the error was the ward (n=19), the radiology suite (n=126), the emergency department (n=45) and the operating theatre (n=2). The staff responsible for the adverse events were medical (n=155), nursing (n=4) and radiology staff (n=15). There were 67 errors of commission and 125 errors of omission. The primary cause was a planning problem in 78 cases and an execution problem in 114. CONCLUSIONS. Errors and adverse events related to obtaining a CT scan following blunt polytrauma are not uncommon and may impact significantly on the patient. Communication is essential to eliminate errors related to performing the wrong type of scan. The commonest errors relate to misinterpretation of the scan.

The ambiguities associated with the lack of gauge invariance in the non-perturbative truncations of Schwinger-Dyson equations (SDEs) are a challenging problem which has not yet been resolved in a decisive fashion. Pursuing this aim, we study dynamical chiral symmetry breaking in quantum electrodynamics in three space-time dimensions (QED3). We investigate the gauge dependence of the chiral condensate both in the quenched and the unquenched versions of the theory and emphasize the importance of taking into account the gauge covariance properties of the fermion propagator as dictated by its Landau-Khalatnikov-Fradkin transformation (LKFT). We present numerical solutions of the SDE of the fermion propagator which respect Ward-Green-Takahashi identities (WGTI) and LKFT simultaneously. As a striking consequence, we obtain a practically gauge independent chiral condensate.