Layer-Specific Damage Modeling of Porcine Large Intestine under Biaxial Tension.

The mechanical behavior of the large intestine beyond the ultimate stress has never been investigated. Stretching beyond the ultimate stress may drastically impair the tissue microstructure, which consequently weakens its healthy state functions of absorption, temporary storage, and transportation for defecation. Due to closely similar microstructure and function with humans, biaxial tensile experiments on the porcine large intestine have been performed in this study. In this paper, we report hyperelastic characterization of the large intestine based on experiments in 102 specimens. We also report the theoretical analysis of the experimental results, including an exponential damage evolution function. The fracture energies and the threshold stresses are set as damage material parameters for the longitudinal muscular, the circumferential muscular and the submucosal collagenous layers. A biaxial tensile simulation of a linear brick element has been performed to validate the applicability of the estimated material parameters. The model successfully simulates the biomechanical response of the large intestine under physiological and non-physiological loads.

Retrospective validation of a risk stratification tool developed for the management of patients with blunt chest trauma (the STUMBL score).

OBJECTIVE: To assess validity of the STUMBL score in New Zealand for complications of blunt chest trauma without multi-trauma and immediate life-threatening injuries. METHODS: A multi-centre, retrospective observational study was carried out in five EDs. Area under the receiver operating characteristic curve (AUROC) was calculated for all, early and late complications and ethnic sub-groups. Youden Index generated for each ROC was used to indicate cut scores for risks of complication, ICU admission, prolonged length of stay (LOS) and mortality. RESULTS: A total of 445 patients were included. AUROC for all complications composite were (0.73, 95% confidence interval [CI] 0.68-0.77), mortality (0.92, 95% CI 0.89-0.94), ICU admissions (0.78, 95% CI 0.73-0.81) and prolonged LOS (0.80, 95% CI 0.76-0.83) were calculated. The score performed better in the New Zealand European (Pakeha) sub-group compared to Maori and Pasifika (AUROC [95% CI]: 0.80 [0.73-0.85], 0.69 [0.56-0.79], 0.66 [0.46-0.82], respectively). Patients with scores >12 were at risk of complications from blunt chest trauma, >15 at risk of prolonged LOS and >18 at risk of ICU admission and mortality. CONCLUSIONS: The STUMBL score at a cut-off of <12 did not predict all complications sufficiently well to recommend for general use in our population. However, a score >15 predicted prolonged LOS and a score >18 predicted mortality sufficiently to be clinically useful for these outcomes. The score is more accurate in New Zealand Pakeha and needs to be used with caution in Maori and Pasifika populations. A larger prospective validation is required to further assess the score.

Coding in surgery: impact of a specialized coding proforma in hepato-pancreato-biliary surgery.

BACKGROUND: Coding inaccuracies in surgery misrepresent the productivity of hospitals and outcome data of surgeons. The aim of this study was to audit the extent of coding inaccuracies in hepato-pancreato-biliary (HPB) surgery and assess the financial impact of introducing a coding proforma. METHODS: Coding of patients who underwent elective HPB surgery over a 3-month period was audited. Codes were based on International Classification of Diseases 10 and Office of Population and Census Surveys-4 codes. A coding proforma was introduced and assessed. New human resource group codes were re-assigned and new tariffs calculated. A cost analysis was also performed. RESULTS: Prior to the introduction of the coding proforma, 42.0% of patients had the incorrect diagnosis and 48.5% had missing co-morbidities. In addition, 14.5% of primary procedures were incorrect and 37.6% had additional procedures that were not coded for at all. Following the introduction of the coding proforma, there was a 27.5% improvement in the accuracy of primary diagnosis (P < 0.001) and 21% improvement in co-morbidities (P = 0.002). There was a 7.2% improvement in the accuracy of coding primary procedures (P = not significant) and a 21% improvement in the accuracy of coding of additional procedures (P < 0.001). Financial loss as a result of coding inaccuracy over our 3-month study period was £56 073 with an estimated annual loss of £228 292. CONCLUSION: Coding in HPB surgery is prone to coding inaccuracies due to the complex nature of HPB surgery and the patient case-mix. A specialized coding proforma completed 'in theatre' significantly improves the accuracy of coding and prevents loss of income.

The Effect of Clinician Feedback Type on the Acquisition of a Vocal Siren.

OBJECTIVE: To compare the effects of different types of clinician feedback (auditory knowledge of performance, KP, kinaesthetic KP and knowledge of results, KR) on the production of a voice task during acquisition. KP conditions directed attention to auditory or kinaesthetic cues. KR feedback was provided as to how close the speaker's production was to a model. PATIENTS AND METHODS: A factorial multivariate 3 × 8 design was used. Thirty-six females were randomly assigned to 3 different feedback groups and trained in the production of a vocal siren. The production of sirens was measured by variants of vocal intensity, cepstral peak prominence, phonation time and pitch phase compliance. RESULTS: All groups showed significant improvement over time in measures of vocal intensity, timing of pitch change and phonation time. The KP group (auditory and kinaesthetic combined) showed significantly more improvement over time in vocal intensity than the KR group. The kinaesthetic KP group maintained better control of vocal clarity across attempts while reducing vocal intensity than the auditory KP group. CONCLUSION: Optimal feedback paradigms during acquisition may be different depending on the parameters of voicing being trained. Learners may benefit from KP feedback to control intensity, and kinaesthetic cues to control vocal clarity.