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??Objective    To investigate the characteristics of indirect injury of periodontal membrane caused by maxillofacial impact injury. Methods    The study was carried out at the laboratory of oral and maxillofacial trauma in Fourth Military Medical University??from November 2013 to January 2014. Totally 18 dogs were divided equally into six groups with random allocation??the right mandible of each dog was impacted by a cylindroid iron cap whose weight was 0.26kg??but teeth were not injured directly??the animals were killed 6 h??24 h??3 d??7 d??2 wk and 4 wk later??respectively??the histopathologic manifestations of periodontal membrane of the fourth premolar of right mandible??the second premolar of right mandible and the second premolar of left mandible were observed. Results    The injury of periodontal membrane of the fourth premolar of right mandible was relatively obvious??but the pathologic changes were reversible??periodontal membrane of the second premolar of right mandible was injured slightly??yet no obvious histopathologic change could be observed in periodontal membrane of the second premolar of left mandible. Conclusion    Maxillofacial impact injury can cause indirect injuries of periodontal membrane of adjacent teeth??but the pathologic changes are reversible??traumatic severity decreases as the distance of the tooth to the wound area increases.     

Use of a Checklist During Observation of a Simulated Cardiac Arrest Scenario Does Not Improve Time to CPR and Defibrillation Over Observation Alone for Subsequent Scenarios

Theory: Immersive simulation is a common mode of education for medical students. Observation of clinical simulations prior to participation is believed to be beneficial, though this is often a passive process. Active observation may be more beneficial. Hypotheses: The hypothesis tested in this study was that the active use of a simple checklist during observation of an immersive simulation would result in better participant performance in a subsequent scenario compared with passive observation alone. Methods: Medical students were randomized to either passive or active (with checklist) observation of an immersive simulation involving cardiac arrest prior to participating in their own simulation. Performance measures included time to cardiopulmonary resuscitation (CPR) and time to defibrillation and were compared between first and second scenarios as well as between passive and active observers. Results: Seventy-nine simulations involving 232 students were conducted. Mean time to CPR was 18 seconds (SD = 11.6) for those using the checklist and 24 seconds (SD = 15.8) for those who observed passively (M difference = 6 seconds), t(35) = 1.46, p =.153. Time to defibrillation was 94 seconds (SD = 26.4) for those using the checklist and 92 seconds (SD = 23.8) for those who observed passively (M difference = –2 seconds), t(38) =.21, p =.837. Time to CPR was 24 seconds (SD = 15.8) for passive observers and 31 seconds (SD = 21.0; M difference = 7 seconds), t(35) = 1.13, p =.265, for their first scenario counterparts. Time to CPR was 18 seconds (SD = 11.6) for active observers and 36 seconds (SD = 26.2; M difference = 18 seconds), t(24) = 2.81, p =.010, for their first scenario counterparts. Time to defibrillation was 92 seconds (SD = 23.8) for passive observers and 125 seconds (SD = 32.2; M difference = 33 seconds), t(33) = 3.63, p =.001, for their first scenario counterparts. Time to defibrillation was 94 seconds (SD = 26.4) for the active observers and 132 seconds (SD = 52.9; M difference = 38 seconds), t(28) =.46, p =.008, for their first scenario counterparts. Conclusions: Observation alone leads to improved performance in the management of a simulated cardiac arrest. The active use of a simple skills-based checklist during observation did not appear to improve performance over passive observation alone.     

Impact of bystander-performed ventilation on functional outcomes after cardiac arrest and factors associated with ventilation-only cardiopulmonary resuscitation: A large observational study

AimTo determine the effectiveness of ventilations in bystander cardiopulmonary resuscitation (BCPR) and to identify the factors associated with ventilation-only BCPR.MethodsFrom out-of-hospital cardiac arrest (OHCA) data prospectively collected from 2005 to 2011 in Japan, we extracted data for 210,134 bystander-witnessed OHCAs with complete datasets but no prehospital involvement of physician [no BCPR, 115,733; ventilation-only, 2093; compression-only, 61,075; and conventional (compressions+ventilations) BCPR, 31,233] and determined the factors associated with 1-month neurologically favourable survival using simple and multivariable logistic regression analyses. In 91,885 patients with known BCPR durations, we determined the factors associated with ventilation-only BCPR.ResultsThe rate of survival in the no BCPR, ventilation-only, compression-only and conventional group was 2.8%, 3.9%, 4.5% and 5.0%, respectively. After adjustment for other factors associated with outcomes, the survival rate in the ventilation-only group was higher than that in the no BCPR group (adjusted OR; 95% CI, 1.29; 1.01–1.63), but lower than that in the compression-only (0.76; 0.59–0.96) or conventional groups (0.70; 0.55–0.89). Conventional CPR had the highest OR for survival in almost all OHCA subgroups. The adjusted OR (95% CI) for survival after dividing BCPR into ventilation and compression components was 1.19 (1.11–1.27) and 1.60 (1.51–1.69), respectively. Older guidelines, female sex, younger patient age, bystander-initiated CPR without instruction, early BCPR and short BCPR duration were associated with ventilation-only BCPR.ConclusionsVentilation is a significant component of BCPR, but alone is less effective than compression in improving neurologically favourable survival after OHCAs.     

Association of the time to first epinephrine administration and outcomes in out-of-hospital cardiac arrest: SOS-KANTO 2012 study

Objective

This study assessed the association between the timing of first epinephrine administration (EA) and the neurological outcomes following out-of-hospital cardiac arrests (OHCAs) with both initial shockable and non-shockable rhythms.

Recipient hypertonic saline infusion prevents cardiac allograft dysfunction

Objective

Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

实体化创伤中心建设提升严重创伤救治能力

为明确实体化创伤中心建设对提升严重创伤救治能力的作用,笔者以兴义市创伤中心实体化建设后所取得的初步成效,从院内多学科团队建设及核心能力维护、创伤救治流程优化、创伤时间节点质量控制与持续改进等方面进行介绍,为实体化创伤中心建设提供借鉴和参考。     

Motion‐compensated b‐tensor encoding for in vivo cardiac diffusion‐weighted imaging

Motion is a major confound in diffusion‐weighted imaging (DWI) in the body, and it is a common cause of image artefacts. The effects are particularly severe in cardiac applications, due to the nonrigid cyclical deformation of the myocardium. Spin echo‐based DWI commonly employs gradient moment‐nulling techniques to desensitise the acquisition to velocity and acceleration, ie, nulling gradient moments up to the 2nd order (M2‐nulled). However, current M2‐nulled DWI scans are limited to encode diffusion along a single direction at a time. We propose a method for designing b‐tensors of arbitrary shapes, including planar, spherical, prolate and oblate tensors, while nulling gradient moments up to the 2nd order and beyond. The design strategy comprises initialising the diffusion encoding gradients in two encoding blocks about the refocusing pulse, followed by appropriate scaling and rotation, which further enables nulling undesired effects of concomitant gradients. Proof‐of‐concept assessment of in vivo mean diffusivity (MD) was performed using linear and spherical tensor encoding (LTE and STE, respectively) in the hearts of five healthy volunteers. The results of the M2‐nulled STE showed that (a) the sequence was robust to cardiac motion, and (b) MD was higher than that acquired using standard M2‐nulled LTE, where diffusion‐weighting was applied in three orthogonal directions, which may be attributed to the presence of restricted diffusion and microscopic diffusion anisotropy. Provided adequate signal‐to‐noise ratio, STE could significantly shorten estimation of MD compared with the conventional LTE approach. Importantly, our theoretical analysis and the proposed gradient waveform design may be useful in microstructure imaging beyond diffusion tensor imaging where the effects of motion must be suppressed.     

Successful avoidance of superior vena cava injury during transvenous lead extraction using a tandem femoral-superior approach

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The marks of gunshot wounds to the face

IntroductionThis article deals with the occurrence of health problems due to gunshot wounds to the face among military police officers, in the metropolitan region of Rio de Janeiro, who were submitted to surgery at the Oral and Maxillofacial Surgery and Traumatology Clinic of Hospital Central da Polícia Militar.ObjectiveTo identify the profile of patients submitted to surgery as a result of gunshot wounds, the anatomical distribution of maxillofacial fractures, the identified sequelae and complications, the health specialties involved in the rehabilitation of these patients, and to discuss the social, emotional and work performance-related effects of work among these subjects.MethodsA retrospective epidemiological study was carried out based on secondary data from military police officers who were submitted to surgery at Hospital Central da Polícia Militar due to gunshot wounds from June 2003 to December 2017.ResultsDuring the study period, 778 surgeries were performed in the operating room by the Oral and Maxillofacial Surgery and Traumatology service at Hospital Central da Polícia Militar, 186 of which were due to gunshot wounds (23.9%). All patients were males and the mean age 34.7 years. Bone segment loss was the most common sequela. Facial esthetic impairment and reports of insomnia were the most often identified late consequences of impact on health and social life. Regarding the occupational impacts of the sustained injury, the mean time away from work due to medical leave for the treatment of maxillofacial injuries was 11.7 months.ConclusionThe treatment of gunshot wounds patients with facial injuries requires multiple surgical interventions and their rehabilitation requires the involvement of different health specialties. Further studies are needed to qualitatively analyze the impact of this type of facial trauma on the patients' lives and their social consequences.