Estimating density limits for walking pedestrians keeping a safe interpersonal distancing.

With people trying to keep a safe distance from others due to the COVID-19 outbreak, the way in which pedestrians walk has completely changed since the pandemic broke out1,2. In this work, laboratory experiments demonstrate the effect of several variables-such as the pedestrian density, the walking speed and the prescribed safety distance-on the interpersonal distance established when people move within relatively dense crowds. Notably, we observe that the density should not be higher than 0.16 pedestrians per square meter (around 6 m2 per pedestrian) in order to guarantee an interpersonal distance of 1 m. Although the extrapolation of our findings to other more realistic scenarios is not straightforward, they can be used as a first approach to establish density restrictions in urban and architectonic spaces based on scientific evidence.

Pedestrian evacuation simulation in the presence of an obstacle using self-propelled spherocylinders.

We explore the role that the obstacle position plays in the evacuation time of agents when leaving a room. To this end, we simulate a system of nonsymmetric spherocylinders that have a prescribed desired velocity and angular orientation. In this way, we reproduce the nonmonotonous dependence of the pedestrian flow rate on the obstacle distance to the door. For short distances, the obstacle delays the evacuation because the exit size is effectively reduced; i.e., the distance between the obstacle and the wall is smaller than the door width. By increasing the obstacle distance to the door, clogging is reduced leading to an optimal obstacle position (maximum flow rate) in agreement with results reported in numerical simulations of pedestrian evacuations and granular flows. For further locations, however, a counterintuitive behavior occurs as the flow rate values fall again below the one corresponding to the case without obstacle. Analyzing the head-times distribution, we evidence that this new feature is not linked to the formation of clogs, but is caused by a reduction of the efficiency of the agent's instantaneous flow rate when the exit is not blocked.

[Sexual assault]. / Agresión sexual.

Offences involving sexual assault are an issue of the greatest current interest in different social fields (legal, medical, police, criminological...). They are significant due to their frequency and to the legal, physical and psychological repercussions involved. It is therefore important to clearly understand the pattern of action in Accidents and Emergencies facing such cases. Great detail is required in the gynaecological report and the taking of samples, prophylaxes for sexually transmitted diseases and unwanted pregnancies must be given and psychological support provided.

[Idiopathic spontaneous pneumothorax: treatment by small-caliber catheter aspiration compared to drainage through a chest tube]. / Neumotórax espontáneo idiopático: tratamiento basado en la aspiración con catéter fino frente a drenaje torácico.

BACKGROUND: Several options are available for treating patients with a first episode of primary spontaneous pneumothorax (ISP). The aim of this study was to compare the efficacy of two treatment alternatives: puncture-aspiration (PA) using a small caliber catheter, and pleural drainage through a chest tube (DCT). PATIENTS AND METHODS: We compared a current series of 91 patients treated with PA with a retrospective series of 216 patients treated with DCT. PA was performed by emergency room physicians and DCT was performed by chest surgeons. Patients were followed for a period of 24 months. RESULTS: The immediate efficacy of PA was superior to DCT (86.7% versus 76%, p < 0.05). The proportion of recurrences after each treatment was similar (23% and 17%, respectively, NS). Duration of hospital stay was shorter for PA-treated patients (24 h) than for DCT-treated patients (138 h) (p < 0.05). The efficacy of the two procedures 24 months later was similar (63.7% and 62.9%, respectively, NS), and the cost of PA was three times less than that of DCT. CONCLUSIONS: PA is as effective a treatment procedure as DCT. PA is simple enough for emergency room physicians to perform correctly. Inconvenience to the patient, cost to the health care system, and time of hospital stay are all significantly less with PA.

Adult celiac disease and hypertransaminasemia.

OBJECTIVE: to determine the incidence of hypertransaminasemia in adult patients with celiac disease with or without relevant chronic liver disease, and to evaluate the response after a gluten-free diet. PATIENTS AND METHODS: retrospective study of 20 cases of adult celiac disease (> 14 years old at diagnosis). Patients were included in the study if they fulfilled the revised EPSGAN criteria. If laboratory tests of liver function revealed alterations, hepatitis B and C viral serology, thyroid hormones, and use of alcohol and drugs were investigated, and liver ultrasound scans were done. Liver biopsy and endoscopic retrograde cholangiopancreatography were done only in patients for whom these studies were considered necessary. RESULTS: ten patients had hypertransaminasemia (50%), ascribed to benzodiazepine use in 1 patient, chronic HCV hepatitis in 1, and celiac disease in 8. In all of these last patients except 1 (benzodiazepine use), laboratory values returned to normal after 4-10 months on a gluten-free diet. CONCLUSIONS: celiac disease was frequently associated with hypertransaminasemia. In most patients transaminase levels returned to normal within 1 year after dietary gluten intake was restricted. If alterations in laboratory values persist, other causes that may be related (e.g., autoimmunity or tumors) or unrelated to celiac disease (e.g., virus) must be ruled out.

[Arteriovenous malformation of the superior mesenteric artery with secondary portal hypertension]. / Malformación arteriovenosa de la mesentérica superior con hiperaflujo e hipertensión portal secundaria.

The case of a 60-year-old patient who was repeatedly admitted for ascitic decompensation secondary to hyperflow portal hypertension provoked by congenital arteriovenous malformation of the superior mesenteric artery is presented. Diagnosis was performed by arteriography. Surgical treatment was conducted with total resection of the malformation thereby achieving complete resolution and normalization of portal pressure. The literature is reviewed and the pathophysiologic mechanism as well as the clinical manifestations, diagnosis and treatment are discussed.

[Clinical and radiological diagnosis of neurocysticercosis: a case report]. / Diagnóstico clínico-radiológico de neurocisticercosis: a propósito de un caso.

BACKGROUND: Neurocysticercosis is the most frequent parasitic disease of the central nervous system and the first cause of acquired epilepsy in endemic areas. Our aim in is to use clinical and radiological criteria to orientate diagnosis where there is suspicion of neurocysticercosis, presenting a clinical case as an example. MATERIALS AND METHODS: We present the case of a 43 year old woman of Bolivian origin, who came to accidents and emergencies after suffering a generalized convulsive crisis, witnessed by relatives of the patient. RESULTS: A cranial computerized axial tomography was taken, which together with her clinical history led to suspicion of neurocysticercosis. She was admitted to the neurosurgery department for completion of the study, which confirmed the diagnosis of suspicion. She received treatment with albendazol and corticoids, with a good evolution. CONCLUSIONS: Neurocysticercosis is an emergent pathology in developed countries, due to the increase of immigration from endemic areas, mainly from Latin America. Epilepsy is the most frequent clinical expression, but presentation can vary greatly. A high degree of suspicion is necessary in order to be able to diagnose this disease.

[Validation of the Ottawa ankle rules for the efficient utilization of radiographies in acute lesions of the ankle]. / Validación de las reglas del tobillo de Ottawa para el uso eficiente de radiografías en las lesiones agudas de tobillo.

OBJECTIVE: To test the validity of Ottawa ankle rules (OAR) in our field. To test the agreement physician/nurse in the assessment of the patient with acute ankle injuries. DESIGN: Observational, with application of rules and prospective outcome measurement. SETTING: Hospital emergency departments. PARTICIPANTS: Adults who attended at the emergency department, suffering from a secondary ankle pain to a traumatic injury, from 1st March to 30th September, 1997. MEASUREMENTS AND MAIN RESULTS: Physicians who participated applied the OAR to the patients and asked for a control radiograph, independently from the result of rules application. 100 patients were valued by a physician and a nurse in order to measure the agreement level. Data from 564 patients were recorded, getting a global sensitivity of the OAR of 97.3% (95% CI 89.7-99.5); specificity of 33.3% (95% CI 29.5-37.3). The positive predictive value was of 15.6 (95% CI 12.4-19.3). Thanks to the application of the rules radiography would reduce by 29.5%. 74 (13.1%) patients suffered form fracture: 48 (8.5%), of the maleolar zone and 26 (4.6%) of the midfoot zone. Attending to the OAR criteria, radiographs wouldn't be necessary in two cases of fracture. CONCLUSIONS: We consider the OAR clinically valuable and useful in our field. They can help to work on the basis of uniform criteria when decisions must be taken and to use properly sanitary resources. Triage nurses can apply them.