Conventional Feed-Grade or Slow-Release Coated Urea as Sources of Dietary Nitrogen for Fattening Lambs.

Twenty-two Assaf male lambs (29.2 ± 0.9 kg live weight and 89 ± 0.2 days of age), distributed in two experimental groups, were used to evaluate the use of either feed-grade conventional urea (Control diet; n = 11) or slow-release urea (SRU diet; n = 11) as sources of dietary nitrogen on animal performance, ruminal fermentation, blood acid-base status, plasmatic metabolic profile, and carcass and meat quality. Animals were housed individually and fed ad libitum. At the end of the fattening period (day 70), the animals were slaughtered to compare the fermentation patterns in ruminal digesta and to evaluate the carcass and meat characteristics. No statistically significant differences (p > 0.05) were observed between treatments in the dry matter intake, final live weight, average daily gain, and feed conversion rate. Regarding the ruminal fermentation parameters, the molar proportion of propionic acid was higher (p < 0.05) and that of butyric acid was lower (p < 0.05) with the SRU than with the Control diet. There were no significant differences (p > 0.05) between experimental treatments in the blood acid-base status and biochemical profile, except for the concentration of urea in plasma, which was significantly (p < 0. 05) greater in SRU than in Control lambs. No statistically significant differences were observed between treatments (p > 0.05) in the carcass and meat characteristics. In conclusion, the use of slow-release urea as a replacement for feed-grade conventional urea in the diet of Assaf fattening lambs, under the experimental conditions of this study, did not improve animal performance and increased the feeding costs.

Estratificación de riesgo del dolor torácico en el servicio de urgencia / Risk stratification of chest pain in the emergency department

El dolor torácico es un motivo de consulta frecuente en los servicios de urgencia. Su espectro de presentaciones y su diagnóstico diferencial es amplio, con patologías de elevada morbilidad y mortalidad asociadas. Es el síntoma principal en pacientes con un síndrome coronario agudo y, ante su sospecha es mandatorio realizar una evaluación inicial centrada en la estratificación de riesgo de sufrir eventos adversos en cada paciente, para así definir su tratamiento y disposición posterior de forma correcta. Objetivo: presentar los elementos que componen la evaluación inicial del dolor torácico ante una sospecha de síndrome coronario agudo y las herramientas disponibles para realizar la estratificación de riesgo y así guiar la disposición desde el servicio de urgencia. Método: Se realizó una revisión bibliográfica de la literatura sobre la estratificación de riesgo del dolor torácico, buscando la evidencia actual respecto a las herramientas diagnósticas utilizadas habitualmente en el servicio de urgencia. Resultados: Se presenta una revisión con generalidades del dolor torácico, sus diagnósticos diferenciales, los elementos de la evaluación inicial y las herramientas clínicas para la evaluación de riesgo de pacientes con dolor torácico y sospecha de síndrome coronario agudo en el servicio de urgencia. Discusión y conclusiones: La presentación del síndrome coronario agudo es variable en la población. Ante la presencia de un cuadro de dolor atípico y/o un electrocardiograma no diagnóstico, recomendamos el uso de un sistema de puntaje validado como el HEART / HEART pathway para reducir la posibilidad de una inadecuada estratificación de riesgo en el servicio de urgencia

Chest pain is a common complaint in emergency departments. The spectrum of presentation and its differential diagnosis are broad, including pathologies associated with high morbidity and mortality, and it is the main symptom in patients suffering from acute coronary syndrome. If suspected, it is mandatory to work out an initial evaluation focused on the risk stratification of adverse events for each patient to define their correct treatment and disposition. Objective: show the elements that involve the initial evaluation of chest pain suspicious of an acute coronary syndrome, the clinical tools available to perform risk stratification, and guide the disposition from the emergency department. Method: a review of the literature on chest pain risk stratification was performed, looking for current evidence of the most commonly used diagnostic tools in emergency departments. Results: we present a literature review of generalities about chest pain and its differential diagnoses, the elements to consider in the initial evaluation, and clinical tools for risk stratification of patients with suspected acute coronary syndrome at the emergency department. Discussion and conclusions: the presentation of acute coronary syndrome is variable in the population. In the presence of atypical chest pain or a non-diagnostic electrocardiogram, we recommend using a validated score as the HEART / HEART Pathway to reduce the chance of inadequate risk stratification in the emergency department.

C 1-Symmetric {cyclopentadienyl/indenyl}-metallocene catalysts: synthesis, structure, isospecific polymerization of propylene and stereocontrol mechanism.

A series of new Me2Si-bridged cyclopentadiene/indene proligands {Me2Si(R2',5'2-R3',4'2-Cp)(R2,R4,R5,R6-Ind)H2} (1a-j) with various substitutions both on the indene and cyclopentadiene moieties was prepared. The corresponding C1-symmetric group 4 ansa-metallocene complexes (M = Zr, Hf), namely, {Me2Si(Me4Cp)(Ind)}ZrCl2 (2a-Zr), {Me2Si(Me4Cp)(2-Me,4-Ph-Ind)}MCl2 (2b-M), {Me2Si(Me4Cp)(2-Me,4-Ph,6-tBu-Ind)}ZrCl2 (2c-Zr), {Me2Si(Me4Cp)(2-Me,4-Ph,5-OMe,6-tBu-Ind)}MCl2 (2d-M), {Me2Si(Me4Cp)(2-R',4-(3',5'-tBu2,4'-OMe-C6H2),5-OMe,6-tBu-Ind)}ZrCl2, R' = Me (2e-Zr), R' = Et (2f-Zr), {Me2Si(2,5-Ph2-3,4-Me2-Cp)(2-Me,4-(3',5'-tBu2,4'-OMe-C6H2),5-OMe,6-tBu-Ind)}ZrCl2 (2g-Zr), {Me2Si(Me4Cp)(2-Me,4-(3',6'-tBu2-carbazol-4'-yl)-Ind)}ZrCl2 (2h-Zr), {Me2Si(2,5-Me2,3,4-iPr2-Cp)(2-Me,4-Ph-Ind)}ZrCl2 (2i-Zr), {Me2Si(2,5-Me2,3,4-iPr2-Cp)(2-Me,4-Ph,6-tBu-Ind)}ZrCl2 (2j-Zr) and {Me2Si(Me4Cp)(2-Me-4,5-[a]anthracene-Ind)}MCl2 (2k-Zr) were synthesized and characterized by NMR spectroscopy and mass spectrometry. The solid-state molecular structures of 2b-Zr, 2d-Zr, 2e-Zr, 2f-Zr, 2j-Zr and 2k-Zr were determined by X-ray crystallography. The zirconocene complexes, once activated with MAO in toluene solution, exhibited propylene polymerization activities at 60 °C up to 161 000 kg(PP) mol(Zr)-1 h-1, affording highly isotactic polypropylenes (iPP) with [m]4 up to 96.5% and Tm up to 157 °C. Also, metallocene complexes 2b-e-Zr were supported on SiO2-MAO and evaluated in slurry bulk propylene polymerization at 70 °C, producing iPPs with [m]4 = 91.7-96.6 mol% and low regiodefects (0.2-0.3 mol%) content, with productivities up to 636 000 kg(PP) mol(Zr)-1 h-1. DFT calculations allowed rationalizing a polymerization reaction mechanism occurring through "chain-stationary" enchainment with preference for 1,2-insertions.

Enfrentamiento de la anafilaxia en el servicio de urgencia / Approach of Anaphylaxis in the emergency room

La anafilaxia es una reacción en su mayoría de hipersensibilidad tipo I, que estimula la activación generalizada de mastocitos, y provoca un cuadro clínico multisistémico que puede ser fatal. Se estima que tiene una incidencia de 0,03-0,1% y una prevalencia de vida de 0,5-2% en la población general. Generalmente, la reacción inmunológica ocurre posterior a la ingesta de alimentos, uso de medicamentos o picaduras de insectos, pero también se han descrito mecanismos no inmunológicos (no IgE) que actúan directamente sobre los mastocitos, llamadas en la literatura "reacciones anafilactoideas". La anafilaxia fue descrita por Paul Portier y Charles Robert Richet en 1902 en perros, los cuales desarrollaban esta reacción posterior a la inyección repetida de veneno de anémonas (medusas). Sin embargo, esta entidad no tuvo criterios diagnósticos ni pilares de manejo estructurado hasta el año 2006. En ese año en se publicó el segundo simposio de manejo de la anafilaxia, en donde se definieron criterios diagnósticos clínicos claros y el rol fundamental de la adrenalina en su manejo; la única droga que cambia el pronóstico del paciente.

Anaphylaxis is mainly a type I hypersensitivity reaction. It triggers a widespread activation of mast cells, causing a multisystemic clinical scenario that can be fatal. It is estimated to have an incidence of 0.03-0.1% and a lifetime prevalence of 0.5-2%. Most immunological reactions occur after food ingestion, medication, or insect stings, but non-immunological (non-IgE) mechanisms that act directly on mast cells, called Anaphylactoid Reactions, have been also described. Anaphylaxis was described by Paul Portier and Charles Robert Richet in 1902 in dogs, that developed this disease after repeated injections of anemones (jellyfish) venom. However, this entity didn't have established diagnostic criteria or an standarized management until 2006. In this year, the second anaphylaxis management sym-posium took place and clear clinical diagnostic criteria were defined. The fundamental role of adrenaline in its management was also established. The former is the only drug that has demonstrated to improve prognosis of the patient

Benchmarking Object Detection Deep Learning Models in Embedded Devices.

Object detection is an essential capability for performing complex tasks in robotic applications. Today, deep learning (DL) approaches are the basis of state-of-the-art solutions in computer vision, where they provide very high accuracy albeit with high computational costs. Due to the physical limitations of robotic platforms, embedded devices are not as powerful as desktop computers, and adjustments have to be made to deep learning models before transferring them to robotic applications. This work benchmarks deep learning object detection models in embedded devices. Furthermore, some hardware selection guidelines are included, together with a description of the most relevant features of the two boards selected for this benchmark. Embedded electronic devices integrate a powerful AI co-processor to accelerate DL applications. To take advantage of these co-processors, models must be converted to a specific embedded runtime format. Five quantization levels applied to a collection of DL models are considered; two of them allow the execution of models in the embedded general-purpose CPU and are used as the baseline to assess the improvements obtained when running the same models with the three remaining quantization levels in the AI co-processors. The benchmark procedure is explained in detail, and a comprehensive analysis of the collected data is presented. Finally, the feasibility and challenges of the implementation of embedded object detection applications are discussed.

Immersive virtual-reality computer-assembly serious game to enhance autonomous learning.

Immersive virtual reality (VR) environments create a very strong sense of presence and immersion. Nowadays, especially when student isolation and online autonomous learning is required, such sensations can provide higher satisfaction and learning rates than conventional teaching. However, up until the present, learning outcomes with VR tools have yet to prove their advantageous aspects over conventional teaching. The project presents a VR serious game for teaching concepts associated with computer hardware assembly. These concepts are often included in any undergraduate's introduction to Computer Science. The learning outcomes are evaluated using a pre-test of previous knowledge, a satisfaction/usability test, and a post-test on knowledge acquisition, structured with questions on different knowledge areas. The results of the VR serious game are compared with another two learning methodologies adapted to online learning: (1) an online conventional lecture; and (2) playing the same serious game on a desktop PC. An extensive sample of students (n = 77) was formed for this purpose. The results showed the strong potential of VR serious games to improve student well-being during spells of confinement, due to higher learning satisfaction. Besides, ease of usability and the use of in-game tutorials are directly related with game-user satisfaction and performance. The main novelty of this research is related to academic performance. Although a very limited effect was noted for learning theoretical knowledge with the VR application in comparison with the other methodologies, this effect was significantly improved through visual knowledge, understanding and making connections between different concepts. It can therefore be concluded that the proposed VR serious game has the potential to increase student learning and therefore student satisfaction, by imparting a deeper understanding of the subject matter to students. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10055-021-00607-1.

Combined Noninvasive Respiratory Support Therapies to Treat COVID-19.

BACKGROUND: The roles of high-flow nasal cannula (HFNC) and CPAP in coronavirus disease 2019 (COVID-19) are controversial. The objective of the study was to evaluate the impact of the application of a noninvasive respiratory support algorithm on clinical outcomes in subjects with COVID-19 and with acute respiratory failure. METHODS: We performed a single-center prospective observational study of subjects with respiratory failure from COVID-19 managed with HFNC and with CPAP plus HFNC (combined therapy). The main outcome was the intubation rate, which defined failure of therapy. We also analyzed the role of the ROX index ([[Formula: see text]/[Formula: see text]]/breathing frequency) to predict the need for intubation. RESULTS: From June to December 2020, 113 subjects with COVID-19 respiratory failure were admitted to our respiratory intermediate care unit. HFNC was applied in 65 subjects (57.52%) and combined therapy in 48 subjects (42.47%). A total of 83 subjects (73.45%) were successfully treated with noninvasive respiratory support. The intubation rate was 26.54%, and the overall mortality rate was 14.15%. The mortality rate in subjects who were intubated was 55.2%. An ROX index of 6.28 at 12 h predicted noninvasive respiratory support failure, with 97.6% sensitivity and 51.8% specificity. CONCLUSIONS: Data from our cohort managed in a respiratory intermediate care unit showed that combined noninvasive respiratory support was feasible, with favorable outcomes. Further prospective studies are required.

Endovascular revascularization of chronic total arterial occlusion of the lower limb using the SAFARI technique.

The SAFARI technique or Subintimal Arterial Flossing with Antegrade-Retrograde Intervention is an endovascular procedure that allows recanalization of Chronic Total Occlusive (CTO) lesions when conventional subintimal angioplasty is unsuccessful. Retrograde access is usually obtained through the popliteal, anterior tibial, dorsalis pedis artery, or posterior tibial arteries and may potentially provide more options for endovascular interventions in limb salvage. The case of an 81-year-old man with a history of uncontrolled hypertension, diabetes mellitus, and dyslipidemia is presented. He presented with a cutaneous ulcer on the right lower limb with torpid evolution and poor healing. The Doppler ultrasound and arteriographic study revealed a CTO lesion of the popliteal artery that was not a candidate for antegrade endovascular revascularization, but was successfully treated using the SAFARI technique. The patient had no perioperative complications, the wound showed better healing, and he was discharged with an indication of daily dressings and control by an external outpatient clinic.

A técnica SAFARI, ou Subintimal Arterial Flossing with Antegrade-Retrograde Intervention, é um procedimento endovascular que permite a recanalização de lesões por oclusão total crônica (OTC) em caso de fracasso da angioplastia subintimal convencional. O acesso retrógrado é geralmente obtido através da artéria poplítea, tibial anterior, pediosa ou tibial posterior e pode fornecer mais alternativas de intervenções endovasculares para o salvamento do membro. É apresentado o caso de um homem de 81 anos com histórico de hipertenção não controlada, diabetes melito e dislipidemia. Ele apresentava uma lesão ulcerativa cutânea no membro inferior direito com evolução tórpida e má cicatrização. O ultrassom Doppler e o estudo arteriográfico revelaram uma lesão por OTC na artéria poplítea. O paciente não era candidato a revascularização endovascular anterógrada; sendo assim, esta foi realizada com successo utilizando a técnica SAFARI. O paciente não apresentou complicações perioperatórias e recebeu alta com indicação de cuidados diários com a ferida e controle em um ambulatório externo. Além disso, a ferida apresentou melhor cicatrização.

Endovascular revascularization of chronic total arterial occlusion of the lower limb using the SAFARI technique / Revascularização endovascular utilizando a técnica SAFARI em casos de oclusão arterial total do membro inferior

Abstract The SAFARI technique or Subintimal Arterial Flossing with Antegrade-Retrograde Intervention is an endovascular procedure that allows recanalization of Chronic Total Occlusive (CTO) lesions when conventional subintimal angioplasty is unsuccessful. Retrograde access is usually obtained through the popliteal, anterior tibial, dorsalis pedis artery, or posterior tibial arteries and may potentially provide more options for endovascular interventions in limb salvage. The case of an 81-year-old man with a history of uncontrolled hypertension, diabetes mellitus, and dyslipidemia is presented. He presented with a cutaneous ulcer on the right lower limb with torpid evolution and poor healing. The Doppler ultrasound and arteriographic study revealed a CTO lesion of the popliteal artery that was not a candidate for antegrade endovascular revascularization, but was successfully treated using the SAFARI technique. The patient had no perioperative complications, the wound showed better healing, and he was discharged with an indication of daily dressings and control by an external outpatient clinic.

Resumo A técnica SAFARI, ou Subintimal Arterial Flossing with Antegrade-Retrograde Intervention, é um procedimento endovascular que permite a recanalização de lesões por oclusão total crônica (OTC) em caso de fracasso da angioplastia subintimal convencional. O acesso retrógrado é geralmente obtido através da artéria poplítea, tibial anterior, pediosa ou tibial posterior e pode fornecer mais alternativas de intervenções endovasculares para o salvamento do membro. É apresentado o caso de um homem de 81 anos com histórico de hipertenção não controlada, diabetes melito e dislipidemia. Ele apresentava uma lesão ulcerativa cutânea no membro inferior direito com evolução tórpida e má cicatrização. O ultrassom Doppler e o estudo arteriográfico revelaram uma lesão por OTC na artéria poplítea. O paciente não era candidato a revascularização endovascular anterógrada; sendo assim, esta foi realizada com successo utilizando a técnica SAFARI. O paciente não apresentou complicações perioperatórias e recebeu alta com indicação de cuidados diários com a ferida e controle em um ambulatório externo. Além disso, a ferida apresentou melhor cicatrização.

Prolonged neuropsychiatric effects following management of chloroquine intoxication with psychotropic polypharmacy.

Susceptibility to quinoline antimalarial intoxication may reflect individual genetic and drug-induced variation in neuropharmacokinetics. In this report, we describe a case of chloroquine intoxication that appeared to be prolonged by subsequent use of multiple psychotropic medications. This case highlights important new considerations for the management of quinoline antimalarial intoxication.

Cytokeratin 5/6 fingerprinting in HER2-positive tumors identifies a poor prognosis and trastuzumab-resistant basal-HER2 subtype of breast cancer.

There is an urgent need to refine the prognostic taxonomy of HER2+ breast carcinomas and develop easy-to-use, clinic-based prediction algorithms to distinguish between good- and poor- responders to trastuzumab-based therapy. Building on earlier studies suggesting that HER2+ tumors enriched with molecular and morpho-immunohistochemical features classically ascribed to basal-like tumors are highly aggressive and refractory to trastuzumab, we investigated the prognostic and predictive value of the basal-HER2+ phenotype in HER2-overexpressing tumors. Our retrospective cohort study of a consecutive series of 152 HER2+ primary invasive ductal breast carcinomas first confirmed the existence of a distinct subgroup co-expressing HER2 protein and basal cytokeratin markers CK5/6, the so-called basal-HER2+ phenotype. Basal-HER2+ phenotype (≥10% of cells showing positive CK5/6 staining), but not estrogen receptor status, was significantly associated with inferior overall survival by univariate analysis and predicted worsened disease free survival after accounting for strong prognostic variables such as tumor size at diagnosis in stepwise multivariate analysis. In the sub-cohort of HER2+ patients treated with trastuzumab-based adjuvant/neoadjuvant therapy, basal-HER2+ phenotype was found to be the sole independent prognostic marker for a significantly inferior time to treatment failure in multivariate analysis. A CK5/6-based immunohistochemical fingerprint may provide a simple, rapid, and accurate method for re-classifying women diagnosed with HER2+ breast cancer in a manner that can improve prognosis and therapeutic planning in patients with clinically aggressive basal-HER2+ tumors who are not likely to benefit from trastuzumab-based therapy.

An improved axillary staging system using the OSNA assay does not modify the therapeutic management of breast cancer patients.

The one-step nucleic acid amplification (OSNA) assay is a molecular procedure that can identify deposits of breast cancer (BC) cells in the sentinel lymph node (SLN). We examined the consistency of the OSNA assay with a classic hematoxylin-eosin (H&E)-based immunohistochemistry (IHC) study and evaluated how OSNA-based axillary staging might impact the therapeutic management of BC patients. SLN biopsy results were considered to be positive in 60 patients (40%) in the OSNA group (N = 148) and in 43 (28%) patients in the IHC cohort (N = 153, p = 0.023). There was no difference in the macrometastasis (22% for OSNA, 15% for H&E, p = 0.139) or micrometastasis (19% for OSNA, 13% for H&E, p = 0.166) rates, but we found statistically significant differences in the number of isolated tumor cells (1% for OSNA, 11% for H&E, p < 0.001). There were no differences in the administration rate of adjuvant systemic therapy between the OSNA (66% in the SLN(+) patients) and the H&E (74% in the SLN(+) patients) groups (p = 0.159). The OSNA assay allows for the detection of SLN metastases more precisely than conventional pathologic methods but does not alter the therapeutic management of SLN(+) BC patients.

Prognostic value of plasmatic tumor M2 pyruvate kinase and carcinoembryonic antigen in the survival of colorectal cancer patients.

Colorectal cancer (CRC) can be cured in most cases if diagnosed at an early stage. Carcinoembryonic antigen (CEA) remains the most widely used cancer marker for determining prognosis of CRC. Previous studies have shown that plasmatic tumor M2 pyruvate kinase (Tu M2-PK) is highly sensitive in CRC detection at an early stage and equally as good as the results for established tumor markers with clinical potential for cancer prognosis and monitoring. The aim of this study was to assess the prognostic value of Tu M2-PK in plasma using a survival analysis in combination with CEA in serum in patients newly diagnosed with CRC. The initial study included 183 patients who had a complete diagnostic colonoscopy. This cohort study was designed to evaluate the survival in patients with histologically confirmed gastrointestinal cancers (n = 41). Tu M2-PK concentrations in EDTA plasma were determined immunologically using an ELISA assay. Plasma Tu M2-PK levels were significantly higher in patients with distant metastases, stage IV for TNM score, and advanced stage (C+D) subgroups of Dukes than other subgroups. The univariate Cox's analysis showed that CEA and Tu M2-PK gave high hazard ratios for risk of death (odds ratio CEA = 3.57 and odds ratioTu M2-PK = 2.23) and comparable values in average survival time. The results for both biomarkers did not overlap. These findings suggest that plasmatic Tu M2-PK levels of more than 20 U/mL may be a predictor of death risk.

[Gastric pneumatosis and gas in the portal venous system secondary to peptic ulcer]. / Neumatosis gástrica y gas en el sistema venoso portal secundario a una úlcera péptica.

A 72-year-old woman presented to the emergency department with recurrent vomiting without abdominal pain. On physical examination, the patient was afebrile and her abdomen was soft and nontender with a giant abdominal-wall hernia. Upper endoscopy showed a deep, 3-cm ulcer at the gastric angulus. Computed tomography (CT) of the abdomen showed gastric dilatation with gas in the wall and a large part of the digestive tract within the hernia sac. CT imaging also revealed gas throughout the portal venous system. The patient declined surgery. Management was conservative and included correction of fluid and electrolyte balance, and nasogastric drainage for gastric decompression with good response.

Neumatosis gástrica y gas en el sistema venoso portal secundario a una úlcera péptica / Gastric pneumatosis and gas in the portal venous system secondary to peptic ulcer

Presentamos el caso de una mujer de 72 años, que acudió aurgencias tras presentar vómitos de repetición, sin dolor abdominal.En la exploración presentaba una gran hernia abdominalsin datos de complicación, no dolorosa y afebril. Laendoscopia digestiva alta (EDA) mostró una úlcera profundade unos 3 cm de tamaño en la incisura angularis. En latomografía computarizada abdominal se apreció una dilatacióngástrica, con neumatosis de toda la pared y gas en elsistema venoso portal. La paciente rechazó el tratamientoquirúrgico de la hernia abdominal. Se realizó un tratamientoconservador con reposición de volumen y del balanceelectrolítico, y una descompresión gástrica con sonda nasogástrica,con buena respuesta por parte de la paciente

A 72-year-old woman presented to the emergency departmentwith recurrent vomiting without abdominal pain. Onphysical examination, the patient was afebrile and her abdomenwas soft and nontender with a giant abdominal-wallhernia. Upper endoscopy showed a deep, 3-cm ulcer at thegastric angulus. Computed tomography (CT) of the abdomenshowed gastric dilatation with gas in the wall and a largepart of the digestive tract within the hernia sac. CT imagingalso revealed gas throughout the portal venous system.The patient declined surgery. Management was conservativeand included correction of fluid and electrolyte balance, andnasogastric drainage for gastric decompression with goodresponse

[Diagnostic value of colonoscopy indication as predictor of colorectal cancer: is it possible to design a fast track diagnosis?]. / Valor de la indicación de la colonoscopia como predictor de diagnóstico de cáncer colorrectal. Se puede diseñar un circuito rápido de diagnóstico?

BACKGROUND: Diagnostic delay in patients with colorectal cancer (CRC) is a quality indicator and its reduction could improve prognosis of the disease. OBJECTIVE: To analyze the diagnostic value of different colonoscopy indications in CRC and to select the signs or symptoms that, if prioritized in a rapid diagnostic circuit, would be most efficient. MATERIAL AND METHODS: A retrospective analysis of 2219 outpatients who underwent colonoscopy from 2000 to 2007 was performed. For each indication we calculated the sensitivity (S), positive predictive value (PPV), positive likelihood ratio (LR+), and number of colonoscopies needed to diagnose a case of CRC (NND). RESULTS: A total of 179 patients were diagnosed with CRC. The indications with greatest PPV were liver metastases (35.3%), suspicious radiological image (20.8%), and non-distal rectal bleeding (22%). Iron deficiency anemia (11%), constitutional syndrome (10%), any rectal bleeding (9.4%) and rectal syndrome (9%) had intermediate PPV. Constipation (6.3%), alternating constipation-diarrhea (3.3%), changes in bowel habits (3%), distal rectal bleeding (2.1%), diarrhea (1.8%) and abdominal pain (1.1%) had low PPV. The NND was 4 in liver metastases, 7 in non-distal bleeding and 8 in suspicious radiological image. Distal bleeding (13), diarrhea (14), abdominal pain (14), changes in bowel habits (15) and alternating constipation-diarrhoea (21) had negative NND. The subgroup of patients aged >or= 50 years showed lower NND in non-distal rectal bleeding (5), suspicious radiological image (5) and any rectal bleeding (16). CONCLUSIONS: Patients with non-distal rectal bleeding should be prioritized over other indications in a strategy of rapid diagnosis of CRC. Age equal to or more than 50 years should also be considered because this factor seems to reduce NND. Distal bleeding, abdominal pain and changes in bowel habits had low PPV and were associated with other diagnoses than CRC. Consequently, prioritization of these factors would be inefficient.