Scielo RSS <![CDATA[Revista médica de Chile]]> https://scielo.conicyt.cl/rss.php?pid=0034-988720070004&lang=es vol. 135 num. 4 lang. es <![CDATA[SciELO Logo]]> https://scielo.conicyt.cl/img/en/fbpelogp.gif https://scielo.conicyt.cl <![CDATA[<b>Honestidad y buena fe</b>: <b>dos pilares en la ética de las publicaciones biomédicas</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400001&lng=es&nrm=iso&tlng=es The editors of medical journals should take the steps necessary to assure its readers that the contents of their publications are based in true data, that they are original and fulfill the ethical rules of biomedical and clinical research, including its reporting. This editors’ role has become increasingly difficult since the pressure to publish scientific papers is progressively stimulated by the role that those papers play in curricula vitae when the authors apply for university positions, academic promotions, research grants and for their personal prestige. As a consequence, increasing instances of misconduct in scientific publications are detected. Some cases are noticed during the editorial process, mostly when peer reviewers identify redundant publications or plagiarism. Other cases are denounced after a manuscript was published. It is the editors’ duty to verify the misconduct, request an explanation from the authors and, if their answer is unsatisfactory, report the problem to the institutional authorities supporting the authors. The editors should denounce the situation in a forthcoming issue of the journal. Universities should enforce the teaching of ethical rules that govern the report of scientific information. Revista Médica de Chile follows recommendations given by the International Committee of Medical Journal Editors, the World Association of Medical Editors and other groups, but honesty and good faith in all the actors involved in the process of biomedical publications (authors, reviewers, editors) remain the cornerstones of scientific good behavior <![CDATA[<b>¿Son los niveles de prolactina y estradiol al tercer mes posparto factores predictores del tiempo de aparición de la primera menstruación posparto?</b>: <b>Modelo predictivo mediante análisis de sobrevida</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400002&lng=es&nrm=iso&tlng=es Background: The variability in the duration of lactational amenorrhoea (LA) lead to develop statistical multivariate models to predict the risk of the appearance of the first postpartum menstruation. Aim: To estimate the probability of recovering the first postpartum menstruation by means of a survival analysis, including hormonal levels and other parameters as predictor variables. Material and Methods: Eighty one mothers in exclusive breastfeeding until the sixth postpartum month, in whom estradiol, basal and post suckling prolactin were measured at the third post partum month, were studied. The variables that better predict the appearance of the first menstruation between the 3rd and 12th postpartum months, were identified using a Cox model survival analysis. Results: The median amenorrhea survival time (the lapse when the chance of recovering menstruation is 50%) was 209 days from delivery. Dichotomized estradiol and post suckling prolactin were the only significant variables that predicted the return of menstruation, with cutoff points of 190 pmol/ and 2,550 mIU/L, respectively. Conclusions: Post suckling prolantin and estradiol levels, measured at the third post partum month, are predictors for the time of appearance of the first postpartum menstruation <![CDATA[<b>¿Es curable el cáncer de mama en etapa precoz?</b>: <b>Resultados del tratamiento combinado con cirugía, radioterapia y quimioterapia</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400003&lng=es&nrm=iso&tlng=es Background: Breast cancer will develop in one out of ten women during their lifetime. Early diagnosis has increased in recent years. Aim: To describe a population of women with breast cancer stage T1N0M0. To analyze radiation therapy toxicity and to evaluate treatment results. Material and methods: Retrospective review of the medical records of 125 women (aged 35 to 80 years) with breast cancer T1N0M0, that were treated between January 1997 and May 2004, with breast conserving surgery and postoperative radiation therapy at an oncology center. Patients lost from follow up were contacted by telephone. Results: An abnormal screening mammography was the reason for consult in 62% of cases. The average tumor size was 11.6 mm. Tumors detected with screening mammogram were smaller than those detected on physical exam. The most common radiotherapy toxicity was erithema, which was severe in 2.5% of cases. No patient had to stop the radiation treatment due to toxicity. One patient developed arm edema. Tamoxifen was prescribed for 5 years to 80% of patients and 17 patients received chemotherapy. After an average follow up of 40 months, no patient has developed local breast relapse, three patients developed contralateral breast cancer and three developed distant metastasis. Two patients died from breast cancer. Disease free survival was 95%. Conclusions: Radiotherapy was well tolerated and had excellent local control. Screening mammography detects small tumors. Survival is excellent for early stage breast cancer <![CDATA[<b>Subdiagnóstico</b><b> de restricción de crecimiento fetal mediante la aplicación de las curvas de crecimiento intrauterino del Ministerio de Salud</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400004&lng=es&nrm=iso&tlng=es Background: Fetal growth restriction (FGR) is associated with increased risk of perinatal morbidity or death. Nationwide implementation of new fetal growth charts, requires a lower fetal weight for the diagnosis of FGR, compared to previous ones. This may lead to an under diagnosis of FGR in a large proportion of neonates. Aim: To compare the morbidity, mortality and anthropometry of neonates with FGR, diagnosed by MINSAL and Juez curves, with normal weight newborns in the same period (2000-2004). Material and methods: Revision of medical records of all births occurring in a maternity hospital between 2000 and 2004. The number of neonatal deaths, and the presence of hyperbilirubinemia, polyglobulia, hypoglycemia and hypothermia, were compared among children classified to be below percentile 10 of fetal growth according to both growth charts. Results: FGR was diagnosed in 4,4% (502/11.289) and 9% (1.029/11.289) of newborns by MINSAL and Juez curves respectively. Compared to normal weight controls, the 527 newborns without FGR according to MINSAL curves, but below percentile 10 of Juez curves, had an odds ratio (OR) for polyglobulina of 8.14 (95% confidence intervals (CI): 1.01-65.34), an OR for neonatal hypoglycemia of 5.10 (95% CI: 1.11-23.39) and an OR for a ponderal index below 10th percentile of 10.98 (95% CI: 6.84-17.64). Conclusions: Newborns without a diagnosis of FGR by MINSAL curves but below 10th percentile by Juez curves, have neonatal outcomes suggesting a true FGR. Juez curves should be maintained as a standard for the evaluation of fetal growth in our population <![CDATA[<b>Seroprevalencia de anticuerpos IgG contra parvovirus B19 en donantes de sangre de hospitales en Santiago, Chile</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400005&lng=es&nrm=iso&tlng=es Background: Parvovirus B19 (B19) is associated with a wide range of disease manifestations, whose severity depends on the immunological and hematological status of the host. Infection with B19 has been reported worldwide and the prevalence of immunoglobulin G antibodies against B19 increases with age and varies by location and time of the last B19 epidemic. Aim: To evaluate the prevalence of IgG antibodies against Parvavirus B19 virus in a population of volunteer blood donors at two hospital blood banks in Santiago, Chile. Material and Methods: A total of 400 serum samples from blood donors aged 18 to 65 years, were examined for the presence of IgG antibodies against Parvovirus B19. Results: The overall prevalence of IgG antibodies was 54.8%. No significant difference was found between men and women (57.6% and 49.3%, respectively). Conclusions: IgG antibody seroprevalence against Parvovirus B19, was 55% in this sample of Chilean blood donors. This figure is in agreement with previous reports from abroad <![CDATA[<b>Descripción del consumo de drogas lícitas e ilícitas por género a través de la metodología de pares</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400006&lng=es&nrm=iso&tlng=es Background: It is possible that men consume a higher amount of legal and illegal drugs than women. This can be assessed using the peer methodology, that is an adaptation of the privileged access interviewers (PAI) method and allows to identify populations in which there may be a tendency to under state a phenomenon (hidden populations) Aim: To compare the consumption of legal and illegal drugs by gender. Material and methods: Drug consumption was assessed using a peer methodology in university students between 18 and 26 years of age. Results: A random sample of 56 women (mean age 21.6 years) and 86 men (mean age 21.5 years), was studied. Women tended to report a higher proportion of tobacco consumption than men. Both genders had a similar consumption behavior of alcohol, total legal drugs, marihuana, cocaine, ecstasies and total illegal drugs. Among subjects that recognized the consumption of legal drugs, men have a higher proportion of illicit drug use and women have a higher proportion of smoking. Men have a higher awareness of the damages caused by drug consumption. Conclusions: The results in these small population sample do not support the hypothesis that men have a higher frequency and proportion of illicit drug consumption <![CDATA[<b>Consejería a adolescentes</b>: <b>descripción epidemiológica y motivos de consulta</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400007&lng=es&nrm=iso&tlng=es Background: Teenager counseling to recognize risks and reinforce strengths is carried out in a primary care outpatient clinic since 2003. Aim: To describe the epidemiology and causes for consultation in this teenage counseling program. Material and methods: Retrospective review of the records of 116 teenagers (median age 13 years, 67% females) that received teenager counseling. Results: Seventy percent of women and 50% of men came from nuclear families. More than two thirds were primogenital. Most adolescents were accompanied by their mother, that were the main adult raw model. Fifty percent had dysfunctional families. All were attending school regularly and 21% of women and 29% of men had repeated a school level. Sixty eight percent of women and 62% of men declared to have a life project. Twenty percent were worried about their physical appearance. Seventy seven percent of women and 62% of men considered themselves as “happy”. Thirty six percent of women and 14% of men smoked. The figures for alcohol consumption were 21% and 14%, respectively. The causes for consultation were obesity, overweight, unspecific symptoms, behavioral problems, bad school achievement, communication problems or pregnancy. Reasons for counseling were family dysfunction, low self esteem, bad school achievement and information about sexuality. Conclusions: The information obtained could help to improve the interdisciplinary work and to coordinate counseling with the family and schools <![CDATA[<b>Resultados inmediatos y tardíos de la miotomía de Heller laparoscópica en pacientes con acalasia esofágica</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400008&lng=es&nrm=iso&tlng=es Background: Achalasia is characterized by an incomplete relaxation of the lower esophageal sphincter. The best treatment is surgical and the laparoscopic approach may have good results. Aim: To assess the results of laparoscopic Heller myotomy among patients with achalasia. Material and methods: Prospective study of patients subjected to a laparoscopic Heller myotomy between 1995 and 2004. Clinical features, early and late operative results were assessed. Results: Twenty seven patients aged 12 to 74 years (12 females) were operated. All had disphagia lasting for a mean of 32 months. Mean lower esophageal sphincter pressure ranged from 18 to 85 mmHg. Eight patients received other treatments prior to surgery but symptoms persisted or reappeared. The preoperative clinical score was 7. No patient died and no procedure had to be converted to open surgery. In a follow up of 21 to 131 months, all patients are satisfied with the surgical results and the postoperative clinical score is 1. Only one patient with a mega esophagus maintained a clinical score of six. Conclusions: In this series of patients, laparoscopic Heller myotomy was an effective and safe treatment for esophageal achalasia <![CDATA[<b>¿Explicitan los autores de la <i>Revista Médica</i><i> de Chile </i>sus fuentes de financiamiento?</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400009&lng=es&nrm=iso&tlng=es Background: Financial relationships between the industry and researchers have raised concerns about the existence of conflicts of interest that could influence the scientific validity of the studies. Aim: To determine the financial sources of research articles published in the Revista Médica de Chile during a five-year period. Material and Methods: Retrospective analysis of all articles classified as “research articles”, published in this journal between years 2001-2005, identifying the funding source and the existence of a declaration of conflicts of interest by the authors. Results: Two hundred seventeen out of 519 research articles published in the period (42%) had an explicit financial source disclosed. Of these, 28% were funded by internal sources, 36% by Fondo Nacional de Desarrollo Científico y Tecnológico and 36% by other sources. Twenty-six studies (5%) received funding from the industry. In only five of these, the authors explicity declared the absence of conflict of interest. Among the studies that did not disclose any financial source, one third required some funding to be carried out. Conclusions: Forty two percent of research articles published in the last five years did not specify the financial source. Those that did specify a funding source were mainly supported by non-profit agencies including university centers and governmental funds. This is in contrast with international reports that evidence an important financial support from the industry. Only a minority of the authors sponsored by the industry declared absence of conflict of interest <![CDATA[<b>Análisis del factor de impacto de las revistas científicas latinoamericanas</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400010&lng=es&nrm=iso&tlng=es Background: Latin American medical journals have a low impact factor. Higher quality articles originated in Latin American countries are published in North American or European journals. Aim: To analyze the impact factor of Latin-American journals according to the language of publication. Material and methods: The data base of periodic journals of the Thomson ISI (Journal of Citation Report) in the year 2004 was used for the analysis. Four countries with more than one journal in the data base of the Thomson ISI were included (Argentina, Brazil, Chile and Mexico). Results: Few Latin-American journals are included in the Thomson ISI data base. The mean impact factor was 0.76 (0.23-3.2) for eight Mexican journals, 0.66 (0.10-2.1) for eight Chilean journals, 0.39 (0.06-0.7) for five Argentinian journals and 0.41 (0.09-1.1) for 16 Brazilian journals. The mean impact factor for 11 journals written in English was 0.74 (0.12-2.1), 0.53 (0.09-3.2) for 18 bilingual journals and 0.28 (0.06-0.56) for eight journals written in native language. The differences between countries and languages were not statistically significant. Conclusions: The journal impact factor was similar in the four countries studied. A non-significant higher impact factor was observed in Latin-American journals published in English <![CDATA[<b>Validez factorial del cuestionario de expectativas hacia el consumo de alcohol (AEQ-III), en adultos de Bucaramanga, Colombia</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400011&lng=es&nrm=iso&tlng=es Background: Alcohol consumption is associated to expectancies of global positive behavioral changes, improvement in sexual performance and a higher level assertiveness. These issues are evaluated by the Alcohol Expectancy Questionnaire (AEQ-III). Aim: To perform a factorial validation of the Alcohol Expectancy Questionnaire (AEQ-III). Materials and methods: The questionnaire was applied to a representative sample of 601 subjects aged 18 to 60 years (334 males). These subjects also answered a socioeconomic questionnaire. The significant variables of the questionnaire were selected using an exploratory factorial analysis. Based on the selected variables, the verification was performed using multiple models of structural equations. Four factors, namely “decrease in physical tension”, “decrease in psychological tension”, “increase in expressivity and sexuality” and “inhibition and feelings of power”, were identified as significant. Results: The factorial solution explains 59% of the variance. All the factors are conceptually and statistically consistent, with a Cronbach alpha ranging between 0.75 and 0.83. The global internal consistency was of 0.85. Pearson correlation coefficient among factors ranged between 0.45 and 0.74. There was a significant difference among socioeconomic levels for the factors “lack of inhibition and feelings of power” and “decrease of psychological tension”. Goodness of fit statistics and parsimony were high, ranging from 0.80 to 0.93. Conclusions: The expectancy “decrease of physical tension” and “decrease of psychological tension” are a part of individual behavior and could predict problem drinking. The factors “increase of expressiveness and sexuality” and “lack of inhibition and feelings of power”, are more associated to group behaviors <![CDATA[<b>Edema pulmonar agudo por uso de tiazidas, ¿existe falla cardíaca?</b>: <b>Comunicación de un caso</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400012&lng=es&nrm=iso&tlng=es Acute pulmonary edema caused by thiazides is uncommon and of difficult diagnosis. It is considered an idiosyncratic reaction and the physiopathology or cardiac function changes are not well known. We report a 60 year-old female with a thiazide induced acute pulmonary edema who was followed with serial measurements of type B n-terminal natriuretic peptide fraction as marker for cardiac dysfunction. There was a significant elevation of the peptide, not associated to evidences of ventricular dysfunction. Its normalization paralleled the resolution of the clinical picture <![CDATA[<b>Feocromocitoma</b>: <b>punción y drenaje percutáneo precirugía en un caso que se presentó como absceso retroperitoneal</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400013&lng=es&nrm=iso&tlng=es We report a 57 year-old woman with a big partially cystic adrenal pheochromocytoma presenting with high fever and abdominal pain. Based on CT scan images and before knowing urinary catecholamines level, the diagnosis of sepsis secondary to an abscessed adrenal macrotumor was done. A diagnostic percutaneous fine-needle puncture and aspiration was done and antibiotic therapy was started. One week later an open surgical drainage and installation of percutaneous drainage tubes was carried out. Both procedures were uneventful and the patient improved dramatically. Three months later a definitive excision surgery was done. After 14 months of follow up, the patient is in excellent conditions and her abdominal CT scan is normal <![CDATA[<b>Tiroglobulina y sus limitaciones en el seguimiento del carcinoma diferenciado del tiroides</b>: <b><i>Report of two cases</i></b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400014&lng=es&nrm=iso&tlng=es Thyroid carcinoma is the most prevalent endocrine tumor, and the papillary carcinoma (PC) is the most common histological type. In the follow-up, after thyroidectomy serum thyroglobulin (s-Tg) is used as a marker to evaluate recurrence of thyroid carcinoma. In most cases, this parameter allows an adequate diagnosis, but occasionally s-Tg may miss the detection of a recurrence. We report a 57 year-old female and a 36 year-old male sujected to a total thyroidectomy for a papillary thyroid carcinoma with intermediate and high-risk of recurrence. Both had a cervical recurrence without a concomitant increase in s-Tg levels. In both, Tg staining was positive in the tumor cells. These cases confirm that in these patients, the follow-up must be done with measurement of s-Tg and complementary diagnostic tests <![CDATA[<b>Gastrectomía laparoscópica en cáncer gástrico</b>: <b>Experiencia preliminar</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400015&lng=es&nrm=iso&tlng=es Background: The development of the laparoscopic surgery has allowed its incorporation to the surgical treatment of gastric cancer. Aim: To evaluate the feasibility and safety of laparoscopic gastrectomy in gastric cancer in our institution. Patients and methods: Prospective data in four patients who underwent laparoscopic gastrectomy for gastric cancer from May to August of 2005 was reviewed. Demographic data, clinical characteristics and postoperative results were registered. Patients were staged according to TNM-AJJC staging system. Results: Four patients aged 48 to 80 years (three males), underwent a completely laparoscopic R0 gastrectomy with lymph node dissection. Two patients underwent total gastrectomy. A subtotal Billroth II gastrectomy was performed in the other two patients. The mean operative time was 260 minutes (Range 180-330). There were no conversions to open surgery. The mean postoperative hospital stay was 6.5 days (Range 6-7 days). There were no complications. According to pathology, one patient presented carcinoma in stage IA, two patients in stage IB and one patient in stage IIIB. The mean number of lymph nodes dissected was 40 (Range 35-54). Conclusions: Laparoscopic gastrectomy is a feasible procedure with good postoperative results in this preliminary experience <![CDATA[<b>Valor predictivo de la historia clínica y el examen físico en el diagnóstico de la neumonía del adulto adquirida en la comunidad</b>: <b>Revisión de la literatura</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400016&lng=es&nrm=iso&tlng=es Distinguishing pneumonia from other causes of respiratory illnesses, such as bronchitis, influenza and upper respiratory tract infections, has important therapeutic and prognostic implications. This decision is usually made by clinical assessment alone or by performing a chest x-ray. The reference standard for diagnosing pneumonia is chest radiography, but many physicians rely on history and physical examination to diagnose or exclude this disease. A review of published studies of patients suspected of having pneumonia reveals that there are no individual clinical findings, or combination of findings, that can predict with certainty the diagnosis of pneumonia. Prediction rules have been recommended to guide the order of diagnostic tests, to maximize their clinical utility. Thus, some studies have shown that the absence of any vital sign abnormalities or any abnormalities on chest auscultation substantially reduces the likelihood of pneumonia to a point where further diagnostic evaluation may be unnecessary. This article reviews the literature on the appropriate use of the history and physical examination in diagnose community-acquired pneumonia <![CDATA[<b>Ética de las publicaciones en revistas médicas</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400017&lng=es&nrm=iso&tlng=es Authors of clinical articles have similar motivations and rules than authors in other scientific fields. In addition, medical research must obey specific ethical rules that apply to studies involving human subjects, including biological samples, tissues, cellular or sub cellular samples obtained from them. When submitting their reports for publication, authors must declare that they have followed such ethical rules and also should declare any possible conflict of interest that may have arisen. External peer reviewers and the editors should also conform to limitations by eventual conflicts of interest. Authors should respect specific ethical norms that apply to the process of submitting, publishing and reproducing their manuscripts. In recent years, the editors of Revista Médica de Chile have become aware of five instances of misconduct committed by authors of articles submitted or already published. Four correspond to redundant publications and one exhibits overt plagiarism in the text and syntax. Appropriate actions have been taken following recommendations published by the International Committee of Medical Journal Editors, the World Association of Medical Editors and other groups. The present article stresses that authors and their sponsoring institutions must be aware of the importance of following ethical rules when reporting scientific work <![CDATA[<b>El proceso diagnóstico</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400018&lng=es&nrm=iso&tlng=es Authors of clinical articles have similar motivations and rules than authors in other scientific fields. In addition, medical research must obey specific ethical rules that apply to studies involving human subjects, including biological samples, tissues, cellular or sub cellular samples obtained from them. When submitting their reports for publication, authors must declare that they have followed such ethical rules and also should declare any possible conflict of interest that may have arisen. External peer reviewers and the editors should also conform to limitations by eventual conflicts of interest. Authors should respect specific ethical norms that apply to the process of submitting, publishing and reproducing their manuscripts. In recent years, the editors of Revista Médica de Chile have become aware of five instances of misconduct committed by authors of articles submitted or already published. Four correspond to redundant publications and one exhibits overt plagiarism in the text and syntax. Appropriate actions have been taken following recommendations published by the International Committee of Medical Journal Editors, the World Association of Medical Editors and other groups. The present article stresses that authors and their sponsoring institutions must be aware of the importance of following ethical rules when reporting scientific work <![CDATA[<b>Análisis crítico de un artículo</b>: <b>¿Es seguro no tratar a pacientes con sospecha de tromboembolismo pulmonar y tomografía axial computarizada negativa?</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400019&lng=es&nrm=iso&tlng=es Context: The clinical validity of using computed tomography (CT) to diagnose peripheral pulmonary embolism is uncertain. Insufficient sensitivity for peripheral pulmonary embolism is considered the principal limitation of CT. Objective: To review studies that used a CT-based approach to rule out a diagnosis of pulmonary embolism. Data sources: The medical literature databases of PubMed, MEDLINE, EMBASE, CRISP, metaRegister of Controlled Trials, and Cochrane were searched for articles published in the English language from January 1990 to May 2004. Study selection: We included studies that used contrast-enhanced chest CT to rule out the diagnosis of acute pulmonary embolism, had a minimum follow-up of 3 months, and had study populations of more than 30 patients. Data extraction: Two reviewers independently abstracted patient demographics, frequency of venous thromboembolic events (VTEs), CT modality (single-slice CT, multidetector-row CT, or electron-beam CT), false-negative results, and deaths attributable to pulmonary embolism. To calculate the overall negative likelihood ratio (NLR) of a VTE after a negative or inconclusive chest CT scan for pulmonary embolism, we included VTEs that were objectively confirmed by an additional imaging test despite a negative or inconclusive CT scan and objectively confirmed VTEs that occurred during clinical follow-up of at least 3 months. Data synthesis: Fifteen studies met the inclusion criteria and contained a total of 3500 patients who were evaluated from October 1994 through April 2002. The overall NLR of a VTE after a negative chest CT scan for pulmonary embolism was 0.07 (95% confidence interval [CI], 0.05-0.11); and the negative predictive value (NPV) was 99.1% (95% CI, 98.7%-99.5%). The NLR of a VTE after a negative single-slice spiral CT scan for pulmonary embolism was 0.08 (95% CI, 0.05-0.13); and after a negative multidetector-row CT scan, 0.15 (95% CI, 0.05-0.43). There was no difference in risk of VTEs based on CT modality used (relative risk, 1.66; 95% CI, 0.47-5.94; P = .50). The overall NLR of mortality attributable to pulmonary embolism was 0.01 (95% CI, 0.01-0.02) and the overall NPV was 99.4% (95% CI, 98.7%-99.9%). Conclusion: The clinical validity of using a CT scan to rule out pulmonary embolism is similar to that reported for conventional pulmonary angiography <![CDATA[<b>BIBLIOGRAFÍA</b>]]> https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0034-98872007000400020&lng=es&nrm=iso&tlng=es Context: The clinical validity of using computed tomography (CT) to diagnose peripheral pulmonary embolism is uncertain. Insufficient sensitivity for peripheral pulmonary embolism is considered the principal limitation of CT. Objective: To review studies that used a CT-based approach to rule out a diagnosis of pulmonary embolism. Data sources: The medical literature databases of PubMed, MEDLINE, EMBASE, CRISP, metaRegister of Controlled Trials, and Cochrane were searched for articles published in the English language from January 1990 to May 2004. Study selection: We included studies that used contrast-enhanced chest CT to rule out the diagnosis of acute pulmonary embolism, had a minimum follow-up of 3 months, and had study populations of more than 30 patients. Data extraction: Two reviewers independently abstracted patient demographics, frequency of venous thromboembolic events (VTEs), CT modality (single-slice CT, multidetector-row CT, or electron-beam CT), false-negative results, and deaths attributable to pulmonary embolism. To calculate the overall negative likelihood ratio (NLR) of a VTE after a negative or inconclusive chest CT scan for pulmonary embolism, we included VTEs that were objectively confirmed by an additional imaging test despite a negative or inconclusive CT scan and objectively confirmed VTEs that occurred during clinical follow-up of at least 3 months. Data synthesis: Fifteen studies met the inclusion criteria and contained a total of 3500 patients who were evaluated from October 1994 through April 2002. The overall NLR of a VTE after a negative chest CT scan for pulmonary embolism was 0.07 (95% confidence interval [CI], 0.05-0.11); and the negative predictive value (NPV) was 99.1% (95% CI, 98.7%-99.5%). The NLR of a VTE after a negative single-slice spiral CT scan for pulmonary embolism was 0.08 (95% CI, 0.05-0.13); and after a negative multidetector-row CT scan, 0.15 (95% CI, 0.05-0.43). There was no difference in risk of VTEs based on CT modality used (relative risk, 1.66; 95% CI, 0.47-5.94; P = .50). The overall NLR of mortality attributable to pulmonary embolism was 0.01 (95% CI, 0.01-0.02) and the overall NPV was 99.4% (95% CI, 98.7%-99.9%). Conclusion: The clinical validity of using a CT scan to rule out pulmonary embolism is similar to that reported for conventional pulmonary angiography