[Incidence of acute leukemia in children in Mexico City, from 1982 to 1991]. / Incidencia de las leucemias agudas en niños de la ciudad de México, de 1982 a 1991.

OBJECTIVE: To measure the incidence rate and trend of acute leukemia (AL) in political districts of Mexico City. MATERIAL AND METHODS: Descriptive longitudinal study conducted at six hospitals that care for nearly 97.5% of all cancer cases among children in Mexico City. Study data were collected in 1995 and 1996, and were analyzed in 1999, at the National Medical Center "Siglo XXI" Children's Hospital, of the Mexican Institute for Social Security. Calculations of acute leukemia annual incidence rates, standardized rates, and standardized morbidity rates (SMR) with 95% confidence intervals, were obtained for each district. Morbidity trends were assessed through average change rates. RESULTS: In this study we observed an increasing trend of acute lymphoblastic leukemia (ALL) incidence in five districts: Alvaro Obregon, Cuauhtemoc, Gustavo A. Madero, Iztacalco, and Venustiano Carranza. Acute myeloblastic leukemia (AML) showed no significantly statistic increase of incidence in any district. AML did show a significant SMR in Alvaro Obregon district (SMR = 2.91, 95% CI 1.63-4.80). Higher SMRs were found in the south and southwest areas of the city. CONCLUSIONS: Increasing incidence of ALL was observed in five districts of Mexico City. AML incidence was the highest in Alvaro Obregon district.

Validation of a prognostic index in the critically ill newborn.

OBJECTIVE: Elaborate and assess the degree of validity of a prognostic model for evaluating patients admitted to the Neonatal Intensive Care Unit (NICU). DESIGN: Cases and controls nested in a cohort. SETTING: NICU of two tertiary hospitals and another second level hospital. PATIENTS: The study was carried out in two phases. During the first phase (elaboration of a model), 336 newborns were studied; 112 belonged to the case group (dead patients) and 224 to the control group (live patients discharged). For the second phase (model validation), 300 patients were included that did not participate in the first phase, 100 cases and 200 controls. MEASUREMENTS: For each patient admitted to the study, clinical, paraclinical, perinatal and comorbidity factors were determined within the first 12 hours. Variables of statistical significance in the bivariate analysis were included in a logistic regression model with the objective of identifying a prognostic model. RESULTS: The variables that constituted the prognostic index were gestational age x birth weight, the paO2/FiO2 ratio x O2 saturation, arrest cardiac, major congenital malformations, septicemia and base excess. The model showed to have a sensitivity of 70% and a specificity of 91% during the elaboration cohort. In the validation cohort, sensitivity was 68% and specificity was 92%, a positive predictive value of 80%, negative predictive value of 85% and a correct classification rate was 84%. CONCLUSIONS: The Neonatal Mortality Prognostic Index (NMPI) developed in this study showed to be useful for the evaluation of hospital mortality for severely ill newborns admitted to NICU.

Satisfaction related factors of attendants to a medical research meeting.

OBJECTIVE: To assess satisfaction of attendants to a National Meeting on Medical Research in relation with the scientific quality and level of discussion of the research work. MATERIAL AND METHODS: An anonymous self-applied questionnaire was handed out to gather opinions about the scientific quality, level of discussion of the research work, and overall satisfaction with the meeting. The studied population included 400 physicians, all of them authors or collaborators of the research work presented. RESULTS: The rate of response was 62% (n = 249). Two hundred and twenty-four approved the scientific quality (90%), and 203 were satisfied with the level of discussion of research (88%); 239 were satisfied with the meeting as a whole (96%). The factors associated with dissatisfaction regarding the quality of the scientific meeting were the masculine gender (OR = 2.7, CI 95% = 0.8-9.l, p = 0.06), having an M.Sc. or Ph.D. degree (OR = 2.3, CI 95% = 0.9-5.5, p = 0.03), and having attending prior meetings more than twice (OR = 5.0, CI 95% = 1.5-18.4, p = 0.001). CONCLUSIONS: Most of the attendants were satisfied with the scientific quality and discussions of the research work. The masculine gender, having an M.Sc. or Ph.D. degree, and prior assistance were the factors associated with dissatisfaction of the scientific quality of the Meeting.

[Descriptive epidemiology of malignant tumors in children]. / Epidemiología descriptiva de las neoplasias malignas en niños.

The object of this study is to present the descriptive epidemiology of cancer in children at the world and national levels. The international and national literature published on cancer in children was comprehensively reviewed, with emphasis on reports treating epidemiological aspects of time, place and person. For practical reasons and with the aim of integrating the information, only the more relevant publications were included. Incidence and child mortality were analyzed. Overall incidence is between 100 and 150 (annual rates = cases x 10(6) children). Specific incidence varies according to the type of cancer, the region and the country. The Latin American pattern of neoplasms is constituted by leukemias, lymphomas, and central nervous system tumors (CNST); in the Northamerican/European pattern the CNST appear in second place and in the African pattern, lymphomas show predominance. Incidence is higher among the younger than 5 year olds, from urban environments, and there is a 1% annual increase of cancer in Northamerican children. Child mortality has diminished remarkably, mainly in developed countries, whereas in developing or underdeveloped countries, incidence remains stable or shows a slight fall. The incidence of cancer in children is greater in developed countries, but in underdeveloped countries it may be underestimated. These countries have not managed to reduce the incidence of child mortality caused by cancer, as have the United States or Great Britain. Further studies on the epidemiology of cancer in children are necessary, since many data remain unknown.

[Characteristics of medical care related to autopsy authorization in a pediatric hospital]. / Características de la atención médica relacionadas con la autorización de autopsias en un hospital pediátrico.

OBJECTIVE: To identify some differences of patients and medical characteristics related to autopsy authorization. DESIGN: Observational, cross-sectional study. SETTING: Third-level medical care in a pediatric hospital. METHODS: A specific mortality questionnaire was analyzed by members of the mortality staff, because they reviewed deaths which occurred between January 1994 and December 1995. Descriptive statistic and non-parametric tests (X2) were calculated to analyze data. RESULTS: A total of 408 deaths were evaluated, in which 116 autopsies were done (28.4%). Children less than 18 months of age had the highest frequencies of autopsies (33.3%-30.7%). The patients referred by other units and the autopsy application done by a medical resident, had the highest frequencies of acceptance (32.5%, 35.3%, p < 0.05). The detection of diagnostic and therapeutic problems were related with high frequencies of autopsies (37.7%, 36% p < 0.05). CONCLUSIONS: The results show us that some medical care factors are related to higher frequencies of autopsies. It is important to consider them in order to increase the capacity of teaching that a postmortem study has.

Factors associated with non-use of Pap test. A population survey.

BACKGROUND: Cervical cancer is the most important cancer in Mexican women. Early detection is possible by means of the Papanicolaou (Pap) test; however, the coverage in Mexico is low. METHODS: A cross-sectional survey was carried out in a representative sample of women from the Tlalpan area of Mexico City. Social, reproductive and health care factors associated with the lack of use of the Pap test with respect to adequate use and misuse were identified. Both bivariate and logistic regression analyses were used for the adjustment of variables. RESULTS: Of 1,215 women studied, 22.5% had never had a Pap smear, 42% had misused the test (< 90% of triennial performance), and 35.5% had adequately used the test (> or = 90% of triennial performance). The main factors related to the lack of use were the following: not knowing about the Pap test (ORa = 35.16, 95% C.I. = 17.4-70.9); having fewer than 6 years of education (ORa = 4.5, 95% C.I. = 2.5-8.4); women younger than 30 years of age (ORa = 3.4 95% C.I. = 2.3-5.1); use of contraceptives (ORa = 0.4, 95% C.I. = 0.2-0.8); history of sexually transmitted diseases (ORa = 0.3, 95% C.I. = 0.1-0.8), and the principal informant about the Pap test, i.e., the health services personnel (ORa = 0.02, 95% C.I. = 0.0008-0.05). CONCLUSIONS: The lack of use and the misuse of Pap smears vary importantly among the different social and reproductive factors. But the principal reasons for lack of use were not knowing about the Pap test and a low educational level. We propose a greater diffusion on the benefits of the test in the Mexican population, through massive means of communication and health services.

[Classification by levels of clinico-epidemiological research designs]. / Clasificación en niveles de los diseños de investigación clínico-epidemiológicos.

The objective was to identify the characteristics of epidemiologic designs enabling their classification. A critical review of the literature in the clinical epidemiologic area was done to establish the main differences between designs. A meeting with experts to discuss this controversial topic and obtain criteria by consensus was organized. We propose an integral classification based on levels with two fundamental shafts: intervention and explanatory reasoning.

[Factors associated with peritoneal dialysis catheter failure in chronic renal insufficiency]. / Factores asociados a falla del catéter de diálisis peritoneal en insuficiencia renal crónica.

AIM: To determine the frequency, time of occurrence and factors associated with the failure of the permanent peritoneal catheter during dialysis in cases of chronic renal failure (CRF). MATERIAL AND METHODS: A retrospective cohort under a nested case control design was studied at a second level health care unit of the Instituto Mexicano del Seguro Social. A total of 149 catheters, double cushion straight Tenckhoff type, were evaluated in 74 patients with CRF due to diabetic nephropathy in 36/74 patients (49%). Information concerning functionality time and causes of catheter failure as well as the clinical and technical factors concerning insertion were obtained from the clinical chart. RESULTS: The cumulated time of dialysis was 814 months. Catheter failure occurred in 101 cases (68%): 67 due to obstruction, 24 due to infection, to leakage in 6 and to other causes in 4. Those of non-infectious origin were more frequent (p < 0.01). In the first month post-insertion there was a higher number of failures than after one month, (p < 0.0005). The global functionality of the catheter at one month, one and two years was 55%, 31% and 16%, respectively. There was a greater permanence of the catheters in continuous ambulatory peritoneal dialysis than in intermittent peritoneal dialysis (p = 0.02). CONCLUSIONS: It is concluded that the frequency of the peritoneal catheter failure was high; that the most frequent cause was due to non-infectious complications during the first month of insertion; and the factor associated to catheter failure was intermittent peritoneal dialysis as compared to continuous ambulatory dialysis.

[Instrument to measure quality of life based on daily performance in pediatric patients with leukemia]. / Un instrumento para medir la calidad de vida por medio del desempeño diario en pacientes pediátricos con leucemia.

The objective of this study was to determine the validity of a questionnaire to measure daily performance as an evaluation of quality of life in pediatric leukemia patients. A questionnaire of the daily activities of a child according to Lickert's criteria was done. A pilot survey was performed in patients without a chronic or disabling disease in order to assess its validity. The impression of the medical attendance of each pediatric patient with leukemia, of their daily performance, was compared with the results of the instrument. A trained nurse applied the questionnaire to 60 mothers of patients (29 female/31 male) as outpatients during the clinical review. Fifteen questionnaires were applied twice to evaluate its consistency. According to the results, 77% of the patients were in remission. 15% in relapse, and 8% during induction to remission. The mean age of the patients was 9 = 3.6 years, ranging from 2-16 years. One hundred percent of the patients obtained a satisfactory grade greater than 35 points. In conclusion, the questionnaire identified adequately the level of the daily performance in addition to the specific affected areas of the patients with leukemia. Our findings are that their level of performance is satisfactory and is not affected because of the disease or the phase of the treatment.

[Medical student traits associated with future success as physicians]. / Características del estudiante de medicina asociadas al éxito ulterior como médico.

OBJECTIVE: To identify the individual and family factors present during medical studies which are associated to success as a physician. RESEARCH DESIGN: Prolective case-control study. SETTING: Mexico City metropolitan area. STUDY UNITS: 120 physicians considered to be successful and 245 physicians who according to an established criteria were considered to be non-successful. MAIN MEASUREMENTS: A success-achieving index was constructed on the opinion of 134 physicians from different health-care institutions private and public. The index was composed by criteria such as being a member of prestiged academic associations; having a practice in third level institutions; having done postgraduate studies; being a professor with teaching and research activities; having obtained directive medical positions; and a high income at the moment of the interview. RESULTS: The main factors associated to success were: frequent attendance to cultural activities by the family of the subjects (OR = 5.2, IC 95% = 3.15-8.60, p = 0.00000001); the global score obtained during their medical studies, i.e. higher than 8.5 over 10 (OR = 4.43, IC 95% = 2.64-7.49, p = 0.00000001); and having been awarded recognitions, prizes or scholarships during their medical studies (OR = 4.3, IC 95% = 2.64-7.03, p = 0.00000001). A logistic regression model selected the cultural activities of the family, global score during medical studies and earning of recognitions, prizes and scholarships as independent variables associated to success achievement (p = 0.00001). CONCLUSIONS: Frequent cultural activities by the family and academic behavior were the factors present during medical studies which were associated to ulterior success as a physician.

[The utility of joint sensitivity and specificity curves applied to a diagnostic test]. / Utilidad de las curvas de sensibilidad y especificidad conjunta en la aplicación de una prueba de diagnóstico.

The aim of this study was to obtain the cut point to determine an individual's seronegativity with respect to measles using commercial reagents. To determine the test sensitivity, the serum of 22 individuals 21 years of age or older, and a positive history of measles (positive control group) was studied. For specificity, the serum of 22 children 15 to 24 months old, and no measles vaccination record nor positive history of measles (negative control group), was analyzed. The antibodies titer determination for both groups was done using the ELISA technique and the Brunell method, subsequently, as well as a ROC curve (Received Operating Curve). When the Brunell method was used, the cut points were 0.4090 (sensitivity 1.0 and specificity 0.95) and 0.5042 (sensitivity 0.95 and specificity 1.0). When a ROC curve was done the cut point was 0.4500, with a sensitivity and specificity of 100 per cent. It was also concluded that the latter is the best method to obtain this cut point, because it does not establish arbitrary values when the data distribution does not follow a normal pattern.

[Granulocytopenia and fever in children with leukemia as indicator of quality of medical care]. / Granulocitopenia y fiebre en niños con leucemia como indicador de calidad de la atención médica.

OBJECTIVES: 1. To identify the quality degree of medical care in patients with acute leukaemia who had fever and granulocytopenia during the hospitalization period. 2. To establish the relationship between the medical care process and the results in this concern. DESIGN: Retrospective survey. STUDY AREA: Children's Hospital of the Mexican Institute of Social Security. STUDY SUBJECTS: Twenty three patients with acute leukaemia were studied. Also, hospitalization episode of these patients, in which they suffered fever and granulocytopenia, was randomly selected. MAIN MEASUREMENTS: Compliance of diagnostic and therapeutic process was measured during hospitalization, according to the protocolized recommendations made by consensus of the hospital expert group. In order to identify the quality degree of medical care, it was taken into account the protocol compliance besides the results observed in the patients. Results were assessed based on patients' survival to fever and granulocytopenia episode, as well as on fever's duration. The correlation was calculated by using Spearman's coefficient. RESULTS: The medical care quality of the hospital was "adequate" (85% on average). Compliance degree, including the total process was 71%; with diagnostic process 63%, and with therapeutic process 76%. The results observed in the patients were considered as "adequate" (89%). By evaluating individual cases, the medical care quality was considered excellent or adequate in 17 patients (74%) regular in five (22%) and poor in one (4%). Diagnostic process was adequate in 6 patients (26%) regular in 12 (53%) poor in three (13%) and very bad in two (8%). On the other hand, therapeutic process was excellent in 14 patients (60%) regular in one (4%) poor in six (26%) and very bad in two (9%). Results observed in 13 cases were excellent (57%) adequate in eight (35%) regular in one (4%) and very bad in one (4%). The relationship between process and result was 0.41 (P < 0.05) between diagnostic process and result 0.14 and, between therapeutic process and result 0.34. CONCLUSIONS: The medical care quality rendered to patients with leukaemia, who suffered a granulocytopenia episode and fever, was considered as adequate. Therapeutic recommendations were followed accurately, meanwhile, diagnostic process had a lower adherence. A positive relationship between process and result was observed.

[Usefulness of residuals in clinical research]. / Utilidad de los residuales en la investigación clínica.

The simple linear regression analysis, multiple linear regression and logistic regression constitute powerful statistical analysis tools widely used in clinical research. These kinds of analyses are based upon mathematical models which at the same time are established on certain basic assumptions. The regression analysis assumptions are basically: a) that the model is really linear, b) that the distribution of data is normal (from a statistical point of view), c) that the variances of the employed data are homogeneous (homocedastics) and that the included data are independent. The regression diagnostic has become popular as a form to evaluate if the assumptions have been accomplished, one of its most important techniques is the residual analysis. A residual can be defined as the value which measures the distance between the regression line and the corresponding value of the variable "y". Among these kinds of residuals used to evaluate the assumptions of regression are: the crude residual, the standardized, of student and the jackknife. The most useful among them is the jackknife residual. The usefulness and limitations of the residuals in the evaluation of the regression analysis assumptions are described, basically referring to the identification and handling of extreme values (outliers).

[Risk factors associated with the development of leukemia in children]. / Factores de riesgo asociados al desarrollo de leucemia en niños.

INTRODUCTION: Leukemia is the most frequent neoplasia in children; in our country it is the main cause of medical attention in children with cancer. The are different risk factors associated with the development of this kind of cancer. OBJECTIVE: To identify which of the already known factors described in the literature associated with the development of leukemia are most frequent in the pediatric population of Mexico City. MATERIAL AND METHODS: A protective case-control study was carried out using prevalent and incident cases. In two third level hospitals of Mexico City, a total of 81 children who had been diagnosed as suffering from different kind of leukemia, confirmed by biopsy of bone marrow, were select and studied. The control were 154 children from two different sources: 77 of them came from the same hospital where the cases received medical care, the selection criteria was not to have any kind of neoplasia; and 77 came from the same community where those diagnosed children cases lived, the selection criteria for this group was that they were healthy children. Both cases and community controls were visited at home and interview to complete precoded questionnaire with the different variables of the study. The information from the hospital controls was obtained during the time they stayed in the hospital. Odds ratio (OR's) for the different associations were calculated, as well as its confidence intervals at 95% (IC) accord to Cornfield and unconditioned logistic regression was carried out to control confounding variables. RESULTS: OR greater than 1 was found in those with familiar cancer background 1.93 (1.2-3.63); the mother being exposed to X-ray during pregnancy 1.89 (0.84-4.22); previous abortions before the child with leukemia was born 2.44 (1-06-5.68); being born from full term birth 2.42 (0.47-16.65); being born with weight greater that 3500 g 2.21 (1.04-4.33); being exposed to fertilizers 4.73 (1.04-24.14) and insecticides 1.93 (1.05-3.56). OR smaller than 1 was found in those who have been in a hospital because of an infectious disease during the first year of life 0.57 (0.17-1.74); to have suffered from chicken pox 0.59 (0.32-1.08). No association to parent's age or job was found. Multivariated analysis shows that the exposure to insecticide is the most important risk factor associated with the development of leukemia in children. CONCLUSIONS: We obtained positive associations to different risk factors described in the literature, having found that exposure to fertilizers is the most important risk factor and finding no association with the parent's occupation. This leads to the need of carrying out further studies to investigate, in more detail, the occupation of the father to confirm whether or not this is a risk factor.

[Residence close to high-tension electric power lines and its association with leukemia in children]. / Residencia cercana a fuentes eléctricas de alta tensión y su asociación con leucemia en niños.

INTRODUCTION: There are different risk factors which have been related to the presence of leukemia in children. In the past years one of these factors has become relevant, the risk of living in an area near to high electric voltage lines, generators of electromagnetic fields of low frequency (EMF), which can cause development of leukemia in children. OBJECTIVE: To learn whether living in an area close to EMF generator sources, electric transformers, high electric voltage distribution or transmission lines and electric substations, is a risk factor in the development of leukemia in children living in Mexico City. MATERIAL AND METHODS: A projective study of case-control was accomplished. The cases were obtained from hospitals of the third level. The diagnosis of leukemia in its different varieties was confirmed through biopsy of bone marrow. The controls were selected in the same hospital from inpatients and outpatients with different problems, except neoplasia. A total sample of 81 cases and 77 controls was analyzed. The residence of the controls and cases were visited using a questionnaire coded with the different study variables. To diminish the memory bias in relation to EMF, the subjects were shown different pictures pointing out the different sources of exposures, which were asked. Having obtained the information, different odds ratios (OR) were calculated for the different associations, as well as the confidence intervals at 95% and an unconditioned logistic regression was accomplished to know the adjusted OR. RESULTS: There were no differences between the cases and controls according to the relative who gave the information, the current age of children, the parents's age, the social class and the parent's occupation. It was found that all the generating sources of EMF, which were involved in the study, had and OR above 1. Being the highest, the ones living near the distribution or transmission wires of high voltage with an OR of 2.63 (1.26-5.36) and 2.5 (0.97-6.67) respectively. When the distance of exposure was controlled, the highest OR was for distribution lines (OR 2.12; 0.79-5.85). When the analysis was applied to persons who have moved from the residence, it was found that the OR was above 1 in all the associations, the highest being the distribution wires and with the distance the highest was the electric substations. Furthermore, the multivariate analysis showed that the risk continued only for the distribution wires. CONCLUSIONS: The EMF exposure was found positive, however this is not very precise, that is why it is necessary to carry out other studies to confirm the existence of the association and correct possible biases which could appear during the research.

[Diagnostic performance of immunologic tests in amebic liver abscess using receiver operating characteristic curves]. / Rendimiento diagnóstico de las pruebas inmunológicas en absceso hepático amibiano a través de curvas de características operantes del receptor.

Objectives. 1) To identify the tests of immunological diagnosis with a high diagnostic efficiency in amebic liver abscess. 2) To determine the ideal cutoff point for such tests. 3) To identify the influence degree of the antigen used over the test efficiency. Design. Comparative survey. Study units. Analysis of 24 articles identified in the medical literature about tests of immunological diagnosis in amebic liver abscess. Measurements. Starting from the articles, operating characteristics curves (ROC) were established derived from the test application to patients with amebic liver abscess. Results. A great variability in the diagnostic efficiency was identified between the various tests, even when the analysis was focused on the investigations of a specific test. It was not possible to conclude which test had a major degree of efficiency due to such variability. The cutoff level considered as relevant was higher than the one traditionally used for indirect hemagglutination and it had concordance with the one presently accepted for the fluorescence antibodies test. By maintaining steady the spectrum of the study patients and the type of test, variability among the tests persisted. This was due to the use of different antigens. Conclusions. A great variation in the diagnostic efficiency of the analyzed tests was identified. The variation source was the type of test, the antigen used and probably the illness spectrum.

[Frequency and risk factors associated with metronidazole therapeutic noncompliance]. / Frecuencia y factores de riesgo asociados al incumplimiento terapéutico con metronidazol.

OBJECTIVE: to determine the frequency and risk factors of non-compliance to oral metronidazole. STUDY DESIGN: comparative cross-sectional survey. STUDY UNITS: 111 patients who received oral metronidazole. SETTING CHARACTERISTICS: two medical units: one primary level unit and one secondary care unit of the Mexican Institute of Social Security. MEASUREMENTS: non-compliance was assessed by home interview and pill count. MAIN RESULTS: frequency of non-compliance was 55%. Risk factors for non-compliance were: female sex (OR = 3.0; p less than 0.05); side effects (OR = 3.1; p less than 0.05); low literacy (OR = 3.75; p less than 0.05). Stratified analysis showed no interaction between variables. CONCLUSIONS: frequency of non-compliance to metronidazole is high, and could affect the effectiveness of medical care. Female patients with low literacy and who suffer side effects are a high risk group for non-compliance.

[Prognostic factors in a pediatric intensive care unit]. / Factores pronósticos en una unidad de terapia intensiva pediátrica.

OBJECTIVES: To identify the mortality prognostic factors from a pediatric intensive care unit. STUDY DESIGN: Retrolective cohort study with an analysis of cases and controls (ambidirectional design). PLACE OF STUDY: The intensive care unit at a Pediatric Third Level Hospital. STUDY UNITS: All of the patients admitted into the I.C.U. for a year (August 1989 to August 1990). MAIN MEASUREMENTS: The patients were identified when admitted into I.C.U., while evaluating their clinical course through their charts. Afterwards, they were placed into two groups, those who died while in I.C.U. (n = 49) and those in the control group which constituted the initial cohort survivors (n = 115). The prognostic factors evaluated were age, sex, diagnosis when admitted, organic failure, changes in diagnosis and treatment. MAIN RESULTS: 164 patients were studied, with a slight predominance of the male sex (53%). The patient's age fluctuated between 1 day and 17 years of age, with a mean age of 10 months. The diagnosis established when admitted were predominantly dealing with infectious problems (n = 54, 32%). The most important prognostic factors seen during the bivaried analysis were the peritoneal dialysis (RM = 12.71, IC 95% = 2.41-98.29, P less than 0.01); a Glasgow index less than or equal to 10 points (RM = 7.33, IC 95% = 1.25-47.26, P less than 0.01), respiratory organic failure (RM = 6.32, IC 95% = 2.46-16.8, P less than 0.01) and assisted mechanical ventilation (RM = 5.61, IC 95% = 2.52-12.68, P less than 0.01). CONCLUSIONS: The mortality rate in I.C.U. was 30%. The most important prognostic factors associated to mortality after adjusting for severity were having a cardiovascular ailment, the need to administer blood products, a Glasgow index less than or equal to 10 points, heart and hematologic organic failure and when respiratory mechanical assistance was provided.