[Spurious hypoxemia due to hyperleukocytosis. Report of one case]. / Hipoxemia espuria por hiperleucocitosis. Reporte de un caso y revisión de la literatura.

BACKGROUND: Arterial gasometry is considered the gold standard for establishing a diagnosis of respiratory failure of any etiology. However, there are some circumstances in which it loses specificity, making necessary to consider other tests such as pulse oximetry to adequately determine hypoxemia. We report a 67 years old patient with sudden hypoacusia, right hemiparesis and polypnea. His laboratory exams on admission, showed extreme hypoxemia in several readings, without correlation to the patient's clinical condition nor the pulse oximetry, and a leukocytosis of 800.000 cells x ml, with many immature cells. Chronic myeloid leukemia was diagnosed and treatment with hydroxyurea was initiated, achieving normalization in the arterial gases in accordance with the fall of the white cell count. Interpretation of laboratory findings according to the general clinical context of the patient allowed to suspect a spurious hypoxemia, saving the patient from unnecessary and risky interventions.

Hipoxemia espuria por hiperleucocitosis: Reporte de un caso y revisión de la literatura / Spurious hypoxemia due to hyperleukocytosis: Report of one case

Background: Arterial gasometry is considered the gold standard for establishing a diagnosis of respiratory failure of any etiology. However, there are some circumstances in which it loses specificity, making necessary to consider other tests such as pulse oximetry to adequately determine hypoxemia. We report a 67 years old patient with sudden hypoacusia, right hemiparesis and polypnea. His laboratory exams on admission, showed extreme hypoxemia in several readings, without correlation to the patient's clinical condition nor the pulse oximetry, and a leukocytosis of 800.000 cells x ml, with many immature cells. Chronic myeloid leukemia was diagnosed and treatment with hydroxyurea was initiated, achieving normalization in the arterial gases in accordance with the fall of the white cell count. Interpretation of laboratory findings according to the general clinical context of the patient allowed to suspect a spurious hypoxemia, saving the patient from unnecessary and risky interventions.

[How can an internist keep updated in the XXIst century?]. / ¿Podemos mantenernos actualizados en medicina en el siglo XXI?

The amount of information in health care has steadily grown in the past years and this trend will probably continue in the near future. Traditional ways to keep updated are no longer sufficient, particularly in broad areas of knowledge as Internal Medicine or Family Medicine. Therefore, it is necessary to use new approaches. The present article describes five proposals for the clinician that tries to maintain updated but feels overwhelmed by the amount of available information.

¿Podemos mantenernos actualizados en medicina en el siglo XXI? / How can an internist keep updated in the XXIst century?

The amount of information in health care has steadily grown in the past years and this trend will probably continue in the near future. Traditional ways to keep updated are no longer sufficient, particularly in broad areas of knowledge as Internal Medicine or Family Medicine. Therefore, it is necessary to use new approaches. The present article describes five proposals for the clinician that tries to maintain updated but feels overwhelmed by the amount of available information.

Medicina basada en evidencias en hepatología III-B: examen físico en el diagnóstico de ascitis y cirrosis hepática / Evidence based medicine in hepatology III-B: physical examination in the diagnosis of ascites and cirrhosis

El siguiente estudio continúa la serie de publicaciones sobre decisiones clínicas en el diagnóstico, tratamiento y costo-utilidad en Hepatología, usando las herramientas de la Medicina Basada en Evidencia (MBE). En un escenario clínico en que se sospecha la presencia de ascitis, la real utilidad de los hallazgos clínicos no ha sido bien establecida. Usando un modelo de búsqueda basado en una pregunta clínica, tres estudios y un artículo de revisión son identificados. Uno de estos estudios es extensamente analizado, incluyendo criterio de validez interna (gold standard, criterios de selección de pacientes, reproducibilidad de los hallazgos y temporalidad), análisis de resultados y discusión de la aplicabilidad. Cuatro signos clínicos (flancos abultados, matidez en los flancos, matidez desplazable y signo de la ola) fueron examinados de manera independiente por tres gastroenterólogos. Los resultados muestran que, usando la ultrasonografía como gold standard, 21 por ciento de los pacientes tenía ascitis. La sensibilidad y especificidad de las maniobras examinadas fue de 50 por ciento a 94 por ciento, y 29 por ciento a 82 por ciento, respectivamente. La matidez en los flancos fue el más sensible y el signo de la ola el más específico. La metodología del estudio está limitada por el reducido número de pacientes, la falta de adecuados criterios de selección de casos y la ausencia de información acerca la temporalidad de los síntomas. Otros signos presentes en cirrosis son descritos y brevemente analizados, usando MBE. Concluimos que los signos del examen físico son útiles en el diagnóstico de ascitis, siendo la matidez en los flancos y el signo de la ola los más útiles. La ecotomografía se recomienda en casos de duda diagnóstica.

Medicina basada en evidencias en hepatología III-A:evaluación de test diagnóstico: utilidad de adenosin deaminasa (ADA) en el diagnóstico de peritonitis tuberculosa / Evidence based medicine in hepatology III-A: critical analysis of diagnostic test: effectiveness of ADA for diagnosing tuberculous peritonitis

El siguiente estudio continúa la serie de publicaciones sobre decisiones clínicas en Hepatología, usando los pasos de la Medicina basada en Evidencia. Se analizó la utilidad de la adenosin deaminasa (ADA) en el diagnóstico de tuberculosis peritoneal (TBP) en un paciente con ascitis. Usando un modelo de búsqueda basado en una pregunta clínica, se identificaron 17 artículos relacionados. Uno de ellos fue extensa y críticamente analizado, incluyendo una revisión de su validez (comparación con gold standard, espectro de pacientes analizados, y reproducibilidad del trabajo), análisis de sus resultados, y discusión de su aplicabilidad. El artículo seleccionado fue prospectivo, incluía a pacientes consecutivos, confirmó el diagnóstico de tuberculosis con una biopsia laparoscópica en todos los pacientes, y realizó la determinación de ADA utilizando el método de Giusti. Los Resultados mostraron que ADA es un test discriminativo para el diagnóstico de TBP, con un punto de corte óptimo de 32 UI/L. Concluimos que la medición de niveles de ADA en líquido ascítico, es una forma efectiva de diagnosticar TBP.

[Critical assessment of randomized controlled trials published in biomedical Chilean journals]. / Análisis crítico de ensayos clínicos randomizados publicados en revistas biomédicas chilenas.

BACKGROUND: Well designed clinical trials yield the strongest evidence for the effect of health care interventions. AIM: To assess the methodological quality of the design and report of randomized clinical trials in a sample, published in biomedical Chilean journals between 1980 and 2002. MATERIAL AND METHODS: All trials identified by hand search by the Unit of Evaluation of Technologies in Health, were assessed for quality of randomization, blinding, analysis of results and other characteristics of trial design, along with the application of Jadad's Score, that assesses the methodological quality of clinical trials in a scale that ranges from 0 to 5. RESULTS: Twenty-eight trials were found and assessed, 75% (n=21) specified the method used for randomization, 29% (n=8) described a correct allocation concealment and 39% (n=11) were double blinded. Withdrawals and dropouts were correctly reported in 21% (n=6) of the articles, whereas intention to treat analysis was done only in one. Thirteen trials had a Jadad score equal or higher than 3 points. CONCLUSIONS: Several design deficiencies were found in the trials assessed. It is difficult to know if methodological weaknesses are due to incomplete reports or to methodologically poor designs. Adopting initiatives like the CONSORT can help improve the quality of randomized clinical trials published in Biomedical Chilean journals.

AngioTAC como método de diagnóstico y decisión quirúrgica en el tromboembolismo pulmonar crónico: Discusión a propósito de un caso / CT angiography as the diagnostic and decision making method used for surgical indication in pulmonary hypertension due to chronic thromboembolism: Report of one case

Pulmonary hypertension due to chronic pulmonary thromboembolism is frequently underdiagnosed and has a very poor prognosis if untreated. When the presence of central pulmonary artery thrombus is confirmed, thromboendarterectomy is the treatment of choice, with very good results. We report a 28 years old male with two previous episodes of deep venous thrombosis (DVT) who was admitted due to 8 months of progressive shortness of breath and a syncope. He underwent a CT pulmonary angiogram and an echocardiogram. Severe pulmonary hypertension was confirmed, secondary to a chronic pulmonary thromboembolism with an overlapped acute component. He received systemic thrombolysis with partial thrombus disappearance. Therefore a pulmonary thromboendarterectomy was performed and an inferior vena cava filter was placed. The patient was discharged with marked improvement in his functional capacity.

Análisis crítico de ensayos clínicos randomizados publicados en revistas biomédicas chilenas / Critical assessment of randomized controlled trials published in biomedical Chilean journals

Background: Well designed clinical trials yield the strongest evidence for the effect of health care interventions. Aim: To assess the methodological quality of the design and report of randomized clinical trials in a sample, published in biomedical Chilean journals between 1980 and 2002. Material and methods: All trials identified by hand search by the Unit of Evaluation of Technologies in Health, were assessed for quality of randomization, blinding, analysis of results and other characteristics of trial design, along with the application of Jadad's Score, that assesses the methodological quality of clinical trials in a scale that ranges from 0 to 5. Results: Twenty eight trials were found and assessed, 75 percent (n=21) specified the method used for randomization, 29 percent (n=8) described a correct allocation concealment and 39 percent (n=11) were double blinded. Withdrawals and dropouts were correctly reported in 21 percent (n=6) of the articles, whereas intention to treat analysis was done only in one. Thirteen trials had a Jadad score equal or higher than 3 points. Conclusions: Several design deficiencies were found in the trials assessed. It is difficult to know if methodological weaknesses are due to incomplete reports or to methodologically poor designs. Adopting initiatives like the CONSORT can help improve the quality of randomized clinical trials published in Biomedical Chilean journals.

Evaluación de meta-análisis: utilidad de corticoides en el tratamiento de la hepatitis alcohólica grave / Evidence based medicine in hepatology II: critical analysis of meta-analysis: effectiveness of corticosteroids therapy in severe alcoholic hepatitis

El siguiente artículo continúa la serie de publicaciones sobre toma de decisiones clínicas terapéuticas en hepatología, usando como herramienta la Medicina Basada en Evidencia. Se evaluará la utilidad de los corticoides en reducir la mortalidad en pacientes con hepatitis alcohólica grave. Usando una pregunta clínica basada en un modelo de búsqueda preestablecido, se encontraron 4 artículos. Uno de ellos es extensamente analizado, incluyendo una evaluación de su validez interna (pregunta clínica, criterios de inclusión, fuentes de información, validez de los estudios incluidos, reproducibilidad de la evaluación, y heterogeneidad), el análisis de sus resultados y una discusión sobre su aplicabilidad. La metodología del estudio analizado está limitada por la ausencia de una pregunta clínica explícita, y porque la evaluación de sus estudios no fue reproducible. Los resultados muestran que los corticoides reducen la mortalidad con un OR = 0,643 (IC 95 por ciento = 0,429-0,935) comparado con placebo o no tratamiento. La ausencia de análisis de efectos adversos, y la ausencia de una definición clara de los criterios de gravedad de la hepatitis alcohólica limitan su aplicabilidad. Los tres meta-análisis restantes fueron brevemente analizados. Dos de ellos muestran que los corticoides reducen en forma significativa la mortalidad, y sólo uno de ellos no encontró diferencias significativas al ser comparado con placebo. Ninguno hizo análisis de efectos adversos, ni de otros outcomes de importancia. Concluimos que la evidencia disponible apoya el uso de corticoides en pacientes con hepatitis alcohólica grave, si bien la calidad metodológica de la evidencia no es óptima.

Revisiones sistemáticas y metaanálisis: ¿son la mejor evidencia? / Systematic reviews and metaanalysis: are the best evidence?

Las RS representan el más alto nivel de evidencia, sí y sólo sí, han sido realizadas con las precauciones necesarias para reducir la posibilidad de sesgo durante su realización, de modo que sintetice de manera confiable toda la evidencia de alta calidad disponible.

Análisis crítico de un artículo

Objective: To compare the safety and clinical outcomes of enteral and parenteral nutrition in patients with acute pancreatitis. Data sources: Medline, Embase, Cochrane controlled trials register, and citation review of relevant primary and review articles. Study selection: Randomized controlled studies that compared enteral nutrition with parenteral nutrition in patients with acute pancreatitis. From 117 articles screened, six were identified as randomized controlled trials and were included for data extraction. Data extraction: Six studies with 263 participants were analyzed. Descriptive and outcome data were extracted. Main outcome measures were infections, complications other than infections, operative interventions, length of hospital stay, and mortality. The metaanalysis was performed with the random effects model. Data synthesis: Enteral nutrition was associated with a significantly lower incidence of infections (relative risk 0.45; 95% confidence interval 0.26 to 0.78, P= 0.004), reduced surgical interventions to control pancreatitis (0.48, 0.22 to 1.0, P= 0.05), and a reduced length of hospital stay (mean reduction 2.9 days, 1.6 days to 4.3 days, P <0.001). There were no significant differences in mortality (relative risk 0.66, 0.32 to 1.37, P = 0.3) or non-infectious complications (0.61, 0.31 to 1.22, P= 0.16) between the two groups of patients. Conclusions: Enteral nutrition should be the preferred route of nutritional support in patients with acute pancreatitis.

Guía para el análisis crítico de estudios que evalúan exámenes diagnósticos / Guidelines for the critical analysis of articles on diagnostic test

El análisis crítico de artículos sobre exámenes diagnósticos permite reconocer su utilidad clínica analizando su validez, resultados y aplicabilidad. En este documento se presenta la metodología para lograr ese objetivo.

Inhibición de la vía del óxido nítrico en el shock séptico refractario / Inhibition of nitric oxide way in the refractary septic shock

To assess the acute effects of methylene blue infusion, an inhibitor of nitric oxyde synthesis, on hemodynamic parameters in patients with refractory septic shock. Fourteen patients admitted to intensive care units with septic shock of diverse etiologies and unable to maintain median arterial pressures over 60 mm Hg with the use of at least 2 vasoactive drugs, were studied. All received a 1 mg/kg bolus of methylene blue. Hemodinamic parameters were measured before and 30, 60, 120 and 180 min after the bolus. Systolic and diastolic blood pressure and systemic vascular resistance increased in all patients. There were no significant changes in cardiac output, oxygen consumption or extraction. Methylene blue has an acute pressor effect in patients with septic shock