Dynamic changes of hepatic vein Doppler velocities predict preload responsiveness in mechanically ventilated critically ill patients.

BACKGROUND: Assessment of dynamic parameters to guide fluid administration is one of the mainstays of current resuscitation strategies. Each test has its own limitations, but passive leg raising (PLR) has emerged as one of the most versatile preload responsiveness tests. However, it requires real-time cardiac output (CO) measurement either through advanced monitoring devices, which are not routinely available, or echocardiography, which is not always feasible. Analysis of the hepatic vein Doppler waveform change, a simpler ultrasound-based assessment, during a dynamic test such as PLR could be useful in predicting preload responsiveness. The objective of this study was to assess the diagnostic accuracy of hepatic vein Doppler S and D-wave velocities during PLR as a predictor of preload responsiveness. METHODS: Prospective observational study conducted in two medical-surgical ICUs in Chile. Patients in circulatory failure and connected to controlled mechanical ventilation were included from August to December 2023. A baseline ultrasound assessment of cardiac function was performed. Then, simultaneously, ultrasound measurements of hepatic vein Doppler S and D waves and cardiac output by continuous pulse contour analysis device were performed during a PLR maneuver. RESULTS: Thirty-seven patients were analyzed. 63% of the patients were preload responsive defined by a 10% increase in CO after passive leg raising. A 20% increase in the maximum S wave velocity after PLR showed the best diagnostic accuracy with a sensitivity of 69.6% (49.1-84.4) and specificity of 92.8 (68.5-99.6) to detect preload responsiveness, with an area under curve of receiving operator characteristic (AUC-ROC) of 0.82 ± 0.07 (p = 0.001 vs. AUC-ROC of 0.5). D-wave velocities showed worse diagnostic accuracy. CONCLUSIONS: Hepatic vein Doppler assessment emerges as a novel complementary technique with adequate predictive capacity to identify preload responsiveness in patients in mechanical ventilation and circulatory failure. This technique could become valuable in scenarios of basic hemodynamic monitoring and when echocardiography is not feasible. Future studies should confirm these results.

Diaphragmatic Ultrasound Predictors of High-Flow Nasal Cannula Therapeutic Failure in Critically Ill Patients With SARS-CoV-2 Pneumonia.

OBJECTIVES: High flow nasal cannula (HFNC) is frequently used in patients with acute respiratory failure, but there is limited evidence regarding predictors of therapeutic failure. The objective of this study was to assess diaphragmatic ultrasound criteria as predictors of failure to HFNC, defined as the need for orotracheal intubation or death. METHODS: Prospective cohort study including adult patients consecutively admitted to the critical care unit, from July 24 to October 20, 2020, with respiratory failure secondary to SARS-CoV-2 pneumonia who required HFNC. After 12 hours of HFNC initiation we measured ROX index (ratio of SpO2 /FiO2 to respiratory rate), excursion and diaphragmatic contraction speed (diaphragmatic excursion/inspiratory time) by ultrasound, both in supine and prone position. RESULTS: In total, 41 patients were analyzed, 25 succeeded and 16 failed HFNC therapy. At 12 hours, patients who succeeded HFNC therapy presented higher ROX index in supine position (9.8 [9.1-15.6] versus 5.4 [3.9-6.8], P < .01), and higher PaO2 /FiO2 ratio (186 [135-236] versus 117 [103-162] mmHg, P = .03). To predict therapeutic failure, the supine diaphragmatic contraction speed presented sensitivity of 89% and a specificity of 57%, while the ROX index presented a sensitivity of 92.8% and a specificity of 75%. CONCLUSIONS: Diaphragmatic contraction speed by ultrasound emerges as a diagnostic complement to clinical tools to predict HFNC success. Future studies should confirm these results.

Respuesta virológica e inmunológica a la terapia anti-retroviral en pacientes portadores de infección por VIH atendidos en una red de salud académica de Chile / Virological and immunological outcomes to antiretroviral therapy in HIV-infected patients of an academic medical center in Chile

Introduction: Red Salud UC is an Academic health network where HIV-infected patients from the public and private health system are followed by a multidisplinary team. Aim: To determine virologic and immunologic response after 144 weeks of starting first antiretroviral therapy in these patients. Methods: A retrospective analysis of adult HIV patients attended between 1992 and 2011 was performed. Demographic and clinical characteristics, antiretroviral therapies data and immunologic and virologic outcomes were collected. CD4 count and HIV viral load changes up to 144 weeks after initiation of antiretroviral therapy were analyzed. Results: 860 patients were included in the analyses. Median age was 42 years, 93% were men. Median CD4+ count at baseline was 202 cells/mm³. The most used ART regimen was zidovudine/lamivudine plus efavirenz. First line anti-retroviral therapy was changed in 42% patients, being the most common cause, drug toxicity. At week 144, median CD4+ lymphocyte cell count was 449 cells/mm³. Ninety percent and 96% had undetectable viral load measured as < 50 copies/mL or < 400 copies/mL respectively. Discussion: First report of a university cohort, with CD4 and viral load follow up for 144 weeks, including Chilean patients from public and private system. After initiation of ART, an excellent immunologic and virologic response was observed in this cohort.

Introducción: La Red de Salud UC es una red académica de atención, donde pacientes portadores del VIH del área pública y privada de salud son atendidos por un equipo profesional multidisciplinario. Objetivo: Determinar las respuestas virológicas e inmunológicas a 144 semanas de iniciada la primera terapia antiretroviral en dichos pacientes. Métodos: Análisis retrospectivo de registros de pacientes adultos portadores de VIH atendidos entre 1992 y 2011. Se recolectaron datos demográficos, clínicos, terapia anti-retroviral, resultados inmunológicos y virológicos. Se analizaron los resultados de linfocitos T CD4+ y carga viral de VIH a las 144 semanas de iniciada la primera terapia anti-retroviral. Resultados: Fueron incluidos en el análisis 860 pacientes. El promedio de edad fue 42 años, 93% hombres. La mediana basal de LT CD4+ fue 202 céls/mm³. La terapia más utilizada fue zidovudina/lamivudina/efavirenz. En 42% de los pacientes se cambió la terapia de primera línea; la causa más común fue toxicidad a los anti-retrovirales. A la semana 144 de iniciada la terapia, la mediana de LT CD4+ fue de 449 céls/mm³. Alcanzaron cargas virales indetectables 90 y 96% con < 50 copias ARN/mL o < 400 copias ARN/mL respectivamente. Discusión: Primer reporte de pacientes tratados en un centro universitario, con seguimiento inmuno-virológico a 144 semanas, que incluye pacientes del área pública y privada de salud chilena. Después del inicio de la terapia, se observó una excelente respuesta inmuno-virológica.

Virological and immunological outcomes to antiretroviral therapy in HIV-infected patients of an academic medical center in Chile.

INTRODUCTION: Red Salud UC is an Academic health network where HIV-infected patients from the public and private health system are followed by a multidisplinary team. AIM: To determine virologic and immunologic response after 144 weeks of starting first antiretroviral therapy in these patients. METHODS: A retrospective analysis of adult HIV patients attended between 1992 and 2011 was performed. Demographic and clinical characteristics, antiretroviral therapies data and immunologic and virologic outcomes were collected. CD4 count and HIV viral load changes up to 144 weeks after initiation of antiretroviral therapy were analyzed. RESULTS: 860 patients were included in the analyses. Median age was 42 years, 93% were men. Median CD4+ count at baseline was 202 cells/mm³. The most used ART regimen was zidovudine/lamivudine plus efavirenz. First line anti-retroviral therapy was changed in 42% patients, being the most common cause, drug toxicity. At week 144, median CD4+ lymphocyte cell count was 449 cells/mm³. Ninety percent and 96% had undetectable viral load measured as < 50 copies/mL or < 400 copies/mL respectively. DISCUSSION: First report of a university cohort, with CD4 and viral load follow up for 144 weeks, including Chilean patients from public and private system. After initiation of ART, an excellent immunologic and virologic response was observed in this cohort.

[Bacterial identification based on protein mass spectrometry: A new insight at the microbiology of the 21st century]. / Identificación bacteriana basada en el espectro de masas de proteínas: Una nueva mirada a la microbiología del siglo XXI.

Bacterial identification is important for the proper treatment of infected patients hospitalized with serious infections especially in critical care units. Identification by conventional methods used in microbiology laboratories takes at least 16 hours since a culture is positive. The introduction of mass spectrometry, specifically MALDI-TOF MS (matrix-assisted laser desorption/ ionization time-of-flight mass spectrometer) in the microbiology laboratory could mean a radical change in the identification accuracy, turn around time (6 minutes per bacteria) and cost (about 5 times cheaper than conventional identification). Since its introduction in clinical microbiology laboratories in 2008, many reports about its usefulness in identifying microorganisms from colonies, as well as directly from positive blood cultures and urine samples have been published. This review describes MALDI-TOF MS methodology, its identification performance for bacteria (aerobic and anaerobic), mycobacterium and yeasts, its future applications in microbiology and its main disadvantages.

Identificación bacteriana basada en el espectro de masas de proteínas: Una nueva mirada a la microbiología del siglo XXI / Bacterial identification based on protein mass spectrometry: A new insight at the microbiology of the 21st century

Bacterial identification is important for the proper treatment of infected patients hospitalized with serious infections especially in critical care units. Identification by conventional methods used in microbiology laboratories takes at least 16 hours since a culture is positive. The introduction of mass spectrometry, specifically MALDI-TOF MS (matrix-assisted laser desorption/ ionization time-of-flight mass spectrometer) in the microbiology laboratory could mean a radical change in the identification accuracy, turn around time (6 minutes per bacteria) and cost (about 5 times cheaper than conventional identification). Since its introduction in clinical microbiology laboratories in 2008, many reports about its usefulness in identifying microorganisms from colonies, as well as directly from positive blood cultures and urine samples have been published. This review describes MALDI-TOF MS methodology, its identification performance for bacteria (aerobic and anaerobic), mycobacterium and yeasts, its future applications in microbiology and its main disadvantages.

La identificación bacteriana es muy importante en el manejo adecuado de los pacientes infectados, especialmente aquellos con infecciones graves hospitalizados en unidades de pacientes críticos. La identificación por los métodos convencionales utilizados en los laboratorios de microbiología clínica demora al menos 16 horas desde que un cultivo es positivo. La introducción de la espectrometría de masas, específicamente del espectrómetro de masas por tiempo de migración (tiempo de vuelo) con desorción/ionización laser asistida por una matriz (MALDI-TOF MS, por su sigla en inglés matrix-assisted laser desorption/ionization time-of-flight mass spectrometer), en el laboratorio de microbiología podría significar un cambio radical en la precisión de la identificación, el tiempo de detección (6 minutos por bacterias) y el costo (aproximadamente 5 veces más económico que la identificación convencional). Desde su introducción en los laboratorios de microbiología clínica en el año 2008, se han escrito numerosas publicaciones sobre su utilidad en la identificación de microorganismos desde colonias, así como directamente desde hemocultivos positivos y de muestras de orina. Esta revisión describe la metodología de MALDI-TOF MS, su rendimiento en la identificación de bacterias aerobias, anaerobias, micobacterias y levaduras, sus futuras aplicaciones en microbiología y sus principales desventajas.

Caracterización de los pacientes con diarrea asociada a clostridium difficile en el hospital dr. Gustavo Fricke entre los años 2003-2008 / Characterization of patients with clostridium difficile associated diarrhea in hospital dr. Gustavo Fricke between the years 2003-2008

Introducción: la mayoría de las diarreas nosocomiales en la población adulta son producidas por Clostridium diffícile. Suele asociarse con terapia antimocrobiana previa al cuadro clínico, en especial Clindamicina. Objetivo: caracterizar el cuadro de diarrea por C. diffícile, en pacientes hospitalizados en el Hospital Gustavo Fricke (HGF). Material y Método: se consideró el registro de exámenes del Laboratorio de Microbiología del Hospital para la detección de toxina A de C. diffícile desde Junio de 2003 a Marzo de 2008, debiendo excluirse 57 casos de 169 por registro incompleto. Se procedió a revisar fichas, tomando en cuenta 22 variables que se analizaron con el programa estadístico SPSS. Se define caso como aquel en que se detectó la toxina A en una muestra de deposiciones de un paciente con diarrea; resolución al cese de la diarrea a los 5 días de terapia con metronidazol oral en dosis convencionales; fracaso como la persistencia de diarrea luego de 5 días con metronidazol oral; recaída a la reaparición de diarrea con un nuevo examen de toxina A positiva luego de al menos una semana de evolucionar con deposiciones normales. Resultados: del total de 112 casos, 52,6 por ciento eran sexo masculino. El promedio de edad fue de 59,9 años. Un 45 por ciento del total de pacientes era diabético tipo 2 y un 41 por ciento hipertenso. Los diagnósticos de ingreso más frecuentes fueron neumonía adquirida en la comunidad (14,2 por ciento) y pie diabético complicado (12 por ciento). Se analizó el número de casos por servicio en relación a sus egresos durante el período en estudio, siendo el servicio más afectado la Unidad de Cuidados Intensivos con 0,45 por ciento casos por cada 100 egresos. Un 98 por ciento del total de pacientes tenía el antecedente de uso de antibiótico previo al inicio de síntomas, ya sea terapia antimicrobiana asociada o monoterapia. En ambos casos las cefalosporinas fueron los mas involucrados, destacando Ceftriaxona.

Introduction: the majority of nosocomial diarrhea in adults ar caused by Clostridium difficile. Often it is associated with antimicrobial therapy prior to clinical symptoms, especially clindamycin. Objective: to characterize C. difficile associated diarrhea in patients hospitalized in the Hospital Gustavo Fricke (HGF). Patients and Methods: we considered the record of examinations of the Laboratory of Microbiology of the detection of C. difficile toxin A from June 2003 to March 2008, with 57 cases excluded for incomplete record. We reviewed medical records, including 22 variables, analyzed with the statistical program SPSS. Case is defined as one in which the toxin A was detected in a stool sample from a patient with diarrhea, resolution as the cessation of diarrhea within 5 days of therapy with conventional-dose of oral metronidazole; failure as the persistence of diarrhea after 5 days with oral metronidazole; relapse as a recurrence of diarrhea with a new examination of toxin A positive after at least a week to move with normal stools. Results: a total of 112 cases were studied, 52,6 percent were male. The average age was 59.9 years. 45 percent of patients hay Type 2 Diabetes and 41 percent hypertension. The most frequent diagnosis on admission was community-acquired pseumonia (14.2 percent) and complicated diabetic foot (12 percent). We analyzed the number of cases by service in relation to their expenditures during the period under review, the most affected was the Intensive Care Unit with 0.45 cases per 100 discharges; 98 percent patients had a history of antibiotic use prior to onset of symptoms, either alone or associated with antimicrobial therapy. In both cases cepthalosporins were the most involved, including ceftriaxone.