Lung histopathological findings in fatal pandemic influenza A (H1N1).

OBJECTIVE: To describe the lung pathological changes in influenza A (H1N1) viral pneumonia. We studied morphological changes, nitro-oxidative stress and the presence of viral proteins in lung tissue. METHODS AND PATIENTS: Light microscopy was used to examine lung tissue from 6 fatal cases of pandemic influenza A (H1N1) viral pneumonia. Fluorescence for oxidized dihydroethydium, nitrotyrosine, inducible NO synthase (NOS2) and human influenza A nucleoprotein (NP) (for analysis under confocal microscopy) was also studied in lung tissue specimens. RESULTS: Age ranged from 15 to 50 years. Three patients were women, and 5 had preexisting medical conditions. Diffuse alveolar damage (DAD) was present in 5 cases (as evidenced by hyaline membrane formation, alveolo-capillary wall thickening and PMN infiltrates), and interstitial fibrosis in one case. In the fluorescence studies there were signs of oxygen radical generation, increased NOS2 protein and protein nitration in lung tissue samples, regardless of the duration of ICU admission. Viral NP was found in lung tissue samples from three patients. Type I pneumocytes and macrophages harbored viral NP, as evidenced by confocal immunofluorescence microscopy. CONCLUSIONS: Lung tissue from patients with pandemic influenza A (H1N1) viral pneumonia shows histological findings consistent with DAD. Prolonged nitro-oxidative stress is present despite antiviral treatment. Viral proteins may remain in lung tissue for prolonged periods of time, lodged in macrophages and type I pneumocytes.

[Latin American survey on delirium in critical patients]. / Encuesta iberoamericana sobre delirium en pacientes críticos.

OBJECTIVES: This study has aimed to establish the intensivist physician's concepts and practices in this region regarding the diagnosis, management and prevention of delirium in intensive care units (ICU). DESIGN: A survey was distributed among the FEPIMCTI member societies for distribution among its medical members. RESULTS: Eight hundred fifty-four intensive care physicians from 12 Latin America countries, most of them from Argentina, Mexico, Chile and Colombia, responded to the survey. There was a majority of academic ICUs (70.5%). A total of 56.55% responded that they always evaluated the diagnosis of delirium and only 10.2% answered never. A general clinical assessment was made by 69.5%, only 19.6% used the CAM-ICU scale and 9% the checklist assessment of delirium. It was agreed or strongly agreed by 88.3% that delirium was an expected event in the ICU and by 90.1% that delirium was underdiagnosed in ICU. A total of 97% responded that it was a problem that requires intervention and which is preventable (66.5%). It was considered that excessive sedation is given in the ICU by 74.5% and 70.5% believed that opiates are associated with the onset of delirium, while 87.1% considered that some sedatives are associated with its development. Ventilator-associated pneumonia (VAP) was considered as a risk factor by 70.2% of the respondents and 87.8% considered that it made extubation difficult. CONCLUSIONS: Although delirium is considered to be a common and preventable problem with serious implications for critically ill patients, the intensivist physicians surveyed do not use a tool for its evaluation in the ICU. Educational efforts are needed to disseminate the effectiveness and usefulness of the scales that allow for early and accurate diagnosis of delirium in the ICU.

BIPAP (Biphasic Positive Airway Pressure): un modo ventilatorio no convencional / Biphasic positive airway pressure: a non conventional ventilatory mode

La presente revisión, realizada con la recopilación y el análisis de la bibliografía obtenida por intermedio de MEDLINE, tiene por objeto estudiar un modo ventilatorio no convencional, destacar las ventajas terapéuticas de su aplicación en Terapia Intensiva y lograr una mayor difusión del mismo. Biphasic Positive Airway Pressure (BIPAP) es un modo ventilatorio limitado por presión ciclado por tiempo, donde dos niveles de Continuous Positive Airway Pressure (CPAP) diferentes, que alternan a intervalos de tiempo preestablecidos, determinan la ventilación mecánica. Además permite la respiración espontánea del paciente, sin límites en ambos valores de CPAP y en cualquier momento del ciclo respiratorio. La duración de cada fase (Tlow, Thigh), como los niveles de presión correspondientes (Plow, Phigh) son programados independientemente y de esta manera es posible modificar la proporción del componente mecánico y el trabajo realizado por el paciente. La combinación de respiración mecánica y espontánea mejora el intercambio gaseoso, optimiza la disponibilidad de oxígeno y favorece la adaptación del paciente al aparato, en consecuencia disminuye la necesidad de sedación y relajación. Finalmente proponemos modificar la actual denominación a "BIFPAP" y contribuir a esclarecer la confusión existente con Bilevel Positive Airway Pressure (BiPAP), un método no invasivo y ampliamente utilizado