Neumomediastino en pacientes con COVID-19 ingresados en UCI: serie de casos y revisión de la literatura / [Pneumomediastinum in patients with COVID-19 admitted to the ICU: case series and review of the literature]

Tras declaración de pandemia en febrero de 2020, se observa un aumento de casos de neumonías bilaterales con insuficiencia respiratoria grave, complicadas a su vez con neumomediastino. Se describe una serie de cuatro pacientes con neumomediastino asociado a distress respiratorio por neumonía por SARS-CoV-2 ingresados en cuidados intensivos del Hospital Universitario Rey Juan Carlos entre diciembre 2020 y enero 2021. En su mayoría son hombres de mediana edad, sin patología pulmonar previa, no fumadores, que han necesitado ventilación mecánica. El diagnóstico de neumomediastino se ha realizado mediante tomografía computarizada y el tratamiento ha sido conservador, con resolución total en todos los casos. Aunque esta complicación es un indicador de destrucción pulmonar y condiciona cambios en el manejo de la ventilación mecánica, no parece estar directamente relacionada con peor pronóstico o aumento de la mortalidad. (AU)

After the declaration of a pandemic in February 2020, an increase in cases of bilateral pneumonia with severe respiratory failure, in turn complicated by pneumomediastinum, has been observed. A series of four patients with pneumomediastinum associated with respiratory distress due to SARS-CoV-2 pneumonia admitted to intensive care at the Rey Juan Carlos University Hospital between December 2020 and January 2021 is described. Most of them are middle-aged men, without previous pulmonary pathology, non- smokers, who have required mechanical ventilation. The diagnosis of pneumomediastinum has been made by computed tomography and the treatment has been conservative, with complete resolution in all cases. Although this complication is an indicator of lung destruction and determines changes in the management of mechanical ventilation, it does not seem to be directly related to a worse prognosis or increased mortality. (AU)

Detection of myocardial infarction in dogs by contrast enhanced sequential CT scans.

Surgically induced myocardial infarcts were studied in ten dogs by contrast enhanced computer transmission tomography at several stages of the infarct evolution. The hearts were scanned sequentially at 3.4 second intervals during intravenous bolus injection of contrast medium and every five minutes following the completion of a ten minute contrast medium infusion. Cardiac borders including those of the infarctions were defined by computer graphic techniques. Data from several consecutive scans were combined into one image; the ventricular chamber boundaries and those of the epicardium were reconstructed from images taken during the bolus injection. Images taken during the contrast medium washout phase were used for infarct area determination. A statistical definition of the boundary between normal tissue and infarcted myocardium was obtained which correlated well with autopsy measurements. Image analysis as described here may serve as a basis for infarct volume estimates as well as differentiation between acute and chronic infarctions.

Ultrasound imaging and identification of microcalcification clusters by correlation of scatter from multiple angles.

Various types of malignant and benign breast tumors are associated with clusters of calcifications with grain sizes 0.1 to a few mm spread out over volumes of a few cc. A series of phantoms containing calcium carbonate grains embedded in a gelatin mixture were made and the ultrasound scattering patterns were measured with 2.25 MHz transducers. Scatterings from the calcifications were distinguished from the larger reflections from tissue interfaces by computer correlation of the signals obtained from transducers placed at three different angles. An automatic gain control detection system was developed for the purpose of amplifying the signal to the right level for the computer correlation and to compensate for the attenuation of the ultrasound in the tissue.

Medical Positron Imaging with a Dense Drift Space MultiWire Proportional Chamber.

A multiplanar positron camera is proposed, made of six MWPC modules, arranged to form the lateral surface of a hexagonal prism. Each 50 x 50 cm(2) module has a single MWPC sandwiched by two 2-cm thick lead glass tube converters. The experimental results for a 15 x 15 cm(2) test module are reported. For 511 keV gamma-rays incident almost perpendicular onto a 1.0-cm thick converter, a detection efficiency of 4.3%, a time resolution of 130 ns (FWHM) and a spatial resolution of 2.8 mm (FWHM) have been measured with a standard Argon-Methane (70-30) mixture at 1.2 atm. The chamber may also be operated in high resolution mode: 1.2-mm (FWHM) spatial resolution has been measured at a 50% lower efficiency. The use of fast delay lines (specific delay 8 ns/cm) for the position read-out ensures a high rate capability. The expected performance of the six-module MWPC camera is discussed and compared with that of a BGO crystal ring camera. The MWPC solution seems very attractive not only for its low cost and simplicity of construction, but also for its fully three-dimensional imaging capability.

Marked suppression of thyroid function in rats with gram-negative septicemia.

Gram-negative septicemia was induced in rats by two daily injections of fecal mixture into the thigh, after which the thyroid function was markedly suppressed for 2 days. Iodine metabolism was studied by organ radioassay and by imaging with a multiwire proportional chamber (MWPC) at various time intervals after intravenous injection of 125I. Plasma T3, T4, and TSH, measured by radioimmunoassays, were suppressed, as were the T3-resin uptakes. Fractional blood supply to the thyroid glands of the infected rats, studied by the 81Rb uptake method, was also found to be markedly reduced. Sections of the thyroid glands showed little structural change during the period of marked thyroid suppression. There was no biochemical evidence of renal failure in the septicemic rats.