Quantification of diffuse myocardial fibrosis using CMR extracellular volume fraction and serum biomarkers of collagen turnover with histologic quantification as standard of reference.

PURPOSE: To compare the assessment of diffuse interstitial myocardial fibrosis in valvular diseases using cardiac magnetic resonance (CMR) extracellular volume fraction (ECV) quantification and serum biomarkers of collagen turnover using results of myocardial biopsy as standard of reference. MATERIALS AND METHODS: This prospective monocentric study included consecutive patients before aortic valvular replacement. All patients underwent: i), 1.5T CMR with pre and post contrast T1 mapping sequence and ECV computation; ii), serum quantification of matrix metalloproteinases (MMPs) and tissue inhibitor of metalloproteinases (TIMPs) and iii), myocardial biopsies were collected during surgery to assess collagen volume fraction (CVF). Patients with coronary artery disease were excluded. Correlation between native T1, ECV, CVF and serum biomarkers were assessed using Pearson correlation test. Agreement between basal anteroseptal ECV with global ECV was assessed using Bland-Altman test. RESULTS: Twenty-one patients, 16 with aortic stenosis and 5 with aortic regurgitation were included. There were 12 men and 9 women with a mean age of 74.1±6.8 (SD) years (range: 32-84 years). Mean global ECV value was 26.7±2.7 (SD) % (range: 23.4-32.5%) and mean CVF value was 12.4±9.7% (range: 3.2-25.7%). ECV assessed at the basal anteroseptal segment correlated moderately with CVF (r=0.6; P=0.0026). There was a strong correlation and agreement between basal anteroseptal ECV and global ECV, (r=0.8; P<0.0001; bias 5.4±6.1%) but no correlation between global ECV and CVF (r=0.5; P=0.10). Global ECV poorly correlated with serum TIMP-1 (r=0.4; P=0.037) and MMP-2 (r=0.4; P=0.047). No correlation was found between serum biomarkers and basal anteroseptal- ECV or native T1. CONCLUSION: In patients with severe aortic valvulopathy, diffuse myocardial fibrosis assessed by anterosepto-basal ECV correlates with histological myocardial fibrosis. Anteroseptobasal ECV strongly correlates with global ECV, which poorly correlates with TIMP-1 and MMP-2, serum biomarkers involved in the progression of heart failure.

Liver hypertrophy: Underlying mechanisms and promoting procedures before major hepatectomy.

Various procedures can promote hypertrophy of the future liver remnant (FLR) before major hepatectomy to prevent postoperative liver failure. The pathophysiological situation following portal vein embolization (PVE), hepatic artery ligation/embolization or hepatectomy remains unclear. On one hand, the main mechanisms of hepatic regeneration appear to be driven by hepatic hypoxia (involving the hepatic arterial buffer response), an increased portal blood flow inducing shear stress and the involvement of several mediators (inflammatory cytokines, vasoregulators, growth factors, eicosanoids and several hormones). On the other hand, several factors are associated with impaired liver regeneration, such as biliary obstruction, malnutrition, diabetes mellitus, male gender, age, ethanol and viral infection. All these mechanisms may explain the varying degrees of hypertrophy observed following a surgical or radiological procedure promoting hypertrophy the FLR. Radiological procedures include left and right portal vein embolization (extended or not to segment 4), sequential PVE and hepatic vein embolization (HVE), and more recently combined PVE and HVE. Surgical procedures include associated liver partition and portal vein ligation for staged hepatectomy, and more recently the combined portal embolization and arterial ligation procedure. This review aimed to clarify the pathophysiology of liver regeneration; it also describes radiological or surgical procedures employed to improve liver regeneration in terms of volumetric changes, the feasibility of the second step and the benefits and drawbacks of each procedure.

Looking for a lost subdermal contraceptive implant? Think about the pulmonary artery.

This case highlights a rare but potentially life-threatening complication of a contraceptive implant insertion that was corrected by a noninvasive endovascular procedure. This procedure requires a quick intervention to be successful.

Utilidad del catéter central de acceso periférico (PICC) en recién nacidos prematuros de la unidad de cuidado intensivo neonatal de la Clínica General del Norte / Suitability of peripherally inserted central catheter (PICC) in pre-term newborn infants in the neonatal intensive care unit of the Clínica General del Norte

Introducción: siendo cada vez mayor la sobrevida de recién nacidos prematuros en Colombia, se necesita implementar unidades de cuidado intensivo neonatal que permitan una atención de calidad en todos los aspectos que atañen a estos pacientes. Generalmente, la atención de los prematuros está enfocada al uso de ventiladores, óxido nítrico y aplicación de surfactante, pero un punto en común para los neonatos que ingresan a una unidad de cuidado intensivo, es que definitivamente necesitan tener un buen acceso venoso y de preferencia, por vía central. Mucho se discute sobre el uso, colocación, tiempo de estancia y complicaciones de catéteres umbilicales o líneas centrales, por lo que la canalización con catéter central de acceso periférico ofrece un método confiable y seguro, siendo un procedimiento que no implica trasladar al paciente al quirófano y que puede realizarlo el personal de enfermería con mucho éxito.\r\nMétodo: en el estudio se incluyeron 230 neonatos que ingresaron a la unidad de cuidado intensivo neonatal entre septiembre de 2009 y septiembre de 2010; a estos neonatos se les colocó un catéter central de acceso periférico según lo establecido en la Unidad de Cuidado Intensivo, de acuerdo a la patología, peso, edad gestacional del paciente y medicaciones a usar. Se estableció además, sitio de inserción, tiempo de estancia y complicaciones presentadas.\r\nResultados: los 230 neonatos que ingresaron al estudio corresponden al 8.1% de todos los nacimientos. El 66,5% de los neonatos pesó entre 1501 gr y 2500 gr. En el 32% de los neonatos la vena periférica más utilizada fue la basílica. Solo 12% de los casos presentó algún tipo de complicación mecánica y un 6% de los recién nacidos prematuros se colonizó en la primera semana de vida.\r\nConclusión: la aplicación del catéter central de acceso periférico mostró ser útil en la Clínica General del Norte. El personal de la Unidad de Cuidado Intensivo evidenció disminución de punciones periféricas, disminución en el tiempo para la consecución de una vía venosa central, que no era necesaria la presencia del cirujano pediatra en la mayoría de los casos, que el número de las complicaciones era bajo y además, que hubo un descenso en las infecciones en los recién nacidos ingresados en la unidad neonatal durante el período de estudio.

Introduction: the increase in survival of preterm newborn infants in Colombia indicates the need for the implementation of neonatal intensive care units to enable quality care in all aspects pertaining to these patients. Generally, the care of preterm babies focuses on the use of ventilators, nitric oxide, and surfactant application, but what all newborns that enter an intensive care unit have in common is that they definitely need to have good venous access and preferably, through a central venous system. There are numerous discussions on the use, placement, extent of time, and complications of the umbilical catheter or central lines. The peripherally inserted central catheter is a safe and reliable method to have an adequate center vascular access from a peripheral vein, the patient does not need to be move to the operating room and the procedure can be performed by the nursing staff with a great success.\r\nMethods: 230 newborns admitted to the neonatal intensive care unit were enrolled in the study, from September 2009 to September 2010. The babies underwent a placement of a peripherally inserted central catheter following the protocol of the intensive care unit, according to pathology, weight, gestational age and medications. The insertion site, length of time, and complications were also established.\r\nResults: the 230 babies enrolled in the study represented 8.1% of all births. 66.5% of babies weighed between 1501 and 2500 gr. In 32% of the newborns the most used peripheral vein was the basilica. Only 12% of cases had some type of mechanical complications and 6% of preterm infants were colonized in the first week of life.\r\nConclusions: the application of peripherally inserted central catheter showed to be useful at the Clínica General del Norte. The staff of the intensive care unit evidenced minimizing of the peripheral canalizations, a reduction in the time it took to find a central venous line, that in the majority of cases the presence of the pediatric surgeon was not required to achieve a central venous, the number of complications was minimal, and a decline of infections in newborns admitted to the neonatal unit during the study period.

Pneumothorax.

This article discusses different types of pneumothorax and aspects of management, including physiotherapy and the insertion and removal of chest drains.

Evaluation of nebulised acetylcysteine and normal saline in the treatment of sputum retention following thoracotomy.

BACKGROUND: The use of acetylcysteine as a mucolytic agent is controversial. In 1962 it was claimed to be "the most effective agent ... for the liquefaction of ... secretions" but was subsequently taken off the market as a respirator solution. Normal saline, on the other hand, is becoming increasingly popular. A study was undertaken to determine which solution is more effective at clearing retained secretions following thoracotomy. METHODS: The study included 10 patients and was of single blind, two-way crossover design. Measurements taken before and after each treatment included sputum viscosity, difficulty of expectoration, weight of sputum expectorated, and oxygen saturation. RESULTS: Following nebulisation of acetylcysteine, sputum viscosity was reduced, difficulty of expectoration was reduced, the weight of sputum expectorated was increased, and oxygen saturation was increased. There were no changes after nebulisation of normal saline. CONCLUSIONS: This study shows that, following thoracotomy, nebulised acetylcysteine reduces sputum viscosity, making expectoration easier and improving oxygenation. Nebulised normal saline has no effect.

The reaction of low levels of nitrogen dioxide with methyl linoleate in the presence and absence of oxygen.

The reaction of methyl linoleate with low levels of nitrogen dioxide in a carrier gas, such as helium or air, at nitrogen dioxide concentrations ranging from 2 to 228 ppm was studied and the products formed were monitored. In both aerobic and anaerobic conditions, low concentrations of nitrogen dioxide reacted with methyl linoleate predominantly to form allylic products. When a 1:1 mixture of methyl palmitate/methyl linoleate was layered over an aqueous buffer and a nitrogen dioxide stream was passed from underneath, so that the stream passed through the aqueous layer before contacting the organic layer, allylic products again predominated. In the absence of air, the allylic products consisted of allylic nitro and nitrite, derivatives of linoleate, whereas in the presence of air, allylic hydroperoxides were the principal products. The findings suggest that fatty acids with doubly allylic hydrogen atoms react preferentially by a hydrogen atom abstraction reaction rather than by the addition of nitrogen dioxide to a double bond.

The identification of the allylic nitrite and nitro derivatives of methyl linoleate and methyl linolenate by negative chemical ionization mass spectroscopy.

The autoxidation of polyunsaturated fatty acids is initiated both in vivo and in vitro by nitrogen dioxide. The mechanism of the initiation process is believed to involve both addition reactions and hydrogen atom abstraction reactions, with hydrogen abstraction predominating at low levels of nitrogen dioxide. Therefore low levels of nitrogen dioxide should react with polyunsaturated fatty acids to give allylic derivatives; in an anaerobic system these derivations should be allylic nitro and nitrite compounds. Using negative methane chemical ionization mass spectrometry and other analytical techniques, we have identified these allylic nitrite and nitro compounds from the reactions of low levels of nitrogen dioxide with methyl linoleate and methyl linolenate in the absence of oxygen.

Evaluation of chest percussion in the treatment of patients with copious sputum production.

The effect of manual chest percussion was studied in nine patients with copious sputum production. Treatment consisting of postural drainage (PD) and the forced expiration technique (FET) produced sputum at the rate of 0.831 g min-1. When percussion was included in the treatment regimen, the rate of sputum production was significantly greater (P less than 0.05), being 1.231 g min-1 for fast percussion and 1.040 g min-1 for slow percussion. Pulmonary function and oxygen saturation were unaffected by any of the treatment regimens. This study demonstrates that manual chest percussion is a useful adjunct to PD and FET in the treatment of patients with copious sputum production.