Non-invasive functional evaluation of the reserve in fatigue and the diaphragm structure using transthoracic echography in B and M modes

The diaphragm is the principal respiratory muscle. Its special characteristics have made it difficult to design instruments capable of performing a non-invasive evaluation of its structure and function in humans. The present study was designed to evaluate the potential use of echography as a non-invasive method to fulfil these objectives.     

Modifications in ventricular fibrillation and capture capacity induced by a linear radiofrequency lesion

Introduction and objectives

An analysis was made of the effects of a radiofrequency-induced linear lesion during ventricular fibrillation and the capacity to capture myocardium through high-frequency pacing.

Methods

Using multiple epicardial electrodes, ventricular fibrillation was recorded in 22 isolated perfused rabbit hearts, analyzing the activation maps upon applying trains of stimuli at 3 different frequencies close to that of the arrhythmia: a) at baseline; b) after radio-frequency ablation to induce a lesion of the left ventricular free wall (length=10 [1] mm), and c) after lengthening the lesion (length=23 [2] mm).

Results

Following lesion induction, the regularity of the recorded signals decreased and significant variations in the direction of the activation fronts were observed. On lengthening the lesion, there was a slight increase in the episodes with at least 3 consecutive captures when pacing at cycles 10% longer than the arrhythmia (baseline: 0.6 [0.7]; initial lesion: 1 [1], no significant differences; lengthened lesion: 3 [2.8]; P<.001), while a decrease was observed in those obtained upon pacing at cycles 10% shorter than the arrhythmia.

Conclusions

The radio-frequency -induced lesion increases the heterogeneity of myocardial activation during ventricular fibrillation and modifies arrival of the activation fronts in the adjacent zones. High-frequency pacing during ventricular fibrillation produces occasional captures during at least 3 consecutive stimuli. The lengthened lesion in turn slightly increases capture capacity when using cycles slightly longer than the arrhythmia.Full English text available from:www.revespcardiol.org     

Transition from prostacyclin to bosentan in five patients with severe pulmonary hypertension: the switch is possible

Prostacyclin improves symptoms, exercise tolerance, and survival in patients with pulmonary arterial hypertension. However, the difficulty of administration (whether intravenous, subcutaneous, or by inhalation) often causes side effects that can reduce the patient's quality of life and which may sometimes be serious. Bosentan, an orally active endothelin receptor antagonist, improves functional class and exercise tolerance in these patients. We describe the successful transition from prostacyclin to bosentan in five patients with severe pulmonary arterial hypertension who suffered serious side effects with prostacyclin treatment.     

Design of a lung simulator for teaching lung mechanics in mechanical ventilation

Over the last 10 years, noninvasive ventilation has become a treatment option for respiratory insufficiency in pulmonology services. The technique is currently included in pulmonology teaching programs. Physicians and nurses should understand the devices they use and the interaction between the patient and the ventilator in terms of respiratory mechanics, adaptation, and synchronization. We present a readily assembled lung simulator for teaching purposes that is reproducible and interactive. Based on a bag-in-box system, this model allows the concepts of respiratory mechanics in mechanical ventilation to be taught simply and graphically in that it reproduces the patterns of restriction, obstruction, and the presence of leaks. It is possible to demonstrate how each ventilation parameter acts and the mechanical response elicited. It can also readily simulate asynchrony and demonstrate how this problem can be corrected.     

Nutritional Status in COPD

Changes in nutritional status, such as weight loss and malnutrition, are a very common complication in patients with chronic obstructive pulmonary disease (COPD). These changes primarily affect the patients' quality of life and functional capacity and they are also independent prognostic indicators of both morbidity and mortality. Malnutrition in these patients is due to multiple factors including increases in resting energy expenditure, decreased food intake, the effects of certain drugs, and, perhaps most importantly, a high systemic inflammatory response. The present review covers the most important facets of the prevalence, etiology, pathogenesis, and consequences of malnutrition in COPD and considers which parameters for nutritional assessment are the most satisfactory for use in routine clinical practice. The strategy used to ensure correct nutritional status in these patients is also discussed.     

Hemodynamic effects of levosimendan compared with dobutamine in patients with low cardiac output after cardiac surgery

INTRODUCTION AND OBJECTIVES: Levosimendan is an inotropic agent that is effective in the treatment of heart failure. However, experience with levosimendan in patients with reduced cardiac output following cardiopulmonary bypass is limited. The objective of this study was to compare the short-term hemodynamic effects of levosimendan with those of dobutamine in managing low cardiac output after cardiac surgery. METHODS: Forty-one patients who had low cardiac output after cardiopulmonary bypass were randomly assigned to dobutamine (n=20), 24-hour infusion of 7.5 microg/kg per min, or levosimendan (n=21), at a loading dose of 12 microg/kg followed by 24-hour infusion of 0.2 microg/kg per min. The following parameters were determined during a 48-hour observation period: arterial, central venous, pulmonary arterial and pulmonary capillary wedge pressure, cardiac index, heart rate, stroke volume, and systemic and pulmonary vascular resistance. RESULTS: Although both dobutamine and levosimendan improved the cardiac index, the increase was significantly greater with levosimendan (2.4 [0.2] l/min per m2 vs 2.9 [0.3] l/min per m2, respectively, at 24 h; P<.05). Moreover, levosimendan significantly reduced systemic and pulmonary vascular resistance, and significantly decreased systemic arterial, pulmonary arterial, pulmonary capillary wedge, and central venous pressure. CONCLUSIONS: Both dobutamine and levosimendan are effective in managing postoperative low cardiac output. However, levosimendan induces non-specific systemic, venous and pulmonary vasodilation which can result in hypotension as a adverse event. In these patients, it is advisable to omit or reduce the loading dose.     

The superior vena cava as a site of ectopic foci in atrial fibrillation

Radiofrequency catheter ablation of ectopic foci that trigger atrial fibrillation has been established as a curative method for patients with symptomatic paroxysmal atrial fibrillation. Although the majority of these foci are located in and around the pulmonary veins, other less common locations have been identified. Recognition that foci can lie outside the pulmonary veins is important for ensuring therapeutic success. The most frequently reported foci of ectopic activity outside the pulmonary veins are in the superior vena cava and the posterior wall of the left atrium. Here we report our experience with the ablation of ectopic foci located in the superior vena cava in patients with symptomatic paroxysmal atrial fibrillation.     

Benefits of cardiac resynchronization therapy in patients with atrial fibrillation who have not undergone atrioventricular node ablation

The aim of this study was to compare the effects of cardiac resynchronization therapy on left ventricular function and reverse remodeling in patients in sinus rhythm with the effects in patients with atrial fibrillation who have not undergone atrioventricular node ablation. Echocardiographic and clinical parameters were evaluated at baseline and after 6 months of cardiac resynchronization therapy in 55 patients: 15 had atrial fibrillation and 40 were in sinus rhythm. Device programming was similar in the 2 groups, as were the reductions in QRS interval and echocardiographic measures of asynchrony observed after implantation. However, although significant improvements in end-systolic volume and ejection fraction were seen in both groups, reverse remodeling was greater in patients in sinus rhythm (reduction in end-systolic volume 30.9%+/-24.6% vs 12.5%+/-18.6%; P=.024), as was the relative increase in ejection fraction (15.4%+/-12.6% vs 5.0%+/-7.2%; P=.010). Cardiac resynchronization therapy in patients with atrial fibrillation who had not undergone atrioventricular node ablation resulted in significant improvements in ejection fraction and reverse remodeling, but these were less than those observed in patients in sinus rhythm.     

Intestinal alterations in patients with a medullary lesion

Loss of bowel control is distressing for persons with a medullary lesion and affects their quality of life. The present study aims to provide an updated review of the topic. Impaired neural control of continence and defecation after a medullary lesion provokes bowel dysfunction, with a high prevalence of two main symptoms: fecal incontinence and constipation. The physiopathology of these disorders is correlated with the neurological characteristics of the lesion, and various physiopathologic patterns have been established that correlate with the clinical manifestations. Evaluation of bowel dysfunction in these patients is normally exclusively clinical and complementary examinations are rarely used, although they seem promising. Treatment is based on establishing a program of evacuation. However, despite correct application, the results can be unsatisfactory and consequently other therapeutic alternatives should be developed.     

The role of the pulmonologist in the assessment of disability in patients with respiratory disease

A high percentage of the individuals who consult respiratory medicine specialists are working adults, and these patients often complain that dyspnea on exertion hinders their ability to do their job. In other cases, patients are referred for assessment by those responsible for evaluating disability. Furthermore, diagnosis of a respiratory disease should be accompanied by a therapeutic regimen which, in addition to pharmacotherapy, should include advice on lifestyle, nutrition, and physical exercise and recommendations on the kind of work the patient can undertake. Pulmonologists are therefore heavily involved in the assessment of disability in patients with respiratory diseases. The aim of this review is to offer respiratory specialists a broad view of the medical and legal procedures used to evaluate functional impairment caused by respiratory disease, and suggest how they can make recommendations to these patients concerning the appropriate working conditions for the prevention and treatment of their disease.     

Migration Flow and Its Impact on Tuberculosis Notification in Portugal

Introduction

Tuberculosis notification in Portugal has decreased in the last few years. As a consequence of the economic crisis, emigration has increased and immigration has decreased. Immigrants are a risk group for tuberculosis. Most emigrants are 20–44 years old and belong to the age group most affected by tuberculosis.

Control microbiológico ambiental

The inanimate hospital environment is rarely implicated in infection transmission, except among vulnerable patients. Some authors argue against the use of environmental surveillance cultures because the tests can be expensive and time consuming, and because they should not be used instead of quality control and good practices in disinfection and maintenance procedures.     

Nutritional support in patients with liver cirrhosis

Given the liver's multiple synthetic, regulatory and detoxifying functions, one of the characteristics accompanying severe hepatocellular dysfunction is the presence of malnutrition. This disorder is highly frequent in liver cirrhosis, even in the relatively early stages of the disease. Independently of the cause of the cirrhosis, poor nutritional status is associated with a worse prognosis and therefore early intervention to correct nutrient deficiency can prolong life expectancy, improve quality of life, reduce complications and increase the probability of successful transplantation. The present article reviews current knowledge of the diagnosis and management of malnutrition in patients with cirrhosis. Special attention is paid to the concept of the late evening snack and its characteristics, composition and probable benefits in the course of the disease.