Rodrigo Ramos de Freitas

Tetralogia de Fallot em cão

Tetralogy of Fallot is a congenital cardiac disease characterized by the presence of hypoxemia because of the pulmonary stenosis and the ventricular septal defect. The symptom in the animal is cianosis. Actually, there are many diagnostic methods of this affection. There are many treatments for Tetralogy of Fallot, such as the medicamentosus treatment and the definitive surgical correction, reparing the cardiac defects. The most used is the palliative surgical treatment, creating systemic-pulmonar shunt. The most famous surgical method is the Blalock-Taussig surgery, when the surgeon creates a communication between the aorta and pulmonary artery, using the left subclavian artery.

Tracheal morphometrics in the Thoroughbred horse

Abstract Equine tracheal lesions have been associated with the orotracheal intubation procedure. These lesions may occur because of differences in the dimensions of the endotracheal tube and the trachea. The importance of the dimensions of the trachea for studies on respiratory mechanics and the lesions produced by the endotracheal tubes encouraged us to determine the size of trachea of the Thoroughbred horse. This study determined and compared the length and internal diameters of the tracheas from 59 Thoroughbred horses, 35 males and 34 females, weighing between 400 kg and 500 kg, and free of signs of respiratory or cardiopulmonary diseases. The tracheas were removed from the horses between 2 and 12 hours after death. The internal diameters were measured in tracheal rings one, twenty, forty and the last before the carina. The length of each trachea was measured in both the normal and extended state. The number of tracheal rings was also determined. In the unstretched trachea, the width of the last tracheal ring and the number of tracheal rings were significantly greater in males than females. The results of this study provide information for better design and manufacturing of endotracheal tubes and as basic information for further studies on equine respiratory mechanics.

Estudo comparativo entre sutura manual e mecânica de coto brônquico em cães submetidos à pneumonectomia esquerda: avaliação histopatológica do pulmão direito e avaliação eletrocardiográfica

The study had purpose to evaluate the possible electrocardiographical alterations and the histopathological alterations in the lung of dogs submited by left pneumonectomy with comparative approach between two types of suture of bronchial stamp (manual and mechanical). We used twelve dogs, males and females, adults, mongrel dogs, weighting between 15 and 20 kilograms and evaluated the macroscopic alterations of right lung and the alterations of electrocardiogram. All animals showed clinical condition satisfactory in the post operated time. The electrocardiographical alterations were deviation of cardiac axis, sinoatrial block and miocardial isquemia. The histopathological alterations were pulmonary atelectasis, proliferations of bronchiole epithelium tended to obliterations and pulmonary emphysema. The study suggested that right lung was submited to pulmonary hipertension.

Anatomicosurgical segmentectomy of the left ventricle for systematized partial resection of the heart: an experimental study

A surgical experimental investigation is being carried out in an attempt to provide a viable alternative to the current approaches to cardiac resection of the left ventricular myocardium in cases of cardiomyopathies with dilated ventricle. The experiments are based upon the presence of anatomicosurgical segments in the dogs heart similar to those existing in the atria and ventricles of humans. So far three mongrel dogs (weight 15 kg) were submitted to cardiac catheterism to evaluate the anatomy of the coronary arteries and their branches, the function and cavity of the left ventricle (LV). A lateral thoracotomy on the left side was performed to expose the heart. Cardiopulmonary bypass (CPB) of each animal was established through the right atrium and the femoral artery (4 mg/kg Heparin, at 32°C, intermittent aorta cross-clamping). The left marginal artery and veins were ligated, causing an area of acute myocardial infarction, showing well-defined sharp limits. Such an area was then resected and the left ventricle was reconstructed. The animals were weaned from CPB, one dog having remained in a stable condition during a 7-day period of observation. The second was sacrificed after 4-day period of observation and the third dog died four hours after CPB owing to an excessive reduction of the LV chamber related to an anatomical variation. Pre and post operation transthoracic echocardiograms were obtained after undergoing cardiac catheterism. The echocardiogram revealed discrete mitral insufficiency, reduction of the diameter of the left ventricle with approximation of the papillary muscles, a dysfunction and an impressive reduction of the cavity of the left ventricle. Peri-sutural areas of infarction were not observed. The orientation given by the anatomicosurgical segmentation of the coronary circulation is an important alternative to the present surgical treatment of cardiomyopathies with dilated ventricle.

Avaliação hemogasométrica em cães submetidos à pneumonectomia esquerda

It is well known that different diseases of infectious, traumatic or neoplasic origin can occur in the lungs of dogs, and pneumonectomy technique may be an option for the treatment of some of these diseases. The objective was to evaluate hemogasometric parameters, oxygen partial pressure (PaO2), carbon dioxide partial pressure (PaCO2), hydrogen ion concentration (pH) and bicarbonate ion concentration on the pre- and post-operative moments of the left pneumonectomy. Eighteen adult mongrel dogs, males and females, were randomly distributed into two groups with 9 dogs each. In Group A, the left bronchial stump of the dogs was sutured manually with polypropylene 5-0, and, in Group B, the left bronchial stump of the dogs was sutured mechanically with a surgical stapler. The data were collected at 6 moments: Before the pre-anesthetic administration (T0), one hour after the extubation (T1EXT), 48 hours after the surgery (T48h), 7 days after the surgery (T7d), 15 days after the surgery (T15d), and 36 days after the surgery (T36d). The results were statistically analyzed. PaO2 values of Group A on T1EXT (67.00±11.31) were significantly lower in relation to T0 (99.4±18.34), a fact that did not happen in Group B: T1EXT (87.00±8.35) in regard to T0 (87.00±7.55). There was no difference on pH values in dogs of Group A, but in Group B was observed a decrease on T1EXT (7.3644±0.0353) in relation to T0 (7.4189±0.0136), although the animals did not develop acidosis. It was concluded that dogs submitted to left pneumonectomy (sutured manually or sutured mechanically of left bronchial) did not show immediate and mediate acid-basic instability during the study.