Edson Azevedo Simões

Comparing the Performance of Rat Lungs Preserved for 6 or 12 Hours After Perfusion With Low-Potassium Dextran or Histidine–Tryptophan–Ketoglutarate

INTRODUCTION In lung transplantation, graft dysfunction is a frequent cause of mortality; the etiopathogenesis is related to ischemia-reperfusion injury. We sought to compare the lung performance of rats after reperfusion after presentation with 3 solutions at 2 ischemia times. METHODS We randomized 60 male Wistar rats to undergo anterograde perfusion via the pulmonary artery with low-potassium dextran (LPD), histidine-tryptophan ketoglutarate (HTK), or saline. After extraction, the heart-lung blocks were preserved in a solution at hypothermia for 6 or 12 hours before perfusion with homologous blood for 60 minutes using ex vivo system Isolated Perfused Rat or Guinea Pig Lung System (Harvard Apparatus). Respiratory mechanics, pulmonary weight, pulmonary artery pressure (PAP), and relative lung oxygenation capacity (ROC) measurements were obtained every 10 minutes. RESULTS Comparing tidal volume (TV), compliance, resistance, ROC, PAP, and pulmonary weight the LPD, HTK, and saline group did not differ at 6 and 12 hours. The TV was higher in the lungs with 6-hour ischemia in the LPD, HTK, and saline groups. Compliance was higher in the lungs with 6-hour ischemia in the LPD and saline groups. There were no differences in ROC values comparing lungs with 6- versus 12-hour ischemia in the LPD group. A significant difference was observed between lungs in the HTK and saline groups. Resistance was higher in the lungs with 12-hour ischemia among the LPD, HTK, and saline groups. There was a gradual weight increase in the lungs, particularly those undergoing 12-hour ischemia, despite the absence of a significant difference between groups. CONCLUSION Rat lungs perfused with LPD and HTK preservation solutions showed similar reperfusion performances in this ex-vivo perfusion model.

Modelo experimental de perfusão pulmonar ex vivo em ratos: avaliação histopatológica e de apoptose celular em pulmões preservados com solução de baixo potássio dextrana vs. solução histidina-triptofano-cetoglutarato

OBJECTIVE: To compare histopathological findings and the degree of apoptosis among rat lungs preserved with low-potassium dextran (LPD) solution, histidine-tryptophan-ketoglutarate (HTK) solution, or normal saline (NS) at two ischemia periods (6 h and 12 h) using an experimental rat model of ex vivo lung perfusion. METHODS: Sixty Wistar rats were anesthetized, randomized, and submitted to antegrade perfusion via pulmonary artery with one of the preservation solutions. Following en bloc extraction, the heart-lung blocks were preserved for 6 h or 12 h at 4oC and then reperfused with homologous blood for 60 min in an ex vivo lung perfusion system. At the end of the reperfusion, fragments of the middle lobe were extracted and processed for histopathological examination. The parameters evaluated were congestion, alveolar edema, alveolar hemorrhage, inflammatory infiltrate, and interstitial infiltrate. The degree of apoptosis was assessed using the TdT-mediated dUTP nick end labeling method. RESULTS: The histopathological examination showed that all of the lungs preserved with NS presented alveolar edema after 12 h of ischemia. There were no statistically significant differences among the groups in terms of the degree of apoptosis. CONCLUSIONS: In this study, the histopathological and apoptosis findings were similar with the use of either LPD or HTK solutions, whereas the occurrence of edema was significantly more common with the use of NS.

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.

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.

Viabilidade da pneumonectomia direita em cães: uma avaliação paramétrica, hemogasométrica e radiográfica

In dogs, the evidence of viability of the right pneumonectomy, as well as the study of complications resulting from surgical procedure, are very important regarding the few specific studies made on the pneumonectomy in this animal species. The objective of this project was to carry out an experimental study to evaluate the viability of the right pneumonectomy in dogs through parametric, hemogasometric and radiographic evaluation. Ten adult healthy mongrel dogs, males and females, weighing 13-32 kg, were used. The dogs were submitted to selective intubation and right thoracotomy at the 5th intercostal space, where the pneumonectomy was performed. A radiografic evaluation was made on days 7, 30 and 60 after the surgery, as well as parametric and hemogasometric evaluations were done (before anesthetic induction, 1 hour after extubation, 48 hours and on days 7, 30 and 60 after the surgical procedure), considered important to evaluate possible complications due to the anesthetic and surgical techniques, as well as complications resulting from these procedures. The results were analyzed statistically. Besides the parametric and hemogasometric alterations, all dogs showed compensation for the gaseous exchanges after removing 57% of the pulmonary volume. Regarding the radiographic evaluation, it could be observed that the expansion of the remaining lung caused heart and lung displacement into the right hemithorax. It can be concluded that the right pneumonectomy is completely feasible in dogs, allowing a parametric, hemogasometric and radiographic satisfactory evaluation in all the animals.

Avaliação eletrocardiográfica em cães submetidos à pneumonectomia direita

The purpose for using lobectomy or pneumonectomy in dogs and cats, is to cure or palliate of bronchopulmonary diseases whenever conservative clinical treatment proves ineffective. Considering the marked changes caused by pneumonectomy, new experimental studies have to be done to assess the advantages of this surgical intervention allow its performance without any risk. The aim of the current study was to evaluate the electrocardiographic alterations in ten adult mongrel dogs of both sexes with between 10 and 30 Kg that were submitted to right pneumonectomy. The clinical parameters of the dogs were evaluated in a daily basis and the alterations in every electrocardiogram derivation were recorded. All dogs presented a good post-operative outcome. In most cases there were no electrocardiographic alterations; when these alterations were observed they were of no clinical significance and included premature ventricular complexes in one dog, most likely resulting from a cardiorespiratory arrest that was reverted to successfully, and a decreased width in the QRS complex amplitude on the first 0-14 days post surgery which returned to normal after sixty days post surgery.