Rogerio Gastal Xavier

Desenvolvimento de uma órtese de Dumon modificada para aplicações traqueais: um estudo experimental em cães

OBJECTIVE: To describe the development of a silicone stent and perform in vivo testing for biocompatibility/applicability in the normal canine trachea. METHODS: Four different densities were tested in order to obtain the silicone prototypes. The pressure required for compression considering a contact area of 1 cm2, and a 30% reduction in diameter was calculated for each density. The best density was 70-75 Shore A hardness. Powdered barium sulfate was added to the silicone to make the stent radiopaque and easily identifiable in radiological imaging. This novel stent presents a corrugated external surface with discontinuous and protruding arcs resembling the tracheobronchial rings (for intercalation and fixation in the lumen of the lower airways), a highly polished inner surface and smooth extremities (to prevent friction-related damage). The prototype considered most appropriate in terms of rigidity and flexibility was bronchoscopically implanted in normal canine tracheas. After eight weeks, the animals were euthanized, and the tracheas were removed for anatomopathological analysis. RESULTS: There were no postimplantation complications, and none had to be removed. After eight weeks, the devices were found to be well-positioned. Histopathology revealed a well-preserved epithelial basal membrane, foci of denuded epithelium, mild submucosal inflammatory infiltrate with scattered granulation tissue, vascular neoformation, and no microorganisms. CONCLUSIONS: The stent developed proved resistant to mechanical stress, biocompatible in the canine trachea and well-preserved at the study endpoint.

Doença de Kikuchi-Fujimoto

Kikuchi-Fujimoto disease is characterized by fever and lymphadenopathy, usually localized in the cervical region. This disease principally affects young females. It can be confused with lymphoma, adenocarcinoma metastasis and tuberculosis. We report two cases of Kikuchi-Fujimoto disease. In the first case, a 28-year-old female had been treated for tuberculosis one year prior and presented with a clinical and histological profile compatible with Kikuchi-Fujimoto disease. The second patient, a 58-year-old female, initially received treatment for Wegeners granulomatosis and, subsequently, for tuberculosis. Histopathological examination followed by immunohistochemical analysis confirmed the diagnosis of Kikuchi-Fujimoto disease in both cases. After the definitive diagnosis had been made, both patients were treated symptomatically, and both presented clinical improvement within one month. Subsequently, the latter patient developed systemic lupus erythematosus.

A correção das estenoses traqueobrônquicas mediante o emprego de órteses

O tratamento cirurgico do paciente com estenose traqueobronquica exige uma avaliacaoindividualizada em razao da complexidade de sua origem, sendo a traqueoplastia considerada amodalidade ideal. As causas mais comuns de estenose sao devidas a intubacao traqueal e aodesenvolvimento de neoplasias e estas condicoes sao justamente as que mais se beneficiam com otratamento endoscopico quando a correcao cirurgica nao esta indicada. Na atualidade, os meiosendoscopicos incluem a aplicacao de diversos tipos de

Using the Cusum curve to evaluate the training of orotracheal intubation with the Truview EVO2® laryngoscope

BACKGROUND AND OBJECTIVES Learning curves have proved to be useful tools to monitor the performance of a worker on a new assignment. Those curves have been used to evaluate several medical procedures. The objective of this study was to evaluate the learning of orotracheal intubation (OTI) with the Truview EVO2 laryngoscope with the CUSUM learning curve. METHODS Four trainees underwent OTI training with the Truview EVO2 laryngoscope in a mannequin. They received orientation on the successful and failure criteria of OTI and alternated during the attempts, for a total of 300 OTI for each one. Four learning curves were plotted using the CUSUM cumulative addition method. RESULTS It was calculated that the 105 OTIs were necessary to achieve proficiency. The four trainees crossed the line of acceptable failure rate of 5% before completing 105 OTIs; the first trainee reached proficiency after 42 OTIs, the second and third after 56 OTIs, and the fourth after 97 OTIs, and from then on their performance remained constant. Differences in the success rate between residents and experienced anesthesiologists were not observed. CONCLUSIONS The CUSUM learning curve is a useful instrument to demonstrate objectively the ability when performing a new task. Laryngoscopy with the Truview EVO2 in a mannequin proved to be an easy procedure for physicians with prior experience in OTI; however, one should be cautious when transposing those results to clinical practice.JUSTIFICATIVA Y OBJETIVOS: Las curvas de aprendizaje han sido herramientas utiles en el monitoreo del desempeno de un trabajador sometido a una nueva tarea. Esas curvas han venido siendo utilizadas en la evaluacion de varios procedimientos en la practica medica. El objetivo de esta investigacion, fue evaluar el aprendizaje de la intubacion orotraqueal (IOT) con el Laringoscopio Truview Evo2® a traves de la curva de aprendizaje CUSUM. METODO: Cuatro aprendices realizaron el entrenamiento de la IOT con el Laringoscopio Truview Evo2® en un maniqui. Se les oriento en cuanto a los criterios de exito y falla en la IOT y se intercambiaban los intentos, en un total de 300 IOT para cada uno de ellos. Cuatro curvas de aprendizaje fueron construidas a partir del metodo de la suma acumulativa CUSUM. RESULTADOS: El numero calculado para adquirir el desempeno en la tarea fue de 105 IOT. Los cuatro aprendices cruzaron la linea de rango de falla aceptable de un 5% antes de completar 105 IOT: el primer aprendiz alcanzo el rango de desempeno despues del 42 IOT, el segundo y el tercer aprendiz despues de 56 IOT, y el cuarto aprendiz, despues de 97 IOT, manteniendose constantes en sus desempenos a partir de ese momento. No se registro diferencias en la tasa de exito entre residentes y anestesiologos expertos. CONCLUSIONES: La curva de aprendizaje CUSUM es un instrumento util para la demostracion objetiva de la habilidad en la ejecucion de una nueva tarea. La laringoscopia con el TruviewEvo2® en un maniqui, demostro ser un procedimiento facil para medicos con experiencia previa en IOT, sin embargo, al llevar los resultados a la practica clinica, eso debera hacerse con cautela.

Aplicação da curva CUSUM para avaliar o treinamento da intubação orotraqueal com o laringoscópio Truview EVO2

BACKGROUND AND OBJECTIVES Learning curves have proved to be useful tools to monitor the performance of a worker on a new assignment. Those curves have been used to evaluate several medical procedures. The objective of this study was to evaluate the learning of orotracheal intubation (OTI) with the Truview EVO2 laryngoscope with the CUSUM learning curve. METHODS Four trainees underwent OTI training with the Truview EVO2 laryngoscope in a mannequin. They received orientation on the successful and failure criteria of OTI and alternated during the attempts, for a total of 300 OTI for each one. Four learning curves were plotted using the CUSUM cumulative addition method. RESULTS It was calculated that the 105 OTIs were necessary to achieve proficiency. The four trainees crossed the line of acceptable failure rate of 5% before completing 105 OTIs; the first trainee reached proficiency after 42 OTIs, the second and third after 56 OTIs, and the fourth after 97 OTIs, and from then on their performance remained constant. Differences in the success rate between residents and experienced anesthesiologists were not observed. CONCLUSIONS The CUSUM learning curve is a useful instrument to demonstrate objectively the ability when performing a new task. Laryngoscopy with the Truview EVO2 in a mannequin proved to be an easy procedure for physicians with prior experience in OTI; however, one should be cautious when transposing those results to clinical practice.JUSTIFICATIVA Y OBJETIVOS: Las curvas de aprendizaje han sido herramientas utiles en el monitoreo del desempeno de un trabajador sometido a una nueva tarea. Esas curvas han venido siendo utilizadas en la evaluacion de varios procedimientos en la practica medica. El objetivo de esta investigacion, fue evaluar el aprendizaje de la intubacion orotraqueal (IOT) con el Laringoscopio Truview Evo2® a traves de la curva de aprendizaje CUSUM. METODO: Cuatro aprendices realizaron el entrenamiento de la IOT con el Laringoscopio Truview Evo2® en un maniqui. Se les oriento en cuanto a los criterios de exito y falla en la IOT y se intercambiaban los intentos, en un total de 300 IOT para cada uno de ellos. Cuatro curvas de aprendizaje fueron construidas a partir del metodo de la suma acumulativa CUSUM. RESULTADOS: El numero calculado para adquirir el desempeno en la tarea fue de 105 IOT. Los cuatro aprendices cruzaron la linea de rango de falla aceptable de un 5% antes de completar 105 IOT: el primer aprendiz alcanzo el rango de desempeno despues del 42 IOT, el segundo y el tercer aprendiz despues de 56 IOT, y el cuarto aprendiz, despues de 97 IOT, manteniendose constantes en sus desempenos a partir de ese momento. No se registro diferencias en la tasa de exito entre residentes y anestesiologos expertos. CONCLUSIONES: La curva de aprendizaje CUSUM es un instrumento util para la demostracion objetiva de la habilidad en la ejecucion de una nueva tarea. La laringoscopia con el TruviewEvo2® en un maniqui, demostro ser un procedimiento facil para medicos con experiencia previa en IOT, sin embargo, al llevar los resultados a la practica clinica, eso debera hacerse con cautela.

Novel Silicone Stent to Treat Tracheobronchial Lesions: Results of 35 Patients

We describe a case series of 35 patients with either benign (14) or malignant (21) tracheal stenosis who were treated using a novel silicone stent, the HCPA-1, designed to prevent migration. Between March 2001 and September 2008, 13 women and 22 men received 41 HCPA-1 stents. The median duration of stenting in benign cases was 457 days (range, 4–2, 961 days). Successful stent removal with curative results was accomplished in 2 patients with tracheomalacia and 1 with post-intubation stenosis. In malignant cases, the median duration of stenting was 162 days (range, 1–1, 279 days). Five patients had tumor progression with obstruction requiring repeated laser resection, dilatation, or additional stents. Two patients died due to airway obstruction despite bronchoscopic intervention. Twelve patients with malignant lesions died with the stent in place. At the end of the study, 3 patients with malignant disease remained alive; 2 were lost to follow-up. The HCPA-1 stent proved to be safe, with no severe complications during the study period, and effective in improving quality of life with relief of dyspnea.

Development of a new experimental model of intramuscular electrical stimulation of the diaphragm in rabbits.

PURPOSE To develop an animal model of diaphragmatic electrical stimulation able to generate an appropriate ventilatory support through the direct implantation of electrodes in the diaphragm (electroventilation). METHODS Six New Zealand female rabbits (2-3 kg) were placed on mechanical ventilation. Then, a laparotomy was performed in order to identify the motor points in each hemidiaphragm, followed by the implantation of the electrodes for diaphragmatic stimulation. We tested two types of electrodes according to the conduction of electrical stimulation: unipolar and bipolar. The electrodes were placed on different occasions in the same animals and tested with current intensities of 20, 26 and 32 mA. Each current intensity was repeated three times for 10 respiratory cycles with 1 minute interval between each cycle, and 5 minutes for new current intensity. We recorded the relationship between current intensity and inspiratory volume. RESULTS The electrodes adequately stimulate the diaphragm and obtain inspired volumes using different intensity currents. The bipolar electrode generated inspiratory volumes as high as 4.5 times of baseline while the unipolar electrode reached up to 3.5 times of baseline. CONCLUSION This model has proved to be effective for studying the performance of the diaphragm under different electrical stimulations using different set of electrodes.

Modelo experimental de estenose traqueal mediante ressecção cirúrgica submucosa de anéis traqueais combinada com instilações de hidróxido de sódio

OBJECTIVE To experimentally develop tracheal stenosis and malacia to test new models of tracheal stents. METHODS We resected three cartilaginous rings from the cervical trachea of dogs in group A (n = 5) and six rings in group B (n = 4) to produce malacia. The mucosa of the region with malacia then received applications of a solution of sodium hydroxide (NaOH) at 23%, and the animals were accompanied with bronchoscopic examinations to observe the development of luminal narrowing of the airway. When the stenosis was of more than 50% or there were minimal signs of ventilatory failure, the animals were sacrificed. The segment of narrowed airway was then collected for histological analysis and calculation of the area of residual lumen in the tracheal segment with stenosis and malacia. RESULTS In histological analysis, fibrosis was found in the submucosa and adventitia, associated with granulomas in the mucosa. The average residual lumen of the segments with stenosis was 9% and 12% in groups A and B, respectively (p> 0.05). CONCLUSION The combination of resection of the cartilaginous rings and the application of 23% NaOH in the respiratory mucosa promoted severe tracheal stenosis, but was associated with loss of animals. Further studies are needed to verify that the isolated use of one of the techniques would be safer and more effective to develop tracheal stenosis.

Changes in respiratory mechanics during respiratory physiotherapy in mechanically ventilated patients

Objective To evaluate the changes in ventilatory mechanics and hemodynamics that occur in patients dependent on mechanical ventilation who are subjected to a standard respiratory therapy protocol. Methods This experimental and prospective study was performed in two intensive care units, in which patients dependent on mechanical ventilation for more than 48 hours were consecutively enrolled and subjected to an established respiratory physiotherapy protocol. Ventilatory variables (dynamic lung compliance, respiratory system resistance, tidal volume, peak inspiratory pressure, respiratory rate, and oxygen saturation) and hemodynamic variables (heart rate) were measured one hour before (T-1), immediately after (T0) and one hour after (T+1) applying the respiratory physiotherapy protocol. Results During the period of data collection, 104 patients were included in the study. Regarding the ventilatory variables, an increase in dynamic lung compliance (T-1 = 52.3 ± 16.1mL/cmH2O versus T0 = 65.1 ± 19.1mL/cmH2O; p < 0.001), tidal volume (T-1 = 550 ± 134mL versus T0 = 698 ± 155mL; p < 0.001), and peripheral oxygen saturation (T-1 = 96.5 ± 2.29% versus T0 = 98.2 ± 1.62%; p < 0.001) were observed, in addition to a reduction of respiratory system resistance (T-1 = 14.2 ± 4.63cmH2O/L/s versus T0 = 11.0 ± 3.43cmH2O/L/s; p < 0.001), after applying the respiratory physiotherapy protocol. All changes were present in the assessment performed one hour (T+1) after the application of the respiratory physiotherapy protocol. Regarding the hemodynamic variables, an immediate increase in the heart rate after application of the protocol was observed, but that increase was not maintained (T-1 = 88.9 ± 18.7 bpm versus T0 = 93.7 ± 19.2bpm versus T+1 = 88.5 ± 17.1bpm; p < 0.001). Conclusion Respiratory therapy leads to immediate changes in the lung mechanics and hemodynamics of mechanical ventilation-dependent patients, and ventilatory changes are likely to remain for at least one hour.

Fiber-reinforced silicone for tracheobronchial stents: An experimental study

A trachea is a tubular structure composed of smooth muscle that is reinforced with cartilage rings. Some diseases can cause sagging in smooth muscle and cartilaginous tissue. The end result is reduction (narrowing) of the trachea diameter. A solution to this problem is the use of tracheal stents, which are small tubular devices made of silicone. One is inserted into the trachea to prevent or correct its constriction. The purpose of tracheal stent use is to maintain cartilage support that would otherwise be lost in the airway. Current tracheal stent models present limitations in terms of shape and characteristics of the silicone used in their production. One of the most important is the large thickness of the wall, which makes its placement difficult; this mainly applies to pediatric patients. The wall thickness of the stent is closely related to the mechanical properties of the material. This study aims to test the reinforcement of silicone with three kinds of fibers, and then stents that were produced using fiber with the best compressive strength characteristics. Silicone samples were reinforced with polypropylene (PP), polyamide (PA), and carbon fiber (CF) at concentrations of 2% and 4% (vol%), which then underwent tensile strength and Shore A hardness testing. Samples with fiber showed good characteristics; surface analyses were carried out and they were used to produce stents with an internal diameter of 11 or 13mm and a length of 50mm. Stents underwent compression tests for qualitative evaluation. Samples with 2% and 4% CF blends showed the best mechanical performance, and they were used to produce stents. These samples presented similar compressive strengths at low deformation, but stents with a 4% CF blend exhibited improved compressive strength at deformations greater than 30-50% of their diameter (P ≤ 0.05). The addition of 2% and 4% CF blends conferred greater mechanical strength and resistance to the silicone matrix. This is particularly true at low deformation, which is the condition where the stent is used when implanted. In the finite element compression strength tests, the stent composite showed greater compression strength with the addition of fiber, and the results were in accordance with mechanical compression tests performed on the stents. In vivo tests showed that, after 30 days of post-implantation in sheep trachea, an inflammatory process occurred in the region of the trachea in contact with the stent composite and with the stent without fiber (WF). This response is a common process during the first few days of implantation.