Monitorización de las presiones de la vía aérea con la modalidad de flujo continuo en cirugía toracoscópica pediátrica. Estudio en modelo animal / Airway pressure monitoring by the continuous flow method in paediatric thoracoscopic surgery. A study in an animal model

Objetivo. Comparar las presiones en la vía aérea obtenidas antes del tubo endotraqueal con las intratraqueales en la modalidad ventilatoria de flujo continuo, en cirugía toracoscópica para ventilación unipulmonar, en modelo pediátrico en animales. Material y métodos. Estudio prospectivo observacional simple. Se emplearon 10 cerdos Large White, con un peso de 4,6±0,8kg. Los animales se ventilaron en modo neonatal (flujo continuo) con un respirador Temel Supra. Mediante traqueotomía realizamos un sellado completo del sistema respiratorio para usar tubos sin neumotaponamiento especiales que permiten el registro traqueal de presiones sin interferir en la ventilación. Se realizó colapso del pulmón derecho por videotoracoscopia y se mantuvo durante 120min. Las variables se analizaron en 10 tiempos: inicio y 5min en bipulmonar, tras el colapso en los tiempos 5, 15, 30, 60, 90 y 120min, y 5 y 15min tras la reexpansión pulmonar. Registramos la presión basal, pico, meseta y teleespiratoria en la boca del animal e intratraqueal. Resultados. La media de la presión pico en la boca del animal en ventilación unipulmonar fue de 23,38mmHg y traqueal de 21,24mmHg, mientras que la media de la presión meseta en la boca de animal en ventilación unipulmonar fue de 21,88mmHg y traqueal de 21,39mmHg, respectivamente, con diferencias significativas en todas (p<0,05). Encontramos diferencias estadísticamente significativas (p<0,05) para la presión pico y meseta al comparar el registro en la boca del animal con el registro traqueal, siendo la diferencia en valor absoluto mayor para el registro de presión pico. Conclusiones. Los parámetros de presiones registrados en la boca del animal fueron asumibles para la cirugía, manteniéndose una adecuada estabilidad respiratoria y hemodinámica. Podemos afirmar que la modalidad de flujo continuo según el estudio de presiones puede ser idónea para este tipo de cirugía, y que el registro en la boca del animal (paciente) para la presión pico no refleja lo que realmente ocurre en el alvéolo, pero sí podemos tener una aproximación clínica adecuada para la presión meseta(AU)

Objective. To compare the airway pressures obtained before the endotracheal tube with the intratracheal ones in the continuous flow ventilation mode, in thoracoscopic surgery for one lung ventilation, in a paediatric model in animals. Material and methods. A simple prospective observational study was conducted. Ten Large White pigs weighing 4.6±0.8kg were used. The animals were ventilated in neonatal mode (continuous flow) with a Temel Supra ventilator. Using tracheotomy, we completely sealed the respiratory system in order to use tubes without special endotracheal cuffs, which would enable tracheal pressures to be registered without interfering with ventilation. Collapse of the right lung was performed by videothoracoscopy and was maintained for 120min. The variables were measured at 10 time periods: start and 5min with both lungs, after collapse at 5, 15, 30, 60, 90 and 120min, and 5 and 15min after lung re-expansion. We recorded the baseline, peak, plateau and positive end expiratory pressure in the mouth of the animal and intratracheal. Results. The mean peak pressure in the mouth of the animal in one lung ventilation was 23.38mmHg and tracheal ventilation was 21.24mmHg, while the mean plateau pressure in the mouth of the animal in one lung ventilation it was 21.88mmHg and tracheal was 21.39mmHg, respectively, with significant differences in all of them (P<.05). We found statistically significant differences (P<.05) for peak and plateau pressure on comparing the record in the animal mouth with the tracheal record. The difference in absolute value was higher for the peak pressure record. Conclusions. The pressure parameters recorded in the animal mouth were acceptable for surgery, with a suitable respiratory and haemodynamic stability being maintained. We can state that the continuous flow mode according to the pressures study may be suitable for this type of surgery, and that the mouth of the animal (patient) record for the peak pressure does not reflect what really happens in the alveoli, but we can give a suitable clinical estimate for the plateau pressure(AU)

[Airway pressure monitoring by the continuous flow method in paediatric thoracoscopic surgery. A study in an animal model]. / Monitorización de las presiones de la vía aérea con la modalidad de flujo continuo en cirugía toracoscópica pediátrica. Estudio en modelo animal.

OBJECTIVE: To compare the airway pressures obtained before the endotracheal tube with the intratracheal ones in the continuous flow ventilation mode, in thoracoscopic surgery for one lung ventilation, in a paediatric model in animals. MATERIAL AND METHODS: A simple prospective observational study was conducted. Ten Large White pigs weighing 4.6 ± 0.8 kg were used. The animals were ventilated in neonatal mode (continuous flow) with a Temel Supra ventilator. Using tracheotomy, we completely sealed the respiratory system in order to use tubes without special endotracheal cuffs, which would enable tracheal pressures to be registered without interfering with ventilation. Collapse of the right lung was performed by videothoracoscopy and was maintained for 120 min. The variables were measured at 10 time periods: start and 5 min with both lungs, after collapse at 5, 15, 30, 60, 90 and 120 min, and 5 and 15 min after lung re-expansion. We recorded the baseline, peak, plateau and positive end expiratory pressure in the mouth of the animal and intratracheal. RESULTS: The mean peak pressure in the mouth of the animal in one lung ventilation was 23.38 mmHg and tracheal ventilation was 21.24 mmHg, while the mean plateau pressure in the mouth of the animal in one lung ventilation it was 21.88 mmHg and tracheal was 21.39 mmHg, respectively, with significant differences in all of them (P<.05). We found statistically significant differences (P<.05) for peak and plateau pressure on comparing the record in the animal mouth with the tracheal record. The difference in absolute value was higher for the peak pressure record. CONCLUSIONS: The pressure parameters recorded in the animal mouth were acceptable for surgery, with a suitable respiratory and haemodynamic stability being maintained. We can state that the continuous flow mode according to the pressures study may be suitable for this type of surgery, and that the mouth of the animal (patient) record for the peak pressure does not reflect what really happens in the alveoli, but we can give a suitable clinical estimate for the plateau pressure.

Propuesta de un programa de formación usando un modelo experimental para el manejo anestésico del trasplante hepático / Proposed experimental model to provide training in the management of anesthesia in liver transplantation

Objetivos: Proponemos y evaluamos un programa de entrenamiento para anestesiólogos, en modelo porcino, para aumentar la calidad del manejo anestésico durante el trasplante hepático. Material y método: Cinco anestesiólogos, facultativos especialistas de área, sin experiencia previa en el manejo anestésico del trasplante hepático que no trabajan en centros donde se realiza la cirugía de trasplante hepático, realizaron el programa de entrenamiento y evaluación de manera voluntaria, anestesiando cinco animales cada uno. La cirugía se realizó bajo anestesia total balanceada, realizando monitorización hemodinámica, ventilatoria, determinación bioquímica, gasometrías arteriales y coagulación. Para evaluar a los alumnos se utilizaron criterios publicados previamente, considerando su habilidad para mantener al paciente estable. Fueron evaluados en los tiempos T1 (basal), T2-15 min fase preanhepática, T3-final fase preanhepática, T4-15 min fase anhepática, T5-final fase anhepática, T6-15 min fase postanhepática, T7-final fase postanhepática. Los alumnos completaron una encuesta al finalizar el programa para valorar su utilidad. Los cambios en la puntuación de los criterios de calidad fueron analizados utilizando ANOVA. Resultados: Durante la fase postimplantación, los cambios metabólicos (acidosis) y cardiacos (hipotensión y bradicardia) fueron las alteraciones más críticas a las que tuvieron que hacer frente los alumnos. Se evidenció un incremento significativo en las habilidades de los alumnos para hacer frente a los cambios hemodinámicos y metabólicos (p < 0,05). Todos los alumnos expresaron su preferencia por la realización de un entrenamiento previo en modelo porcino. Conclusiones: Utilizando este modelo de entrenamiento, los cambios hemodinámicos y fisiológicos que acontecen durante el trasplante, fueron entendidos y manejados. En nuestra opinión, la realización de un programa de formación en modelo porcino permite al anestesiólogo adquirir experiencia y habilidad para el manejo anestésico del trasplante hepático(AU)

Objetive: To propose and evaluate the use of a porcine model for training in how to manage and improve the quality of anesthesia during liver transplantation. Material and Methods: Five trained anesthesiologists who had no previous experience in managing anesthesia during liver transplantation and who did not work in hospitals where the procedure was performed volunteered for the training course and evaluated it. Each trainee anesthetized 5 animals. Surgery was performed under total balanced anesthesia with monitoring of hemodynamics, ventilation, biochemistry, arterial blood gases, and coagulation. Previously set criteria were used to evaluate the trainees' skill in maintaining patient stability. Their work was assessed 7 times: at baseline, 15 minutes into the preanhepatic phase, at the end of the preanhepatic stage, 15 minutes into the anhepatic phase, at the end of the anhepatic phase, 15 minutes into the postanhepatic phase, and at the end of the postanhepatic phase. After completing the course, the trainees filled in a questionnaire to evaluate its usefulness. Analysis of variance was applied to score changes in anesthetic quality criteria. Results: After implantation, changes in metabolic (acidosis) and cardiac (hypotension and bradycardia) status were the most critical abnormalities the trainees faced. Their skill in coping with hemodynamic and metabolic changes improved significantly (P<.05). All participants expressed a preference for receiving training in a porcine model before providing anesthesia in this surgical setting. Conclusions: Under this training model, the anesthesiologists understood and were able to manage the hemodynamic and physiologic changes that develop during a liver transplant procedure. We believe that training using a porcine model allows an anesthesiologist to acquire experience and skill in this setting(AU)

[Proposed experimental model to provide training in the management of anesthesia in liver transplantation]. / Propuesta de un programa de formación usando un modelo experimental para el manejo anestésico del trasplante hepático.

OBJECTIVE: To propose and evaluate the use of a porcine model for training in how to manage and improve the quality of anesthesia during liver transplantation. MATERIAL AND METHODS: Five trained anesthesiologists who had no previous experience in managing anesthesia during liver transplantation and who did not work in hospitals where the procedure was performed volunteered for the training course and evaluated it. Each trainee anesthetized 5 animals. Surgery was performed under total balanced anesthesia with monitoring of hemodynamics, ventilation, biochemistry, arterial blood gases, and coagulation. Previously set criteria were used to evaluate the trainees' skill in maintaining patient stability. Their work was assessed 7 times: at baseline, 15 minutes into the preanhepatic phase, at the end of the preanhepatic stage, 15 minutes into the anhepatic phase, at the end of the anhepatic phase, 15 minutes into the postanhepatic phase, and at the end of the postanhepatic phase. After completing the course, the trainees filled in a questionnaire to evaluate its usefulness. Analysis of variance was applied to score changes in anesthetic quality criteria. RESULTS: After implantation, changes in metabolic (acidosis) and cardiac (hypotension and bradycardia) status were the most critical abnormalities the trainees faced. Their skill in coping with hemodynamic and metabolic changes improved significantly (P<.05). All participants expressed a preference for receiving training in a porcine model before providing anesthesia in this surgical setting. CONCLUSIONS: Under this training model, the anesthesiologists understood and were able to manage the hemodynamic and physiologic changes that develop during a liver transplant procedure. We believe that training using a porcine model allows an anesthesiologist to acquire experience and skill in this setting.

Propuesta de un programa de formación usando un modelo experimental para el manejo anestésico del trasplante hepático / Proposed experimental model to provide training in the management of anesthesia in liver transplantation

Objetivos: Proponemos y evaluamos un programa de entrenamiento para anestesiólogos, en modelo porcino, para aumentar la calidad del manejo anestésico durante el trasplante hepático. Material y método: Cinco anestesiólogos, facultativos especialistas de área, sin experiencia previa en el manejo anestésico del trasplante hepático que no trabajan en centros donde se realiza la cirugía de trasplante hepático, realizaron el programa de entrenamiento y evaluación de manera voluntaria, anestesiando cinco animales cada uno. La cirugía se realizó bajo anestesia total balanceada, realizando monitorización hemodinámica, ventilatoria, determinación bioquímica, gasometrías arteriales y coagulación. Para evaluar a los alumnos se utilizaron criterios publicados previamente, considerando su habilidad para mantener al paciente estable. Fueron evaluados en los tiempos T1 (basal), T2-15 min fase preanhepática, T3-final fase preanhepática, T4-15 min fase anhepática, T5-final fase anhepática, T6-15 min fase postanhepática, T7-final fase postanhepática. Los alumnos completaron una encuesta al finalizar el programa para valorar su utilidad. Los cambios en la puntuación de los criterios de calidad fueron analizados utilizando ANOVA. Resultados: Durante la fase postimplantación, los cambios metabólicos (acidosis) y cardiacos (hipotensión y bradicardia) fueron las alteraciones más críticas a las que tuvieron que hacer frente los alumnos. Se evidenció un incremento significativo en las habilidades de los alumnos para hacer frente a los cambios hemodinámicos y metabólicos (p < 0,05). Todos los alumnos expresaron su preferencia por la realización de un entrenamiento previo en modelo porcino. Conclusiones: Utilizando este modelo de entrenamiento, los cambios hemodinámicos y fisiológicos que acontecen durante el trasplante, fueron entendidos y manejados. En nuestra opinión, la realización de un programa de formación en modelo porcino permite al anestesiólogo adquirir experiencia y habilidad para el manejo anestésico del trasplante hepático(AU)

Objetive: To propose and evaluate the use of a porcine model for training in how to manage and improve the quality of anesthesia during liver transplantation. Material and Methods: Five trained anesthesiologists who had no previous experience in managing anesthesia during liver transplantation and who did not work in hospitals where the procedure was performed volunteered for the training course and evaluated it. Each trainee anesthetized 5 animals. Surgery was performed under total balanced anesthesia with monitoring of hemodynamics, ventilation, biochemistry, arterial blood gases, and coagulation. Previously set criteria were used to evaluate the trainees' skill in maintaining patient stability. Their work was assessed 7 times: at baseline, 15 minutes into the preanhepatic phase, at the end of the preanhepatic stage, 15 minutes into the anhepatic phase, at the end of the anhepatic phase, 15 minutes into the postanhepatic phase, and at the end of the postanhepatic phase. After completing the course, the trainees filled in a questionnaire to evaluate its usefulness. Analysis of variance was applied to score changes in anesthetic quality criteria. Results: After implantation, changes in metabolic (acidosis) and cardiac (hypotension and bradycardia) status were the most critical abnormalities the trainees faced. Their skill in coping with hemodynamic and metabolic changes improved significantly (P<.05). All participants expressed a preference for receiving training in a porcine model before providing anesthesia in this surgical setting. Conclusions: Under this training model, the anesthesiologists understood and were able to manage the hemodynamic and physiologic changes that develop during a liver transplant procedure. We believe that training using a porcine model allows an anesthesiologist to acquire experience and skill in this setting(AU)

Effects of premedication with tiletamine/zolazepam/medetomidine during general anesthesia using sevoflurane/fentanyl in swine undergoing pancreas transplantation.

OBJECTIVE: To assess cardiac and hemodynamic responses and body temperature during long-term general anesthesia using sevoflurane/fentanyl after premedication with a tiletamine/zolazepam/medetomidine combination in swine undergoing experimental pancreas transplantation. MATERIALS AND METHODS: Twelve Landrace female pigs of means weight 46.4 +/- 5.1 kg were premedicated by intramuscular administration of tiletamine/zolazepam (3.5 mg/kg), medetomidine (0.03 mg/kg), and atropine (0.02 mg/kg), before anesthesia with 0.75 minimum alveolar concentration sevoflurane and continuous intravenous fentanyl infusion (5.7 +/- 0.7 microg/kg/h). Assessment of heart rate, arterial blood pressure, and temperature in pigs undergoing allogenic pancreas transplant surgery were registered at the start of anesthesia (T0), as well as at 60 (T60), 120 (T120), and 180 (T180) minutes after T0, and finally at the end of anesthesia (T anesthesia end), when we switched off the sevoflurane vaporizer. Analysis of variance was used to determine differences between times with P < .05 considered significant. Results are given as mean values +/- standard deviations. RESULTS: Arterial blood pressure significantly decreased from T120 to the end of anesthesia, while a significantly decreased heart rate was only evident at T60. Body temperature decreased significantly from T60 to the end of anesthesia. These decreases, however, lacked clinical relevance; all parameters were within normal range. No major anesthetic complications were observed in this study. CONCLUSIONS: The administration of a tiletamine/zolazepam/medetomidine combination as premedication in swine subjected to pancreas transplantation allowed for a safe reduction of sevoflurane/fentanyl requirements during long-term general anesthesia. Despite arterial blood pressure and body temperature evidencing a decrease during anesthetic maintenance, all parameters remained within normal range values.

Relationship of bispectral index values, haemodynamic changes and recovery times during sevoflurane or propofol anaesthesia in rabbits.

The aim of this study was to determine and compare the degree of hypnosis achieved during propofol or sevoflurane anaesthesia in rabbits using bispectral index (BIS), and to evaluate its usefulness as a predictor of both haemodynamic changes during anaesthesia and recovery times. Twenty adult male New Zealand White rabbits, average weight 4.4 +/- 0.4 kg, were used for this study. Animals were randomly allocated to one of two groups with 10 rabbits/group. An electroencephalographic recording was obtained from each conscious rabbit prior to drug administration. All animals received buprenorphine as a preanaesthetic medication (0.05 mg/kg, intravenous [i.v.]). Anaesthesia was induced with propofol (8 mg/kg, i.v.) in all animals; 10 rabbits were maintained with sevoflurane via inhalation (1 minimum alveolar concentration--end-tidal sevoflurane concentration of 3.7%--at a fresh gas flow rate of 3 L/min; group I), and 10 were maintained with i.v. propofol (0.6 mg/kg/min; group II). The rabbits were orotracheally intubated and spontaneous ventilation was maintained throughout the study (100% oxygen). After abdominal surgery through a ventral midline laparotomy, rabbits were allowed to recover from anaesthesia. Cardiovascular variables and BIS values were recorded at intervals throughout the procedure, as was the duration of recovery from anaesthesia. In both groups, mean BIS values were significantly decreased immediately after induction, compared with baseline values obtained during consciousness. Anaesthetic depth (evaluated by clinical observation) was similar in both groups; however, group II rabbits had significantly higher (P<0.001) BIS values from 30 s before incision until anaesthesia was discontinued. There was no significant difference in BIS recorded 1 and 5 min after incision as compared with values obtained 30 s before incision in either group. During sevoflurane or propofol administration, correlations were found between BIS values and mean arterial blood pressure (MABP), and between BIS values and heart rate (HR). Mean BIS values at discontinuation of administration of the anaesthetic agent were greater in group II (69.1 +/- 6.0) than in group I (49.3 +/- 2.2). However, recovery from anaesthesia was significantly longer in group II (38.4 +/- 7.2 min) than in group I (11.5 +/- 2.5 min). In conclusion, BIS can be used to differentiate between conscious and unconscious states during anaesthesia in rabbits. BIS values derived from an electroencephalogram at the end of anaesthesia were not useful for predicting the speed of anaesthetic recovery in sevoflurane or propofol-anaesthetized rabbits undergoing abdominal surgery. Despite the correlation found between BIS and haemodynamic parameters, its usefulness as a predictor of clinically important changes in arterial blood pressure and HR in anaesthetized rabbits was limited.