Efectos del reclutamiento alveolar y la presión positiva al final de la espiración óptima sobre la distensibilidad del sistema respiratorio y la oxigenación arterial en perros durante la anestesia general

Résumé

Alveolar recruitment manoeuvres (ARMs), followed by the application of positive end-expiratory pressure (PEEP), can be used to prevent or treat lung atelectasis during general anaesthesia. In human medicine, the individualization of PEEP and the application of optimal PEEP after ARM in each patient are recommended. In healthy people, ARMs followed by the use of PEEP improve respiratory system compliance (Crs) and intraoperative arterial oxygenation and could also improve postoperative arterial oxygenation. In healthy dogs, ARMs followed by a fixed PEEP (not individualized to patient) of 4 or 5 cmH2O improve Crs and intraoperative arterial oxygenation, but the effect of ARMs followed by optimal PEEP (individualized to patient) on Crs during anaesthesia and postoperative arterial oxygenation has not been assessed. Besides, factors affecting the optimal PEEP and Crs following ARM in this species are unknown.This thesis included three clinical studies and objectives. In clinical study 1, the aim was to assess the effect of a stepwise ARM, followed by optimal PEEP, on Crs and to compare it to those of controlled mechanical ventilation without PEEP or with a fixed PEEP of 5 cmH2O without previous ARM. In clinical study 2, the aim was to assess the effect of patient’s recumbency and body condition score on optimal PEEP value and Crs following stepwise ARM. In clinical study 3, the objective was to assess the effect of a stepwise ARM, followed by optimal PEEP, on early postoperative arterial oxygenation and to compare it to those of spontaneous ventilation and controlled mechanical ventilation without PEEP...