Abstract
Arterial blood pressure, blood-gases and pH during anesthesia under spontaneous breathing or controlled intermittent positive pressure ventilation (IPPV) in dorsally recumbent horses were measured. Spontaneous breathing anesthesia (90 min) produced respiratory acidosis (blood pH; 7.275, PaCO ; 60.4 mmHg) and hypoxemia (57.7 mmHg) . On the contrary, controlled IPPV anesthesia (120 min) produced moderate acidosis (blood pH ; 7.414, PaCO2 ; 52.8 mmHg) and no hypoxemia. However, arterial blood pressure and arterial oxygen tension in either of the ventilation methods gradually decreased with the longer duration of anesthesia. In conclusion, the use of IPPV is usefull for improving arterial oxygenation in dorsally recumbent anesthetized horses. However, cardiopulmonary depression in prolonged anesthesia must be anticipated and further improvement of the method must be required.
