Positive end-expiratory pressure in anaesthetized spontaneously breathing horses.
Horses breathing spontaneously under halothane anaesthesia were subjected to expiratory resistance by the introduction of a water-trap into the expiratory limb of a circle absorber. Resistances of 10 and 20 cm H2O produced no significant increase in PaO2 (P greater than 0.05) during halothane/air and halothane/oxygen anaesthesia. The imposition of resistance was associated with an increase in PaCO2 and a significant increase in mixed venous PCO2. In three animals subjected to 20 cm H2O resistance under halothane/air anaesthesia, the cardiac output was reduced (P less than 0.01). It was concluded that the indiscriminate application of end-expiratory pressure has no place in routine equine anaesthesia.
D000403:Airway Resistance; D000768:Anesthesia, General / Q000662:veterinary*; D000818:Animals; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output; D002496:Central Venous Pressure; D006221:Halothane; D006736:Horses / Q000502:physiology*; D007384:Intermittent Positive-Pressure Breathing; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D011175:Positive-Pressure Respiration; D012129:Respiratory Function Tests
D002245:Carbon Dioxide; D010100:Oxygen; D006221:Halothane