[Haemodynamic and cardiac and respiratory changes during enflurane-monoanaesthesia in the Göttingen minipig (author's transl)].

Two groups of 10 Göttingen minipigs each were anaesthetized with enflurane in a mixture of O2 and N2O for 90 minutes. One group breathed spontaneously. In the other controlled respiration was used following relaxation with succinylcholine-chloride. Control values of ECG, blood pressure, aortic blood flow, arterial oxygen and carbon dioxide tensions, arterial pH, the maximum rate of rise of the left ventricular pressure (max. dp/dt) were recorded from all animals. Anaesthesia was induced with enflurane using a face mask. On reaching the stage of deep surgical anaesthesia the pigs were quickly intubated and anaesthesia was maintained for up to 90 minutes. Max. dp/dt, blood gas tensions and pH were measured again 60 minutes after induction of anaesthesia. A third arterial blood sample was taken in the 100th minute at the end of the experiment. Enflurane produced a negative chronotropic and inotropic effect on the heart muscle. Blood pressure decreased by 40% and cardiac output by 32%. Total peripheral resistance was reduced in the 20th minute by 28% but returned to the control level towards the end of the experiment. We observed a few disturbances of cardiac rhythm and conduction. The spontaneously breathing group developed a respiratory acidosis. Within 10 minutes of discontinuing enflurane administration all parameters returned to the control levels. An obvious overdose of enflurane caused transitory convulsions in two animals. Similar symptoms are well known in humans. We prefer enflurane in the minipig since, in contrast to other inhalation anaesthetics, almost none is metabolised. This is especially important in cases of repeated anaesthesia in the same animal.