[An extended evaluation of a neuroleptanesthesia for the guinea pig with analysis of mixed expiratory gases during spontaneous breathing. Effects of fasting on the cardiorespiratory system and metabolism].

The artificially ventilated guinea pig was frequently used for neurophysiological and respiratory studies. This species is also preferable for an evaluation of hemoglobin based artificial oxygen carriers, because its oxygen hemoglobin binding is very similar to that of man. But the narcosis of this animal-species is very difficult, because of cardiorespiratory depression induced by conventional procedures. The following intraperitoneal administered neuroleptanesthesia was proved in guinea pigs: 0.2 mg Fentanyl (Janssen/D), 10 mg Droperidol (Janssen/D) and 400 mg Urethan in 10 ml isotonic sodium chloride solution per kg body weight. Our new animal model with a special valve system enables to assess the gas exchange under spontaneous breathing, cardiovascular and the acid-base parameters. The vital parameters of animals were stable over 6 hours and very close to those of awake animals, especially the arterial average blood pressure. For that reason, this established neuroleptanesthesia of guinea pigs is preferable for research purpose. The fasted animals show significantly decreased values of arterial blood pH (7,345 vs. 7401), of heart frequency (244 vs. 277 min(-1)), and of ventilation value (167 vs. 205 ml/min) compared to non-fasted animals.