Anesthesia for cesarean section in large animals.

Respiratory minute volume, blood volume, RBC mass and cardiac output increase while the functional residual capacity decreases during late pregnancy. General anesthetics reach the fetus in high concentrations and tend to persist in the fetus after delivery. Use of small doses of a combination of anesthetics is recommended. Ephedrine increases vascular tone and cardiac output. Glycopyrrolate and fentanyl-droperidol are used to restrain sows for cesarean section. Morphine alone or with acepromazine works well in depressed sows. Acepromazine or xylazine, used with ketamine, is good in restraining small ruminants. A sedative and local blocks can be used in standing cows. Anesthesia in mares is induced with xylazine, guaifenesin and ketamine and maintained with halothane, guaifenesin or thiopental. Large doses of xylazine should be avoided. Lidocaine toxicity can result from overuse in local blocks.