Perioperative risk factors for puppies delivered by cesarean section in the United States and Canada

The purpose of this study was to evaluate perioperative risk factors affect ing neonatal survival after cesarean section. Data from 807 cesarean-derive d litters (3,908 puppies) was submitted by 109 practices in the United Stat es and Canada. Survival rates immediately, two hours, and seven days after delivery were 92% (n=3,127), 87% (n=2,951), and 80% (n=2,641), respectively , for puppies delivered by cesarean section (n=3,410) and were 86% (n=409), 83% (n=366), and 75% (n=283), respectively, for puppies born naturally (n= 498). Maternal mortality rate was 1% (n=9). Of 776 surgeries, 453 (58%) wer e done on an emergency basis, The most common breed of dog was bulldog (n=1 38; 17%). The most common methods of inducing and maintaining anesthesia we re administration of isoflurane for induction and maintenance (n=266; 34%) and administration of propofol for induction followed by administration of isoflurane for maintenance (n=237; 30%). A model of cesarean-derived puppie s surviving to birth, between birth and two hours, and between two hours an d seven days was designed to relate litter survival to perioperative factor s. The following factors increased the likelihood of all puppies being aliv e: the surgery was not an emergency; the dam was not brachycephalic; there were four puppies or less in the litter; there were no naturally delivered or deformed puppies; all puppies breathed spontaneously at birth; at least one puppy vocalized spontaneously at birth; and neither methoxyflurane nor xylazine was used in the anesthetic protocol.