Perioperative factors associated with puppy vigor after delivery by cesarean section.

This prospective study examined the perioperative factors associated with puppy vigor in a clinical population of 807 litters containing 3,410 cesarean-derived puppies. Information was obtained from 109 private and institutional practices in the United States and Canada. Puppy vigor was determined by assessing three spontaneous conditions within 2 minutes after delivery: breathing, moving, and vocalizing. The percentages of live-born puppies with these characteristics were 85%, 73%, and 60%, respectively. After screening tests, logistic-regression models were run on all remaining factors using the litter as the unit of analysis, and odds ratios [OR] were determined. An OR <1.0 means that the odds are decreased for that puppy vigor condition when the factor is present, compared with a litter in which the factor is not present. Conversely, when the OR is >1.0, the odds are increased for that puppy vigor condition when that factor is present. The following factors were associated with the litter having all puppies breathing at birth: using an inhalant anesthetic (0.36 OR) or ketamine (0.43 OR), surgery at one particular private practice (3.52 OR), and surgery at a teaching institute rather than a private practice (0.36 OR). The following factors were associated with the litter having any spontaneously moving puppies at birth: all puppies breathing spontaneously (2.72 OR), any puppy vocalizing spontaneously (117 OR), using inhalant anesthesia (0.26 OR), and using thiopental or thiamylal (0.37 OR). The following factors were associated with the litter having any spontaneously vocalizing puppies at birth: all puppies breathing spontaneously (2.58 OR), any puppy moving spontaneously (152 OR), brachycephalic dam (0.62 OR), the dam was a Labrador retriever (7.23 OR), and using isoflurane (2.51 OR). In conclusion, the anesthetic factors associated with increased puppy vigor included the use of isoflurane and the avoidance of ketamine, thiamylal, and thiopental.