Effect of Anesthesia on Hematologic Parameters of Female Domestic Swine (Sus scrofa domestica)

Swine are commonly used in biomedical research as surgical models and in other experiments requiring the use of anesthesia. Isoflurane is a common inhalant anesthetic used in swine that has been shown to alter hematologic parameters in other species. However, the effects of isoflurane on hematologic parameters of swine over time have not been defined. In this study, we examined the effect of isoflurane anesthesia on hematologic parameters in 29 female Yorkshire/Landrace hybrid domestic swine at 3 timepoints. A secondary objective was to compare hematologic values in isoflurane-anesthetized animals that received intramuscular tiletamine-zolazepam (TZ) or a combination of ketamine-acepromazine-hydromorphone (KAH) for induction. Swine were induced with TZ or KAH, followed by nose cone delivery of 3.5% to 5% isoflurane to facilitate endotracheal intubation, and maintained with 1.75% to 3.5% isoflurane. Venous whole blood was collected for hematologic analysis at baseline upon recumbency after intramuscular administration of TZ or KAH, and at 30 min (T30) and 60 min (T60) of isoflurane administration. There were significant decreases in red blood cell (RBC) count, hematocrit (Hct), and hemoglobin after 30 min of isoflurane anesthesia, and between 30 and 60 min of isoflurane anesthesia. Hct decreased from 35.4% at baseline to 31.8% after 30 min of isoflurane anesthesia, and 31.1% after 60 min of isoflurane anesthesia. The decrease in RBC parameters was accompanied by a significant increase in reticulocyte count at T30 and T60 compared with baseline. When comparing the TZ and KAH groups, Hct and hemoglobin were significantly lower at T30 and T60 in the TZ group, and WBC and neutrophils were significantly higher at T60 in the KAH group. These results indicate that anesthesia alters certain hematologic parameters in swine, thus veterinarians and researchers should take care to avoid misinterpretation of CBCs when blood is collected from anesthetized swine.