Levobupivacaína epidural associada ao sufentanil ou fentanil para cesariana em cadelas de raças braquicefálicas: efeitos maternos e neonatais

Abstract

The aim of this study was to evaluate the maternal and neonatal effects of lumbosacral epidural administration of levobupivacaine combined with sufentanil or fentanyl in brachycephalic dogs undergoing elective cesarean section. The anesthetic protocol consisted of intramuscular morphine (0.2 mg/kg), followed by an intravenous bolus of propofol, in a dose sufficient to allowed the puncture of the lumbosacral space. The dogs were randomly allocated to receive 0.5% levobupivacaine (1 mg/kg) plus fentanyl (2.5 µg/kg; GLF:n = 9) or sufentanil (1 µg/kg; GLS: n = 11). Maternal cardiovascular and respiratory parameters were monitored prior to anesthetic procedure (baseline) and at specific time points during surgery. Maternal arterial and cord umbilical venous blood gases and pH were measured immediately prior to uterine delivery. Neonatal health was evaluated using a modified Apgar score and by the assessment of suction, dorsal flexion, withdrawal and anogenital reflexes at 5 and 60 minutes after birth. Puppies’ survival rate was recorded until 48 hours after birth. Data were analyzed using ANOVA, Tukey's test, Mann-Whitney test, Friedman's test, Fisher's exact test and Spearman's correlation (P <0.05). Maternal cardiovascular and respiratory variables were remained stable in both treatment groups. The mean umbilical pH was lower than 7.2 in both groups, with an incidence of acidemia (pH < 7) of 14% and 4% in GLF and GLS, respectively. Significantly higher umbilical lactate concentration was observed in GLF. The neurological reflex response did not differ between groups, however the percentage of neonates classified as having high viability in the Apgar score was higher in the GLS (P = 0.007). The neonatal mortality rate did not differ between groups (P = 0.11), with 4 deaths recorded in the GLF and none in the GLS. Both anesthetic protocols provided maternal-fetal safety, representing an alternative to canine cesarean section. However, the addition of fentanyl was associated with greater neonatal depression in the first 5 minutes after birth.