Matias Bassinello Stocco

Effects of intracameral injection of epinephrine and 2% lidocaine on pupil diameter, intraocular pressure, and cardiovascular parameters in healthy cats

OBJECTIVES To investigate the effects of the intracameral injection of epinephrine and two doses of 2% lidocaine on pupil diameter (PD), intraocular pressure (IOP), heart rate (HR), and mean arterial pressure (MAP) in healthy cats. METHODS Five treatment groups were formed (10 cats/each). Animals received 0.2 mL of epinephrine, 0.2 or 0.3 mL of 2% lidocaine, or 0.2 mL of BSS. Cats were anesthetized, and all solutions were injected intracamerally. PD, IOP, HR, and MAP were assessed at baseline, following anterior chamber paracentesis (T0), and at every 5 minutes, until anesthesia was terminated (T60). PD and IOP continued to be assessed for 2 additional hours during recovery from anesthesia. In another group, cats were not anesthetized and one of the eyes was treated with one drop of 0.5% tropicamide to check for maximal pupil diameter. RESULTS Faster onset and longer duration of sufficient mydriasis (>10 mm) were observed in epinephrine treatment group, when comparing with cats treated with both doses of lidocaine. Eyes treated with epinephrine achieved the largest maximum pupil diameter (mm) when comparing with eyes treated with 0.3 mL of lidocaine (11.01 ± 0.16), tropicamide (10.66 ± 0.17), and 0.2 mL of lidocaine (10.23 ± 0.12) (P < .0001). In all groups, IOP decreased significantly at T0, but tended to return to baseline at T60. HR and MAP did not change significantly during time and among treatments. CONCLUSIONS The intracameral injection of 0.2 mL of 1:100 000 epinephrine and 0.3 mL of 2% lidocaine can be used as an alternative to tropicamide in healthy cats. Both treatments produced satisfactory and long-lasting mydriasis without adverse effects on IOP, HR, and MAP.

Rural area of the Brazilian Pantanal wetlands associated with the occurrence of anti- Leishmania spp. antibodies in dogs

An evaluation was made of the presence of anti- Leishmania infantum chagasi antibodies in domestic dogs from the urban and rural areas of Brazil’s Pantanal wetland region using serological techniques. A total of 429 dogs were sampled in three areas of the Pantanal biome, including the municipalities of Pocone, Santo Antonio de Leverger, and Barao de Melgaco, in the state of Mato Grosso, and in the municipality of Corumba, in the state of Mato Grosso do Sul. The immunofluorescence assay (IFA) was used to detect antibodies (cut-off point 40) using Leishmania infantum chagasi antigen. Because of the possibility of cross-reactivity between species of the genus Leishmania , samples that were positive in the IFA against L. infantum chagasi were also tested by IFA in the same conditions, using L. amazonensis and L. braziliensis antigens. IFA-positive samples to L. infantum chagasi were also evaluated using Enzyme-Linked Immunosorbent Assay (ELISA). The results showed the presence of antibodies against L. infantum chagasi in 23 (5.36%; 95% CI: 3.50%-8.05%) dogs and at least one seroreactive dog was found in each of the municipalities evaluated in this study. Antibody titers ranged from 40 to 5,120, and all IFA positive samples were positive in the ELISA. Among the 23 positive dogs, nine were also were seroreactive for L. amazonensis and L. braziliensis antigens. The occurrence of anti- L. infantum chagasi antibodies in dogs was higher in rural areas (7.06%) than in urban areas (2.50%) (P < 0.05). Based on this study, we concluded that dogs from rural areas of the Pantanal wetlands were in contact with Leishmania species, which is relevant information given their importance to public health.

Total Intravenous Anesthesia with Propofol Associated with Fentanyl, Lidocaine or Ketamine in Bitches Submitted to Elective Ovariohysterectomy

Background: Total intravenous anesthesia with propofol is an alternative to inhalation anesthesia because it offers smoother anesthetic recovery, however, since propofol does not have adequate analgesic action, it is necessary to associate it with some drug to avoid the pain process. In addition, the combination may minimize cardiovascular depression resulting from continuous infusion of propofol by reducing infusion rate. The aim of this study was to evaluate cardiorespiratory parameters and anesthetic recovery in bitches submitted to continuous infusion of fentanyl, lidocaine and ketamine associated with total intravenous anesthesia with propofol and submitted to elective ovariohisterectomy. Materials, Methods & Results: Twenty-four bitches were medicated intramuscularly with 0.03 mg/kg of acepromazine. After 30 min, they were divided into three groups with different analgesic treatments: group F (GF) received a loading dose (LD) of 0.0036 mg/kg fentanyl, followed by continuous infusion of 0.0036 mg/kg/h; group L (GL), LD of 3 mg/kg lidocaine, followed by 3 mg/kg/h and group K (GK), LD of 0.6 mg/kg ketamine, followed by 0.6 mg/kg/h. First a LD of analgesic treatment was administered, followed by induction (to the effect) and beginning of continuous infusion of the analgesic treatment and propofol. The animals were intubated with endotracheal tube of adequate size, and connected to 100% oxygen, being kept under spontaneous ventilation during the entire period of anesthetic maintenance. The infusion of propofol started at 0.34 mg/kg/min and was adjusted so as to maintain the surgical anesthesia plane of Guedel and the cardiovascular parameters within the physiological limits for the species. The cardiorespiratory parameters were measured at different moments: basal (before application of any drug) and 5, 15, 20, 30, 40, 50, 60, 70 and 80 min after induction. The surgery started 20 min after anesthetic induction and lasted 60 min. At the end of the surgery, infusions were terminated and anesthesia recovery was evaluated by measuring the extubation time, sternal decubitus, and quadrupedal position in min. A variance analysis was performed to compare means of cardiorespiratory parameters for the moments and groups followed by the Scott-knott test. Differences were considered significant when P < 0.05. The baseline parameters, age, weight and dose of propofol IC were not statistically different between groups. The infusion rate of propofol increased in all groups from M5 to M15. GF and GL presented lower values for heart rate and GK presented higher values for the same variable. Blood pressure decreased after induction and increased in M40, M50 and M60. The variables EtCo2, PaCo2 and HCO3 increased and pH decreased showing respiratory depression in all groups. The mean time, in min, for orotracheal extubation, sternal decubitus and quadrupedal position were respectively 5 ± 3, 20 ± 6 and 39 ± 13 for GF; 6 ± 2, 23 ± 7 and 51 ± 15 for GL; 4 ± 2, 18 ± 6 and 42 ± 22 for GK and did not present statistical difference between the groups. Discussion: The combination of continuous infusion of fentanyl, lidocaine or ketamine to total intravenous anesthesia with propofol provides cardiovascular stability, but does not prevent respiratory function depression. The dose of propofol IC was the same in all groups, thus demonstrating that analgesics have the same potency in the transoperative period and justifies similar anesthetic recovery times. Thus, it can be concluded that these associations are feasible for total intravenous anesthesia provided proper monitorins for respiratory function.