RESUMO

The aim of this study was to compare the effects of constant rate infusions (CRI) of fentanyl alone or combined with lidocaine and ketamine (FLK), on physiological parameters, isoflurane requirements and the number of postoperative analgesic rescues in dogs undergoing unilateral mastectomy. Twenty-two dogs were premedicated with acepromazine 0.02 mg/kg and morphine 0.5 mg/kg and anesthetized with propofol and isoflurane. Dogs were randomly assigned to 1 of 2 groups: Fentanyl group (fentanyl 5 µg/kg loading dose [LD] and 9 µg/kg/h CRI; n = 11); FLK group (fentanyl [same doses]; lidocaine 2 mg/kg LD and 3 mg/kg/h CRI; ketamine 1.0 mg/kg LD and 0.6 mg/kg/h CRI; = 11). Intraoperative evaluations were performed before the start of surgery and administration of the treatments (T0); three minutes after the LD (T1); during incision and tissue divulsion (T2); during closure of the surgical wound (T3). Meloxicam (0.1 mg/kg) was administered at T3. Blood samples were collected for determination of plasma concentrations of fentanyl, lidocaine and ketamine. Pain scores and the number of postoperative analgesic rescues with morphine (0.5 mg/kg) were evaluated for 24 hours postoperatively using the short form of the Glasgow Composite Measure Pain Scale. Compared to T0, significant decreases in heart rate (from 84 ± 28 to 53 ± 16 bpm in the Fentanyl group and from 93 ± 16 to 63 ± 15 bpm in FLK) and mean arterial pressure (from 61 ± 5 to 49 ± 10 mmHg in Fentanyl and from 59 ± 3 to 38 ± 6 mmHg in FLK) were observed at T1. Arterial hypotension was transient, with normalization of values at T2 and T3. The expired fraction of isoflurane did not differ significantly between the groups. Plasma concentrations of fentanyl, lidocaine and ketamine remained within the therapeutic range. Postoperatively, the number of dogs requiring analgesic rescue was significantly lower in the FLK (0/11, 0%) than in the Fentanyl group (5/11, 45%). In dogs administered morphine and meloxicam as part of the anesthesia protocol, an intraoperative CRI of FLK abolished the requirement for postoperative analgesic rescue for 24 hours in dogs undergoing mastectomy.

Assuntos

Doenças do Cão , Isoflurano , Ketamina , Cães , Animais , Fentanila/farmacologia , Fentanila/uso terapêutico , Lidocaína/farmacologia , Lidocaína/uso terapêutico , Ketamina/farmacologia , Ketamina/uso terapêutico , Isoflurano/uso terapêutico , Meloxicam/uso terapêutico , Mastectomia/veterinária , Mastectomia/métodos , Analgésicos/uso terapêutico , Morfina , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/prevenção & controle , Dor Pós-Operatória/veterinária , Doenças do Cão/tratamento farmacológico , Doenças do Cão/cirurgia

RESUMO

CASE SUMMARY: A 6-year-old mixed-breed male cat was evaluated for a routine annual health assessment. No alterations on physical examination were observed other than mild pain on palpation of the right kidney. Complete blood count, serum biochemistry (including symmetric dimethylarginine), urinalysis and urine protein:creatinine ratio were within the reference intervals for the species. Abdominal ultrasonography showed the presence of asymmetric kidneys, decreased corticomedullary definition, presence of a cyst on the left kidney and moderate renal pelvis dilatation on the right kidney. Dynamic renal scintigraphy (technetium [99mTc]-diethylenetriamine pentaacetic acid) revealed a single functioning kidney on the left. Static renal scintigraphy (99mTc-dimercaptosuccinic acid) exhibited renal activity practically restricted to the left kidney (relative uptake was 99% for the left kidney and 1% for the right kidney). Results of renal scintigraphy showed that the left kidney was compensating for the lack of function of the right one. GFR was 2.17 ml/min/kg, which is considered subclinical renal insufficiency and is in accordance with the case, as the cat was asymptomatic and did not present alterations in laboratory parameters. RELEVANCE AND NOVEL INFORMATION: Renal scintigraphy was an important tool to determine the loss of renal function in one of the kidneys and mild reduction of global GFR. In this case report, renal scintigraphy proved to be more sensitive in the assessment of renal function than other tests routinely performed.