Pre-emptive methadone or tramadol analgesia for mastectomy and ovariohysterectomy in bitches / Analgesia preventiva con tramadol o metadona para mastectomia y ovario histerectomía en perras / Analgesia preventiva com tramadol ou metadona para mastectomia e ováriohisterectomia em cadelas

Summary Background: mastectomy in bitches is a critical surgery and pain control can be challenging. Objective: to evaluate the efficacy of pre-emptive analgesia with methadone (MET) or tramadol (TRA) in postoperative pain management, cardiorespiratory effects, and anaesthetic/analgesic consumption in female dogs undergoing ovariohysterectomy (OVH) and mastectomy. Methods: a prospective randomized blind clinical trial was used to evaluate 48 bitches of various breeds, aged 10±3.7 years, weighing 16±12 kg, and with multiple mammary tumours. The animals were distributed in two groups: TRA group received 5 mg/kg tramadol and MET group 0.5 mg/kg methadone intramuscularly, 10 minutes prior to anaesthesia induction with propofol followed by maintenance with isoflurane. Heart (HR) and respiratory (RR) rates, mean arterial pressure (MAP), propofol induction dose (PID), oxyhemoglobin saturation (SpO2), end-tidal isoflurane concentration (EtISO), and carbon dioxide pressure (EtCO2) were measured during the intra-operative period. Post-operative pain was evaluated for 12 hours and rated according to the Melbourne pain scale. Rescue analgesia (0.5 mg/kg methadone, 2 mg/kg lidocaine, or 0.01 mg/kg/min ketamine IV) was given when necessary and post-operative analgesic consumption recorded. Statistical tests were used to compare treatments. Results: rescue analgesia requirements, pain score, PID and analgesic consumption were significantly lower (p<0.05) in MET group. The HR was higher in TRA group, while EtCO2 and MAP were higher in MET group (p<0.05). Conclusions: methadone was more effective than tramadol in pre-emptive analgesia but not completely adequate on controlling pain in bitches subjected to unilateral mastectomy and OVH. MET led to lower cardiovascular depression and lower propofol dose required for anesthesia induction. However, methadone increased EtCO2 and thus special care with patient ventilation is advised.

Resumen Fundamento: la mastectomia en perras es un procedimiento severamente álgido y el control del dolor es un desafío. Objetivo: evaluar la eficacia del tratamiento analgésico preventivo con metadona (MET) o tramadol (TRA) sobre el dolor postoperatorio, parámetros cardiorrespiratorios y consumo de anestésicos en perras sometidas a ovariohisterectomía (OVH) y mastectomía. Métodos: ensayo clínico prospectivo aleatorizado ciego en 48 perras de diversas razas, edad 10±3,7, peso corporal 16±12 kg y con múltiples tumores mamarios. Los animales fueron distribuidos en dos grupos: el grupo TRA recibió 5 mg/kg de tramadol y el grupo MET 0,5 mg/kg de metadona por vía intramuscular 10 minutos antes de inducir anestesia con propofol seguido de mantenimiento con isofluorano. Las variables evaluadas fueron: frecuencia cardíaca (HR), respiratoria (RR), presión arterial media (MAP), dosis de inducción con propofol (PID), saturación de oxihemoglobina (SpO2), concentración de isofluorano (EtISO) y presión de dióxido de carbono (EtCO2) medidos durante el proceso intra-operativo. El dolor postoperatorio fue evaluado de acuerdo con la escala Melbourne durante 12 horas. Analgesia de rescate (metadona 0.5 mg/kg, lidocaína 2 mg/kg, o ketamina 0.01 mg/kg/min IV) se suministró cuando se consideró necesario, y se registró el consumo de analgésico posterior a la cirugia. Se aplicaron pruebas estadísticas para comparar los tratamientos. Resultados: los requerimientos de rescate analgésico, intensidad del dolor, PID y consumo analgésico fueron significativamente menores (p<0,05) en el grupo MET. La HR fue mayor en el grupo TRA, mientras que EtCO2 y MAP fueron mayores en el grupo MET (p<0,05). Conclusiones: la administración preventiva de MET es más eficaz que el tramadol, pero no completamente adecuada para el control del dolor posoperatorio en perras sometidas a mastectomia unilateral y OVH. MET promueve menor depresión cardiovascular y requerimiento de propofol para inducción anestésica. Sin embargo, dado que MET incrementa la EtCO2, se recomienda cuidado especial con la ventilación de estos pacientes.

Resumo Introdução: a mastectomia em cadelas é um procedimento severamente álgido e o controle da dor é um desafio. Objetivo: avaliar a eficácia da analgesia preventiva com metadona ou tramadol sob dor pós-operatória, parâmetros cardiorrespiratórios e consumo anestésico em cadelas submetidas à ovariohisterectomia e mastectomia. Métodos: ensaio clínico prospectivo cego randomizado em 48 cadelas, de diferentes raças, idade 10 ± 3,7 anos, peso 16 ± 12 kg com tumores mamários múltiplos. Os animais foram distribuídos em dois grupos: grupo TRA, tramadol 5 mg/kg e grupo MET, metadona 0,5 mg/kg por via intramuscular, administrados 10 minutos antes da indução anestésica com propofol e manutenção com isofluorano. As variáveis mensuradas foram: frequência cardíaca (FC), respiratória (fR), pressão arterial média (PAM), dose de indução propofol (PID), saturação da oxihemoglobina (SpO2), concentração de isofluorano (EtISO) e pressão de dióxido de carbono (EtCO2) ao final da expiração. A dor pós-operatória foi avaliada durante 12 horas (Escala Melbourne). A necessidade de resgate (metadona 0.5 mg/kg, lidocaína 2 mg/kg, ou cetamina 0.01 mg/kg/min IV) analgésico e o consumo pós-operatório de analgésicos foram registrados. Testes estatísticos foram utilizados para comparar os tratamentos. Resultados: a necessidade de resgate analgésico, escore de dor, PID e o consumo de analgésicos foram menores (p<0,05) no grupo MET. A FC maior no grupo TRA, enquanto EtCO2 e PAM maiores no grupo MET (p<0,05). Conclusões: a administração preventiva de metadona foi mais eficaz, mas não totalmente adequada para o controle da dor pós-operatória do que o tramadol, promovendo redução na depressão cardiovascular e o requerimento de propofol para indução da anestesia. No entanto, a metadona aumentou a EtCO2, recomendando cuidado especial com a ventilação dos pacientes.

Distribution of cortical granules and meiotic maturation of canine oocytes in bi-phasic systems.

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72h in base medium (BM) with 10IUmL(-1) human chorionic gonadotrophin (hCG), 1µgmL(-1) progesterone (P4) and 1µgmL(-1) oestradiol (E2); in bi-phasic System B oocytes were matured for 48h in BM with hCG and for 24h in BM with P4; in bi-phasic System C oocytes were matured for 48h in BM with hCG, P4 and E2, and for 24h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P<0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P<0.001). The stage of the oestrous cycle did not influence maturation rates.

The effects of anesthesia with a combination of intramuscular xylazine-diazepam-ketamine on heart rate, respiratory rate and cloacal temperature in roosters.

OBJECTIVE: To examine the anesthetic effects of a xylazine-diazepam-ketamine (XDK) combination in roosters. STUDY DESIGN: Prospective experimental trial. ANIMALS: Six healthy white Leghorn roosters weighing 2.03 +/- 0.08 kg. METHODS: Each rooster was pre-medicated with xylazine (3 mg kg(-1), IM) and after 15 minutes anesthesia was induced with a diazepam (4 mg kg(-1)) and ketamine (25 mg kg(-1)) combination injected into the pectoral muscles. Heart and respiratory rates were recorded before anesthesia and every 15 minutes after induction for 165 minutes. Cloacal temperature was measured before and 15 minutes after pre-medication and every 75 minutes thereafter during anesthesia. Quality of induction and recovery were scored subjectively; duration of loss of righting reflex, abolition of response to a painful stimulus and palpebral reflex were also recorded. RESULTS: Intramuscular injection of xylazine smoothly induced loss of the righting reflex within 3-4 minutes. Loss of response to a painful stimulus occurred at 13.1 +/- 2.9 minutes (mean +/- SD) after the administration of the D-K combination, and lasted for 63.0 +/- 5.3 minutes. Roosters anesthetized with this combination had a significant decrease in heart and respiratory rates and cloacal temperature. The recovery period lasted for up to 4 hours (227.5 +/- 15.4 minutes). Quality of recovery was satisfactory for four roosters but excitation was noted in two birds. CONCLUSIONS AND CLINICAL RELEVANCE: The XDK combination was a useful anesthetic technique for typhlectomy in roosters. Nevertheless this drug combination should be used with caution and cardiopulmonary parameters monitored carefully. Under the conditions of this experiment it was associated with a decreased cloacal temperature and prolonged recoveries.