Fluid balance, glomerular filtration rate, and urine output in dogs anesthetized for an orthopedic surgical procedure

OBJECTIVE: To determine fluid retention, glomerular filtration rate, and urine output in dogs anesthetized for a surgical orthopedic procedure. ANIMALS: 23 dogs treated with a tibial plateau leveling osteotomy. PROCEDURES: 12 dogs were used as a control group. Cardiac output was measured in 5 dogs, and 6 dogs received carprofen for at least 14 days. Dogs received oxymorphone, atropine, propofol, and isoflurane for anesthesia (duration, 4 hours). Urine and blood samples were obtained for analysis every 30 minutes. Lactated Ringer's solution was administered at 10 mL/kg/h. Urine output was measured and glomerular filtration rate was estimated. Fluid retention was measured by use of body weight, fluid balance, and bioimpedance spectroscopy. RESULTS: No difference was found among control, cardiac output, or carprofen groups, so data were combined. Median urine output and glomerular filtration rate were 0.46 mL/kg/h and 1.84 mL/kg/min. Dogs retained a large amount of fluids during anesthesia, as indicated by increased body weight, positive fluid balance, increased total body water volume, and increased extracellular fluid volume. The PCV, total protein concentration, and esophageal temperature decreased in a linear manner. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs anesthetized for a tibial plateau leveling osteotomy retained a large amount of fluids, had low urinary output, and had decreased PCV, total protein concentration, and esophageal temperature. Evaluation of urine output alone in anesthetized dogs may not be an adequate indicator of fluid balance

O butorfanol na anestesia pela romifidina-tiletamina-zolazepam em gatos Butorphanol in romifidine-tiletamine-zolazepam anesthesia in cats

Visando observar os efeitos do butorfanol (B) na anestesia produzida pela associação de romifidina (R) e tiletamina-zolazepam (TZ), foram utilizados seis gatos adultos, de forma que todos animais receberam a associação de romifidina-tiletamina-zolazepam (grupo RTZ) ou a associação de romifidina-tiletamina-zolazepam-butorfanol (grupo RTZB). Os animais receberam em aplicação única, por via intramuscular, 7mg.kg-1 de tiletamina e 7mg.kg-1 de zolazepam e 40µg.kg-1 de romifidina (grupo RTZ) ou a mesma associação acrescida de 0,2mg.kg-1 de B (grupo RTZB). A freqüência cardíaca, freqüência respiratória, pressão arterial sistólica, diastólica e média por método não-invasivo oscilométrico, saturação de oxihemoglobina e temperatura retal foram avaliadas durante 120 minutos e comparadas aos valores basais. Os efeitos anestésicos foram caracterizados por meio de um sistema de escores. Outros dados como período de latência, período anestésico hábil e período de recuperação foram mensurados para efeito comparativo. Os períodos de latência e anestésico hábil foram significativamente mais prolongados no grupo RTZB. Ocorreu diminuição da freqüência respiratória no grupo RTZB, havendo decréscimo transitório no grupo RTZ. A freqüência cardíaca não variou no grupo RTZ até os 60 minutos e decresceu significativamente no grupo RTZB. Conclui-se que a associação RTZ produz anestesia com mínimos efeitos cardiovasculares e que a adição do butorfanol à associação prolonga o tempo anestésico hábil, além de proporcionar analgesia mais duradoura, mas provoca efeitos colaterais como decréscimo da freqüência cardíaca e da freqüência respiratória em gatos.<br>The effect of butorphanol was investigated in six adult cats anesthetized with romifidine-tiletamine-zolazepam. Cats were given romifidine (40µg.kg-1) tiletamine (7mg.kg-1) and zolazepam (7mg.kg-1) (RTZ) intramuscularly, or RTZ and butorphanol (0.2mg.kg-1) (RTZB). Heart rate, respiratory rate, oscillometric systolic blood pressure, diastolic blood pressure and mean blood pressure, oxihemoglobin saturation and rectal temperature were determined for 120 minutes and compared to baseline values. Anesthetic effects were evaluated using a score system. Time of induction, anesthesia and recovery were also determined for comparison. Induction time and anesthetic time were significantly longer in RTZB. In the RTZB group a significant decrease in respiratory rate was observed while in the RTZ group this was transitory. Heart rate did not change in the RTZ group until 60 minutes and decreased significantly in the RTZB group from the time of injection. It is concluded that RTZ is an effective anesthetic combination with minimal cardiovascular side effects and that addition of butorphanol to this combination prolongs the anesthetic time and induces analgesia for a longer period, but causes a decrease in heart and respiratory rate in cats