Ronise Tocheto

Sedative, hematologic and hemostatic effects of dexmedetomidine–butorphanol alone or in combination with ketamine in cats

Acute stress induced by physical restraint can interfere with the validity of laboratory findings. Sedation could minimize such stress. However, it is not known whether sedation can affect hematologic and hemostatic parameters in cats. The purpose of this study was to evaluate hematologic and hemostatic parameters in domestic cats subjected to physical restraint in addition to one of two sedation protocols. In total, 50 cats were subjected to physical restraint and were then randomly divided into two groups of 25 animals, receiving dexmedetomidine (5 µg/kg) and butorphanol (0.3 mg/kg; DB group) or dexmedetomidine (5 µg/kg), butorphanol (0.3 mg/kg) and ketamine (3 mg/kg; DBK group). The cats were assessed for acute stress, sedation level, onset of sedation and duration of sedation. Blood samples were collected after handling and after sedation. The complete blood count (CBC), platelet count, buccal mucosal bleeding time (BMBT), whole-blood clotting time, prothrombin time (PT), activated partial thromboplastin time (aPTT) and thrombin time (TT) were determined for each sample, before and after chemical restraint. No statistically significant differences were found in the hematologic parameters. Certain hemostatic parameters (PT, aPTT and TT) were higher in the DB group (P <0.05). The onset of sedation was similar in the two groups, and the duration of sedation was longer in the DBK group. Both sedation protocols were effective for short-duration chemical restraint for blood collection from the studied cats, and no clinically relevant effects on hematologic or hemostatic parameters were detected.

Efeitos de dois protocolos de sedação sobre as variáveis bioquímicas em gatos

The use of sedation protocols to assist in the restraint of cats to perform blood collections is of great importance, but the use of some drugs can alter the results and interpretation. Moreover, the physical restraint may generate intense stress, especially in animals of the feline species, which may also interfere with the results. This study aimed to evaluate examinations of clinical biochemistry in the use of physical restraint and chemistry in cats subjected to two sedation protocols. We used 50 cats, 26 females and 24 males, of mixed-breed, who underwent physical restraint and immediately after underwent two sedation protocols, DB (dexmedetomidine 5μg / kg and 0.3mg butorphanol / kg) and DBC (dexmedetomidine 5μg / kg butorphanol 0.3mg / kg ketamine and 3mg / kg), applied intramuscularly. Blood samples were taken after physical restraint and then after the use of one of the sedation protocols. The following parameters were evaluated: urea, creatinine, alanine aminotransferase (ALT), alkaline phosphatase (ALP), total serum protein (TP), albumin, globulin, cholesterol, triglycerides, calcium, magnesium and chloride in serum samples, and lactate and glucose in fluoride plasma samples. Statistical difference was found between groups for albumin, triglycerides, TP and cholesterol with higher values being found in the DBC group. A statistical difference between moments was found for cholesterol, and ALP with higher values in physical restraint only in the DBC group. Glucose had greater values after sedation for both groups. The study revealed that the use of these protocols implies restrictions on some biochemical parameters studied here, and that their interpretations should be evaluated carefully.

Avaliação da analgesia pós-operatória da metadona, da cetamina ou da sua associação em gatas submetidas a ovariossalpingo-histerectomia

The prevention and control of pain are basic components to have an adequate anesthesia. The aim of this study was to investigate the postoperative analgesia of ketamine in subanestesica dose, of methadone and the association of both intramuscularly in cats. A total of 24 cats proven healthy were referred for elective ovariossalpingohisterectomia. The day before the beginning of the experiment animals were anesthetized for placing a catheter in the jugular vein for subsequent blood sampling for measurement of serum concentration of cortisol. The next day, animals were randomly allocated to three groups (n = 8), which received ketamine (GC) at a dose of 0.5mg/kg; methadone (GM) at a dose of 0.3mg/kg; methadone and ketamine (GCM) at doses of 0.5mg/kg and 0.3mg/kg, respectively, all in the intramuscular route. All groups received the drug 20 minutes before induction of anesthesia, which was performed with propofol and maintained with isoflurane. The parameters evaluated were the measurement of cortisol in moments M0 (baseline-before surgery), M1(intraoperative), M2, M3, M4, M8, M12 and M24 (2,3,4,8,12 and 24 hours after the end of surgery) and evaluation of pain score by multidimensional scale of acute pain in cats in the moments M0, M2, M3, M4, M8, M12 and M24. The cortisol levels were higher in GC compared to GM and GCM in M2 and M3. Pain scores were higher in GC in moments M2 and M3 compared to GM and GCM, respectively. In summation of points in M2, GC showed higher values than GM and GCM, and M4, GC obtained values greater than GCM. Comparing the number of rescues postoperatively in GC 8/8 of animals required rescue, in GM /8 and in GCM 3/8. It was concluded that the combination of methadone and ketamine in cats undergoing elective OSH provides adequate postoperative analgesia, reducing the requirement for analgesics in the postoperative period.

Avaliação dos valores de troponina I, eletrocardiograma e ecocardiograma em felinos sedados com cetamina e midazolam, suplementados ou não com oxigênio

Myocardium injuries caused by low myocardial oxygenation and perfusion might be induced by anesthetics agents like ketamine. These injuries can be detected by specific biomarkers and, among them, troponin I. The aim of this study was to evaluate the cardiovascular changes based on troponin I (TnI) values, electrocardiography (ECG) and echocardiography in cats sedated with ketamine and midazolam, supplemented or not with oxygen. Blood samples were collected from 12 intact male healthy cats for troponin I (T0) and they were then submitted to electrocardiographic and echocardiographic evaluation, as well as measurements of heart rate (HR) and systolic blood pressure (SBP) (M0). Subsequently, they were ketamine-midazolam (10mg.kg-1 and 0,5 mg.kg-1 respectively) anesthetized by intramuscular route. After about 10 minutes, the animals were randomly allocated into two groups with or without oxygen supplementation (GCO or GSO, respectively), again being subjected to the tests mentioned. Blood samples for troponin I were collected at 6, 12 and 24 hours after sedation. HR, SBP and ECG did not change among groups. The TnI values rise significantly in T6 comparing to baselines in both groups (0,507±0,335 ng/mL in GSO and 0,777±0,505 ng/mL in GCO). In echocardiography, the cardiac output decreased at M1, in both groups compared to baseline (M0 0,472±0,115 and M1 0,234±0,08 in GSO and M0 0,356±0,095 and 0,222±0,09 in GCO, L/min). We concluded that ketamine and midazolam sedation in healthy cats did not cause changes electrocardiography, increase troponin I values, with an 6 hours peak after administration, reduces cardiac output and oxygen supplementation, via facial mask, did not attenuated these alterations.