Parâmetros ecocardiográficos em cães saudáveis tratados com acepromazina, meperidina e sua associação / Echocardiographic parameters in healthy dogs treated with acepromazine, meperidine and their association

Objetivou-se avaliar os efeitos da tranquilização com meperidina, acepromazina e de sua associação sobre os parâmetros ecocardiográficos em cães. Foram utilizados 12 cães adultos, da raça Rottweiler, submetidos ao exame ecocardiográfico sem utilização de sedação (controle - TC) e a três protocolos de tratamento, utilizando-se meperidina (TM), acepromazina (TA) e a associação dos medicamentos (TMA). As variáveis foram analisadas pelo teste de Tukey (P<0,05). Observou-se que as médias obtidas na onda A do fluxo mitral em TA e TMA diminuíram significativamente com relação ao TM, que não diferiu do TC. Houve uma diminuição significativa no valor de movimento anular mitral (MAM) e excursão sistólica do plano anular tricúspide (ESPAT) no TA. Não houve diferença significativa para os valores de fração de encurtamento (FE) entre TA e os demais tratamentos. Entretanto, observou-se que 57,3% dos cães apresentaram valores de FE abaixo da normalidade. As alterações encontradas podem ser decorrentes dos efeitos hipotensores da acepromazina utilizada de forma isolada. Conclui-se que a meperidina ou sua associação com acepromazina não alteram os parâmetros ecocardiográficos em cães saudáveis e que a acepromazina, utilizada isoladamente, causa alteração nos parâmetros de função sistólica dos cães, não sendo recomendada para a contenção química dos cães submetidos ao ecocardiograma, o que poderia levar à má interpretação do exame.(AU)

The aim of this study was to evaluate the effects of sedation with meperidine, acepromazine and its association on the echocardiographic parameters in dogs. Twelve adult Rottweilers were used and subjected to the echocardiography examination without the use of sedation (control - CT) and subjected to three treatment protocols using meperidine (MT), acepromazine (AT), and the combination of drugs (MAT). Variables were analyzed by Tukey test (p<0,05). The averages obtained in A-wave of mitral inflow in AT and MAT decreased significantly compared to MT, which did not differ from CT. There was a significant decrease in the measurement of mitral annulus motion (MAM) and tricuspid annular plane systolic excursion (TAPSE) at TA. There was no significant difference in shortening fraction (SF) values between TA and other treatments. However, it was observed that 57.3% of the dogs showed SF values below the normal range for the species. All changes found may be due to the hypotensive effects of acepromazine used in isolation. In conclusion, meperidine or its association with acepromazine does not alter echocardiographic parameters in healthy dogs and acepromazine, used alone, causes changes in the parameters of systolic function and is not recommended for sedation of dogs submitted to echocardiogram, since it could cause a misinterpretation of the exam.(AU)

Nociceptive thermal threshold testing in horses - effect of neuroleptic sedation and neuroleptanalgesia at different stimulation sites.

BACKGROUND: Aim of the study was to compare the effect of neuroleptic sedation with acepromazine and neuroleptanalgesia with acepromazine and buprenorphine on thermal thresholds (TT) obtained at the nostrils and at the withers. The study was carried out as a randomized, blinded, controlled trial with cross-over design. Thermal thresholds were determined by incremental contact heat applied to the skin above the nostril (N) or the withers (W). Eleven horses were treated with saline (S), acepromazine (0.05 mg/kg) (ACE) or acepromazine and buprenorphine (0.0075 mg/kg) (AB) intravenously (IV). Single stimulations were performed 15 minutes prior and 15, 45, 75, 105, 165, 225, 285, 405 and 525 minutes after treatment. Sedation score, gastrointestinal auscultation score and occurrence of skin lesions were recorded. Data were analysed with analysis of variance for repeated measurements. RESULTS: There were no significant differences in TT between N and W with all treatments. The TT remained constant after S and there was no difference in TT between S and ACE. After AB there was a significant increase above baseline in TT until 405 minutes after treatment. Restlessness occurred 30-90 minutes after AB in 7 horses. All horses had reduced to absent borborygmi after AB administration for 165 to 495 minutes. CONCLUSION: Thermal stimulation at both described body areas gives comparable results in the assessment of cutaneous anti-nociception in horses. There is no differential influence of neuroleptic sedation or neuroleptanalgesia on TTs obtained at N or W. Buprenorphine combined with acepromazine has a long lasting anti-nociceptive effect associated with the typical opioid induced side effects in horses.

Treatment of medial condylar fractures of the third metatarsus in three horses with fibreglass casts under standing neuroleptanalgesia.

Minimally displaced condylar fractures propagating into the third metatarsal diaphysis were treated conservatively in one thoroughbred and two Arabian racehorses. In each case a neuroleptanalgesic protocol provided adequate pain relief for a rigid fibreglass cast to be applied in a weight-bearing position. The fractures healed completely and the three horses recovered uneventfully. Two of them returned successfully to racing and the third was used for breeding.

Neuroleptanalgesia in wild Asian elephants (Elephas maximus maximus).

OBJECTIVE: To evaluate the suitability of etorphine with acepromazine for producing prolonged neuroleptanalgesia in wild Asian elephants. ANIMALS: Ten adult wild elephants (four males, six females), free-roaming in the jungles of the north-western province of Sri Lanka. MATERIALS AND METHODS: Ten wild elephants were tranquilized for attachment of radio transmitter collars from September to November 1997, using Large-Animal Immobilon (C-Vet Veterinary Products, Leyland, UK), which is a combination of etorphine (2.45 mg mL(-1)) and acepromazine (10 mg mL(-1)). This was injected using projectile syringes fired from a Cap-Chur gun (Palmer Chemical Co. Inc., Atlanta, USA). A volume of 3.3 (2.5-4.5) mL Immobilon (6.12-11.02 mg of etorphine and 25-45 mg acepromazine) was injected intramuscularly after body mass estimation of individual elephants. RESULTS: The body condition of all darted elephants was good, and the mean (minimum-maximum) shoulder height was 225 (180-310) cm. The average approximate distance to elephants at firing was 26 (15-50) m. The average time to recumbency after injection was 18 (15-45) minutes. Nine out of 10 elephants remained in lateral recumbency (and did not require additional dosing) for a period of 42 (28-61) minutes. The respiratory and heart rates during anaesthesia were 7 (4-10) breaths and 52 (40-60) beats minute(-1), respectively. An equal volume (8.15-14.67 mg) of diprenorphine hydrochloride (Revivon, 3.26 mg mL(-1) diprenorphine; C-Veterinary Products, Leyland, UK) was given intravenously when the procedure was completed. Recovery (return to standing position) occurred in 6 (2-12) minutes after diprenorphine injection. Immediately afterwards, all elephants slowly retreated into the jungle without complications. Continuous radio tracking of the animals involved in this study indicated no post-operative mortality for several months after restraint. CONCLUSIONS/CLINICAL RELEVANCE: Etorphine-acepromazine combinations can be used safely in healthy wild Asian elephants for periods of restraint lasting up to 1 hour.

The sedative and analgesic effects of detomidine-butorphanol and detomidine alone in donkeys.

Butorphanol and detomidine constitute an effective combination for sedation and analgesia in horses. This trial was undertaken to assess the effectiveness of this combination in donkeys. The detomidine and butorphanol were given intravenously one after the other. A dose of 10 microg/kg of detomidine and 25 microg/kg of butorphanol was used. Sedation is easily extended by additional doses of butorphanol. The average dose of detomidine was 11.24 microg/kg and that of butorphanol was 28.0 microg/kg. Four donkeys in the detomidine group required additional sedation and analgesia. Detomidine alone did not totally eliminate coronary band pain. Heart rates dropped significantly in the first minute after the injection of the combination. One donkey developed an atrioventricular block, while another developed a sino-atrial block. Four donkeys developed a Cheyne-Stokes respiratory pattern. The combination of detomidine and butorphanol is an effective combination for sedation and analgesia of donkeys for standing procedures.

[The transmucosal measurement of oxygen partial pressure (PO2) in dogs]. / Untersuchungen zur transmukösen Messung des Sauerstoffpartialdrucks (PO2) am Hund.

A transmucosal measuring method for monitoring PO2 continuously is described. In an undisturbed microcirculation, the transmucosal PO2 measurement may complement the measurement of PO2 in arterialized blood in order to diagnose several respiratory diseases as well as heart diseases and circulatory disorders. Investigations with uraemic patients and with dogs under conditions of neuroleptoanalgesia serve to explain the influence of microcirculation on transmucosal PO2. This influence allows an inference from transmucosal PO2 to the function or dysfunction of microcirculation in an organism. Therefore transmucosal PO2 measurement offers the possibility of monitoring high-risk patients continuously.

[The intraerythrocytic acid-base status in dogs]. / Untersuchungen zum intraerythrozytären Säure-Basen-Status beim Hund.

The determination of the intracellular acid-base state is reported in this paper, using erythrocytic haemolysate in dogs as an example. Reference values are given for 217 clinically healthy dogs. The effects of various selected stages of illness and additional stresses on the erythrocytic acid-base equilibrium are reported and compared with acid-base changes in the blood. The metabolic acidosis observed may occur earlier and be stronger in the intracellular space than in the blood. There seems to be a closer correlation between a disturbed intraerythrocytic acid-base equilibrium and the degree of clinical symptoms than between the (commonly investigated) acid-base changes in the blood and the clinical presentations. The investigation of the blood alone does not provide a satisfactory indication of the patient's acid-base state and of the necessity for treatment.

Advantages and guidelines for using opioid agonists for induction of anesthesia.

Opioids have a central role in the anesthetic management of small animals, as premedicants, as part of a balanced anesthetic technique, or for the provision of postoperative analgesia. These drugs are safe to use, provide excellent analgesia, and are easily reversible. They cause minimal cardiovascular depression and induce no deleterious renal or hepatic changes. These agents, combined with a sedative, generally provide an ideal anesthetic state.

Anesthesia for cesarean section in the dog.

At the time of cesarean section, the mother may suffer respiratory depression, hypotension, increased gastric acidity, and increased predisposition to regurgitation, and the newborn may suffer anesthetic-induced respiratory depression. Preanesthetic metaclopramide, cimetidine, and anticholinergic agent are recommended. Sedatives can be administered if necessary. Neuroleptanalgesic and low-dose general anesthetic, with local anesthetic line-blocks, are preferred techniques. Supportive care of the newborn is mandatory.

Haemodynamic responses following meperidine and promazine induced neuroleptanalgesia in calves.

Induction of neuroleptanalgesia in 6 calves by i/v administration of a combination of meperidine (/ 12 mg/kg body weight) and promazine (/ 3 mg/kg body weight) elicited various haemodynamic responses. The MAP and CVP exhibited significant (p less than 0.01) overall variations with fluctuating fall and rise at different observation periods. A significant (p less than 0.01) rise could be observed in HR which manifested a maximum and an abrupt rise (104.31%) at 5 minutes postinjection. Cardiac output, cardiac index, stroke volume, stroke index and total peripheral resistance exhibited significant (p less than 0.01) overall variations with an initial fall in their values as compared to the respective base values. The cardiac output and cardiac index showed an alternate fall and rise from the preceeding value while the stroke volume, stroke index and total peripheral resistance manifested decreased values throughout the observation period as compared to base value. The values of all parameters measured, except heart rate, stroke volume, stroke index and total peripheral resistance, nearly returned to preinjection level by 120 minutes.

[Anesthesia in the patient with stomach dilatation-volvulus]. / Anesthesie bij de patiënt met maagdilatatie-volvulus.

Before a decision on the anesthetic protocol and the various patient support measures can be taken, the pathophysiological changes that occur during a gastric dilatation-volvulus need to be evaluated. The most important changes are of a circulatory and/or respiratory nature, inducing hypotension, hypovolaemia, cardiac dysrhythmias, a decreased respiratory minute volume, and subsequently resulting in changes in the acid-base balance and plasma electrolyte concentration. In view of these changes and the increased anaesthetic risk for the patient with gastric dilatation-volvulus, the use of barbiturates or ketamine cannot be recommended for anaesthetising these patients. With the use of neurolept-analgesic combinations, such as methadone-droperidol or sufentanil-midazolam, an increased cardiovascular stability and an ample analgesic effect can be obtained. Especially with the potent sufentanil in combination with midazolam, an excellent anaesthesia for patients with gastric dilatation-volvulus can be achieved.

Chemical restraint and analgesia in the horse.

Chemical restraint in the standing horse is used for a variety of procedures in veterinary medicine. The choice of agent depends on the physical status, temperament, and size of the patient; the procedure to be performed; and safety for the patient, veterinarian, and owner. The combination of certain agents may provide more desirable restraint and analgesia than does the use of individual agents. The use of analgesics in the horse is not without side effects, some of which may be detrimental to the patient's condition. Analgesics should be chosen with these untoward effects in mind. Draft breeds possess differences that may provide a challenge to the practitioner. One such difference is their clinically apparent increased sensitivity to tranquilizers and sedative-hypnotics; consequently, reduced dose regimens for chemical restraint should be employed initially.

Reversal of fentanyl/fluanisone neuroleptanalgesia in the rabbit using mixed agonist/antagonist opioids.

The reversal of the neuroleptanalgesic combination of fentanyl/fluanisone using mixed agonist/antagonist opioids has been investigated in the rabbit. All of the compounds studied (naloxone, nalbuphine, meptazinol, butorphanol, buprenorphine, pentazocine, doxapram) reversed the respiratory depression and sedation produced by fentanyl/fluanisone. Fentanyl/fluanisone produced profound analgesia for 180 min, which was rapidly and completely antagonized by naloxone. The mixed agonist/antagonist opioids produced a reduction in the degree of analgesia but, in contrast to naloxone, analgesic activity persisted from 120 min (meptazinol) to 420 min (buprenorphine). Administration of buprenorphine to rabbits anaesthetized with fentanyl/fluanisone and midazolam confirmed that the reversal of respiratory depression was accompanied by the return of arterial pH, PCO2 and PCO2 to preanaesthetic values. The use of neuroleptanalgesic anaesthetic regimens, which have been shown to provide effective surgical anaesthesia, combined with reversal using a mixed agonist/antagonist opioid to provide postoperative analgesia, appears to be a valuable refinement of current laboratory animal anaesthetic practice.

Haemodynamic, metabolic and physical responses to a neuroleptanalgesic-glyceryl guaiacolate combination in the horse.

A commercial neuroleptanalgesic acepromazine-etorphine combination administered intramuscularly to four horses produced a severe tachycardia and an increase in muscular tone, together with hypoxaemia, hypercapnia, metabolic acidosis associated with an increase in the packed cell volume and hyperglycaemia. No electrolyte changes were found. After reversal of the action of etorphine with diprenorphine, there was a prolonged decrease in the calcium and phosphorus serum concentrations and decreases in the packed cell volume and the total protein serum concentration. In a second experiment on the same four horses, glyceryl guaiacolate (10 g/100 kg body weight intravenously) was given as soon as the horses were anaesthetized with acepromazine-etorphine. The muscular rigidity disappeared and the tachycardia was less evident. There was a more pronounced hypoxaemia but the changes in the other parameters were similar to those in the first experiment. It was concluded that the neuroleptanalgesic-glyceryl guaiacolate combination is not a safe anaesthetic procedure in horses.

Management of craniotomy in young rabbits.

A safe and easy-to-manage technique for various craniotomy procedures in young rabbits has been developed. This technique, which minimizes the need for special instrumentation, has been tested in 90 animals with a minimal mortality and morbidity: one death perioperatively caused by sagittal sinus bleeding and one rabbit disclosing a brief period of postoperative illness, respectively. The technique, including postsurgical strategy, is described in detail.

[Anesthesia in swine]. / Anästhesie beim Schwein.

Pigs are not only anaesthetized in case of operations but often also if diagnostic and therapeutic procedures are necessary. Choice of the anaesthetic and way of application depend on the size of the patient and the indication. The only important local anaesthesia in pigs is epidural anaesthesia. It is indicated in all longer lasting painful procedures in caudal regions. The technique of this anaesthesia is described. From the possible methods of general anaesthesias, in practice injection anaesthesia has been generally accepted for several reasons. Together with barbiturate anaesthesia neurolept-analgesia with Azaperone--Metomidate has become more and more important, because with this form of anaesthesia the technically easy intra-abdominal application is possible in pigs under 15 kg of body weight.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on noxious stimulus perception in adult male rats.

The increased use of rats for laboratory studies has increased the urgency for a better understanding of their perception of painful or noxious stimuli and the means of obtunding such stimuli. Four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam, were evaluated in this study. Unlike previous studies in rodents, this study has quantitated noxious stimulus perception following a temporal sequence of observations. Results showed the greatest inhibition of noxious stimulus perception with Innovar-Vet, lesser inhibition with ketamine-xylazine and ketamine-diazepam, and the least obtunding of nociception with pentobarbital. Results of this study also suggested that a spatial orientation, similar to that present in man, exists within the CNS of rats for receipt of noxious stimulation.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on core and surface body temperature regulation in adult male rats.

Many commonly used anesthetics cause hypothermia by inhibiting central and peripheral thermoregulatory mechanisms. Although it is probable that a loss of thermal homeostasis contributes directly to the high mortality frequently reported following anesthesia of laboratory rodents, this adverse effect has been investigated rarely in the past. This study compared the effects of three parenteral anesthetics (pentobarbital, ketamine-xylazine and ketamine-diazepam) and a neuroleptanalgesic (fentanyl-droperidol) on core and surface body temperature regulation in rats. Results showed a profound hypothermia with all dosages of pentobarbital, while ketamine-xylazine and ketamine-diazepam caused a dose-dependent depression in core and surface body temperature. All dosages of fentanyl-droperidol (Innovar-Vet) caused minimal depression in thermoregulation, suggesting that it is the drug which requires the least external thermal support. Results of this study also suggested that inability to compensate for heat loss, particularly from the body core, may profoundly influence anesthetic toxicity and the safety of anesthetic procedures.

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on arterial blood pH, blood gases, mean arterial blood pressure and heart rate in adult male rats.

Although anesthetics are known to cause respiratory and cardiovascular depression in humans, these adverse effects rarely have been investigated in laboratory rodents. This study evaluated the effects of four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam on the respiratory and cardiovascular systems of rats. Results showed marked acidosis, hypercarbia and hypoxia with high doses of Innovar-Vet, moderate respiratory depression with all dosages of pentobarbital and minimal respiratory depression with ketamine-xylazine and ketamine-diazepam. Innovar-Vet, ketamine-xylazine and pentobarbital caused profound hypotension, particularly at high dosages, while ketamine-diazepam caused the least depression in mean arterial blood pressure of all drugs evaluated. None of the drugs studied produced significant alterations in heart rate. Throughout all dosages investigated, the ketamine-diazepam combination showed the least overall effects on ventilation and perfusion of the four parenteral drug combinations studied.

The effect of neuroleptanalgesia on some cardiorespiratory variables in the rabbit.

A technique of neuroleptanalgesia during which rabbits breathed spontaneously for as long as 6 h without any outward sign of stress and with full recovery within 12 h is described. The method involved the constant infusion of a solution comprising fentanyl (0.05 mg/ml) and droperidol (0.13 mg/ml) in 5% dextrose following an intramuscular dose of fentanyl and droperidol. Hourly measurements of blood gases, lung mechanics, mean arterial blood pressure and heart rate were made to assess changes in ventilation and in these physiological parameters for the length of the study. The animals' tracheas were intubated under direct vision with an uncuffed tube. The animals breathed spontaneously and their cardiovascular and respiratory systems were stable throughout the entire monitoring period. There was no statistical difference between the values for all the parameters measured (P less than 0.1). A two-way analysis of variance statistical test was applied to all the measurements.