Comparison of the sedative and cardiovascular effects of the combination of acepromazine-clonidine versus acepromazine-xylazine in horses.

The aim of this study was to compare the sedative and cardiovascular effects of the combination of acepromazine-clonidine versus acepromazine-xylazine in horses. Four healthy cross-bred horses were included in the study. They were assigned to two treatments. In treatment I (T1), the animals received xylazine hydrochloride (1.00 mg kg-1) in combination with acepromazine maleate (0.05 mg kg-1) intravenously (IV). In treatment II (T2), the animals received intra-gastric administration of clonidine (0.002 mg kg-1) followed by acepromazine (0.05 mg kg-1; IV) after 60 min. Head height above the ground (HHAG) and echocardiographic indices were evaluated. In T1, recordings were made 5 min before and 5, 15, 30, 60, and 90 min after drug administration. In T2, recordings were made 5 min before clonidine, 55 min after clonidine administration, and then 5, 15, 30, 60, and 90 min after acepromazine injection. Analyses of the data showed there were not significant differences regarding HHAG and echocardiographic indices between two treatments. For sedation of healthy horses, it was concluded that intra-gastric administration of clonidine and IV administration of acepromazine showed similar sedative and cardiovascular effects compared to IV acepromazine-xylazine administration.

Dobutamine use in horses during romifidine and isoflurane anaesthesia.

This retrospective study aimed to assess the incidence of hypotension and the subsequent administration of dobutamine in horses anesthetized with isoflurane and romifidine during elective surgery. Time from induction of anaesthesia to administration of dobutamine was registered, as well as the time and dose needed to restore mean arterial pressure (MAP) ≥ 70 mmHg. Additionally, the influence of patient and anaesthesia related parameters on the need for dobutamine supplementation was evaluated. In total, 118 horses were included in this retrospective study. Dobutamine was administered to effect when MAP<70 mmHg. Data registered: patient weight, acepromazine premedication, body position, administration of intraoperative ketamine bolus, locoregional anaesthesia, mechanical ventilation, duration of anaesthesia, dose and duration of dobutamine administration, heart rate, MAP before dobutamine administration, MAP and time required to increase MAP≥70 mmHg. Dobutamine infusion was needed in 54.2% of the horses 30 ± 17 min after isoflurane-romifidine anaesthesia started. Dobutamine 0.55 ± 0.18 µg kg-1 min-1 achieved a MAP≥70 mmHg in 12 ± 8 min. Duration of dobutamine infusion was 56 ± 37 min. An univariable logistic regression showed a significant association between dobutamine and acepromazine administration (p = 0.01; OR = 3.43), anaesthesia time (p = 0.02; OR = 2.41) and dorsal recumbency (p < 0.001; OR = 8.40). In a multivariable logistic regression, only dorsal recumbency significantly increased the need for dobutamine supplementation (p < 0.001; OR = 7.70). There was no significant association between patient weight (p = 0.11; OR = 1), locoregional anaesthesia (p = 0.07; OR = 0.47), administration of a ketamine bolus (p = 0.95; OR = 0.98) or volume controlled ventilation (p = 0.94; OR = 1.04) and dobutamine administration. Low doses of dobutamine were suitable to restore MAP above 70 mmHg within a limited time period. Only dorsal recumbency increased the need of dobutamine administration.

Phenylephrine and norepinephrine increase blood pressure through opposing physiologic mechanisms in isoflurane-anesthetized dogs receiving acepromazine.

OBJECTIVE: To elucidate the cardiovascular effects of escalating doses of phenylephrine and norepinephrine in dogs receiving acepromazine and isoflurane. ANIMALS: 8 beagles aged 1 to 2 years (7.4 to 11.2 kg). METHODS: All dogs received acepromazine 0.01 mg/kg, propofol 4 to 5 mg/kg, and isoflurane and were mechanically ventilated. Mean arterial pressure (MAP) from a femoral artery catheter and continuous electrocardiogram were recorded. Cardiac output (CO) was measured with transpulmonary thermodilution. Systemic vascular resistance (SVR), global end-diastolic volume (GEDV), and global ejection fraction (GEF) were subsequently calculated. Phenylephrine and norepinephrine were infused in random order at 0.07, 0.3, 0.7, and 1.0 µg/kg/min. All variables were measured after 15 minutes of each infusion rate. The effects of dose, agent, and their interaction on the change of each variable were evaluated with mixed-effect models. A P < .05 was used for significance. RESULTS: Atrial premature complexes occurred in 3 dogs during norepinephrine infusion at doses of 0.3, 0.7, and 1 µg/kg/min; no dysrhythmias were seen with phenylephrine administration. MAP increased during dose escalation (P < .0001) within each agent and did not differ between agents (P = .6). The decrease in HR was greater for phenylephrine (P < .0001). Phenylephrine decreased CO and GEF and increased GEDV and SVR (all P < .03). Norepinephrine decreased the SVR and increased CO, GEDV, and GEF (all P < .03). CLINICAL RELEVANCE: Our results confirm that phenylephrine increases arterial pressures mainly through vasoconstriction in acepromazine-premedicated dogs while norepinephrine, historically considered a vasopressor, does so primarily through an increase in inotropism.

Effect of Classical Music on Depth of Sedation and Induction Propofol Requirements in Dogs.

The main objective of this prospective, randomized, blind, cross-over experimental study was to evaluate the effect of classical music on the depth of sedation and propofol requirements for the induction of anaesthesia in dogs. Twenty dogs were involved, and each was subjected to three different treatments with a 3-month gap: Chopin music, Mozart music, and no music, via loudspeakers. The dogs were premedicated with acepromazine and butorphanol by intramuscular injection, and anaesthesia was induced using propofol intravenously. To compare the depth of sedation and propofol requirements for the induction of anaesthesia among the different treatments, we utilized non-parametric tests (Kruskal-Wallis test) for the depth of sedation due to a slight deviation from the normal distribution and parametric (ANOVA) for propofol requirements. When exposed to music (Chopin or Mozart), dogs exhibited deeper sedation and required less propofol for their intubation compared to the no-music treatment (p < 0.05). Exposure to classical music had a positive impact on the level of sedation, and more profound central nervous system depression seemed to contribute to approximately 20% lower propofol dose requirements for tracheal intubation. Therefore, classical music during the preoperative period appeared to exert a beneficial effect, at least when applying the specific pre-anaesthetic medications used in the present study.

Successful treatment of idiopathic tetanus using metronidazole, magnesium, and acepromazine in Hanwoo (Korean indigenous cattle) yearling bull.

Bovine tetanus is a serious infectious disease of the central nervous system caused by the exotoxin produced by Clostridium tetani and is characterized by persistent tension and spasm of the rhabdomyocytes. Currently, many studies have focused on diagnosing tetanus; however, only a few studies on treatment methods have been conducted. Therefore, cattle with tetanus have been treated using symptomatic therapy. In this case, severe muscle spasticity and spasms were observed in a 9-month-old Hanwoo (Korean indigenous cattle) bull, and aspartate aminotransferase and creatine kinase levels were increased in serum biochemical tests. Clinically, bovine tetanus was strongly suspected, and metronidazole was administered orally for 5 days. To treat the intensifying bloat, a temporary rumenostomy was performed on the third day of onset, and the toxin gene (tetanospasmin) of C. tetani was amplified by polymerase chain reaction analysis from the collected ruminal fluid. Magnesium and sedatives (acepromazine) were administered for 7 days to treat muscle spasticity and spasms. Muscle spasticity and spasm markedly improved, and the bull stood up from the lateral recumbent position. On the 17th day after onset, all tetanus-related symptoms resolved and a normal diet was started. Our findings demonstrated that treatment with metronidazole, magnesium, and acepromazine was effective in the bull with tetanus.

Welfare and Clinical Assessment on Physical Captures Followed by Anesthesia in Apennine Chamois (Rupicapra pyrenaica ornata).

The Apennine chamois (Rupicapra pyrenaica ornata) is one of the rarest subspecies in Italy, listed in Annexes II and IV of the Habitats Directive and currently included as a vulnerable subspecies in the International Union for Conservation of Nature (IUCN) Red List. The Maiella National Park population has recently been defined as a source population for reintroduction into other parks. Since collective captures allow for better selection of target animals for the establishment of new colonies, the aim of this study is to evaluate the physiological conditions and animal welfare in free-ranging Apennine chamois after collective physical capture followed by chemical immobilization with medetomidine 0.054 mg ± 0.007, ketamine 2.14 mg ± 0.28, and acepromazine 0.043 mg ± 0.006. Twenty-one Apennine chamois (18 females and 3 males) were captured and translocated for conservation purposes. The effects of capture and anesthesia were evaluated using clinical variables, hematology, serum biochemistry, and venous blood gas analysis, the latter being used in the field for the first time in chamois capture. A risk of metabolic acidosis and capture myopathy was identified, although it did not compromise the survival of 19 chamois, which adapted to novel environments and founded new colonies, as verified through GPS radiocollars. The protocol applied in this study represents an innovative approach to assessing animal physiology and welfare in collective mountain ungulate captures, useful for improving management activities for conservation purposes.

Morphine with or without Acepromazine in Horses: A Kinematic Evaluation.

The objective was to demonstrate walking locomotor pattern alterations after co-administration of acepromazine and morphine in horses. Six mature horses receiving four different treatments were used. Treatments consisted of a single dose of saline solution, 0.2 mg/kg bwt of morphine hydrochloride, 0.02 mg/kg bwt of acepromazine maleate, and a combination of 0.2 mg/kg bwt of morphine hydrochloride with 0.02 mg/kg bwt of acepromazine maleate. A three-dimensional accelerometric device was used to collect data. Walking tests were performed 10 min prior to injection, and then at 5, 10, 15, and 20 min after the injection, and then every 10 min for 3 h. Eight variables were calculated including stride kinematic, coordination, and energetic parameters; moreover ground-to-lip distance (GLD), as a tranquilization parameter, was also measured. A significant interaction was observed in all the variables studied but regularity, mediolateral power, the propulsive part of the power, and the GLD. An evident counteraction of the effects caused by both, opioids and phenothiazines, in the gait pattern was observed. The co-administration of acepromazine and morphine could allow a safe opiate administration while minimizing the possible central nervous system (CNS) excitation and reducing potential locomotor adverse effects.

Effects of intravenous acepromazine and butorphanol on propofol dosage for induction of anesthesia in healthy Beagle dogs.

OBJECTIVE: To determine the effects of intravenous (IV) premedication with acepromazine, butorphanol or their combination, on the propofol anesthetic induction dosage in dogs. STUDY DESIGN: Prospective, blinded, Latin square design. ANIMALS: A total of three male and three female, healthy Beagle dogs, aged 3.79 ± 0.02 years, weighing 10.6 ± 1.1 kg, mean ± standard deviation. METHODS: Each dog was assigned to one of six IV treatments weekly: 0.9% saline (treatment SAL), low-dose acepromazine (0.02 mg kg-1; treatment LDA), high-dose acepromazine (0.04 mg kg-1; treatment HDA), low-dose butorphanol (0.2 mg kg-1; treatment LDB), high-dose butorphanol (0.4 mg kg-1; treatment HDB); and a combination of acepromazine (0.02 mg kg-1) with butorphanol (0.2 mg kg-1; treatment ABC). Physiologic variables and sedation scores were collected at baseline and 10 minutes after premedication. Then propofol was administered at 1 mg kg-1 IV over 15 seconds, followed by boluses (0.5 mg kg-1 over 5 seconds) every 15 seconds until intubation. Propofol dose, physiologic variables, recovery time, recovery score and adverse effects were monitored and recorded. Data were analyzed using mixed-effects anova (p < 0.05). RESULTS: Propofol dosage was lower in all treatments than in treatment SAL (4.4 ± 0.5 mg kg-1); the largest decrease was recorded in treatment ABC (1.7 ± 0.3 mg kg-1). Post induction mean arterial pressures (MAPs) were lower than baseline values of treatments LDA, HDA and ABC. Apnea and hypotension (MAP < 60 mmHg) developed in some dogs in all treatments with the greatest incidence of hypotension in treatment ABC (4/6 dogs). CONCLUSIONS AND CLINICAL RELEVANCE: Although the largest decrease in propofol dosage required for intubation was after IV premedication with acepromazine and butorphanol, hypotension and apnea still occurred.

Effects of dissociative anesthesia opioid-free protocols combined with local anesthesia, with or without flumazenil or atipamezole postoperatively, for orchiectomy in cats.

OBJECTIVE: To evaluate the anesthetic effects of two drug combinations with local anesthesia, with or without postoperative antagonists, for orchiectomy in cats. STUDY DESIGN: Prospective, randomized blinded clinical study. ANIMALS: A total of 64 healthy cats. METHODS: Cats were assigned to four equal groups: ketamine (5 mg kg-1) and dexmedetomidine (10 µg kg-1) were administered intramuscularly (IM), followed postoperatively with intravenous (IV) saline (5 mL; group KDS) or atipamezole (50 µg kg-1; group KDA); and ketamine (14 mg kg-1) with midazolam (0.5 mg kg-1) and acepromazine (0.1 mg kg-1) IM, with postoperative IV saline (5 mL; group KMAS) or flumazenil (0.1 mg kg-1; group KMAF). Lidocaine (2 mg kg-1) was divided between subcutaneous and intratesticular injection. Physiologic variables were recorded at time points during anesthesia. Ketamine rescue dose was recorded. The degree of sedation and the quality of recovery were evaluated postoperatively. RESULTS: Time to loss of pedal reflex was longer in groups KMAS and KMAF than in groups KDS and KDA (p = 0.010). Total rescue dose of ketamine was higher in KMAS and KMAF than in KDS and KDA (p = 0.003). Heart rate (HR) during anesthesia was higher in KMAS and KMAF than in KDS and KDA (p = 0.001). Times to head up (p = 0.0005) and to sternal recumbency (p = 0.0003) were shorter in KDA than in KDS, KMAS and KMAF. Lower sedation scores were assigned sooner to KDA than KDS, KMAS and KMAF (p < 0.001). Recovery quality scores were good in all groups. CONCLUSIONS AND CLINICAL RELEVANCE: Both anesthetic protocols allowed the performance of orchiectomy. Groups KMAS and KMAF required higher rescue doses of ketamine before injecting lidocaine. HR and oscillometric systolic pressure were minimally changed in groups KD and tachycardia was recorded in groups KMA. Only atipamezole shortened the anesthetic recovery.

Evaluation of Tear Production as Measured by Schirmer Test I in Dogs after Acepromazine and Acepromazine-Methadone Premedication.

The purpose of the current study was to investigate the effects of two commonly used sedation protocols in dogs, acepromazine (ACP) and acepromazine-methadone (ACP-MET) combination, on tear production measured by the Schirmer Tear Test (STT) 1. We hypothesized that both sedation protocols cause a reduction in canine tear production for a variable time. Fifteen client-owned dogs were recruited for the study. Each dog was subjected to sedation twice, 2-3 weeks apart, and they were randomly allocated to one of two groups receiving ACP (0.015 mg kg-1) or ACP-MET (0.010 mg kg-1 and 0.2 mg kg-1) intramuscularly. In both eyes, tear production was measured 15 min before sedation (T0) and 20 min (T20 m), 40 min (T40 m), 1 h (T1), 2 h (T2), 4 h (T4) and 8 h (T8), after drug administration. Two-way repeated measures ANOVA, followed by the Bonferroni post hoc test (p < 0.05), showed a significant effect of time (p < 0.0001) and treatment (p < 0.0001). A significant decrease in tear production at T20 m, T40 m, T1 and T2 compared to T0 was observed in the ACP experimental protocol, while in the ACP + MET protocol, this reduction persisted until T8. Comparing the two experimental protocols, no statistically significant differences were observed at T0 or T20 m, and STT 1 values were statistically lower in the ACP + MET than the ACP protocol at the other data points. In the ACP + MET group, at T40 m, 100% of dogs showed STT 1 readings lower than 15 mm/min. This finding is clinically relevant as it can predispose dogs to corneal injuries. The major reduction in tear production due to the ACP + MET protocol proves the need for adequate corneal hydration, particularly to discourage its use in animals with altered tear production. The data obtained provide important information helping clinicians to better manage the drug's effects on tear production.

Pharmacokinetic, Clinical, and Myeloid Marker Responses to Acepromazine Sedation in Arabian Camels.

Sedatives and tranquilizers are important in the control of excited camels during camel transport. This study was conducted to investigate the clinical sedation of camels with acepromazine and its correlation with pharmacokinetics and pharmacodynamics. The sedation score, heart rate, respiration, body temperature, and pharmacokinetics were monitored before and after acepromazine injection, and myeloid marker expression was analyzed using membrane immunofluorescence and flow cytometry. The distribution (t1/2α) and elimination (t1/2ß) half-lives were 0.1 and 9.4 h, respectively. The volume of distribution at steady state (Vss) was 20.01 L/kg, and the mean residence time (MRT) was 12.25 h. Sedation started rapidly within 10 min followed by persistent low-medium sedation for 2 h with an average sedation score of 1.2 ± 0.61, which might be associated with a slow elimination phase and prolonged MRT. Compared to horses, camels showed a lower clearance rate, higher volume of distribution, and higher elimination half-life. Slight changes in body temperature and heart and respiratory rate, as well as a lower hematocrit and changes in blood cell composition, suggest the careful application of acepromazine in animals with abnormal blood parameters or poor vital conditions.

Effects of Medetomidine, Dexmedetomidine and their combination with Acepromazine on the intraocular pressure (IOP), tear secretion and pupil diameter in dogs.

BACKGROUND: A great number of sedatives and anaesthetics have been used to perform surgeries or routine ophthalmologic examinations in animals and sometimes the combination of these medicines has more suitable effects than each one alone. OBJECTIVES: This paper aims to explore the main effects of Medetomidine + Acepromazine, Dexmedetomidine + Acepromazine on intraocular pressure, tear secretion and pupil diameter. METHODS: To accomplish the aforementioned aim, 32 adult dogs (aged one-to-three-years-old) were clinically examined. Dogs were divided into four groups consisting of group DA, Dexmedetomidine (5 µg/kg) + Acepromazine (0.05 mg/kg); Group D, Dexmedetomidine (5 µg/kg); Group M, Medetomidine (10 µg/kg); Group MA, Medetomidine (10 µg/kg) + Acepromazine (0.05 mg/kg). The ocular factors including tear production, pupil diameter and intraocular pressure of both right and left eyes were first measured and then recorded in each dog at time T0 (-15 min). Afterwards, the drugs were administered intramuscularly, based on which the ocular factors were re-measured at T1 (+5 min), T2 (+15 min) and T3 (+20 min). All four groups showed a reduction in intraocular pressure, which was significant in DA, D and M groups. RESULTS: Furthermore, there was a fluctuation in the amount of tear secretion in DA and D groups (increase and then decrease), as well as a significant reduction in M and MA groups. Decreasing in pupil diameter also occurred in all four groups, but the reduction was significant only in DA and MA groups. CONCLUSION: According to the results obtained, as the changes caused by the systemic administration of the above drug compounds did not exceed the physiological range, it can be concluded that these combinations could be utilized as suitable sedatives or pre-anaesthetic compounds in the eye surgeries.

Development, Validation, and Reliability of a Sedation Scale in Horses (EquiSed).

The lack of standardization of sedation scales in horses limits the reproducibility between different studies. This prospective, randomized, blinded, horizontal and controlled trial aimed to validate a scale for sedation in horses (EquiSed). Seven horses were treated with intravenous detomidine in low/high doses alone (DL 2.5 µg/kg + 6.25 µg/kg/h; DH 5 µg/kg +12.5 µg/kg/h) or associated with methadone (DLM and DHM, 0.2 mg/kg + 0.05 mg/kg/h) and with low (ACPL 0.02 mg/kg) or high (ACPH 0.09 mg/kg) doses of acepromazine alone. Horses were filmed at (i) baseline (ii) peak, (iii) intermediate, and (iv) end of sedation immediately before auditory, visual and pressure stimuli were applied and postural instability evaluated for another study. Videos were randomized and blindly evaluated by four evaluators in two phases with 1-month interval. Intra- and interobserver reliability of the sum of EquiSed (Intraclass correlation coefficient) ranged between 0.84-0.94 and 0.45-0.88, respectively. The criterion validity was endorsed by the high Spearman correlation between the EquiSed and visual analog (0.77), numerical rating (0.76), and simple descriptive scales (0.70), and average correlation with head height above the ground (HHAG) (-0.52). The Friedman test confirmed the EquiSed responsiveness over time. The principal component analysis showed that all items of the scale had a load factor ≥ 0.50. The item-total Spearman correlation for all items ranged from 0.3 to 0.5, and the internal consistency was good (Cronbach's α = 0.73). The area under the curve of EquiSed HHAG as a predictive diagnostic measure was 0.88. The sensitivity of the EquiSed calculated according to the cut-off point (score 7 of the sum of the EquiSed) determined by the receiver operating characteristic curve, was 96% and specificity was 83%. EquiSed has good intra- and interobserver reliabilities and is valid to evaluate tranquilization and sedation in horses.

Comparison between dexmedetomidine and acepromazine in combination with methadone for premedication in brachycephalic dogs undergoing surgery for brachycephalic obstructive airway syndrome.

OBJECTIVE: To compare dexmedetomidine with acepromazine for premedication combined with methadone in dogs undergoing brachycephalic obstructive airway syndrome (BOAS) surgery. STUDY DESIGN: Randomized, blinded clinical study. ANIMALS: A group of 40 dogs weighing mean (± standard deviation) 10.5 ± 6 kg, aged 2.6 ± 1.9 years. METHODS: Dogs received either acepromazine 20 µg kg-1 (group A) or dexmedetomidine 2 µg kg-1 (group D) intramuscularly with methadone 0.3 mg kg-1. Anaesthesia was induced with propofol and maintained with sevoflurane. Sedation (0-18), induction (0-6) and recovery (0-5) qualities were scored. Propofol dose, hypotension incidence, mechanical ventilation requirement, extubation time, additional sedation, oxygen supplementation, regurgitation and emergency intubation following premedication or during recovery were recorded. Data were analysed using t tests, Mann-Whitney U or Chi-square tests. RESULTS: Group A dogs were less sedated [median (range): 1.5 (0-12)] than group D [5 (1-18)] (p = 0.021) and required more propofol [3.5 (1-7) versus 2.4 (1-8) mg kg-1; p = 0.018]. Induction scores [group A: 5 (4-5); group D 5 (3-5)] (p = 0.989), recovery scores [group A 5 (4-5); group D 5(3-5)](p = 0.738) and anaesthesia duration [group A:93 (50-170); group D 96 (54-263) minutes] (p = 0.758) were similar between groups. Time to extubation was longer in group A 12.5 (3-35) versus group D 5.5 (0-15) minutes; (p = 0.005). During recovery, two dogs required emergency intubation (p > 0.99) and five dogs required additional sedation (p > 0.99). Oxygen supplementation was required in 16 and 12 dogs in group A and D, respectively (p = 0.167); no dogs in group A and one dog in group D regurgitated (p = 0.311). CONCLUSIONS AND CLINICAL RELEVANCE: Dexmedetomidine 2 µg kg-1 produces more sedation but similar recovery quality to acepromazine 20 µg kg-1 combined with methadone in dogs undergoing BOAS surgery.

Feline procedural sedation and analgesia: When, why and how.

PRACTICAL RELEVANCE: Procedural sedation and analgesia (PSA) describes the process of depressing a patient's conscious state to perform unpleasant, minimally invasive procedures, and is part of the daily routine in feline medicine. Maintaining cardiopulmonary stability is critical while peforming PSA. CLINICAL CHALLENGES: Decision-making with respect to drug choice and dosage regimen, taking into consideration the cat's health status, behavior, any concomitant diseases and the need for analgesia, represents an everyday challenge in feline practice. While PSA is commonly perceived to be an uneventful procedure, complications may arise, especially when cats that were meant to be sedated are actually anesthetized. AIMS: This clinical article reviews key aspects of PSA in cats while exploring the literature and discussing complications and risk factors. Recommendations are given for patient assessment and preparation, clinical monitoring and fasting protocols, and there is discussion of how PSA protocols may change blood results and diagnostic tests. An overview of, and rationale for, building a PSA protocol, and the advantages and disadvantages of different classes of sedatives and anesthetics, is presented in a clinical context. Finally, injectable drug protocols are reported, supported by an evidence-based approach and clinical experience.

Comparison of the effects of methadone and butorphanol combined with acepromazine for canine gastroduodenoscopy.

OBJECTIVE: To evaluate the feasibility of gastroduodenoscopy in dogs premedicated with acepromazine in combination with butorphanol or methadone. STUDY DESIGN: Prospective, randomized, double-blinded clinical trial. ANIMALS: A group of 40 client-owned dogs. METHODS: Dogs were randomly allocated to one of two groups and give intramuscular acepromazine 0.02 mg kg-1 combined with either butorphanol 0.3 mg kg-1 (group ACEBUT) or methadone 0.2 mg kg-1 (group ACEMET). General anaesthesia was induced with propofol and ketamine and maintained with sevoflurane (2.3%) in oxygen. Cardiopulmonary variables were recorded at 5 minute intervals during anaesthesia. Feasibility of the entire gastroduodenoscopy was evaluated with a visual analogue scale (VAS) from 0 (best) to 100 (worst) (primary outcome of the study). Lower oesophageal sphincter dilatation and duodenal intubation were scored. Pylorus diameter was measured with standard endoscopic inflatable balloons. Overall cardiovascular stability was assessed during anaesthesia, using a VAS (0-100), as was the presence of fluid in the oesophagus, regurgitation, need for mechanical ventilation, and intraoperative and postoperative rescue analgesia (secondary outcomes of the study). Differences between treatments were analysed with Mann-Whitney U, Student t test, Fisher exact test or mixed model analysis of variance as appropriate. Subsequently, feasibility VAS of the gastroduodenoscopy was assessed for noninferiority between groups. The noninferiority margin was set as -10. RESULTS: All gastroduodenoscopies were successfully completed in both groups using an endoscope tip diameter of 12.8 mm in all but one dog. Feasibility of gastroduodenoscopy was evaluated as 2.9 ± 5.6 in group ACEBUT and 5.1 ± 5.8 in group ACEMET. No significant differences between groups were detected in any measured or assessed variables, and noninferiority was confirmed. CONCLUSION AND CLINICAL RELEVANCE: In our study population, the effects of methadone and butorphanol when combined with acepromazine were comparable.

Evaluation of anesthesia produced by ketofol in acepromazine- or medetomidine-sedated dogs.

OBJECTIVE: A randomized, blinded clinical study was conducted to evaluate ketofol (Ketamine + Propofol combination) anesthesia in 12 entire male mongrel dogs sedated with either acepromazine (ACP) or medetomidine. MATERIALS AND METHODS: Group A (6) dogs were pre-medicated with ACP and Group B (6) dogs with medetomidine. Anesthesia was induced and maintained using ketofol (ketamine and propofol). Routine open pre-scrotal castration was performed. Sedation score and ease of arousal were assessed and recorded. Duration and depth of anesthesia were evaluated using apnea and the absence of palpebral and pedal reflexes, attempts to stand up, and muscle tremors and post-operative pain. Simple statistics were compared using Student t-test and Mann-Whitney test (p < 0.05). RESULTS: Medetomidine-sedated dogs had higher sedation scores compared to ACP-sedated dogs. Medetomidine-ketofol produced significantly (p < 0.05) longer duration of anesthesia (24.5 ± 3.1 min) compared to ACP-ketofol (10.0 ± 4.4 min). Sixty-seven percent of dogs anesthetized with ACP-ketofol required top up with ketofol to complete the castration. However, none of the Med-ketofol anesthetized dogs required top up. Med-ketofol produced a more profound depth of anesthesia and smoother recovery from anesthesia compared to ACP-ketofol. Med-ketofol (median score 6) attained better overall post-operative analgesia compared to ACP-ketofol (median score 7), though not statistically significant (p = 0.25). Although both protocols provided adequate anesthesia for castration, top up was required to complete the operation in more than half of ACP-ketofol anesthetized dogs, making Med-ketofol a better protocol. CONCLUSION: The study recommends the use of Med-ketofol anesthesia for castration in a dog, and post-operative analgesia to be administered with either protocol, but more so in ACP-ketofol anesthetized dogs undergoing castration.

Effect of different anesthetic mixtures-ketamine-xylazine, ketamine-acepromazine and tiletamine-zolazepam-on the physiological and blood biochemistry parameters of male rhesus monkeys (Macaca mulatta) at different ages.

BACKGROUND: Anesthetic agents are commonly utilized in the handling of non-human primates for prevent the stress caused in physical exploration or physical restrain. For this reason, the objective of this work was to describe the effect of age and dissociative anesthetics (ketamine and tiletamine), and their combinations with acepromazine, xylazine and zolazepam, on the physiological and blood biochemical parameters in Macaca mulatta. METHODS: Eighty male Macaca mulatta were divided into four experimental groups depending on the anesthetic mixture applied. Each group of 20 males was divided into five sub-groups according to age. Physiological parameters were recorded every 5 minutes during a 30-minute period. A blood sample was drawn to analyze blood biochemistry. RESULTS: Statistical analyses revealed significant differences in the physiological parameters between the ketamine-acepromazine and ketamine-xylazine groups compared to the control group. The analysis of blood biochemistry found significant differences by age and by anesthetic mixture among all groups. CONCLUSION: These findings contribute to standardizing this animal model in biological research.

Effect of premedication on dose requirement, cardiovascular effects and recovery quality of alfaxalone total intravenous anaesthesia in dogs.

OBJECTIVE: To investigate alfaxalone total intravenous anaesthesia (TIVA) following premedication with methadone combined with acepromazine (ACP) or dexmedetomidine in bitches undergoing ovariohysterectomy. STUDY DESIGN: Prospective, blinded, randomized, experimental study. ANIMALS: A group of 12 female Beagles. METHODS: Dogs were premedicated intravenously with methadone (0.2 mg kg-1) combined with ACP (20 µg kg-1, group AM) or dexmedetomidine (5 µg kg-1, group DM). Anaesthesia was induced with alfaxalone (2 mg kg-1). Anaesthetic maintenance was obtained with an alfaxalone variable rate infusion (VRI) started at 0.15 mg kg-1 minute-1 and adjusted every 5 minutes based on clinical assessment. Mechanical ventilation was initiated when necessary to maintain normocapnia. Anaesthetic monitoring included electrocardiogram, heart rate (HR), invasive diastolic (DAP), systolic (SAP) and mean arterial blood pressure, arterial haemoglobin oxygen saturation, respiratory variables and oesophageal temperature. Data were recorded every 5 minutes. A mixed model statistical approach was used to compare cardiovascular variables within and between groups (α = 0.05). A Wilcoxon rank-sum test was used to compare body temperature, VRI alfaxalone rate, administered rescue analgesia, sedation, induction, intubation, recovery scores and recovery times between treatments. RESULTS: Overall HR, SAP and DAP differed between groups (p = 0.001, 0.016, 0.019, respectively). The mean VRI dose rate of alfaxalone differed between groups DM [0.13 (0.11-0.14) mg kg-1 minute-1] and AM [0.18 (0.13-0.19) mg kg-1 minute-1; p = 0.030]. Rescue analgesia was administered more in group AM (p = 0.019). No significant difference in recovery times and scores was observed between protocols. CONCLUSIONS AND CLINICAL RELEVANCE: Alfaxalone TIVA following dexmedetomidine/methadone premedication produced a more stable plane of anaesthesia to perform ovariohysterectomy than ACP/methadone. A dose reduction of alfaxalone of 27.7% was obtained in group DM compared with group AM. Recovery quality and recovery times were comparable between both groups.

Comparison of intraocular pressure and pupil diameter after sedation with either acepromazine or dexmedetomidine in healthy dogs.

OBJECTIVE: To compare intraocular pressure (IOP) and pupillary diameter (PD) following intravenous (IV) administration of dexmedetomidine and acepromazine in dogs. STUDY DESIGN: Prospective, randomized experimental trial. ANIMALS: A group of 16 healthy adult dogs aged (mean ± standard deviation) 4.9 ± 3.3 years and weighing 15.7 ± 9.6 kg, without pre-existing ophthalmic disease. METHODS: IV dexmedetomidine hydrochloride (0.002 mg kg-1; DEX) or acepromazine maleate (0.015 mg kg-1; ACE) was administered randomly to 16 dogs (eight per group). The IOP and PD, measured using applanation tonometry and Schirmer's strips mm scale, respectively, and the heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures and respiratory rate (fR) were recorded at baseline, at time of injection, and then 5, 10, 15, 20 and 25 minutes after injection. A single ophthalmologist, unaware of treatment, performed all measurements under consistent light conditions. Values were compared with baseline and among treatments using a multivariate mixed-effects model (p ≤ 0.05). RESULTS: The IOP was significantly lower in the DEX group compared with the ACE group at 10 (p < 0.01) and 15 minutes (p < 0.01) after drug injection. PD was significantly smaller compared to baseline for the entire duration of the study (p < 0.01) in both groups. Dogs in the DEX group had significant lower HR (p < 0.01) and fR (p < 0.01), higher SAP (p < 0.01) and DAP (p < 0.01) at all time points, and higher MAP (p < 0.01) during the first 15 minutes following drug injection in comparison with the ACE group. CONCLUSIONS AND CLINICAL RELEVANCE: Our results suggest that premedication with IV dexmedetomidine temporarily decreases IOP when compared with IV acepromazine. Both drugs cause miosis.