Sedative and cardiorespiratory effects of dexmedetomidine alone or combined with acepromazine in healthy cats.

The purpose of this study was to assess sedation, emesis and cardiovascular effects of dexmedetomidine alone or combined with acepromazine in healthy cats. Fourteen male cats aged 0.9 ± 0.5 years and weighing 3.7 ± 0.7 kg were randomly assigned to one of two experimental groups: GD, dexmedetomidine 5 µg/kg; and GDA, dexmedetomidine 5 µg/kg with acepromazine 0.03 mg/kg, all intramuscularly. Measurements were recorded at baseline, at 20 minutes and then at 10-minute intervals following sedation and included heart rate (HR), respiratory rate (FR), systolic arterial pressure (SAP), rectal temperature (RT), number of episodes of emesis and sedation score (0-4). Data were compared using ANOVA for repeated measures followed by Sídák and Dunnet test. Sedation scores were compared between groups at T20 using Mann-Whitney test. Significance was considered when P <0.05. At T20, HR was significantly lower in GDA (99 ± 14 beats/min) compared with GD (133 ± 19 beats/min) and SAP was significantly lower in both groups compared with baseline (126 ± 14 vs. 148 ± 26 and 111 ± 13 vs. 144 ± 17 mmHg in GD and GDA, respectively). Duration of sedation was similar between groups, although sedation scores differed significantly at T20, with 1 (0-4) in GD and 4 (4-4) in GDA. More episodes of emesis were recorded in GD compared with GDA. The combination of dexmedetomidine and acepromazine produced more profound sedation with faster onset and lower incidence of emesis compared with dexmedetomidine alone in healthy cats.

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.

A highly efficient and portable laser-scribed graphene-based electrochemical system for forensic-oriented determination of acepromazine.

Acepromazine (ACP) is a phenothiazine derivative drug commonly used as a tranquilizer veterinary medication due to its sedative properties. Benefiting from sedative properties, ACP has emerged as a drug of abuse and has been associated with drug-facilitated sexual assaults. Herein, we report, for the first time, the electrochemical behavior of ACP using a miniaturized and environmentally friendly laser-scribed graphene-based (LSG) sensor fabricated on a polyetherimide (PEI) substrate. The LSG device presented high porosity, as demonstrated by scanning electron microscopy (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements of the PEI-LSG electrode confirmed the enhanced electroactive area (3.1-fold increase) caused by the rough surface and revealed a low charge transfer resistance of the electrode material, with a heterogeneous electron transfer rate constant (k0) of 8.66 × 10-3 cm s-1 for potassium ferricyanide redox probe. A simple and accurate method was applied to quantify ACP by using square wave voltammetry (SWV) under optimized experimental conditions, which exhibited high sensitivity (0.686 ± 0.008 A L mol-1 cm-2) and a low limit of detection (LOD) of 7.43 × 10-8 mol L-1, with a linear concentration ranging from 0.5 to 100 µmol L-1 ACP. Aiming for on-site analysis, the PEI-LSG sensor was integrated with a miniaturized potentiostat controlled by using a smartphone and applied as proof of applicability to ACP detection in commercial beverage and synthetic urine samples. These studies demonstrated adequate recoveries, ranging from 95.1% to 115.8%. The analytical parameters highlight the robustness and reliability of the proposed method for analyses of ACP directly at a potential crime scene.

Effect of common sedation agents on feline splenic size determined via ultrasonography.

AIMS: To evaluate the effect of IM administration of three sedative drugs, acepromazine, alfaxalone and dexmedetomidine, in combination with morphine, on the size of the feline spleen using ultrasonography. METHODS: Twenty-four client-owned cats undergoing elective de-sexing or minor procedures were recruited for a focused ultrasonographic examination of the spleen prior to and at 10, 20 and 30 minutes following administration of one of three randomly assigned IM sedation protocols: 0.05 mg/kg acepromazine (ACE group), 3 mg/kg alfaxalone (ALF group), or 10 µg/kg dexmedetomidine (DEX group), in combination with 0.5 mg/kg morphine. B-mode images of the spleen were collected and measured following a standardised protocol. Cardiorespiratory parameters and sedation score were also recorded. Mean thickness of the head, body and tail of the spleen for each group at 10, 20 and 30 minutes after drug administration was compared to baseline. RESULTS: Mean splenic thickness increased over time in the ACE group (thickness of body at T0 = 8.9 (SE 2.1) mm and at T30 = 10.5 (SE 2.0) mm; p = 0.001) and the ALF group (thickness of body at T0 = 8.8 (SE 1.0) mm and at T30 = 10.3 (SE 1.7) mm; p = 0.022) but not in the DEX group (thickness of body at T0 = 8.6 mm (1.2) and at T30 = 8.9 mm (0.6); p = 0.67). Mean arterial blood pressure in the DEX group was significantly higher than in the other groups (p = 0.002). Sedation scores in the DEX group were consistently high for the entire period. However, the sedation score in the ACE group increased over 30 minutes (p = 0.007). Sedation score in the ALF group was highest at 10 minutes but gradually decreased over the following 20 minutes (p = 0.003). CONCLUSIONS: Sedation with IM dexmedetomidine and morphine did not change splenic size, whereas acepromazine or alfaxalone and morphine increased it regardless of the degree of sedation. CLINICAL RELEVANCE: Where splenomegaly is identified in a cat sedated with acepromazine or alfaxalone, the effects of the sedation protocol could be considered as a possible cause.

Acupuncture in the Anesthetic Recovery of Bitches Submitted to Ovariohysterectomy.

Background: Cardiorespiratory depression caused by anesthesia decreases the quality and increases the time of postoperative recovery. The acupoint Governor Vessel 26 (GV26) is a resuscitation point that can reverse this depression and can be safely used without side effects. Objectives: The objective of this study was to evaluate the stimulation and anesthetic recovery time of GV26 in bitches submitted to ovariohysterectomy (OH) under dissociative anesthesia. Methods: As pre-anesthetic protocol, acepromazine 0.2% (0.1 mg/kg) and tramadol hydrochloride (2 mg/kg) was used, and induction was performed using midazolam (0.5 mg/kg) and ketamine (10 mg/kg). For the control group, standard procedure was performed for OH, with anesthetic recovery and post-surgical procedures. For the acupuncture group (AP), the stimulation of acupoint GV26 was performed 20 minutes after the anesthetic induction and maintained for 5 minutes. Respiratory rate, amplitude (superficial, normal or deep), type of respiratory movement (abdominal, abdominocostal or thoracoabdominal), heart rate, capillary filling time, temperature, presence or absence of laryngotracheal reflex, presence or absence of interdigital reflexes were assessed immediately before PAM application, and 2 (T1), 5 (T2), 10 (T3), 15 (T4), 20 (T5), 25 (T6) and 30 (T7) minutes after treatment. The results were tabulated and statistically analyzed. Results: When comparing the AP group with the control group, an improvement in amplitude of the chest cage was observed at all times, where the animals remained in normal or deep respiratory amplitude. The heart rate was significantly higher for the AP group (155.5 ± 34.4 bpm) than the control group at T1 (105.1 ± 15.4 bpm), while recovery time was lower for the AP group (54.1 ± 14.9 min) when compared to control group (79.9 ± 17.9 min). Conclusion: The present paper demonstrated the efficacy of GV26 in maintaining adequate respiratory amplitude and decreasing the anesthetic recovery time.

Ketamine-propofol for total intravenous anaesthesia in rabbits: a comparison of premedication with acepromazine-medetomidine, acepromazine-midazolam or acepromazine-morphine.

OBJECTIVE: To describe ketamine-propofol total intravenous anaesthesia (TIVA) following premedication with acepromazine and either medetomidine, midazolam or morphine in rabbits. STUDY DESIGN: Randomized, crossover experimental study. ANIMALS: A total of six healthy female New Zealand White rabbits (2.2 ± 0.3 kg). METHODS: Rabbits were anaesthetized on four occasions, each separated by 7 days: an intramuscular injection of saline alone (treatment Saline) or acepromazine (0.5 mg kg-1) in combination with medetomidine (0.1 mg kg-1), midazolam (1 mg kg-1) or morphine (1 mg kg-1), treatments AME, AMI or AMO, respectively, in random order. Anaesthesia was induced and maintained with a mixture containing ketamine (5 mg mL-1) and propofol (5 mg mL-1) (ketofol). Each trachea was intubated and the rabbit administered oxygen during spontaneous ventilation. Ketofol infusion rate was initially 0.4 mg kg-1 minute-1 (0.2 mg kg-1 minute-1 of each drug) and was adjusted to maintain adequate anaesthetic depth based on clinical assessment. Ketofol dose and physiological variables were recorded every 5 minutes. Quality of sedation, intubation and recovery times were recorded. RESULTS: Ketofol induction doses decreased significantly in treatments AME (7.9 ± 2.3) and AMI (8.9 ± 4.0) compared with treatment Saline (16.8 ± 3.2 mg kg-1) (p < 0.05). The total ketofol dose to maintain anaesthesia was significantly lower in treatments AME, AMI and AMO (0.6 ± 0.1, 0.6 ± 0.2 and 0.6 ± 0.1 mg kg-1 minute-1, respectively) than in treatment Saline (1.2 ± 0.2 mg kg-1 minute-1) (p < 0.05). Cardiovascular variables remained at clinically acceptable values, but all treatments caused some degree of hypoventilation. CONCLUSIONS AND CLINICAL RELEVANCE: Premedication with AME, AMI and AMO, at the doses studied, significantly decreased the maintenance dose of ketofol infusion in rabbits. Ketofol was determined to be a clinically acceptable combination for TIVA in premedicated rabbits.

Effect on physiological parameters and anaesthetic dose requirement of isoflurane when tramadol given as a continuous rate infusion vs a single intravenous bolus injection during ovariohysterectomy in dogs.

BACKGROUND: Tramadol produces a significant reduction in both sevoflurane and isoflurane minimum alveolar concentrations in dogs under experimental conditions. This study aims to compare the effects of tramadol administered as a constant rate infusion (CRI) with those of tramadol administered as a single intravenous bolus on physiological parameters and isoflurane requirements in dogs undergoing ovariohysterectomy. METHODS: In this study, forty female dogs undergoing ovariohysterectomy were enrolled. The bitches were anesthetized with 5 mg/kg of tiletamine/zolazepam combined with 0.05 mg/kg of acepromazine intravenously. Anesthesia was maintained with isoflurane delivered in 100% oxygen. The group A (n = 20) received tramadol 4 mg/kg in a single intravenous bolus, whereas the group B (n = 20) received tramadol 1.5 mg/kg in an intravenous bolus followed by tramadol 2.6 mg/kg/h as a CRI. The following parameters were recorded: heart rate, respiratory rate, non-invasive blood pressure, body temperature, EtCO2, SpO2 and inspired and expired concentrations of isoflurane. Parameter measurements were performed from pre-preedication (baseline) to skin suturing. RESULTS: The dogs were healthy subjects that demonstrated no abnormalities on laboratory investigations. Significant tachycardia was recorded after administration of tiletamine/zolazepam combined with acepromazine in both groups. Heart rate decreased after intubation but remained significantly higher compared to baseline values in both groups. Systolic blood pressure significantly decreased in both groups but the recorded values were within the physiological range. Mild reduction in body temperature was recorded in both groups. SpO2 and EtCO2 remained within the physiological range. Isoflurane requirement was significantly lower in the group B compared to the group A. Transient twitching was recorded in two dogs belonging to the group A after tramadol administration. CONCLUSIONS: Compared to tramadol given as a single intravenous bolus injection during ovariohysterectomy in dogs, tramadol administered as a CRI reduces isoflurane requirements in dogs anesthetized with tiletamine/zolazepam combined with acepromazine. Both tramadol given as a CRI and a single intravenous bolus injection, induce decrease in heart rate, respiratory rate and in body temperature but the values of these parameters remain within physiological range in dogs undergoing ovariohysterectomy.

Clinical and Antinociceptive Effects of Distal Inferior Alveolar Nerve Block in Ponies With Tramadol 5% or Lidocaine 2.

This study aimed to compare the antinociceptive effects of tramadol 5% and lidocaine 2% on mental nerve block in horses of the Brazilian Pony breed. Eight adult non-pregnant mares were used in this study. The ponies were tranquilized with acepromazine (5 µg kg-1, IV), and the infiltration of the mental foramen was performed in Treatment 1- tramadol 5% (T, 150 mg) or Treatment 2- lidocaine 2% (L, 60 mg), both at a total dose of 3 ml in each foramen. Heart rate (HR), respiratory rate (RR), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), rectal temperature (RT), and formation of skin lesions (SL) were evaluated. Evaluation of nociception of the outer lip (OL), inner lip (IL), and gingiva (GG) were performed using an electronic von Frey device with the evaluation of the ponies' reactions to each stimulus. From these reactions, we determined latency time (LT) and duration of antinociception (DAN). Analysis of variance with 16 observations was performed for HR, RR, SAP, DAP, MAP, LT and DAN. Data were expressed as mean ± standard deviation and the means were compared by the SNK and Student's t-test (P< 0.05). Changes in HR, RR, SAP, DAP, and MAP between evaluation times were associated with the effects of acepromazine (P>0.05). No formation of skin lesions was observed. Latency time did not differ between treatments (P>0.05). Both lidocaine 2% and tramadol 5% produced an antinociceptive effect. We conclude that the duration of the antinociceptive effect of tramadol 5% is longer than that of lidocaine 2%.

Diurnal Variation and Effects of Dilation and Sedation on Intraocular Pressure in Infant Rhesus Monkeys.

PURPOSE: Intraocular pressure (IOP) is an important factor in numerous ocular conditions and research areas, including eye growth and myopia. In infant monkeys, IOP is typically measured under anesthesia. This study aimed to establish a method for awake IOP measurement in infant rhesus monkeys, determine diurnal variation, and assess the effects of dilation and sedation. METHODS: Awake IOP (iCare TonoVet) was measured every 2 h from 7:30 am to 5:30 pm to assess potential diurnal variations in infant rhesus monkeys (age 3 weeks, n = 11). The following day, and every 2 weeks to age 15 weeks, IOP was measured under three conditions: (1) awake, (2) awake and dilated (tropicamide 0.5%), and (3) sedated (ketamine and acepromazine) and dilated. Intraclass correlation coefficient (ICC) was used to determine intersession repeatability, and repeated measures. ANOVA was used to determine effects of age and condition. RESULTS: At age 3 weeks, mean (±SEM) awake IOP was 15.4 ± 0.6 and 15.2 ± 0.7 mmHg for right and left eyes, respectively (p=.59). The ICC between sessions was 0.63[-0.5 to 0.9], with a mean difference of 2.2 ± 0.3 mmHg. Diurnal IOP from 7:30 am to 5:30 pm showed no significant variation (p=.65). From 3 to 15 weeks of age, there was a significant effect of age (p=.01) and condition (p<.001). Across ages, IOP was 17.8 ± 0.7 mmHg while awake and undilated, 18.4 ± 0.2 mmHg awake and dilated, and 11.0 ± 0.3 mmHg after sedation and dilation. CONCLUSIONS: Awake IOP measurement was feasible in young rhesus monkeys. No significant diurnal variations in IOP were observed between 7:30 am and 5:30 pm at age 3 weeks. In awake monkeys, IOP was slightly higher after mydriasis and considerably lower after sedation. Findings show that IOP under ketamine/acepromazine anesthesia is significantly different than awake IOP in young rhesus monkeys.

Estimation of the intraoperative blood loss in dogs undergoing enucleation.

PURPOSE: To quantify the surgical blood loss during canine enucleation and to investigate the relationship between this and any patient, surgical, and anesthetic factors. METHODS: A prospective observational analysis was conducted on 121 client-owned dogs (130 eyes) undergoing enucleation at a referral ophthalmology clinic. Blood loss was estimated by the gravimetric method (weight difference between dry and blood-containing surgical materials) to provide absolute blood loss (ABL) in milliliters, expressed as a percentage of circulating blood volume, to establish relative blood loss (RBL). RESULTS: Median ABL was 12 ml (1.6-116 ml), and median RBL was 1.3% (0.1%-6.7%). A higher RBL was associated with the following: use of a bupivacaine splash block versus retrobulbar nerve block (1.9 vs. 1%; p < .001), transpalpebral versus subconjunctival approach (2.2 vs. 1.3%; p = .003), and small versus large breed dogs (1.7% vs. 1.1%; p = .001). Both ABL and RBL differed significantly between surgeons. There was no significant difference in hemorrhage associated with the presence of ocular hypertension, systemic illness, surgical time, administration of meloxicam or choice of pre-medicant (acepromazine vs medetomidine). No dog required supportive intervention in response to surgical hemorrhage. CONCLUSIONS: This study has established a surgical blood loss estimate for dogs undergoing enucleation at an ophthalmology referral centre. Subconjunctival enucleation may be preferred for patients at greater risk of haemodynamic complications.

Sedative and cardiopulmonary effects of intramuscular combinations of hydromorphone, acepromazine, dexmedetomidine, and glycopyrrolate followed by intravenous propofol and inhalant isoflurane anesthesia in healthy dogs.

OBJECTIVE: To evaluate the sedative and cardiopulmonary effects of various combinations of acepromazine, dexmedetomidine, hydromorphone, and glycopyrrolate, followed by anesthetic induction with propofol and maintenance with isoflurane in healthy dogs. ANIMALS: 6 healthy adult female Beagles. PROCEDURES: Dogs were instrumented for hemodynamic measurements while anesthetized with isoflurane. Two hours after recovery, dogs received 1 of 4 IM combinations in a crossover design with 1 week between treatments: hydromorphone (0.1 mg/kg) and acepromazine (0.005 mg/kg; HA); hydromorphone and dexmedetomidine (0.0025 mg/kg; HD); hydromorphone, acepromazine, and dexmedetomidine (HAD); and hydromorphone, acepromazine, dexmedetomidine, and glycopyrrolate (0.02 mg/kg; HADG). Sedation was scored after 30 minutes. Physiologic variables and cardiac index were measured after sedation, after anesthetic induction with propofol, and every 15 minutes during maintenance of anesthesia with isoflurane for 60 minutes (target expired concentration at 760 mm Hg, 1.3%). RESULTS: Sedation scores were not significantly different among treatments. Mean ± SD cardiac index was significantly higher for the HA (202 ± 45 mL/min/kg) and HADG (185 ± 59 mL/min/kg) treatments than for the HD (88 ± 31 mL/min/kg) and HAD (103 ± 25 mL/min/kg) treatments after sedation and through the first 15 minutes of isoflurane anesthesia. No ventricular arrhythmias were noted with any treatment. CLINICAL RELEVANCE: In healthy dogs, IM administration of HADG before propofol and isoflurane anesthesia provided acceptable cardiopulmonary function with no adverse effects. This combination should be considered for routine anesthetic premedication in healthy dogs.

Comparison of the sedative effects of three nalbuphine doses, alone or combined with acepromazine, in dogs.

OBJECTIVE: To compare sedative, cardiopulmonary, and adverse effects of 3 nalbuphine doses, administered alone or in combination with acepromazine, in dogs. ANIMALS: 6 healthy dogs. PROCEDURES: Dogs were administered nalbuphine (1.0, 1.5, or 2.0 mg/kg, intravenously [IV]) combined with physiologic saline solution (1 mL, IV; treatments SN1.0, SN1.5, and SN2.0, respectively) or acepromazine (0.05 mg/kg, IV; treatments AN1.0, AN1.5, and AN2.0, respectively) in random order, with a 1-week washout interval between treatments. Sedation scores, heart rate, mean arterial pressure, respiratory rate, and rectal temperature were recorded before and 20 minutes after administration of saline solution or acepromazine (T0), and nalbuphine was administered at T0. Measurements were repeated 15, 30, 60, 90, and 120 minutes after nalbuphine administration. RESULTS: Treatments SN and AN resulted in at least 120 minutes of mild sedation and 60 minutes of moderate sedation, respectively. Sedation scores were greater for treatments AN1.0, AN1.5, and AN2.0 at various times, compared with scores for treatments SN1.0, SN1.5, and SN2.0, respectively. Administration of nalbuphine alone resulted in salivation and panting in some dogs. CLINICAL RELEVANCE: All nalbuphine doses promoted mild sedation when administered alone, and moderate sedation when combined with acepromazine. Greater doses of nalbuphine did not increase sedation scores. All treatments resulted in minimal changes in heart rate, respiratory rate, rectal temperature, and mean arterial pressure. Nalbuphine alone resulted in few adverse effects.

Comparison of Alfaxalone-Midazolam, Tiletamine-Zolazepam, and KetamineAcepromazine Anesthesia during Plethysmography in Cynomolgus Macaques (Macaca fascicularis) and Rhesus Macaques (Macaca mulatta).

Plethysmography is used in nonhuman primates (NHPs) to measure minute volume before aerosol exposure to an agent to calculate total time necessary in the exposure chamber. The consistency of respiratory parameters during the entire exposure time is paramount to ensuring dosing accuracy. Our study sought to validate an alfaxalone-midazolam (AM) anesthetic combination for use in aerosol studies. We hypothesized that AM would provide an adequate duration of anesthesia, achieve and maintain steady state minute volume (SSMV) for 20 min, and have anesthetic quality and side effects comparable to or better than either tiletamine-zolazepam (TZ) and ketamine-acepromazine (KA), the most common anesthetics used for this purpose currently. Two groups of NHPs, one consisting of 15 cynomolgus macaques and one of 15 rhesus macaques, received 3 intramuscular anesthetic combinations (AM, TZ, and KA), no less than one week apart. Anesthetized NHPs were placed in a plethysmograph chamber and their minute volumes were measured every 10 s to determine whether they had achieved SSMV and maintained it for at least 20 consecutive min. Achieving and reliably maintaining an SSMV for at least 20 min facilitates precise aerosol dosing of a challenge agent. Quality of anesthesia, based on the NHP's ability to achieve and maintain SSMV, was higher with AM compared with TZ and KA in both species, and AM had a longer duration of SSMV as compared with TZ and KA in cynomolgus macaques. Average SSMV was larger with AM compared with TZ in cynomolgus macaques, but larger with KA compared with AM in rhesus macaques. Duration of anesthesia was sufficient with all combinations but was longer for TZ than both AM and KA in both species. These results suggest that the AM anesthetic combination would produce the most accurate dosing for an aerosol challenge.

A randomized clinical trial to compare ketamine-butorphanol-azaperone-medetomidine and detomidine-etorphine-acepromazine for anesthesia of captive Przewalski horses (Equus przewalskii).

OBJECTIVE: To compare ketamine-butorphanol-azaperone-medetomidine (KBAM) to detomidine-etorphine-acepromazine (DEA) for field anesthesia in captive Przewalski horses (Equus przewalskii). ANIMALS: 10 adult Przewalski horses. PROCEDURES: A prospective randomized crossover trial was conducted. Each horse was immobilized once with KBAM (200 mg ketamine, 109.2 mg butorphanol, 36.4 mg azaperone, and 43.6 mg medetomidine) and once with DEA (40 mg detomidine premedication, followed 20 minutes later by 3.9 to 4.4 mg etorphine and 16 to 18 mg acepromazine). Both protocols were administered by IM remote dart injection with a washout period of 6 months between treatments. Selected cardiorespiratory variables and quality of anesthesia were recorded. Antagonists were administered IM (KBAM, 215 mg atipamezole and 50 mg naltrexone; DEA, 4 mg RX821002 and 100 mg naltrexone). RESULTS: All horses were anesthetized and recovered uneventfully. Inductions (DEA, 6.8 min; KBAM, 11.6 min; P = 0.04) and recoveries (DEA, 3.2 min; KBAM, 19.6 min; P < 0.01) were faster with DEA compared with KBAM. Quality scores for induction and recovery did not differ between protocols, but maintenance quality was poorer for DEA (P < 0.01). Clinical concerns during DEA immobilizations included apnea, severe hypoxemia (arterial partial pressure of oxygen < 60 mm Hg), muscle rigidity, and tremors. Horses treated with KBAM were moderately hypoxemic, but arterial partial pressures of oxygen were higher compared with DEA (P < 0.01). CLINICAL RELEVANCE: Captive Przewalski horses are effectively immobilized with KBAM, and this protocol results in superior muscle relaxation and less marked hypoxemia during the maintenance phase, but slower inductions and recoveries, compared with DEA.

Effects of acepromazine and dexmedetomidine, followed by propofol induction and maintenance with isoflurane anaesthesia, on the microcirculation of Beagle dogs evaluated by sidestream dark field imaging: an experimental trial.

OBJECTIVE: To investigate the effects of intramuscularly administered acepromazine or dexmedetomidine on buccal mucosa microcirculation in Beagle dogs. STUDY DESIGN: Experimental, blinded, crossover study. ANIMALS: A group of seven Beagle dogs aged 7.5 ± 1.4 years (mean ± standard deviation). METHODS: Microcirculation was assessed on buccal mucosa using sidestream dark field videomicroscopy. After baseline measurements, 5 µg kg-1 dexmedetomidine or 30 µg kg-1 acepromazine were administered intramuscularly. After 10, 20 and 30 minutes, measurements were repeated. At 40 minutes after premedication, anaesthesia was induced with propofol intravenously and maintained with isoflurane. Measurements were repeated 50, 60 and 65 minutes after the injection of the investigated drugs. Analysed microcirculatory variables were: Perfused de Backer density, Perfused de Backer density of vessels < 20 µm, Proportion of perfused vessels and Proportion of perfused vessels < 20 µm. Heart rate (HR), systolic, diastolic (DAP) and mean (MAP) arterial pressures were recorded at the same time points. Macro- and microcirculatory variables were analysed using a linear mixed model with baseline as a covariate, treatment, trial period and repetition as fixed effects and time and dog as random effect. Results are presented as effect size and confidence interval; p values < 0.05 were considered significant. RESULTS: After acepromazine, Perfused de Backer density was greater during sedation and anaesthesia [3.71 (1.93-5.48 mm mm-2, p < 0.0001) and 2.3 (0.86-3.75 mm mm-2, p < 0.003)], respectively, than after dexmedetomidine. HR was significantly lower, whereas MAP and DAP were significantly higher with dexmedetomidine during sedation and anaesthesia (p < 0.0001 for all) compared with acepromazine. CONCLUSIONS AND CLINICAL RELEVANCE: The sedative drugs tested exerted a significant effect on buccal mucosal microcirculation with a higher Perfused de Backer density after the administration of acepromazine compared with dexmedetomidine. This should be considered when microcirculation is evaluated using these drugs.

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.

Immobilization of captive plains zebras (Equus quagga) with a combination of etorphine hydrochloride, acepromazine, and xylazine hydrochloride.

The plains zebra (Equus quagga) is a zebra species commonly kept in zoos around the world. However, they are not tame like their domestic relatives and are difficult to immobilize. We immobilized 30 captive plains zebra with a combination of etorphine hydrochloride (2-4 mg), acepromazine (8 mg), and xylazine hydrochloride (30 or 50 mg) to perform physical examination and blood sample collection for disease diagnostics. Physiological parameters including heart rate, respiratory rate, body temperature, and hemoglobin oxygen saturation were recorded. All zebras exhibited satisfactory anesthesia and fully recovered without re-narcotization. The results suggest that etorphine hydrochloride-acepromazine-xylazine hydrochloride combination for plains zebra immobilization is a safe and sufficient regimen for short procedures such as wellness examinations and sample collection.

Effectiveness of orally administered maropitant and ondansetron in preventing preoperative emesis and nausea in healthy dogs premedicated with a combination of hydromorphone, acepromazine, and glycopyrrolate.

OBJECTIVE: To compare effectiveness of maropitant and ondansetron in preventing preoperative vomiting and nausea in healthy dogs premedicated with a combination of hydromorphone, acepromazine, and glycopyrrolate. ANIMALS: 88 dogs owned by rescue organizations. PROCEDURES: Dogs received maropitant (n = 29) or ondansetron (28) PO 2 hours prior to premedication or did not receive an antiemetic (31; control). Dogs were evaluated for vomiting, nausea, and severity of nausea (scored for 6 signs) for 15 minutes following premedication with hydromorphone, acepromazine, and glycopyrrolate. RESULTS: A significantly lower percentage of dogs vomited after receiving maropitant (3/29 [10%]), compared with control dogs (19/31 [62%]) and dogs that received ondansetron (15/28 [54%]). A significantly lower percentage of dogs appeared nauseated after receiving maropitant (3/29 [10%]), compared with control dogs (27/31 [87%]) and dogs that received ondansetron (14/28 [50%]), and a significantly lower percentage of dogs appeared nauseated after receiving ondansetron, compared with control dogs. Nausea severity scores for hypersalivation, lip licking, hard swallowing, and hunched posture were significantly lower for dogs that received maropitant than for control dogs, and scores for hypersalivation, lip licking, and hard swallowing were significantly lower for dogs that received ondansetron than for control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Oral administration of maropitant 2 hours prior to premedication with hydromorphone reduced the incidence of vomiting and the incidence and severity of nausea in healthy dogs. Oral administration of ondansetron reduced the incidence and severity of nausea but not the incidence of vomiting.

Minimally invasive protocols and quantification for microglia-mediated perineuronal net disassembly in mouse brain.

Enzymatic digestion of the extracellular matrix with chondroitinase-ABC reinstates juvenile-like plasticity in the adult cortex as it also disassembles the perineuronal nets (PNNs). The disadvantage of the enzyme is that it must be applied intracerebrally and it degrades the ECM for several weeks. Here, we provide two minimally invasive and transient protocols for microglia-enabled PNN disassembly in mouse cortex: repeated treatment with ketamine-xylazine-acepromazine (KXA) anesthesia and 60-Hz light entrainment. We also discuss how to analyze PNNs within microglial endosomes-lysosomes. For complete details on the use and execution of this protocol, please refer to Venturino et al. (2021).