Anaesthetic induction and recovery characteristics of a diazepam-ketamine combination compared with propofol in dogs

A dose characterization study evaluating the pharmacodynamics and safety of a concentrated alfaxalone solution (4%) as an intramuscular sedative in dogs

Alfaxalone is a commonly employed veterinary anaesthetic induction and sedation agent. A 4% w/v preserved, aqueous formulation of alfaxalone 'RD0387' (A4%) has recently been developed. To evaluate the sedative effects of A4%, three doses, 5 mg kg-1 (A5); 7.5 mg kg-1 (A7.5) and 10 mg kg-1 (A10) were administered intramuscularly into the epaxial musculature of six healthy adult mixed-breed dogs in an experimental, randomized, blinded, crossover study. Sedation time variables, quality of sedation (including onset of sedation and recovery), physiological variables, response to cephalic vein catheterization and frequency of undesirable events were recorded. Continuous variables were analysed between treatments (one-way ANOVA or restricted maximum likelihood modelling) and within treatments compared with baseline (Tukey's test). Categorical data were analysed between treatments (Kruskal-Wallis' test) and within treatments from baseline (Dunn's test). Significance was set at p < .05. All dogs became sedated (laterally recumbent) and sedation onset was significantly faster in groups A7.5 (9.8 ± 5.3 min) and A10 (9.1 ± 5.6 min) compared to A5 (25.6 ± 16.1 min) (p = .033, p = .027, respectively). Duration of sedation was significantly longer in A10 (168.5 ± 70.6 min) and A7.5 (143.8 ± 58 min) compared to A5 (63.8 ± 28.2 min) (p = .005 and p = .003, respectively). Dogs in A10 had a superior quality of onset of sedation compared to A5 (p = .028). Sedation scores and quality of recovery from sedation were not significantly different between doses. Two dogs (2/6) in A5 were insufficiently sedated for cephalic catheterization. Ataxia was the most frequently observed undesirable event with an overall frequency of 78% (14/18) and 89% (16/18) during sedation onset and recovery, respectively. Overall, A4% administered IM in dogs at 7.5 and 10 mg kg-1 resulted in sufficient sedation for IV catheterization in dogs. To improve the speed and quality of the sedation, it is recommended that future research focuses on combining A4% with other sedative or analgesic drugs.

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.

Scoping review of quality of anesthetic induction and recovery scales used for dogs

OBJECTIVE

To compare, describe and assess the level of validation of all instruments measuring quality of induction and recovery from anesthesia in dogs.

DATABASES USED

A search was performed using the electronic database PubMed to find articles containing an induction quality scale, a recovery quality scale or both in dogs. Articles not directly accessible through PubMed were obtained through the Auburn University Library website and Google Scholar. The phrases 'induction scoring systems dogs', 'recovery scoring systems dogs', 'anesthetic induction score dogs', and 'anesthetic recovery score dogs' were used for searches using the 'best match search' function. The time frame searched was from 1980 to May 2020. The search was conducted from March 2020 to May 2020.

CONCLUSIONS

A thoroughly tested and validated scale for measuring the quality of induction and recovery does not exist in the current veterinary literature. A large disagreement exists between studies on the use of induction and recovery scales, and many have reported inconsistent results with current instruments. It is recommended that an induction and recovery scale intended for wide-scale use be constructed and tested extensively for psychometric validation and reliability.

The effect of induction with propofol or ketamine and diazepam on quality of anaesthetic recovery in dogs

OBJECTIVE

To evaluate the quality of recovery in dogs undergoing elective orthopaedic surgery induced with either propofol or a combination of ketamine and diazepam.

MATERIALS AND METHODS

Sixty client-owned dogs undergoing single-limb elective orthopaedic procedures were enrolled. Dogs were randomly assigned to receive induction with propofol (4 mg/kg) (group P) or ketamine (5 mg/kg) with diazepam (0.25 mg/kg) (group KD) to which all scorers were blinded. The recovery monitoring period lasted for 1 hour following extubation. The recovery period was video-recorded for blinded scoring at a later time. Scoring for quality of recovery was carried out using three different systems (lower numbers=better quality): a simple descriptive scale (1 to 5), a visual analogue scale (0 to 10 cm) and a numeric rating scale (0 to 10). Videos were reviewed by three ACVAA board-certified anaesthesiologist raters.

RESULTS

Five dogs were deemed to be ineligible. The mean (±SD) duration of anaesthesia was 260.4 ±57.84 minutes in group KD and 261.1 ±51.83 minutes in group P. There was no difference between groups for time to extubation, head lift or sternal recumbency. The number of dogs having a recovery that was scored overall as bad (mean simple descriptive scale > 4, mean visual analogue scale or numeric rating scale > 5) was not different between groups. Dogs in group KD had significantly lower scores than group P dogs (simple descriptive scale P=0.01, numeric rating scale P=0.03, visual analogue scale P=0.03).

CLINICAL SIGNIFICANCE

Induction with ketamine and diazepam resulted in a smoother recovery from anaesthesia than induction with propofol.

Effects of intravenous administration of tiletamine-zolazepam, alfaxalone, ketamine-diazepam, and propofol for induction of anesthesia on cardiorespiratory and metabolic variables in healthy dogs before and during anesthesia maintained with isoflurane

OBJECTIVE To compare effects of tiletamine-zolazepam, alfaxalone, ketamine-diazepam, and propofol for anesthetic induction on cardiorespiratory and acid-base variables before and during isoflurane-maintained anesthesia in healthy dogs. ANIMALS 6 dogs. PROCEDURES Dogs were anesthetized with sevoflurane and instrumented. After dogs recovered from anesthesia, baseline values for cardiorespiratory variables and cardiac output were determined, and arterial and mixed-venous blood samples were obtained. Tiletamine-zolazepam (5 mg/kg), alfaxalone (4 mg/kg), propofol (6 mg/kg), or ketamine-diazepam (7 and 0.3 mg/kg) was administered IV in 25% increments to enable intubation. After induction (M₀) and at 10, 20, 40, and 60 minutes of a light anesthetic plane maintained with isoflurane, measurements and sample collections were repeated. Cardiorespiratory and acid-base variables were compared with a repeated-measures ANOVA and post hoc t test and between time points with a pairwise Tukey test. RESULTS Mean ± SD intubation doses were 3.8 ± 0.8 mg/kg for tiletamine-zolazepam, 2.8 ± 0.3 mg/kg for alfaxalone, 6.1 ± 0.9 mg/kg and 0.26 ± 0.04 mg/kg for ketamine-diazepam, and 5.4 ± 1.1 mg/kg for propofol. Anesthetic depth was similar among regimens. At M₀, heart rate increased by 94.9%, 74.7%, and 54.3% for tiletamine-zolazepam, ketamine-diazepam, and alfaxalone, respectively. Tiletamine-zolazepam caused higher oxygen delivery than propofol. Postinduction apnea occurred in 3 dogs when receiving alfaxalone. Acid-base variables remained within reference limits. CONCLUSIONS AND CLINICAL RELEVANCE In healthy dogs in which a light plane of anesthesia was maintained with isoflurane, cardiovascular and metabolic effects after induction with tiletamine-zolazepam were comparable to those after induction with alfaxalone and ketamine-diazepam.

Effects of midazolam on cardiovascular responses and isoflurane requirement during elective ovariohysterectomy in dogs

Background

A prospective, randomized, placebo-controlled, blinded clinical study was conducted to determine whether a single dose of midazolam affects the cardiovascular response to surgical manipulation of the ovaries during elective ovariohysterectomy. Thirty-nine client-owned dogs undergoing elective ovariohysterectomy were recruited. After scoring cage demeanour, dogs were premedicated with acepromazine (0.03 mg kg^-1) and pethidine (3 mg kg^-1) intramuscularly into the quadriceps muscle and 20 min later sedation was scored. Anaesthesia was induced with propofol intravenously (IV) to effect. The study treatment (group M: midazolam (0.25 mg kg^-1); or group P: placebo (Hartmann’s solution) (0.125 ml kg^-1)) was administered IV before the intra-operative manipulation of the first ovary. Anaesthesia was maintained with isoflurane in oxygen. Morphine (0.3 mg kg^-1 IV) was administered prior to the start of surgery. The vaporizer setting was adjusted according to the depth of anaesthesia. If an end-tidal isoflurane concentration (FE’Iso) above 1.6% was required additional analgesia was provided with fentanyl (2 μg kg^-1). Dogs received meloxicam (0.2 mg kg^-1 IV) at the end of procedure. Heart rate, mean arterial blood pressure, respiratory rate and end-tidal partial pressure of carbon dioxide as well as FE’Iso were recorded and analysed.

Results

A statistical significant difference between groups was detected in FE’Iso, with group M requiring a significantly lower FE’Iso than group P (14.3%) after administration of midazolam. No differences between groups was shown for percentage change in heart rate and mean arterial blood pressure, or end-tidal carbon dioxide and requirement for mechanical ventilation, or rescue analgesia. There was no statistically significant difference in the incidence of complications in group M and P. Group M received significantly more succinylated gelatin solution pre-administration of midazolam than group P, but no differences in fluid administration post-administration of the study treatment (midazolam/placebo) were detected. No statistical significant difference was demonstrated for the use of anticholinergic agents, dobutamine or noradrenaline.

Conclusion

No significant effect on cardiovascular parameters could be observed with administration of midazolam, but a modest (14.3%) isoflurane-sparing effect was detected.

Bloqueio do plexo braquial em um tamanduá-mirim (Tamandua tetradactyla) utilizando estimulador de nervos periféricos: relato de caso

RESUMO Objetivou-se relatar a utilização do neurolocalizador para bloqueio do plexo braquial bilateral em tamanduá-mirim (Tamandua tetradactyla). O animal, pesando 5kg, atendido pelo Centro de Reabilitação de Animais Silvestres, foi encaminhado ao Hospital Veterinário da Universidade Federal de Mato Grosso do Sul para realização de exames complementares, sendo, posteriormente, encaminhado para cirurgia de osteossíntese de úmero e rádio/ulna esquerdo e colocação de fio de cerclagem em olécrano direito. O paciente foi pré-medicado com cetamina S (5mg/kg) + midazolam (0,15mg/kg), indução anestésica com propofol (5mg/kg) e manutenção anestésica com isoflurano, com o auxílio de máscara. Os parâmetros cardiovasculares e respiratórios foram monitorados durante todo o procedimento. Realizou-se o bloqueio do plexo braquial em ambos os membros utilizando-se estimulador de nervos periféricos. Os anestésicos locais empregados foram lidocaína 2% sem vasoconstritor (3mg/kg) + ropivacaína 0,75% sem vasoconstritor (1mg/kg). O bloqueio foi realizado primeiramente no membro torácico direito, e, após realização do procedimento cirúrgico, o mesmo bloqueio foi realizado no membro contralateral. O paciente teve recuperação tranquila ausente de vocalização e expressão álgica, e a soltura ocorreu após 120 dias.

Comparative experimental study on two designed intravenous anaesthetic combinations in dogs

The goal of the present study is to design a good anaesthetic program for dogs which can lead to optimal anaesthesia with no or minimal post-operative adverse effects. For this purpose, we designed two anaesthetic combinations and compared their effects in Mongrel dogs: combination 'A' consisting of atropine, xylazine, ketamine plus propofol, and combination 'B' consisting of atropine, diazepam, ketamine plus propofol. The onset and duration of anaesthesia induction, the duration of maintenance as well as the period of recovery were recorded and compared for both combinations. Furthermore, heart rate, respiratory rate, body temperature as well as blood picture were analyzed before and after administration of the proposed anaesthetic regimens. Administration of combination 'A' lead to rapid onset, within seconds, and induction of anaesthesia. The anaesthetic effect was maintained for approximately 29 minutes after injection of propofol. This was followed by very smooth recovery within approximately 68 minutes after induction of anaesthesia. In contrast, a less efficient induction and maintenance of anaesthesia as well as individual variability was observed after administration of combination 'B'. Approximately 14 minutes were needed for anaesthesia induction, which was maintained for 23 minutes after injection of propofol. Furthermore, administration of combination 'B' was associated with alterations in heart rate, body temperature and hematological picture. In conclusion, our results revealed that combined administration of atropine, xylazine, ketamine plus propofol (combination 'A') is considered satisfactory for anaesthesia in dogs with minimal post-operative side effects.

Clinico-anesthetic changes following administration of propofol alone and in combination of meperidine and pentazocine lactate in dogs

Aim:

The aim of this study is to find out the effect of propofol and its combination with meperidine and pentazocine lactate on certain clinico-anesthetic profiles in dogs.

Materials and Methods:

15 apparently healthy mongrel dogs of either sex of about 1 year of age were randomly divided into three groups of five dogs each. The animals of Group I were administered propofol intravenously alone “to effect,” whereas meperidine at 2 mg/kgb.wt. and pentazocine lactate at 2 mg/kg b.wt. were injected intramuscularly 15 min before propofol “to effect” in Groups II and III, respectively. Atropine sulfate at 0.04 mg/kgb.wt. was injected intramuscularly 20 min before each treatment. Rectal temperature, heart rate, respiration rate, and anesthetic indices were recorded before and at 5, 10, 20, 30, and 60 min of induction.

Results:

As compared to Group I, the animals of Groups II and III exhibited a significant decrease (p<0.05) in the level of rectal temperature, respiration rate, and heart rate. Duration of recumbency, time of standing, time of recovery as well as the duration of analgesia were longer in pentazocine lactate (Group III) followed by meperidine (Group II) as compared to propofol alone (Group I). Meperidine treated dogs showed defecation and muscle twitching during anesthesia.

Conclusion:

Meperidine and pentazocine are suitable opioids used in combination with propofol for achieving surgical anesthesia and helpful in reduction of propofol dose.