Induction Of Anaesthesia In Dogs Research Articles

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.

Development of the Auburn Induction Scale for evaluating induction quality in dogs

ObjectiveTo develop and begin establishing evidence for validity of an instrument to assess the quality of induction in dogs. Study designCross-sectional survey and video scoring. Animals and populationA total of 51 veterinary anesthesia personnel, four board-certified anesthesiologists and videos of induction of anesthesia in 18 dogs. MethodsIn Part 1, an online survey was sent to veterinary anesthesia personnel to solicit expressions and words that they associate with induction of anesthesia. These expressions were evaluated by four anesthesiologists to create a composite scale (Auburn Induction Scale). In Part 2, 18 videos were reviewed by the same four anesthesiologists on two separate occasions. The videos were scored using the Auburn Induction Scale, a simple descriptive scale (SDS) and a visual analog scale (VAS). Intra-rater and inter-rater reliability was measured using an intraclass correlation coefficient (ICC). Significance was set at p < 0.05. ResultsThe survey yielded 51 responses that were condensed into 133 expressions. The four anesthesiologists created 18 items incorporating the 133 expressions. The mean ± standard deviation intra-rater reliability ICC was 0.81 ± 0.08 for the Auburn Induction Scale, 0.71 ± 0.02 for the SDS and 0.71 ± 0.08 for the VAS for all raters. The mean ± standard deviation inter-rater reliability ICC was 0.69 ± 0.04 for the Auburn Induction Scale, 0.61 ± 0.05 for the SDS and 0.60 ± 0.06 for the VAS. Conclusions and clinical relevanceIn a research setting, widespread use of this scale may be helpful in increasing the accuracy of data and improving agreement between studies assessing induction of anesthesia in dogs. The results of this study have yielded a composite scale that is more reliable between and among raters than a unidimensional scale.

A BIOCHEMICAL STUDY OF DIAZEPAM AS A PRE-ANESTHETIC IN COMBINATION WITH VARIOUS ANESTHETICS DURING ORCHIDECTOMY IN DOGS

Diazepam as a Pre-anesthetic with Propofol or Ketamine HCl has vital combinations for the induction of anesthesia in dogs. The main objective of the study was to provide cost effective and safest injectable anesthetic cocktail for induction of anesthesia in dogs and to evaluate undesired effects on liver and kidneys of the anesthetic agent. Experimental dogs (n=12) were placed equally in two groups (A and B). Each animal from group A was administer Diazepam with Propofol blend while that of group B was given Diazepam with Ketamine HCl. Orchidectomy was performed as per standard protocols for considering as a pain module. Physical parameters like temperature (P&gt;0.05), pulse (P&lt;0.05) and respiration (P&lt;0.05) and Biochemical parameters like renal (P&gt;0.05) and liver functioning test (P&lt;0.05) were performed. This research reveals that Diazepam with Ketamine HCl depicts better results over Diazepam with Propofol. It can be concluded that Diazepam with Ketamine HCl shows a safe, cost effective, ideal and easily obtainable anesthesia with least drastic hazards over kidney and liver. So, Diazepam in combination with Ketamine HCl can be used for induction of anesthesia and to execute major as well as minor surgical exercises on dogs.

Dose requirement and cardiopulmonary effects of diluted and undiluted propofol for induction of anaesthesia in dogs

ObjectiveTo compare the dose, cardiopulmonary effects and quality of anaesthetic induction in dogs using propofol (10 mg mL–1) and diluted propofol (5 mg mL–1). Study designRandomized, blinded, clinical study. AnimalsA total of 28 client-owned dogs (12 males/16 females). MethodsFollowing intramuscular acepromazine (0.02 mg kg–1) and methadone (0.2 mg kg–1), propofol (UP, 10 mg mL–1) or diluted propofol (DP, 5 mg mL–1) was administered intravenously (0.2 mL kg–1 minute–1) by an anaesthetist unaware of the allocated group to achieve tracheal intubation. Sedation, intubation and induction quality were scored from 0 to 3. Pre- and post-induction pulse rate (PR), respiratory rate (fR) and systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressure were compared. Time to first breath and induction dose were recorded. Data were analysed for normality and Mann–Whitney U or Student t tests were performed where appropriate. Significance was set at p < 0.05. Data are presented as mean ± standard deviation or median (range). ResultsThe propofol dose administered to achieve induction was lower in the DP group (2.62 ± 0.48 mg kg–1) than in the UP group (3.48 ± 1.17 mg kg–1) (p = 0.021). No difference was observed in pre- and post-induction PR, SAP, MAP, DAP and fR between groups. The differences between post-induction and pre-induction values of these variables were also similar between groups. Time to first breath did not differ between groups. Sedation scores were similar between groups. Quality of tracheal intubation was marginally better with UP 0 (0–1) than with DP 1 (0–2) (p = 0.036), but overall quality of induction was similar between groups [UP 0 (0–1) and DP 0 (0–1), p = 0.549]. Conclusion and clinical relevanceDiluting propofol reduced the dose to induce anaesthesia without significantly altering the cardiopulmonary variables.

Intra and postoperative effectives of oral transmucosal administration of phenylbutazone for pain managament in dogs

The aim of the present study was to evaluate the efficacy and analgesic duration of single dose of phenylbutazone administered by oral transmukosal route immediately before induction of anesthesia in dogs undergoing elective ovariohysterectomy. Eight-teen sexually intact female dogs (weiging between 5 and 30 kg, and 1 to 7 yrs of age) referred for ovariohysterectomy procedure from a local shelter at regular intervals over 3 months were included in the study. The dogs were administered phenylbutazone on the basis of their respective treatment group (20 mg/kg via oral transmucosal administration) immediately before anesthetic induction. The syringe was placed in the cheek pouch of the dog, and phenylbutazone was slowly administered over a period of 1 to 3 minutes to ensure the drug did not drip out of the dog’s mouth, or was not swallowed by the dog. In control group, 0.9% NaCl was administered in the cheek pouch of the dog. Throughout the study, pre and postoperative pain was assessed at baseline (before induction of anesthesia) and then at 0.5, 1, 2, 3, 8, and 24 hrs after the surgery. Group oral transmucosal had significantly lower Glascow pain scores than the control group at the 0.5, 1, 2, 3, and 8 hour postoperative periods. In conclusion, a single dose of phenylbutazone administered via the oral transmucosal route before surgery may be particularly beneficial for acheiving reasonable perioperative analgesia, but not in postoperative period.

Efficacy of intravenous phenylbutazone for pain management in dogs undergoing ovariohysterectomy

The aim of the present study was to evaluate the efficacy and analgesic duration of single dose of PBZ administered the IV route immediately before induction of anesthesia in dogs undergoing elective OVH. Eight-teeen sexually intact female dogs (weiging between 4.5 and 28 kg, and 1 to 8 yrs of age) referred for OVH procedure from a local shelter at regular intervals over 4 months were included in the study. The dogs were administered PBZ on the basis of their respective treatment group (20 mg/kg, IV administration) immediately before anesthetic induction. For the IV treatment, PBZ was administered over a period of one minute. Time of completion of PBZ administration was designed as time 0. In control group, 0.9% NaCl was administered IV as over a period of one minute. Throughout the study, pre and postoperative pain was assessed at baseline (before induction of anesthesia) and then at 0.5, 1, 2, 3, 8, and 24 hrs after the surgery. Group IV had significantly lower CMPS-SF scores than the control group at the 0.5, 1, 2, 3, and 8 hour postoperative periods. In conclusion, a single dose of PBZ administered via the IV route before surgery may be particularly beneficial for acheiving reasonable perioperative analgesia, but not in postoperative period.

Effects of Alfaxalone or Propofol on Giant-Breed Dog Neonates Viability During Elective Caesarean Sections.

Simple SummaryNowadays, thanks to the increased awareness of owners and breeders and to the most recent techniques available to veterinarians, the management of parturition, especially of C-sections, has become a topic of greater importance. Anesthesia is crucial and must be targeted to both the mother and neonates. The present study aimed to evaluate the effect of the induction agent alfaxalone on the vitality of puppies born from elective C-section, in comparison to propofol. After inducing general anesthesia for elective C-section, puppies from the mothers induced with alfaxalone had higher 5-min Apgar scores than those induced with propofol. The concentration of cortisol in fetal fluids collected at birth is neither influenced by the anesthetic protocol used, nor does it differ between amniotic and allantoic fluids. Nevertheless, the cortisol concentration in fetal fluids affects the relationship between anesthesia and the Apgar score: the present study highlights a significant relationship between the anesthetic protocol used and Apgar score in puppies, and fetal fluids cortisol concentration acts as a covariate of this relationship. Alfaxalone is a safe and effective drug for the induction of anesthesia in dogs, and it can be successfully employed for elective C-section, with neonatal wellbeing improvements.Attention must be paid to C-section anesthesia effects on mother and offspring. Alfaxalone induction results in improved puppy viability when compared to propofol. The present study aims to evaluate effects of alfaxalone or propofol induction for elective C-section on newborns, expressed as Apgar score and fetal fluids cortisol concentration. Anesthesia was induced with alfaxalone 3 mg/kg iv in 5 bitches (group A), and propofol 4 mg/kg iv in another 5 (group P), maintained with isoflurane. Amniotic and allantoic fluids were collected to determine cortisol concentration. Apgar score, litter size, newborn gender, birth-weight, maternal age, and parity were recorded. ANOVA, U Mann-Whitney test and ANCOVA assessed the effects of drugs on the Apgar score and fetal fluids cortisol. Thirty-six puppies were randomly selected for the study: 16 from group A and 20 from group P. Only the Apgar score significantly differed between groups. ANCOVA confirmed a significantly higher Apgar score in group A underlining the influence of fetal fluids cortisol concentrations, both resulting in covariates. Present results confirm the effect of anesthesia on the Apgar score of newborns, which is significantly higher for alfaxalone than propofol, suggesting the use of fetal fluids cortisol as a covariate. These findings could be a starting point for further investigations when less viable puppies are detected or expected, such as during an emergency C-section.

Effect of fixed value positive end expiratory pressure valves on canine thoracic volume and atelectasis.

The objective of this study was to investigate whether a fixed 10 cm H2 O positive end-expiratory pressure valve would increase the aeration of, and reduce atelectasis formation in, the lungs after induction of anaesthesia in dogs undergoing thoracic CT. 28 dogs were paired based on breed, bodyweight and body condition score and then randomly allocated to either Group Z (0 cm H2 O) or Group P (10 cm H2 O positive end-expiratory pressure valve) immediately after the induction of anaesthesia. All patients received a standardised anaesthetic protocol, and their lungs were manually hyperventilated before image acquisition. Cardiorespiratory parameters were recorded every 5 minutes. Total lung volume, lung density and degree of atelectasis were determined for each dog from the acquired images. The 10 cm H2 O positive end-expiratory pressure valve significantly increased lung volume (mL/kg) (Group Z: 52 ±14; Group P: 83 ±17; P<0·001) whilst significantly reducing lung density (Hounsfield units) (Group Z: -775 ±30; Group P: -856 ±22; P<0·001) and the amount of atelectasis (P=0·004). Dogs in Group P had significantly higher end-tidal carbon dioxide (P<0·05), but there was no difference between the groups for respiratory rate or any cardiovascular variable. A fixed-value positive end-expiratory pressure valve provides a simple, cost-effective technique for improving expiratory thoracic CT studies by increasing lung volume and decreasing atelectasis formation.

Comparative study between propofol and propofol-ketamine for induction of anesthesia in dogs

Os procedimentos anestésicos em animais são amplamente utilizados em hospitais para cirurgias de rotina. Para a indução anestésica em cães o propofol tem se mostrado o fármaco de escolha. O objetivo deste estudo foi a avaliação da indução anestésica com propofol ou propofol-cetamina. Vinte cães foram divididos de forma aleatória nos grupos com tratamento e controle. Em todos os pacientes administrou-se acepromazina (0,05 mg kg-1) e fentanil (5 µg kg-1) como medicação pré-anestésica por via intramuscular (IM). Nos cães do grupo de tratamento foi administrado cetamina (1 mg kg-1), enquanto que os cães do grupo controle receberam solução salina a 0,9%, pela via intravenosa (IV). A indução da anestesia foi realizada com propofol IV a uma taxa de 1 mL minuto-1. Os padrões cardiopulmonares foram avaliados antes da aplicação da medicação pré-anestésica, 15 minutos após a mesma e após a indução da anestesia. Além disso, avaliou-se o escore de intubação traqueal, a presença de efeitos adversos e a dose de propofol necessária para a indução da anestesia. De forma significativa, o grupo controle apresentou mais efeitos adversos e alterações nos padrões cardiopulmonares quando comparado com o grupo de tratamento. Houve uma redução clinicamente importante da dose de propofol necessária para a indução de anestesia quando associado à cetamina. A associação de cetamina ao propofol para indução de anestesia em cães saudáveis foi capaz de reduzir a dose do anestésico geral necessária para intubação traqueal. Além disso, houve uma redução na ocorrência de efeitos adversos e depressão cardiopulmonar, o que permitiu um procedimento mais seguro para os pacientes.

Comparison of the effects of propofol and emulsified isoflurane alone or combined with dexmedetomidine on induction of anesthesia in dogs

ObjectiveTo compare the respective effects of propofol and emulsified isoflurane administered alone and in combination with dexmedetomidine on the quality of induction of anesthesia, physiological variables and recovery in dogs. Study designProspective, randomized, experimental trial. AnimalsThirty-six adult mixed-breed dogs. MethodsAnimals were randomly assigned to one of four induction protocols: propofol alone (group P); emulsified isoflurane alone (group EI); both propofol and dexmedetomidine (group PD), or both emulsified isoflurane and dexmedetomidine (group EID). Pulse rate (PR), respiratory rate (fR), non-invasive arterial blood pressure and arterial blood gases were measured at baseline, before induction, immediately after intubation (time 0), and at 5 minute intervals until the dog began to swallow and the trachea was extubated. The quality of induction and recovery, and degree of ataxia were scored by a single investigator unaware of group assignment. The durations of anesthesia and recovery, and the incidence of adverse events were recorded. ResultsThere were no clinically significant differences among the groups in induction quality. Systolic arterial pressure was lower in EID compared with P at 5 minutes. PR and fR were lower in PD and EID compared with P after induction. The PaCO2 at 5 minutes was higher than at baseline in group P. Ataxia score was lower in EID than in P. Time from induction to extubation and time from extubation to sternal recumbency were lower in EID compared with PD. Conclusions and clinical relevanceThere were no clinically significant differences among the groups in induction quality. In PD and EID, but not in P, PR and fR were decreased after induction. The EID combination resulted in smooth and rapid induction and recovery and thus may be useful clinically for induction of anesthesia.

Comparison of the cardiorespiratory effects of a combination of ketamine and propofol, propofol alone, or a combination of ketamine and diazepam before and after induction of anesthesia in dogs sedated with acepromazine and oxymorphone

To evaluate the cardiorespiratory effects of IV administration of propofol (4 mg/kg), ketamine hydrochloride and propofol (2 mg/kg each; K-P), or ketamine hydrochloride (5 mg/kg) and diazepam (0.2 mg/kg; K-D) before and after induction of anesthesia (IoA) in dogs sedated with acepromazine maleate and oxymorphone hydrochloride. 10 healthy adult Beagles. Each dog was randomly allocated to receive 2 of 3 treatments (1-week interval). For instrumentation prior to each treatment, each dog was anesthetized with isoflurane. After full recovery, acepromazine (0.02 mg/kg) and oxymorphone (0.05 mg/kg) were administered IV. Fifteen minutes later (before IoA), each dog received treatment IV with propofol, K-P, or K-D. Cardiorespiratory and arterial blood gas variables were assessed before, immediately after, and 5 minutes after IoA. Compared with findings before IoA, dogs receiving the K-P or K-D treatment had increased cardiac output, oxygen delivery, and heart rate 5 minutes after IoA; K-P administration did not change mean arterial blood pressure or stroke volume and decreased systemic vascular resistance. Propofol decreased mean arterial blood pressure and systemic vascular resistance immediately after IoA but did not change heart rate, cardiac output, or oxygen delivery. All treatments caused some degree of apnea, hypoventilation, and hypoxemia (Pao2 < 80 mm Hg). In dogs, K-P treatment maintained mean arterial blood pressure better than propofol alone and increased heart rate, cardiac output, or oxygen delivery, as did the K-D treatment. Supplemental 100% oxygen should be provided during IoA with all 3 treatments.

Randomized clinical trial of the effects of a combination of acepromazine with morphine and midazolam on sedation, cardiovascular variables and the propofol dose requirements for induction of anesthesia in dogs

The present study evaluated the effects of acepromazine combined with midazolam and morphine on sedation and cardiovascular variables as well as the propofol dose required for induction of anesthesia in dogs compared with acepromazine–morphine or midazolam–morphine. Dogs were randomly assigned to receive an intramuscular administration of (1) acepromazine (0.05mg/kg) with 0.5mg/kg of morphine (group AM, n=10), (2) midazolam (0.5mg/kg) with 0.5mg/kg of morphine (group MM, n=9), or (3) acepromazine with midazolam and morphine at the same doses (group AMM, n=10). After 30min, sedation was assessed by a numeric descriptive scale (NDS, range 0–3) and a simple numerical scale (SNS, range 0–10). Dogs were then administered IV propofol to allow endotracheal intubation.NDS and SNS scores were significantly higher in the AMM than in the MM group (P<0.05). There was a trend towards more dogs presenting with intense sedation (NDS=3) in AMM (6/10 dogs) compared with AM (1/10 dogs) and MM (1/9 dogs) (P=0.057). The propofol dose required for induction of anesthesia was significantly lower in AMM (4.0mg/kg) compared with MM (6.0mg/kg, P<0.01) but not AM (4.6mg/kg). Heart rate decreased in AM after treatment and after intubation. Blood pressure decreased in groups AM and AMM following treatment and in all groups after intubation. The combination AMM resulted in intense sedation more frequently than AM and MM, and provided the greatest sparing effect in the propofol dose. Administration of AM and AMM but not MM decreased blood pressure although hypotension was not recorded in healthy dogs.

Use of propofol for induction of anesthesia in dogs undergoing definitive radiation therapy: 31 cases (2006–2009)

To evaluate changes in serial hemograms and serum biochemical profiles in tumor-bearing dogs undergoing daily anesthesia with propofol as an induction agent for radiation therapy. Retrospective case series. 31 dogs with cutaneous or subcutaneous malignancies over the trunk or limbs. Radiation therapy consisted of 18 daily treatments administered Monday through Friday over a period of 24 days. Propofol was administered IV to effect for induction of anesthesia. Complete blood count and serum biochemical data were generated at the beginning, middle, and end of radiation therapy and compared to identify changes over time via either a repeated-measures ANOVA or Friedman test. Leukocyte and platelet parameters did not differ significantly over time. Calculated Hct, erythrocyte count, hemoglobin concentration, and mean corpuscular hemoglobin concentration decreased overtime, whereas mean corpuscular volume increased overtime. Dogs receiving propofol for induction of anesthesia and radiation therapy had a decrease in RBC count, although these changes were not determined to be of clinical importance in this patient population. The cause of these alterations was not immediately apparent. Propofol appeared to be a safe choice for induction of anesthesia in dogs during daily radiation therapy.

Evaluation of the quality of the recovery after administration of propofol or alfaxalone for induction of anaesthesia in dogs anaesthetized for magnetic resonance imaging

ObjectiveTo compare the quality of the recovery when propofol or alfaxalone were administered for the induction of anaesthesia in dogs undergoing neurological diagnostic procedures. Experimental designProspective, randomized clinical trial. AnimalsForty two client-owned dogs, 21 females and 21 males, weighing between 5.7 and 55 kg. MethodsEach dog was sedated with methadone (0.2 mg kg−1 intramuscularly or 0.1 mg kg−1 intravenously). Sedation was scored after 30 minutes. Anaesthesia was induced either with propofol or alfaxalone, administered to enable orotracheal intubation, after which anaesthesia was maintained with sevoflurane in oxygen. At the end of the procedure, the animals recovered in the clinical area. Quality of recovery was scored (early recovery) using simple descriptive and visual analogue scales (SDS and VAS). When sternal recumbency was achieved, dogs were moved to the recovery room and recovery was scored again (late recovery). Quantitative data were assessed with the Mann–Whitney U test, Kruskal–Wallis test, Spearman's rank correlation and Bland Altman plots as appropriate, whilst categorical data were analysed with the Chi square test and weighted kappa. ResultsSex, behaviour and duration of anaesthesia did not influence recovery scores. Dogs had poorer late recovery scores in the alfaxalone group compared to the propofol group (SDS, p = 0.014; VAS, p = 0.017). Degree of sedation after premedication influenced assessed SDS scores during early (p = 0.038) and late recovery (p = 0.008) (dogs more heavily sedated recovered better). However by VAS scores, sedation did not statistically influence early recovery (p = 0.299) but did affect late recovery (p = 0.013). Rescue sedation (medetomidine) was required only in two dogs in the alfaxalone group. ConclusionsInduction of anaesthesia with alfaxalone was associated with poorer recovery than with propofol in animals receiving premedication with methadone. Clinical relevanceGreater attention to the recovery environment may be advisable when using alfaxalone for induction of anaesthesia where minimal premedication has been used. Further sedation in recovery may be required.

Clinical efficacy and cardiorespiratory effects of alfaxalone, or diazepam/fentanyl for induction of anaesthesia in dogs that are a poor anaesthetic risk

ObjectiveTo evaluate the clinical efficacy and cardiorespiratory effects of alfaxalone as an anaesthetic induction agent in dogs with moderate to severe systemic disease. Study designRandomized prospective clinical study. AnimalsForty dogs of physical status ASA III-V referred for various surgical procedures. MethodsDogs were pre-medicated with intramuscular methadone (0.2 mg kg−1) and allocated randomly to one of two treatment groups for induction of anaesthesia: alfaxalone (ALF) 1–2 mg kg−1 administered intravenously (IV) over 60 seconds or fentanyl 5 μg kg−1 with diazepam 0.2 mg kg−1± propofol 1–2 mg kg−1 (FDP) IV to allow endotracheal intubation. Anaesthesia was maintained with isoflurane in oxygen and fentanyl infusion following both treatments. All dogs were mechanically ventilated to maintain normocapnia. Systolic blood pressure (SAP) was measured by Doppler ultrasound before and immediately after anaesthetic induction, but before isoflurane administration. Parameters recorded every 5 minutes throughout subsequent anaesthesia were heart and respiratory rates, end-tidal partial pressure of carbon dioxide and isoflurane, oxygen saturation of haemoglobin and invasive systolic, diastolic and mean arterial blood pressure. Quality of anaesthetic induction and recovery were recorded. Continuous variables were assessed for normality and analyzed with the Mann Whitney U test. Repeated measures were log transformed and analyzed with repeated measures anova (p < 0.05). ResultsTreatment groups were similar for continuous and categorical data. Anaesthetic induction quality was good following both treatments. Pre-induction and post-induction systolic blood pressure did not differ between treatments and there was no significant change after induction. The parameters measured throughout the subsequent anaesthetic procedures did not differ between treatments. Quality of recovery was very, quite or moderately smooth. Conclusions and clinical relevanceInduction of anaesthesia with alfaxalone resulted in similar cardiorespiratory effects when compared to the fentanyl-diazepam-propofol combination and is a clinically acceptable induction agent in sick dogs.

Comparison between tow techniques for induction of general anesthesia : popofol –fentanyl and ketamine fentanyl in dogs

This study was conducted to evaluate the anesthetic quality between propofol-fentanyl mixture (P-F)(2 mg/kg+0.004 mg/kg, i.v., respectively)and ketamine-fentanyl mixture (K-F)(10 mg/kg+0.004 mg/kg, i.v., respectively) in six adult dogs premedicated with atropine (0.05 mg/kg, i.m.) and xylazine (2 mg/kg, i.m.).The results revealed the presence of significant difference (p&lt; 0.05) only in the induction of anesthesia, recovery and standing period between both protocols.P-F mixture produced rapid, smooth and free of excitement induction (9.50 ± 0.76 sec) with transit apnea (19.16±2.4 sec). The duration of anesthesia was (23.33 ± 2.10 min), narcosis (32.50± 1.70 min) and anesthesia characterized by good muscle relaxation and abolishment of all reflexes with decrease in R.R. and increase in H R. Recovery was calm and rapid (46.6±2.25 min) and standing time was short (14.16±1.40 min),While anesthesia with K-F mixture characterized by slow and rough induction (29.16±1.53 sec), poor to moderate muscle relaxation and relatively shorter duration of anesthesia (18.83 ± 3.11 min)with narcosis for about(30.83 ± 5.23 min). The reflexes did not abolish completely especially eye reflexes (corneal and palpebral) and the eyes remained open. H.R. was increased but R.R. was decreased. Recovery was long and rough (78.33 ± 4.77 min) and stand time for (47.50±3.09 min).In conclusion, (P-F) mixtures produce excellent induction of general anesthesia rather than (K-F) in dogs and up to know this is the first report on the uses of these mixtures for induction of anesthesia in dogs.

Comparison of two thiopental infusion rates for the induction of anaesthesia in dogs

ObjectiveTo compare the induction dose requirements of thiopental using two different infusion rates for induction of anaesthesia in dogs. Study designProspective, randomized study. AnimalsFifty, healthy (ASA I or II) client-owned dogs with a mean age of 4.1 years and a mean mass of 20.4 kg undergoing elective surgery. Materials and methodsAnimals were randomly assigned to receive an infusion of 2.5% thiopental at a rate of either 0.1 ml kg−1 minute−1 or 0.4 ml kg−1minute−1, 30–40 minutes after pre-anaesthetic medication with intramuscular acepromazine (0.025 mg kg−1) and pethidine (3.5 mg kg−1). Thiopental administration was controlled by a precision syringe driver. Statistical analyses of the results, using the outcome ‘mg kg−1 required for induction’ (log-transformed) included unpaired t-tests for all categorical data (thiopental infusion rate, breed, sex, obesity, sedation quality) and univariable linear regression for continuous variables (mass, age). All variables were then considered in a multivariable linear regression model. The quality of induction with the two different infusion rates was also assessed. ResultsAfter controlling for quality of sedation, the thiopental induction dose requirement was significantly less (p < 0.001) with the slower infusion rate (median = 7.5 mg kg−1; range 4.9–13.7) compared with the faster infusion rate (median =11.0 mg kg−1; range 6.6–18.0). The quality of sedation also affected the dose required (p = 0.03). The slower infusion rate was associated with a significantly poorer induction quality (p = 0.3). ConclusionsSlow thiopental infusion (0.1 ml kg−1 minute−1) for anaesthesia induction after acepromazine/pethidine pre-anaesthetic medication reduced the induction dose requirement, although the quality of induction was inferior. Clinical relevanceThe induction dose of thiopental was reduced with a slower administration rate and so slow administration is recommended in thiopental-sensitive animals.

Echocardiographic evaluation of dogs receiving 1:1 thiopental/propofol in a clinical setting

The purpose of this study was to compare the echocardiographic Doppler blood pressure and heart rate effects of 1:1 thiopental/propofol with thiopental and propofol, when used as anesthesia-induction agents. Seven healthy dogs (six Beagles and one Pembroke Welsh Corgi), ranging in age from 1 to 9 years and weighing 14.2 ± 2.4 kg (mean ± SD), were used during the study. In a cross-over study design with a minimum drug interval of 3 days, each dog received propofol, thiopental, or a mixture of propofol–thiopental IV until each dog received all the three anesthetic agents. An initial dose (propofol 4.9 ± 0.8 mg kg−1; thiopental 12.9 ± 2.4 mg kg−1; propofol–thiopental 2.3 ± 0.3 mg kg−1 (P)−5.7 ± 0.8 mg kg−1 (T)) of each anesthetic agent was titrated IV until intubation was accomplished. Echocardiographic Doppler blood pressure and heart rate variables were recorded prior to anesthesia and at 1, 5, and 10 minutes after induction of anesthesia. anova and the Bonferroni's t-test were used to evaluate the groups for differences. Alpha was <0.05. There was no significant effect of treatment on systolic or diastolic ventricular wall thickness, septal thickness, left atrial diameter, or systolic left ventricular diameter. There was a tendency for diastolic left ventricular diameter to decrease over time. There was a tendency for heart rate to increase with a significant difference at the 10-minute time period between propofol (109 ± 26 beats minute−1) and thiopental (129 ± 23 beats minute−1). At the 10-minute recording period, heart rate following the propofol/thiopental mixture (110 ± 34 beats minute−1) was closer to that following propofol than to that following thiopental. With all induction agents, indirect blood pressure tended to decrease over time (p = 0.005); however, there was no difference between the groups. The changes observed were not considered to be of clinical significance. The propofol/thiopental mixture produces similar changes in echocardiographic variables when compared to propofol or thiopental, and could be substituted for propofol for induction of anesthesia in dogs.

Comparison of diazepam–ketamine and thiopentone for induction of anaesthesia in healthy dogs

ObjectiveTo compare the anaesthetic and cardiopulmonary effects of a diazepam–ketamine combination with thiopentone for induction of anaesthesia in dogs. Animal populationTwenty healthy dogs of various breeds weighing between 3.8 and 42.6 kg undergoing major orthopaedic or soft tissue surgery. Materials and methodsPre-anaesthetic medication in all cases was intramuscular acepromazine and methadone given 30 minutes before induction of anaesthesia. Each animal was then randomly assigned to receive either thiopentone or diazepam and ketamine. Quality of conditions for, and time to tracheal intubation were recorded. Anaesthesia was maintained with halothane in oxygen and nitrous oxide. Heart rate, respiratory rate, systolic blood pressure, end tidal carbon dioxide tensions and oxygen saturation were recorded at 10 minute intervals throughout surgery. The quality of recovery from anaesthesia was assessed. ResultsThe quality of induction in both groups was satisfactory. The total mean time (± SD) to tracheal intubation (162 ± 84 seconds) was significantly longer in dogs receiving diazepam and ketamine compared to dogs receiving thiopentone (62 ± 28 seconds). Heart rate, systolic blood pressure and end tidal carbon dioxide concentration were not significantly different between groups. Respiratory rate was significantly higher in the diazepam–ketamine group between 0 and 30 minutes. The quality of recovery was similar in each group. ConclusionsThere appear to be fewer differences between the induction agents examined in this study than was previously believed. No pressor, or other cardiovascular stimulating effects were detected in the dogs that received diazepam and ketamine. Clinical relevanceThe absence of obvious differences between groups suggests that pre-anaesthetic medication, inhaled anaesthetics and the physiological effects of surgery itself probably had a greater effect on the variables studied than the induction agent used. Further studies are required to determine whether diazepam and ketamine offers significant advantages over other induction agents in the unhealthy dog.

Comparative study of propofol or propofol and ketamine for the induction of anaesthesia in dogs

The effects of propofol alone or propofol and ketamine for the induction of anaesthesia in dogs were compared. Thirty healthy dogs were premedicated with acepromazine and pethidine, then randomly allocated...