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

Abstract

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.

Alfaxalone total intravenous anaesthesia in dogs: pharmacokinetics, cardiovascular data and recovery characteristics

“…Time points T0, T30, T60, T90, T135 and T180 are statistically compared using Dunnett's multiple comparisons technique (at global a ¼ 0.05) Cardiovascular function was well maintained during anaesthesia with both protocols, although a significant decrease in HR was found at T30 compared with T0, and HR significantly decreased over time during anaesthesia with both protocols. In contrast, several authors reported an increase in HR when alfaxalone was administered as a single bolus (Morgaz Rodriguez et al 2012;Amengual et al 2013;Hampton et al 2019). A decrease of SAP and MAP was observed following induction of anaesthesia, for 90 minutes and 60 minutes, respectively.…”

Clinical review of the pharmacological and anaesthetic effects of alfaxalone in dogs

“…This increase in Qt was associated to higher contractility and higher stroke volume index (Morgaz Rodríguez et al 2012). Tiletamine-zolazepam, ketamine-diazepam and propofol did not affect Qt and SVR (Hampton et al 2019a).…”

“…Both hypoventilation and hypoxaemia were reported after administering clinical doses of alfaxalone to dogs (Ambros et al 2008, Psatha et al 2011, Morgaz Rodríguez et al 2012, Maney et al 2013, Pinelas et al 2014, Barr et al 2017, Bigby et al 2017a,b, White & Yates 2017, Zapata et al 2018, Hampton et al 2019a but their severity was dose-dependent (Muir et al 2008). Similar respiratory complications were reported after propofol (Ambros et al 2008;Maney et al 2013;Barr et al 2017;Bigby et al 2017a,b;White & Yates 2017), etomidate (Morgaz Rodríguez et al 2012) and ketamine (White & Yates 2017) administration to healthy dogs, or after fentanyldiazepam-propofol administration to dogs with systemic disease (Psatha et al 2011).…”

“…The incidence of PIA after alfaxalone administration varies between studies depending on pre-anaesthetic medications, the total dose of alfaxalone administered, and the speed of injection. In non-premedicated dogs, in which clinical doses of alfaxalone were used, the median (range) incidence of PIA was 0 (0 to 50)% (Muir et al 2008, Keates & Whittem 2012, Morgaz Rodríguez et al 2012, Costa et al 2014, Pinelas et al 2014, Hampton et al 2019a. The use of pre-anaesthetic medications increased the incidence to 9.15 (0 to 70)% (Ambros et al 2008, Maddern et al 2010, Psatha et al 2011, O'Hagan et al 2012, Suarez et al 2012, Herbert et al 2013, Pinelas et al 2014, Quiros-Carmona et al 2014, Dehuisser et al 2017, Muñoz et al 2017, Quiros-Carmona et al 2017, White & Yates 2017, Bigby et al 2017a, Italiano & Robinson 2018, Zapata et al 2018, Hunt et al 2019, Miller et al 2019, Dehuisser et al 2019b, Bustamante et al 2020.…”

Cardiopulmonary (No Ventilation) and Anesthetic Effects of Dexmedetomidine–Tiletamine in Dogs

“…However, tiletamine can cause depression in guinea pigs and rabbits (5,6). It is usually provided with zolazepam in veterinary settings as a narcotic sedative (tiletamine/zolazepam or Zoletil R ) for use as a shortterm anesthetic for surgical procedures in dogs (7)(8)(9). It has been observed that dexmedetomidine-butorphanol-tiletaminezolazepam (DBTZ) administered intramuscularly (IM) in healthy dogs rapidly induced short-term anesthesia and analgesia (7).…”