TY - JOUR
T1 - Effects of dexmedetomidine and xylazine on cardiovascular function during total intravenous anaesthesia with midazolam and ketamine and recovery quality and duration in horses
AU - Hopster, Klaus
AU - Müller, Christina
AU - Hopster-Iversen, Charlotte
AU - Stahl, Jessica
AU - Rohn, Karl
AU - Kästner, Sabine
N1 - © 2013 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.
PY - 2014/1
Y1 - 2014/1
N2 - OBJECTIVES: To compare cardiovascular effects and recovery quality and duration of total intravenous anaesthesia (TIVA) with xylazine-ketamine-midazolam or dexmedetomidine-ketamine-midazolam.STUDY DESIGN: Prospective, randomized experimental cross-over trial.ANIMALS: Eight adult warmblood horses.METHODS: After sedation with acepromazine and either xylazine [0.5 mg kg(-1) , intravenously (IV)] or dexmedetomidine (3.5 μg kg(-1) IV) anaesthesia was induced with ketamine and midazolam and maintained with a constant rate infusion (CRI) of xylazine (1 mg kg(-1) hour(-1) ) [XKM] or dexmedetomidine (7 μg kg(-1) hour(-1) ) [DKM] in combination with midazolam (0.1 mg kg(-1) hour(-1) ), and ketamine infusion (initially 3 mg kg(-1) hour(-1) ) for 120 minutes. Ketamine infusion rate was increased in response to positive reactions to electrical nociceptive stimulation performed every 30 minutes. Heart rate (HR), mean arterial blood pressure (MAP) and cardiac output (Q˙t) were measured before treatment (baseline), after sedation (not Q˙t), and during anaesthesia. Xylazine, dexmedetomidine, midazolam and ketamine kinetics were calculated, from plasma drug concentrations. Twenty minutes after end of TIVA, flumazenil (0.01 mg kg(-1) IV) was administered. Recovery quality and duration were assessed. Two-way analysis of variance with repeated measurements or Wilcoxon signed rank test as relevant were used to analyse data with an alpha of 5%.RESULTS: Compared to baseline, MAP did not change, while similar, but limited, decreases in HR and Q˙t were observed in both TIVA's. Mean ketamine doses of 3.7 mg kg(-1) hour(-1) were required with both treatments. Plasma concentrations of dexmedetomidine and xylazine showed high intra- and inter-individual changes with elimination half-lifes of 46 ± 7 minutes and 64 ± 13 minutes, respectively. Recovery quality was good to excellent with mean duration of 37 ± 16 and 46 ± 21 minutes after stopping TIVA with XKM and DKM, respectively.CONCLUSIONS AND CLINICAL RELEVANCE: Both drug combinations are suitable to maintain anaesthesia for two hours, with good cardiovascular and good to excellent recovery conditions.
AB - OBJECTIVES: To compare cardiovascular effects and recovery quality and duration of total intravenous anaesthesia (TIVA) with xylazine-ketamine-midazolam or dexmedetomidine-ketamine-midazolam.STUDY DESIGN: Prospective, randomized experimental cross-over trial.ANIMALS: Eight adult warmblood horses.METHODS: After sedation with acepromazine and either xylazine [0.5 mg kg(-1) , intravenously (IV)] or dexmedetomidine (3.5 μg kg(-1) IV) anaesthesia was induced with ketamine and midazolam and maintained with a constant rate infusion (CRI) of xylazine (1 mg kg(-1) hour(-1) ) [XKM] or dexmedetomidine (7 μg kg(-1) hour(-1) ) [DKM] in combination with midazolam (0.1 mg kg(-1) hour(-1) ), and ketamine infusion (initially 3 mg kg(-1) hour(-1) ) for 120 minutes. Ketamine infusion rate was increased in response to positive reactions to electrical nociceptive stimulation performed every 30 minutes. Heart rate (HR), mean arterial blood pressure (MAP) and cardiac output (Q˙t) were measured before treatment (baseline), after sedation (not Q˙t), and during anaesthesia. Xylazine, dexmedetomidine, midazolam and ketamine kinetics were calculated, from plasma drug concentrations. Twenty minutes after end of TIVA, flumazenil (0.01 mg kg(-1) IV) was administered. Recovery quality and duration were assessed. Two-way analysis of variance with repeated measurements or Wilcoxon signed rank test as relevant were used to analyse data with an alpha of 5%.RESULTS: Compared to baseline, MAP did not change, while similar, but limited, decreases in HR and Q˙t were observed in both TIVA's. Mean ketamine doses of 3.7 mg kg(-1) hour(-1) were required with both treatments. Plasma concentrations of dexmedetomidine and xylazine showed high intra- and inter-individual changes with elimination half-lifes of 46 ± 7 minutes and 64 ± 13 minutes, respectively. Recovery quality was good to excellent with mean duration of 37 ± 16 and 46 ± 21 minutes after stopping TIVA with XKM and DKM, respectively.CONCLUSIONS AND CLINICAL RELEVANCE: Both drug combinations are suitable to maintain anaesthesia for two hours, with good cardiovascular and good to excellent recovery conditions.
KW - Anesthesia Recovery Period
KW - Anesthetics, Dissociative/administration & dosage
KW - Animals
KW - Blood Pressure/drug effects
KW - Cross-Over Studies
KW - Dexmedetomidine/administration & dosage
KW - Drug Therapy, Combination
KW - Heart Rate/drug effects
KW - Horses
KW - Hypnotics and Sedatives/administration & dosage
KW - Ketamine/administration & dosage
KW - Midazolam/administration & dosage
KW - Time Factors
KW - Xylazine/administration & dosage
U2 - 10.1111/vaa.12095
DO - 10.1111/vaa.12095
M3 - Journal article
C2 - 24127757
VL - 41
SP - 25
EP - 35
JO - Veterinary Anaesthesia and Analgesia
JF - Veterinary Anaesthesia and Analgesia
SN - 1467-2987
IS - 1
ER -