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American Journal of Veterinary Research Nov 2023To elucidate the cardiovascular effects of escalating doses of phenylephrine and norepinephrine in dogs receiving acepromazine and isoflurane.
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.
Topics: Animals; Dogs; Acepromazine; Isoflurane; Norepinephrine; Phenylephrine; Blood Pressure
PubMed: 37657733
DOI: 10.2460/ajvr.23.06.0147 -
Veterinary Sciences Jul 2023The 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...
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 ( < 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.
PubMed: 37505838
DOI: 10.3390/vetsci10070433 -
American Journal of Veterinary Research Aug 2023To compare the analgesia provided by incisional (Incisional), transverse abdominis plane (TAP), and rectus sheath (RS) blocks in dogs submitted for ovariohysterectomy...
OBJECTIVE
To compare the analgesia provided by incisional (Incisional), transverse abdominis plane (TAP), and rectus sheath (RS) blocks in dogs submitted for ovariohysterectomy (OHE).
ANIMALS
22 female mixed-breed dogs were allocated into 3 treatments of Incisional (n = 7), TAP (n = 7), and RS (n = 8) and underwent OHE from April 4 to December 6, 2022.
PROCEDURES
After premedication with acepromazine (0.05 mg/kg) and morphine (0.5 mg/kg), anesthesia was induced (6 mg/kg) and maintained (0.4 mg/kg/min) with propofol. Each dog randomly received either an incisional (blind technique), TAP, or RS (ultrasound-guided) block. Intraoperative analgesia was assessed using cardiorespiratory variables. Postoperative analgesia was evaluated up to 6 hours after the operation with a Short Form of Glasgow Pain Scale (SF-GCPS) and Visual Analog Scale (VAS). Fentanyl was administered as a rescue analgesic when needed.
RESULT
During surgery, all data remained within normal limits without any significant differences. Fentanyl was administered to 1 dog in the Incisional and 1 in the TAP. Post-operatively, a single dose of fentanyl was given to 1 dog in the TAP and 1 in the RS. Four dogs in the Incisional and 3 in the RS received both doses of fentanyl. There was no significant difference regarding postoperative rescue analgesia among treatments.
CLINICAL RELEVANCE
All 3 techniques demonstrated acceptable intra- and post-operative analgesia efficacy in dogs undergoing OHE. Further studies are warranted to confirm these findings.
Topics: Dogs; Female; Animals; Pain, Postoperative; Nerve Block; Hysterectomy; Analgesia; Fentanyl; Dog Diseases
PubMed: 37385601
DOI: 10.2460/ajvr.23.02.0040