Kobluk K, Pypendop BH. Effects of dopamine, norepinephrine or phenylephrine on the prevention of hypotension in isoflurane-anesthetized cats administered vatinoxan or vatinoxan and dexmedetomidine.
Vet Anaesth Analg 2021;
49:54-64. [PMID:
34906421 DOI:
10.1016/j.vaa.2021.11.001]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/03/2021] [Accepted: 11/05/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE
To determine the dose of phenylephrine, norepinephrine and dopamine necessary to maintain mean arterial pressure (MAP) within 70-80 mmHg during administration of isoflurane, isoflurane and vatinoxan and isoflurane, vatinoxan and dexmedetomidine at three plasma concentrations.
STUDY DESIGN
Randomized crossover experimental study.
ANIMALS
A group of five adult healthy neutered male cats.
METHODS
Instrumentation occurred during anesthesia with isoflurane in oxygen. Isoflurane end-tidal concentration was set to 1.25 × minimum alveolar concentration (MAC). Phenylephrine, norepinephrine or dopamine was administered to maintain MAP 70-80 mmHg. A target-controlled infusion system was used to administer vatinoxan at a target plasma concentration of 1 μg mL-1 and three dexmedetomidine concentrations (5, 10 and 20 ng mL-1). Isoflurane concentration was altered to maintain an equivalent 1.25 MAC. Heart rate, arterial blood pressure, central venous pressure, pulmonary artery pressure, pulmonary artery occlusion pressure, body temperature, arterial and mixed venous blood gas, cardiac output and drug concentrations were measured at baseline (isoflurane alone), during vatinoxan administration, and during administration of vatinoxan and dexmedetomidine at the three target concentrations.
RESULTS
MAP < 70 mmHg was observed with vatinoxan alone and in the dopamine treatment with dexmedetomidine concentrations ≤ 10 ng mL-1. Norepinephrine and phenylephrine maintained MAP 70-80 mmHg during vatinoxan and dexmedetomidine ≤ 10 ng mL-1. As the target dexmedetomidine concentration increased, the dose of norepinephrine and phenylephrine needed to maintain MAP 70-80 mmHg decreased; no treatment was necessary to maintain MAP > 70 mmHg at the 20 ng mL-1 target dexmedetomidine concentration in most cats.
CONCLUSIONS AND CLINICAL RELEVANCE
Norepinephrine and phenylephrine, but not dopamine, are effective to prevent hypotension in isoflurane-anesthetized cats administered dexmedetomidine and vatinoxan.
Collapse