Hemodynamic and electrocardiographic effects of different combinations of midazolam and opioids in healthy dogs

Abstract

Opioids, together with benzodiazepines, are widely used drugs for routine sedation aiming at minimizing perioperative stress, pain and discomfort. Methadone and fentanyl are opioids that present particularities capable of causing cardiovascular changes, which differs from morphine and butorfanol, also opioids, but which do not cause significant changes in the same system. The object of this study is to compare cardiovascular changes of dogs sedated with intramuscular midazolam combined with different opioids. Twenty-four healthy client-owned dogs will be enrolled in four groups of six subjects and will be sedated with a combination of midazolam and morphine (GMOR), methadone (GMET), butorfanol (GBUT) or fentanyl (GFEN). Recordings will be taken before (MB) and 20 minutes following sedation (MS). Mean arterial pressure will be obtained through oscillometry. Heart rate will be obtained through electrocardiography and cardiac index will be assessed by echocardiography. The left ventricular work index and total peripheral resistance index will be further calculated. Data will be analyzed for distribution using the Kolmogorov-Smirnov test and mean comparisons will be performed using ANOVA or Kruskal-Wallis test followed by Tukey or Dunn test, under 5% significance. The project was designed to be executed in 12 months and the results will be published in scientific journals and events.