Effects of midazolam on cardiovascular responses and isoflurane requirement during elective ovariohysterectomy in dogs

Abstract

BackgroundA prospective, randomized, placebo-controlled, blinded clinical study was conducted to determine whether a single dose of midazolam affects the cardiovascular response to surgical manipulation of the ovaries during elective ovariohysterectomy. Thirty-nine client-owned dogs undergoing elective ovariohysterectomy were recruited. After scoring cage demeanour, dogs were premedicated with acepromazine (0.03 mg kg-1) and pethidine (3 mg kg-1) intramuscularly into the quadriceps muscle and 20 min later sedation was scored. Anaesthesia was induced with propofol intravenously (IV) to effect. The study treatment (group M: midazolam (0.25 mg kg-1); or group P: placebo (Hartmann’s solution) (0.125 ml kg-1)) was administered IV before the intra-operative manipulation of the first ovary. Anaesthesia was maintained with isoflurane in oxygen. Morphine (0.3 mg kg-1 IV) was administered prior to the start of surgery. The vaporizer setting was adjusted according to the depth of anaesthesia. If an end-tidal isoflurane concentration (FE’Iso) above 1.6% was required additional analgesia was provided with fentanyl (2 μg kg-1). Dogs received meloxicam (0.2 mg kg-1 IV) at the end of procedure. Heart rate, mean arterial blood pressure, respiratory rate and end-tidal partial pressure of carbon dioxide as well as FE’Iso were recorded and analysed.ResultsA statistical significant difference between groups was detected in FE’Iso, with group M requiring a significantly lower FE’Iso than group P (14.3%) after administration of midazolam. No differences between groups was shown for percentage change in heart rate and mean arterial blood pressure, or end-tidal carbon dioxide and requirement for mechanical ventilation, or rescue analgesia. There was no statistically significant difference in the incidence of complications in group M and P. Group M received significantly more succinylated gelatin solution pre-administration of midazolam than group P, but no differences in fluid administration post-administration of the study treatment (midazolam/placebo) were detected. No statistical significant difference was demonstrated for the use of anticholinergic agents, dobutamine or noradrenaline.ConclusionNo significant effect on cardiovascular parameters could be observed with administration of midazolam, but a modest (14.3%) isoflurane-sparing effect was detected.

Retrospective evaluation of systemic hypertension in dogs with nonassociative (primary) immune‐mediated hemolytic anemia (December 2016 to April 2019): 26 cases

“…Antiepileptic medications have not been shown to alter BP in dogs; however, they may sedate animals and blunt any situational hypertension. 27,28 However, in the 16 dogs that were stable on long-term medication, we believe this effect would have been decreased. Clinically, our experience is that these dogs are often more stressed in the ICU than the critical patients.…”

Effects of Cisatracurium in Sevoflurane and Propofol Requirements in Dog-Undergoing-Mastectomy Surgery

“…In fact, in animals with low cardiac output or low blood pressure, the onset of action may be delayed due to the vasodilation caused by some pre-anaesthetic medications [ 3 ]. In this study, the pre-anaesthetic midazolam, causing minimal cardiovascular changes at clinically relevant doses [ 23 , 24 ], allowed us to avoid this inconvenience. Although some studies reported behavioural alterations in dogs after the administration of midazolam alone, due to its excitatory effects, such as an increased motor activity associated with an intense sniffing [ 25 , 26 ], in the present clinical study, no subject showed similar side effects.…”

Echocardiographic Examination of the Effects of Midazolam on Volume Change in Patients Who are Hospitalized in Intensive Care, Who Have Spontaneous Breathing

“…Midazolam sedasyonunun hastaların rölatif hipovolemisini artırdığını düşündük. [16][17][18][19][20][21][22][23]27 Biz, çalışmamızda, iki kez PBKT i uyguladık, birincisi midazolam uygulanması yapılmadan önceydi; supin pozisyon ve PBKT sonrası iki kez SAB, CI, CO, VTI ölçümü yaptık. Midazolam…”

“…16 PBKT, hipovolemiyi EKO parametreleriyle de tanımlayabilir. [17][18][19][20][21] PBKT yapmadan da VCI-CI, delta velocite peak (Delta Vpeak) ve kardiyak out-put (CO) artış yüzdesi ile de hipovolemi tanısı konabilir. 13,22,23 Sedatif ilaçlar, yoğun bakım ünitelerinde yatan hastalarda sık kullanılan ilaçlardır.…”