Sevoflurane with opioid or dexmedetomidine infusions in dogs undergoing intracranial surgery: a retrospective observational study

Abstract

This study reports the clinical use of two sevoflurane-based anesthetic techniques in dogs undergoing craniectomy. Twenty-one animals undergoing elective rostrotentorial or transfrontal craniectomy for brain tumor excision, anesthetized with sevoflurane, were enrolled in this retrospective, observational study. Anesthetic records were allocated to two groups: Sevo-Op (sevoflurane and short acting opioid infusion): 8 dogs and Sevo-Dex (sevoflurane and dexmedetomidine infusion): 13 dogs. Average mean arterial pressure (MAP), heart rate, end-tidal carbon dioxide, end-tidal sevoflurane and intraoperative infusion rates during surgery were calculated. Presence of intra-operative and post-operative bradycardia, tachycardia, hypotension, hypertension, hypothermia, hyperthermia was recorded. Time to endotracheal extubation, intraoperative occurrence of atrioventricular block, postoperative presence of agitation, seizures, use of labetalol and dexmedetomidine infusion were also recorded. Data from the two groups were compared with Fisher's exact test and unpaired t tests with Welch's correction. Odds ratio (OR) and 95% confidence interval (CI) were calculated for categorical variables. Intra-operatively, MAP was lower in Sevo-Op [85 (± 6.54) vs. 97.69 (± 7.8) mmHg, p = 0.0009]. Time to extubation was longer in , p = 0.0033]. No differences were found for the other intra-operative and post-operative variables investigated. Post-operative hypertension and agitation were the most common complications (11 and 12 out of 21 animals, respectively). These results suggest that the infusion of dexmedetomidine provides similar intra-operative conditions and post-operative course to a short acting opioid infusion during sevoflurane anesthesia in dogs undergoing elective rostrotentorial or transfrontal intracranial surgery.

Retrospective evaluation of labetalol as antihypertensive agent in dogs

“…Sixty percent of the cases enrolled in our study underwent craniotomy to remove an intracranial mass; in accordance with both human and veterinary reports, this is the most frequent perioperative scenario in which treatment of hypertension is likely required [ 13 , 14 ]. Hypertension, arbitrarily defined as SAP ≥ 190 mmHg and/or DAP 100 mmHg on 2 consecutive readings [ 32 ], significantly increases morbidity after this type of procedure as it is considered to predispose to intracranial haemorrhage, although a causative effect has not been fully demonstrated [ 15 ].…”

“…Systemic hypertension is a well-recognized complication during and after intracranial surgery in both humans and dogs, with an incidence of up to 57% reported in human medicine [ 12 ] and 52% in dogs [ 13 ]. Overzealous treatment of hypotension with vasopressors, pain induced sympathetic stimulation, fluid overload and a direct effect of brain manipulation have all been proposed as possible causes [ 14 ].…”

Ultrasonic Image Restoration Algorithm for Prevention of Nervous Disorders during the Recovery Period of Patients Receiving Sevoflurane Anesthesia

“…It can act on α 2 receptors to inhibit the release of norepinephrine, thereby achieving sedation, analgesia, and antianxiety [10]. Relevant studies have shown that 1 μg/kg Dex can reduce the incidence of emergency agitation in children and maintain good hemodynamics of children in operation [11].…”

Peripheral nerve block of the dorsal cranium in two dogs undergoing craniotomy

“…Limited studies investigating different anaesthesia protocols for managing canine craniotomy patients are found in the literature, and some that describe an anaesthetic protocol do so in the context of focussing on diagnostic imaging or surgical techniques 5,14,17,18 . Studies that do consider anaesthetic management as a primary outcome use multimodal protocols without describing locoregional techniques 5,17,18 …”

“…Furthermore, complications of craniotomy in dogs described in the literature are often associated with changes in ICP, either intracranial hypovolaemia following mass resection or raised ICP due to infection or haematoma formation, either of which can cause CNS depression and seizures 12,13 . In terms of anaesthetic recovery after craniotomy, agitation and hypertension are the most reported problems in dogs, which in turn can also increase ICP 14 . In people, chronic pain following craniotomy is an additional common complication, and although the mechanism behind this is poorly understood, it has been suggested that local anaesthetic techniques could mitigate its occurence 2 …”