Positioning
The patient was positioned in sternal recumbency with a 30 ° head tilt , which is suggested to encourage venous drainage and aid the reduction in ICP [ 19 ] . It is important to ensure the jugular veins are not occluded by any positioning aids , as this will lead to venous backflow and increased ICP .
Medications
Following induction , the patient was started on a constant rate infusion ( CRI ) of dexmedetomidine at 0.25 μg / kg / hour IV . A dexmedetomidine CRI allows lower inhalation gas flow percentages , which reduces the impact on blood pressure while maintaining a suitable depth of anaesthesia ( also known as minimum alveolar concentration ( MAC ) sparing ). Dexmedetomidine also has analgesic effects , and its inherent vasoconstriction properties contribute to the maintenance of blood pressure . Additionally , the use of a CRI reduces the incidence of bradycardia , which is often caused by a bolus dose of a sedative .
While the patient was being clipped and prepared for surgery , a 0.1 mg / kg dose of dexamethasone was administered IV . Dexamethasone is a corticosteroid that reduces cerebral oedema [ 6 ] , which in turn reduces ICP before the surgical procedure .
During the surgery , a dose of mannitol at 1 g / kg IV was administered as a CRI over 20 min at the veterinary surgeon ' s ( VS ' s ) request . Mannitol is an osmotic diuretic that draws interstitial fluid from tissues into blood vessels , which reduces ICP and increases cerebral perfusion [ 4 ] .
Two IV boluses of glycopyrrolate at 10 µ g / kg were administered during the procedure . The first was to correct bradycardia , which was successful . The second dose was given to increase the MAP , which was below the target of 70 mmHg . This was successful and ensured the MAP remained above 70 mmHg for the remainder of the procedure .
Throughout the procedure , IV fluid therapy was maintained at 3 ml / kg / hour , in line with the 2024 American Animal Hospital Association Guidelines , which suggest intraoperative fluid rates of 3 – 5 ml / kg / hour [ 20 ] . This was to ensure adequate perfusion and normotension , and to replace fluids lost during surgery . The lower end of the range was used to compensate for the additional volume from the dexmedetomidine CRI and prevent fluid overload .
Postoperative care
Following surgery and postoperative computed tomography ( CT ), the patient was weaned off the ventilator to ensure that a regular and effective spontaneous respiratory pattern and normocapnia were maintained . The patient was carefully extubated once ear twitching was seen and the palpebral reflex returned , taking care to prevent a cough reflex on extubation , which may have led to transient spikes in ICP . The patient recovered with continuing multiparameter monitoring , including electrocardiography and pulse oximetry . Owing to the extensive duration of surgery , the patient was mildly hypothermic on recovery , although an active warming device was used throughout the procedure . Shivering caused by postoperative hypothermia increases the body ' s oxygen consumption [ 21 ] , so the patient was placed in a pre-warmed incubator with access to oxygen supplementation if required . It is recommended to supplement oxygen if the peripheral oxygen saturation ( SPO 2
) is less than 92 % [ 6 ] .
Aspiration pneumonia with secondary bacterial infection is the most common complication within the first 24 – 36 hours following craniotomy surgery . Therefore , it is extremely important that the patient is continuously supervised for clinical signs such as pyrexia and tachypnoea or dyspnoea , which may indicate possible aspiration [ 22 ] . Hourly respiratory rate and effort checks were implemented following the initial recovery period , to continue monitoring for changes that may indicate aspiration .
The patient recovered in the high-dependency unit , with multiple members of staff consistently monitoring her to ensure that if any postoperative complications occurred they were swiftly noticed and addressed . The patient was placed in a dimly lit , quiet recovery area with minimal stimuli to minimise excitement and agitation and thereby help to prevent any secondary impact on ICP due to sympathetic stimulation .
The patient was positioned in sternal recumbency with her head elevated at 30 ° to continue promoting venous drainage and prevent increases in ICP . IV fluids were reduced to 2 ml / kg / hour to ensure normotension and prevent dehydration in the initial recovery phase .
Methadone 0.1 mg / kg IV was given every 4 hours to manage pain postoperatively . Pain scoring using the Glasgow Feline Composite Measure Pain Scale was implemented every 4 hours , between doses , to assess whether an additional top-up of methadone 0.1 mg / kg was required , should the patient score 5 or greater .
Owing to the administration of opioids , the patient ' s eyes were lubricated every 4 hours to prevent adverse ocular side effects as a result of decreased tear production and reduced blink reflex caused by the opioids [ 23 ] .
A seizure plan was formulated by the team of VNs and the VS , in case a seizure occurred during the recovery phase . The prescribed dose of midazolam 0.2 mg / kg IV was calculated and countersigned by two VNs . The plan was written on a laminated sheet placed on the front of the patient ' s kennel , with the required medication ,
42 Veterinary Nursing Journal