None listed
Conditions
Brief summary
Currently there is no standard anesthetic agent recommended for robotic pelvic and abdominal surgery. Anaesthetic agents have variable effects on the cerebral vasculature and it has been hypothesized that some may be more suitable for robotic pelvic and abdominal surgery than others. For instance, Sevoflurane, a volatile anesthetic agent, increases cerebral vasodilation and hence decreases vascular resistance. This may impair cerebral autoregulation. Propofol, an intravenous agent, has not been shown to affect cerebral vasodilation. A feature of robotic surgery is the requirement for carbon dioxide pneumoperitoneum in conjunction with steep head-down positioning. We hypothesise that the cerebrovasodilatory effects of carbon dioxide combined with the potential for oedema from head-down positioning could render the brain particularly susceptible to the vasodilatory effects of volatile anaesthetics, including sevoflurane. Cerebral oedema is a recognised, although rare, complication of robotic prostate surgery. These are long procedures with the patient in a steep head-down position. Previous studies have shown alterations in cerebral blood flow towards the end of surgery. Therefore, the primary outcome of this study will be the last cerebral autoregulation recording at the end of surgery, with a comparison between patients with their anaesthesia maintained with propofol or sevoflurane
Interventions
Patients undergoing robotic prostate surgery will have anaesthesia initiated by Propofol. After initiation, patients will then be randomised to have their anaesthesia maintained using the volatile anaesthetic agent, sevoflurane, or the intravenous agent, propofol.
A Bispectral Index (BIS) monitor will be used to measure the depth of anaesthesia in subjects. The target BIS score is 45 +/- 5. The dosage of Propofol or Sevoflurane will vary between subjects in order to keep the BIS constant. Prop
Patients undergoing robotic prostate surgery will have anaesthesia initiated by Propofol. After initiation, patients will then be randomised to have their anaesthesia maintained using the volatile anaesthetic agent, sevoflurane, or the intravenous agent, propofol. A Bispectral Index (BIS) monitor will be used to measure the depth of anaesthesia in subjects. The target BIS score is 45 +/- 5. The dosage of Propofol or Sevoflurane will vary between subjects in order to keep the BIS constant. Propofol and Sevoflurane will be constantly administered throughout the operation. Autoregulation will be tested at hourly intervals, starting before the initiation of the steep Trendelenburg position and every hour thereafter. Autoregulation testing will require the administration of phenylephrine. Phenylephrine will be administered in order to alter Mean Arterial Pressure (MAP) between 80-100 mmHg. This is required in order to test cerebral autoregulation. Cerebral autoregulation will be tested using a TransCranial Doppler (TCD) machine. The TCD will gather blood flow velocity data from the middle cerebral artery, this will be combined with data on MAP to calculate the auto regulation index (ARI). The intraoperative opioid will be remifentanil, administered by a target-controlled infusion with a targeted effect-site concentration of 2 mcg/mL - 4 mcg/mL.
Sponsors
Sydney Local Health District
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Masking
Open (masking not used) (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
Male
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Robotic prostatectomy
Exclusion criteria
History of cerebral vascular disease Intracranial pathology Allergy to Propofol. Contraindication to Sevoflurane, including malignant hyperthermia or history of severe postoperative nausea and vomiting.
Outcome results
None listed