None listed
Conditions
Brief summary
During shoulder surgery patients are positioned into an upright sitting position for optimal access to the shoulder joint. In some patients blood pressure may decrease and a concern of the anaesthetist is whether sufficient blood reaches the brain during such surgery. Even though this can be routinely treated with cardiac drugs, the exact effect of this treatment on the brain is unknown. This study plans to investigate the changes in flow to the brain when patients are anaesthetised and placed upright. The surgery will be performed using the anaesthetic technique that we use for the majority of the surgeon’s cases. Special monitoring of the oxygen level within the brain, using reflected light waves, will be used. This technique is non-invasive and presents no harm to the patient. The study will investigate whether the administration of medication to gently increase blood pressure has an effect on blood flow to the brain, and on recovery following surgery. A number of commonly used drugs will be studied by infusing them into a large vein within the arm. By agreeing to the study patients will give us permission to make these extra measurements during anaesthesia. This will help us understand whether we are protecting the brain during surgery.
Interventions
This study will investigate the effects of clinically used vasopressor drugs versus saline infusion on cerebral blood flow and oxygenation, in patients placed into beach chair position for shoulder surgery. Following interscalene brachial plexus anaesthesia with 20-30 ml ropivicaine 0.75%, general anaesthesia will be induced with propofol 50-200mg and maintained on sevoflurane 2-3%. Following stabilisation an infusion of either noradrenaline (20 microg/ml), phenylephrine (100 microg/ml), ephedri
This study will investigate the effects of clinically used vasopressor drugs versus saline infusion on cerebral blood flow and oxygenation, in patients placed into beach chair position for shoulder surgery. Following interscalene brachial plexus anaesthesia with 20-30 ml ropivicaine 0.75%, general anaesthesia will be induced with propofol 50-200mg and maintained on sevoflurane 2-3%. Following stabilisation an infusion of either noradrenaline (20 microg/ml), phenylephrine (100 microg/ml), ephedrine (300 microg/ml) or vasopressin (0.3 U/ml) will be commenced. Infusions are equipotent in concentration and will initially commence at a rate of 6 ml/hr. At 2.5 minutely intervals, the infusion rate will be increased stepwise to 15, 30, 45 and 60 ml/hr. Infusion is titrated until the mean arterial pressure increases to 120 % baseline/or cerebral desaturation decreases to 80% baseline. Infusion is maintained within these limits whilst patient placed into beachchair position for surgery. The duration of intervention is 1 hour.
Sponsors
Melbourne Orthopaedic Research Group
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Caregiver, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
>18 years of age Shoulder surgery suitable for beach chair position Able to provide informed consent
Exclusion criteria
Previous cerebrovascular event Current cardiac disease including pacemaker Cerebrovascular disease Significant cardiac or respiratory impairment Contraindications to interscalene block Inadequate understanding of English Body Mass Index (BMI) > 35
Outcome results
None listed