None listed
Conditions
Brief summary
The ‘beach chair’ or sitting position is commonly used during shoulder surgery. Maintenance of adequate cerebral perfusion is a key goal of anaesthetic technique. Rare but catastrophic outcomes (stroke, brain death) have been reported. Further concern has been raised that relative hypoperfusion could lead to subclinical cerebral damage in vulnerable patients. Cerebral oximetry is a non-invasive monitor which can be used to measure cerebral oxygenation. Among patients undergoing shoulder surgery, studies have looked at the impact of position, regional techniques, and anaesthetic agent. This is the first randomised control trial looking at cerebral oximetry in ventilated vs spontaneously breathing patients in beach chair position. The objective of our study is to compare the effect of the two ventilatory strategies on cerebral oximetry in the beach chair position. Secondary objectives are • to see if ventilatory strategy affects the incidence of cerebral desaturation events. • If possible, to report changes in cerebral oximetry by ethnicity
Interventions
Intermittent positive pressure ventilation (IPPV) group: Post-induction and following placement of a laryngeal mask airway, patients randomized to the IPPV group will be given atracurium 0.3mg/kg via intravenous injection and receive positive pressure ventilation continuously throughout the duration of the surgery. Initial ventilator settings will be an inspired oxygen concentration of 40%, a respiratory rate of 14, an inspiratory/expiratory ratio of 1:2, and tidal volumes of 7ml/kg and a PEEP o
Intermittent positive pressure ventilation (IPPV) group: Post-induction and following placement of a laryngeal mask airway, patients randomized to the IPPV group will be given atracurium 0.3mg/kg via intravenous injection and receive positive pressure ventilation continuously throughout the duration of the surgery. Initial ventilator settings will be an inspired oxygen concentration of 40%, a respiratory rate of 14, an inspiratory/expiratory ratio of 1:2, and tidal volumes of 7ml/kg and a PEEP of 5cmH2O. These settings will be titrated to ETCO2 level of 5-7kPa. If capnography or airway pressure readings suggest that diaphragmatic movement is opposing the action of the ventilator, patients in the ventilated group will be given a further 0.1-0.2mg/kg of atracurium, unless surgery is nearing completion. Anaesthetic records will be reviewed and dose of atracurium given as well as intra-operative inspired oxygen and end-tidal carbon dioxide recorded to monitor adherence. A cerebral oximetry monitor will be applied prior to induction in both studied groups. This involves 2 sensor stickers being placed on the forehead, the data is recorded continuously throughout the duration of the surgery.
Sponsors
Counties Manukau Health Research Office
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Prevention
Masking
Blinded (masking used) (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
ASA1-2 patients aged 18-70 undergoing arthroscopic shoulder surgery in the beach chair position under general anaesthesia with interscalene blockade (either ‘single shot’ or catheter-based).
Exclusion criteria
Known cerebrovascular or peripheral vascular disease, uncontrolled hypertension, a history of severe postoperative nausea and vomiting (which may mandate a total intravenous based anaesthetic).
Outcome results
None listed