Comparison of upper airway properties during dexmedetomidine and propofol sedation
Comparison of upper airway properties during light and deep levels of dexmedetomidine and propofol sedation in healthy individuals
Sir Charles Gairdner Hospital
20 participants
Aug 20, 2015
Interventional
Conditions
Summary
Dexmedetomidine is increasingly used for procedural and intensive care unit sedation. This growing popularity is based on the belief that it has relatively little impact on both ventilatory drive and upper airway collapsibility, in contrast to benzodiazepines and propofol, which are known to depress ventilation and predispose to upper airway obstruction. However, we have preliminary data demonstrating that, at similar levels of sedation, the degree of upper airway collapsibility observed with dexmedetomidine is similar to that with propofol. Formal evaluation is now required. This study will compare the effects of dexmedetomidine and propofol on upper airway function in healthy people. Information gained from this study will improve our understanding of the effects of dexmedetomidine and its safe use for procedural and intensive care unit sedation Aim: To compare the degree of upper airway collapsibility and mechanisms underlying it during light and deep levels of dexmedetomidine and propofol sedation in healthy individuals Hypothesis: Upper airway collapsibility will increase with increasing depth of sedation but will be similar at comparable depths of dexmedetomidine and propofol sedation.
Eligibility
Inclusion Criteria1
- healthy volunteers
Exclusion Criteria7
- known cardiovascular or respiratory disease
- uncontrolled hypertension or diabetes
- current smoking
- BMI >37kg/m2
- history of hypotension, bradycardia, kidney/liver impairment
- pregnancy
- elevated anaesthesia risk
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Interventions
A randomised cross over study design will be employed. 20 healthy volunteers will participate in two daytime anaesthesia studies during which they will receive light or deep sedation with intravenous dexmedetomidine or propofol in randomized order on two separate days. Study days are separated by at least 1 week. Airway collapsibility (pharyngeal critical pressure; Pcrit and pharyngeal closing pressure; Pclose), neuromuscular responsiveness derived from genioglossus EMG (EMGgg), and sedation depth (Observer’s Assessment of Alertness/Sedation (OAAS) Scale, Richmond Agitation Sedation Scale (RASS), University of Michigan Sedation Scale (UMSS) and processed EEG/EMG (Bispectral Index Score; BIS)) will be assessed at light and deep levels of sedation. Pclose will also be assessed at 2 minute intervals following cessation of drug infusion. EEG (O1,C3,F3,M2), End-tidal CO2 (EtCO2), transcutaneous CO2 (TcCO2) and oesophageal pressure (Pes) will be monitored continuously. Drug dosing involves a bolus dose (10 minutes at 0,6 microg/kg (DEX) or 4,5 mg/kg/h (= 75 microg/kg/min)(Propofol)) followed by a maintenance infusion aiming for light sedation (DEX: 0,5 microg/kg/h; Propofol 2,5 mg/kg/h (= 42 microg/kg/min)) then deep sedation (DEX: 1,5 microg/kg/h; Propofol 5 mg/kg/h (= 83 microg/kg/min)). At each level of sedation 20 mins is allowed for attainment of steady state prior to beginning measurements. Venous blood samples will be collected at baseline and completion of measurements at light and deep sedation levels for determining drug plasma concentrations. The first measurement will be made at completion of the 30min bolus/steady state period and sedation will not extend beyond 75 mins from the time of the start of the first measurement.
Locations(1)
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ACTRN12616000085471