Sedation in Patients at Risk for Upper Airway Collapse

Not Applicable

Completed

Conditions: Obstructive Sleep Apnea

Interventions: Drug: Propofol
Drug: Dexmedetomidine

Registration Number: NCT01045122

Lead Sponsor: University of Rochester

Brief Summary: Overview of Protocol:

Between Subject - Repeated Measures design will be used to assess the airway response of two groups of subjects under two different sedated conditions. Each group will be comprised of six subjects and will be categorized according to their baseline profile for risk for SDB (\< 10 RDI or \> 25 RDI). Some subjects will have been prescribed continuous positive airway pressure (CPAP) therapy by their treating physician as a result of their overnight sleep study. CPAP treatment is effective in splinting the airway open and thus decreasing the incident of airway collapse during sleep. Thus, CPAP utilization will also be tracked as an independent and continuous variable as regular CPAP use has been found to be associated with increased resistance to UAC (upper airway collapse).

The experimental conditions will evaluate upper airway patency and instability in response to two forms of intravenous sedation: propofol and dexmedetomidine.

Subjects will be continuously monitored during each experimental condition for respiratory effort and flow, and for EEG, EMG, and ECG.

Respiratory instability will first be assessed while subjects are under sedation without any airway provocation. The degree of respiratory instability will be quantified in terms of the following measurements: a modified Respiratory Disturbance Index (RDIsedated), respiratory arousals, and minute ventilation. The apneic periods will be classified by their mixture of central and obstructive components.All outcome measurements are assessed over the period of sedation which last for approximately one hour.

Upper airway patency will be quantified in terms of the critical pharyngeal pressure (Pcrit) (the pressure beyond which complete upper airway collapse occurs, see background).

Detailed Description: The propensity to experience sleep disordered-breathing (SDB) is controlled by the interplay of anatomic factors (i.e. BMI, neck circumference, retrognathia) and neurological drive (sleep stage, arousal). The interaction of baseline anatomic factors and drug-induced altered neurologic drive may also convey a risk for upper airway collapse (UAC) in patients receiving analgesics, or sedation/anesthesia.1;2 While there is mainly only anecdotal evidence to support the proposition that SDB is a strong predictor of sedation-related adverse events,3;4 there is such a remarkable consensus of opinion regarding this association that, for example, the American Society of Anesthesiologists is developing guidelines to specifically address the issue of managing this group of "at risk" patients who are to undergo sedation or anesthesia. SDB is a term that is used to describe a spectrum of sleep-related breathing disturbances. Obstructive Sleep Apnea (OSA) is a condition that incorporates SDB with daytime symptoms (i.e. hypersomnolence). These terms are commonly used interchangeably.

At this juncture, what is needed are clear demonstrations: 1) that SDB confers risk for sedation-related adverse events (epidemiologically and/or experimentally), 2) of the patient and drug factors that moderate/mediate the risk, and 3) of the mechanisms responsible for the patient by drug interactions.

This proposed project will, in a preliminary way, address the first and second of these issues. Specifically, the upper airway characteristics of patients with different severity classifications of SDB will be assessed while under the influence of two, neuropharmacologically distinct, intravenous sedatives.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 15

Inclusion Criteria

Patients with mild or no Sleep disorder breathing
Patients with moderate to severe Sleep disorder breathing

Exclusion Criteria

No unstable medical conditions
Anatomic pathology of airway
Pregnancy or nursing
Inability to fit an anesthesia facemask
Excessive alcohol or drug abuse
Bleeding abnormalities
Claustrophobia

Study & Design

Study Type: INTERVENTIONAL

Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Propofol	Propofol	Is an alkylphenol, is primarily indicated for use as a general anesthetic and has minimal analgesic properties.
Dexmedetomidine	Dexmedetomidine	Dexmedetomidine is an alpha-2 adrenoreceptor agonist that has sedative, hypnotic, and analgesic effects.

Primary Outcome Measures