Oxygen Saturation Monitoring During Surgery

Completed

Brief Summary: Patients with Obstructive Sleep Apnea (OSA) have cyclical patterns of lower blood oxygen during sleep because of repeated episodes of upper airway obstruction that cause their breathing to stop. When these patients have surgery, anesthetic drugs may worsen these patterns of lower blood oxygen. This study monitors ten patients at high risk for OSA and ten patients at low risk for OSA during surgery. Patterns of lower oxygen saturations should arise in the high risk group but not the low risk group.

Detailed Description: Patients with Obstructive Sleep Apnea (OSA) have episodes of upper airway obstruction during sleep which have been shown to be accompanied by multiple oxygen desaturations followed by short recovery intervals until rising PaCO2 causes sleep disruption/rescue arousal. In the postoperative and conscious sedation arena, these patterns can deteriorate from a stable pattern to a severely unstable pattern which may go unrecognized and lead to an adverse event (respiratory/cardiac arrest; death).

Anesthesia and the higher consumption of analgesics produce a profound reduction in pharyngeal tone, a dampening of both chemoreceptor sensitivity and arousal/rescue response. Thus the first 48 hours post operatively presents a vulnerable period. Respiratory disturbances are more prominent - respiratory arrest and hypopnea being the main adverse occurrences during this period.

An algorithm has been developed that monitors saturation and indicates repetitive reductions in airflow through the upper airway and into the lungs. Presence of this pattern in the procedural sedation patient population has not been tested for its prevalence. This study will monitor patients during surgery to determine if this pattern occurs in this hospital setting.

Recruitment & Eligibility

Inclusion Criteria

Age greater than 21 years
Patients scheduled for a procedure that requires analgesia and/or sedation by any route (intravenous, intramuscular, oral, epidural or intrathecal).
Patients with an anticipated length of sedation greater than or equal to one hour.
Patients in the ASA category I through III.
Patients who only receive propofol, benzodiazepines, and opioids.

Exclusion Criteria

Primary Outcome Measures

Name	Time	Method
Number of Participants With Saturation Pattern Detection (SPD) Indicative of Repetitive Reductions in Air Flow	3 hours	Saturation Pattern Detection (SPD) is the pattern of oxygen saturation values plotted against time that occurs when patients have cyclical reduced air movement during breathing. Their blood oxygen level decreases and increases as they slow and increase their breathing.
Number of Participants Requiring Airway Support	3 hours	Drugs during surgery may cause the throat to relax and block breathing. To treat this, the caregiver administers airway support. Airway support is moving the jaw forward, inserting a plastic tube (nasal-oral airway) or applying a mask with positive pressure.

Secondary Outcome Measures