Abstracts and Programme: EUROANAESTHESIA 2011: The European Anaesthesiology Congress: Ambulatory Anaesthesia
Anaesthesia for somnoendoscopy: A preliminary study
Background and Goal of Study: Somnoendoscopy allows to investigate snorers and Obstructive Sleep Apnea Syndromes (OSAS). This under sedation nasoendoscopy allows a dynamic visualization of upper-airway (UA) during an induced sleep to locate obstruction site and propose the appropriate treatment (prosthetic or surgical, with or instead of a continous positive airway pressure (CPAP) ventilation). Data are poor concerning the anaesthetic technique for this examination (1). The objective of our study was to assess feasability of bispectral index (BIS) monitored general anesthesia using traget-controlled infusion (TCI) of propofol for somnoendoscopy.
Materials and Methods: Prospective moncentric study. Patients scheduled for somnoendoscopy were included. Anaesthetic procedure used TCI of propofol (Schnider's model) associated with BIS monitoring. The initial effect-site target concentration (Ce) of propofol was 2 μg/ml. Ce was increased by 0.2 μg/ml to obtain a BIS range of 40-60 while maintaining spontaneous ventilation. Then nasendoscopy was realized. Oxygen flow of 6 l/min was delivered during the whole procedure. Cardiac frequency, arterial pressure, SpO2, Ce and BIS values were watched every 2 minutes. Central or obstructive apnea was diagnosed by EtCO2 and chest movements observation.
Results and Discussion: Thirty-four patients were included: 18 snorers and 16 OSAS, with 9 already treated with CPAP. Sex Ratio M/F: 22/12. Age: 52±9 years old. BMI: 28±5 kg/m2. ASA score: 2 [1,3]. Mean procedure duration was 20±8 min. Mean Ce of propofol was 3±0.4 μg/ml during examination. Mean BIS value was 57±16 during endoscopy. Site of UA obstruction was identified in every case. UA obstruction was located in more than one site in all patients: the tongue base (94%) or the soft palate (85%) collapsed against the posterior pharyngeal wall and the nose (53%). In all cases, mandibular advancement improved the laryngeal view and the UA collapse during examination. The mean lowest SpO2 during procedure was 91±6%. Two minor incidents led to stop endoscopy: one laryngospasm and one epistaxis.
Conclusion: BIS monitored anaesthesia using TCI of propofol seems to be feasible and safe for somnoendoscopy. This anaesthetic procedure provides sufficient muscular relaxation to cause UA collapse without central apnea. Hypoxemia can occur but more rarely than during polysomnography.
© 2011 European Society of Anaesthesiology
(1) Roblin G, Target-controlled infusion in sleep endoscopy. Laryngoscope 2001;111:175-6