achieve a target effect site (brain) concentration of propofol. However, patients may lose consciousness at variable effect site concentrations (Ce), with a higher Ce being associated with higher upper airway critical closing pressure.6,7 Most DISE procedures are started shortly after the patients lose consciousness. Objective:To evaluate the effect of sedation depth on druginduced sleep endoscopy (DISE). Methods: Ninety patients with obstructive sleep apnea (OSA) and 18 snorers underwent polysomnography and DISE under bispectral index (BIS)-guided propofol infusion at two different sedation levels: BIS 65-75 (light sedation) and 50-60 (deep sedation). Results: For the patients with OSA, the percentages of velopharynx, oropharynx, hypopharynx, and larynx obstructions under light sedation were 77.8%, 63.3%, 30%, and 33.3%, respectively. Sedation depth was associated with the severity of velopharynx and oropharynx obstruction, oropharynx obstruction pattern, tongue base obstruction, epiglottis anteroposterior prolapse and folding, and arytenoid prolapse. In comparison, OSA severity was associated with the severity of velopharynx obstruction, severity of oropharynx obstruction, and arytenoid prolapse (odds ratio (95% confi dence interval); 14.3 (4.7-43.4), 11.7 (4.2-32.9), and 13.2 (2.8-62.3), respectively). A good agreement was noted between similar DISE fi ndings at different times and different observers (kappa value 0.6 to 1, respectively 1 Drug-induced sleep endoscopy (DISE) has been used for decades to directly examine the upper airways in sedative-induced sleep and improve treatment outcomes by acting as an adjuvant tool to assess surgical or nonsurgical treatment options. 2-4Various sedation methods have been used to allow for the performance of DISE. Roblin introduced target-controlled infusion (TCI) of propofol to DISE to allow for better control of the sedation level.5 TCI of propofol uses computer-based pharmacokinetic and pharmacodynamic models to predict and Bispectral Index in Evaluating Effects of Sedation Depth on Drug-Induced Sleep EndoscopyYu-Lun Lo, MD BRIEF SUMMARYCurrent Knowledge/Study Rationale: Drug-induced sleep endoscopy (DISE) were performed under different sedative conditions and might affect upper airway obstructions. We aimed to evaluate the affects of sedation depth and obstructive sleep apnea severity on different upper airway obstruction patterns. Study Impact: Under DISE, sedation depth affected velopharynx and oropharynx obstruction severity, oropharynx obstruction pattern, tongue base obstruction, epiglottis anteroposterior prolapse and folding, and arytenoid prolapse; however, OSA severity was associated with velopharynx and oropharynx obstruction severity as well as arytenoid prolapse. Bispectral index guided DISE offers an objective and reproducible method to evaluate upper airway collapsibility.

ObjectivesTarget-controlled infusion (TCI) provides precise pharmacokinetic control of propofol concentration in the effect-site (Ce), eg. brain. This pilot study aims to evaluate the feasibility and optimal TCI regimen for flexible bronchoscopy (FB) sedation.MethodsAfter alfentanil bolus, initial induction Ce of propofol was targeted at 2 μg/ml. Patients were randomized into three titration groups (i.e., by 0.5, 0.2 and 0.1 μg/ml, respectively) to maintain stable sedation levels and vital signs. Adverse events, frequency of adjustments, drug doses, and induction and recovery times were recorded.ResultsThe study was closed early due to significantly severe hypoxemia events (oxyhemoglobin saturation <70%) in the group titrated at 0.5 μg/ml. Forty-nine, 49 and 46 patients were enrolled into the 3 respective groups before study closure. The proportion of patients with hypoxemia events differed significantly between groups (67.3 vs. 46.9 vs. 41.3%, p = 0.027). Hypotension events, induction and recovery time and propofol doses were not different. The Ce of induction differed significantly between groups (2.4±0.5 vs. 2.1±0.4 vs. 2.1±0.3 μg/ml, p = 0.005) and the Ce of procedures was higher at 0.5 μg/ml titration (2.4±0.5 vs. 2.1±0.4 vs. 2.2±0.3 μg/ml, p = 0.006). The adjustment frequency tended to be higher for titration at 0.1 μg/ml but was not statistically significant (2 (0∼6) vs. 3 (0∼6) vs. 3 (0∼11)). Subgroup analysis revealed 14% of all patients required no further adjustment during the whole sedation. Comparing patients requiring at least one adjustment with those who did not, they were observed to have a shorter induction time (87.6±34.9 vs. 226.9±147.9 sec, p<0.001), a smaller induction dose and Ce (32.5±4.1 vs. 56.8±22.7 mg, p<0.001; 1.76±0.17 vs. 2.28 ±0.41, p<0.001, respectively), and less hypoxemia and hypotension (15.8 vs.56.9%, p = 0.001; 0 vs. 24.1%, p = 0.008, respectively).ConclusionTitration at 0.5 μg/ml is risky for FB sedation. A subgroup of patients required no more TCI adjustment with fewer complications. Further studies are warranted to determine the optimal regimen of TCI for FB sedation.Trial RegistrationClinicalTrials.gov NCT01101477