Bispectral Index in Evaluating Effects of Sedation Depth on Drug-Induced Sleep Endoscopy: DISE or No Dice

Abstract

British otolaryngologists Pringle and Croft fi rst introduced drug-induced sleep endoscopy (DISE) in 1991 as a technique to identify the anatomic location of obstruction in the airway of patients with snoring and obstructive sleep apnea. 1Since then, DISE, or sleep nasendoscopy, has been widely adopted as a diagnostic tool for dynamic airway evaluation. This technique is complementary to polysomnographic data, as it is used to differentiate the site of obstruction. DISE is commonly utilized to direct subsequent management, including selection of specifi c surgical interventions; however, there remains a general lack of agreement regarding standardization of the technique.3 Areas requiring more investigation include an optimal and standard scoring system as well as a standardized sedation protocol.In this issue of JCSM, the article by Lo et al. proposes a standardized sedation model for DISE using a propofol infusion guided by a bispectral index (BIS) monitor. 4 The authors suggest that sedation maintained at a BIS level of 65-75 provides an objective target to create the ideal conditions for DISE. The BIS level is not a physiologic measurement, but rather a dimensionless number derived from a proprietary algorithm that integrates multiple electroencephalogram tracings. Although prior investigations have examined the relationship of BIS during sedation and natural sleep, as well as the effects of sedation on airway obstruction, the results have not been consistent. [5][6][7][8] While BIS levels decrease during natural sleep in much the same way as during sedation, the technology does not allow for discrimination of different stages of sleep.9 Furthermore, BIS scores associated with depth of anesthesia are dependent upon the anesthetic agent being used, are relatively ineffective during sedation with ketamine, nitrous oxide, or dexmedetomidine, and can be unpredictable in the presence of opioids. 10And fi nally, in the B-Unaware trial, BIS was found to be ineffective in guiding the administration of volatile anesthetics. 11Moreover, BIS was not sensitive enough to detect clinically signifi cant changes in minimum alveolar concentration and suffered from interpatient variability .The Lo study 4 investigated the effect of sedation on DISE fi ndings and found that deep sedation levels (BIS levels of 50 to 60) resulted in greater airway collapsibility and more complete collapse at multiple sites than did evaluation at light sedations levels (BIS levels of 65 to 75). They also found that DISE fi ndings were consistent over 2 separate periods at each sedation level (deep and light). Real-time and video evaluation of DISE fi ndings were also shown to have a high level of interrater reliability. However, there is no comment on the therapy recommended by this evaluation or correlation with outcomes after these therapies were carried out. In addition, there was no comment on the correlation between BIS levels and clinical symptoms. This makes it diffi cult to generalize these fi ndings to situations when DISE is performed w...

Dexmedetomidine versus propofol at different sedation depths during drug‐induced sleep endoscopy: A randomized trial

“…Therefore, we thought it reasonable to include lower levels of BIS (40–60) for DISE examination. There have been arguments in the literature that BIS might be ineffective with dexmedetomidine . Kasuya and colleagues found that while comparing propofol and dexmedetomidine in healthy volunteers, BIS values were significantly lower with dexmedetomidine than propofol at the same sedation score .…”

“…In OSA patients, obstruction is more severe in the rapid eye movement phase of sleep, and neither of the study drugs has any effect on rapid eye movement sleep . Second, the use of BIS for monitoring sedation depth with dexmedetomidine still has not been proven . However, there has been recent evidence that a BIS value of 40 to 60 can be used to determine deep sedation depth with dexmedetomidine .…”

The safety and efficacy of esketamine in comparison to dexmedetomidine during drug-induced sleep endoscopy in children with obstructive sleep apnea hypopnea syndrome: A randomized, controlled and prospective clinical trial

“…Second, the depth of sleep and wakefulness cannot be assessed effectively in an accurate and consistent way. Based on previous research, adequate depth of sedation and anesthesia for DISE in OSAHS children was UMSS score of 3 or BIS 65–75 in this study ( Stierer and Ishman, 2015 ; Lo et al, 2015 ; Shields et al, 2005 ; Malviya et al, 2002 ). The scores for pediatric awakening depth were very few.…”

The influence of different application patterns of propofol on the sedation courses during drug‐induced sleep endoscopy

“…Numerous publications provide evidence that the levels, patterns, and intensity of the collapse of the upper airway can change depending on the depth of sedation. [8][9][10][11] Therefore, it seems appropriate to monitor the depth of sedation during DISE aiming to reach a level of sedation which imitates different sleep stages of natural sleep. BiSpectral Index™ (BIS) is used as a common method for measuring the depth of sedation during DISE.…”