Drug-induced sleep endoscopy: from obscure technique to diagnostic tool for assessment of obstructive sleep apnea for surgical interventions

The Prevalence of Sentinel Central Events (SCent) During Drug-Induced Sleep Endoscopy

OBJECTIVE

With the recent addition of airflow and respiratory effort channels, our group has observed central and mixed apnea events during drug-induced sleep endoscopy (DISE). We measured the frequency and timing of sentinel central and/or mixed events (SCents), as well as assessed for differences in velum, oropharynx, tongue, and epiglottis (VOTE) classification compared to obstructive events.

STUDY DESIGN

Prospective single-cohort study.

SETTING

Tertiary Care Academic Medical Center.

METHODS

Patients underwent DISE between June 2020 and November 2022. Nasal airflow, thoracoabdominal effort belt signals, and videoendoscopy were simultaneously captured. Demographics, sleep study, and DISE data were compared among patients with and without SCents using Student's T tests or χ2 tests.

RESULTS

On average, the cohort (n = 103) was middle-aged (53.5 ± 12.1 years), overweight (body mass index of 29.7 ± 5.3 kg/m2), and had severe obstructive sleep apnea (apnea-hypopnea index of 30.7 ± 18.7 events/h). Forty-seven patients (46%) were found to have at least 1 SCent. Among those with SCent, 45 (95.7%) transitioned to obstructive pathology after an average of 7.91 ± 2.74 minutes, with at least 95% of patients expected to do so within 12.57 minutes. Twenty-nine out of 47 patients (61.2% [95% confidence interval: 46.4.9%, 75.5%]) with SCent had meaningful differences between central/mixed and obstructive VOTE scores.

CONCLUSION

Central events were present in almost half of our cohort. At least 95% of patients were expected to transition to obstructive events within 12 to 13 minutes of propofol initiation. In addition, over half of patients demonstrate significantly different VOTE scores between central and obstructive events. These factors should raise awareness of central events and scoring passive apneas during DISE and consider delaying VOTE scoring.

Efficacy of high-flow nasal oxygen during drug-induced sleep endoscopy in patients with obstructive sleep apnea

PURPOSE

High-flow nasal oxygenation (HFNO) can provide a low level of continuous positive airway pressure and alveolar recruitment. We aimed to compare the efficacy of pre-oxygenation with HFNO and low-flow nasal oxygenation (LFNO) during drug-induced sleep endoscopy (DISE).

METHODS

In the LFNO group, preoxygenation was performed for 10 min at 3 L·min-1. In the HFNO group, preoxygenation was performed for 10 min at 30 L·min-1 at a fraction of inspired oxygen of 100% using the Optiflow device. From the start of sedative administration to the end of DISE, vital signs were monitored continuously. The primary outcome was the lowest oxygen saturation (SpO2) during DISE.

RESULTS

Of 24 patients enrolled, 12 were randomly assigned to the LFNO and 12 to the HFNO groups. The prevalence of hypoxia events was 75% in the LFNO group and 58% in the HFNO group. The difference in lowest oxygen saturation between the two groups was not significant between the two groups (P=0.665). The lowest SpO2 during all procedures was comparable between the two groups (86.8 ± 6.5% in the LFNO group and 87.2 ± 8.0% in the HFNO group; P=0.912).

CONCLUSIONS

The findings suggest that HFNO may not be superior to LFNO as a preoxygenation tool to prevent hypoxia during DISE.

Sleep Endoscopy with Positive Airway Pressure: A Method for Better Compliance and Individualized Treatment of Patients with Obstructive Sleep Apnea

In this study, we aimed to observe the effects of positive airway pressure (PAP) on individual levels of obstruction during drug-induced sleep endoscopy (DISE) of the upper airways (UA), to evaluate at which pressures the obstruction disappeared or worsened, and to identify cases in which PAP was ineffective. This prospective study was conducted from June 2018 to June 2022. PAP testing was performed during DISE in patients with moderate and severe OSA. The pressure was gradually increased over the range from 6.0 to 18.0 hPa. Our findings were evaluated using the VOTE classification. The examination was performed in 56 patients, with a median apnea-hypopnea index (AHI) of 26.4. Complete obstruction of the soft palate was observed in 51/56 patients (91%), oropharyngeal obstruction in 15/56 patients (27%), tongue base obstruction in 23/56 patients (41%), and epiglottic collapse in 16/56 patients (29%). PAP was most effective in cases of complete oropharyngeal obstruction, and least effective in cases of epiglottic collapse, where it was ineffective in 11/16 patients. DISE with PAP is a simple diagnostic method that can be helpful for identifying anatomic and dynamic reasons for PAP intolerance. The main indication is ineffective PAP treatment.

The anesthesia airway evaluation: Correlation with sleep endoscopy findings

PURPOSE

Drug-induced sleep endoscopy (DISE) is a cost-effective, safe, and reliable tool to evaluate obstructive sleep apnea (OSA) patients by revealing upper airway sites, patterns, and severity of obstruction. DISE provides valuable data because reliable evaluation of the OSA airway while awake has remained elusive. Few studies (with mixed results) have analyzed the correlation between pre-operation, awake airway assessments routinely performed by anesthesia and DISE results.

METHODS

Preoperative anesthesia evaluation records and subsequent DISE reports were obtained for 99 adult patients undergoing DISE between 2016 and 2018. All patients carried the diagnosis of OSA, based on polysomnography. Anesthesia-collected variables were compared with DISE findings in an effort to determine if commonly-utilized physical exam findings correlated to patterns of upper airway collapse observed on sleep endoscopy.

RESULTS

Most anesthesia preoperative evaluation variables were not found to be predictive of any identifiable patterns of collapse on DISE, including Mallampati score, ability to prognath, and overall airway assessment score. Obesity did not correlate with circumferential collapse at the velopharynx, or to multi-level collapse. Thyromental distance <6.5 cm was found to be statistically correlated to total epiglottic collapse (E = 2+). Friedman tongue position scores were found to be correlated to velopharyngeal collapse (p < 0.05).

CONCLUSIONS

Anesthesia airway assessment algorithms and physical exam findings do not correlate well with findings on sleep endoscopy. DISE remains the gold standard for evaluating levels of collapse and operative planning in the OSA population.

Drug-Induced Sleep Endoscopy in Treatment Options Selection

Drug-induced sleep endoscopy is a safe and practical technique to evaluate the dynamic upper airway collapse during sleep. We review drug-induced sleep endoscopy in adults, including its indications, technique, evaluation of upper airway collapse, and clinical application. Drug-induced sleep endoscopy is useful to improve treatment options selection for patients with obstructive sleep apnea, especially for those who are unable to accept or tolerate continuous positive airway pressure therapy. Owing to a lack of standardization for drug-induced sleep endoscopy, it is difficult to compare the published literature from different sleep centers across the world.