Types of Epiglottic Collapse in Breathing Sleep Disorder and Their Impact in Clinical Practice.

Introduction Obstructive sleep apnea (OSA) is a severe form of sleep-disordered breathing (SDB) that is strongly correlated with comorbidities, in which epiglottic collapse (EC) and other contributing factors are involved. Objectives To evaluate the occurrence of EC in OSA patients through drug-induced sleep endoscopy (DISE) and to determine the factors contributing to EC. Methods A retrospective study of 37 adult patients using medical history. Patients were assessed for laryngopharyngeal reflux (LPR) and lingual tonsil hypertrophy (LTH) using reflux symptom index and reflux finding score (RFS); for OSA using polysomnography, and for airway collapse through DISE. An independent t -test was performed to evaluate risk factors, including the involvement of three other airway structures. Results Most EC patients exhibited trap door epiglottic collapse (TDEC) (56.8%) or pushed epiglottic collapse (PEC) (29.7%). Lingual tonsil hypertrophy, RFS, and respiratory effort-related arousal (RERA) were associated with epiglottic subtypes. Laryngopharyngeal reflux patients confirmed by RFS (t(25) = -1.32, p = 0.197) tended to suffer PEC; LTH was significantly associated (X2(1) = 2.5, p = 0.012) with PEC (odds ratio [OR] value = 44) in grades II and III LTH patients; 11 of 16 TDEC patients had grade I LTH. Pushed epiglottic collapse was more prevalent among multilevel airway obstruction patients. A single additional collapse site was found only in TDEC patients. Conclusion Laryngopharyngeal reflux causes repetitive acid stress toward lingual tonsils causing LTH, resulting in PEC with grade II or III LTH. Trap door epiglottic collapse requires one additional structural collapse, while at least two additional collapse sites were necessary to develop PEC. Respiratory effort-related arousal values may indicate EC.

Types of Epiglottic Collapse in Breathing Sleep Disorder and Their Impact in Clinical Practice

Abstract Introduction Obstructive sleep apnea (OSA) is a severe form of sleep-disordered breathing (SDB) that is strongly correlated with comorbidities, in which epiglottic collapse (EC) and other contributing factors are involved. Objectives To evaluate the occurrence of EC in OSA patients through drug-induced sleep endoscopy (DISE) and to determine the factors contributing to EC. Methods A retrospective study of 37 adult patients using medical history. Patients were assessed for laryngopharyngeal reflux (LPR) and lingual tonsil hypertrophy (LTH) using reflux symptom index and reflux finding score (RFS); for OSA using polysomnography, and for airway collapse through DISE. An independent t-test was performed to evaluate risk factors, including the involvement of three other airway structures. Results Most EC patients exhibited trap door epiglottic collapse (TDEC) (56.8%) or pushed epiglottic collapse (PEC) (29.7%). Lingual tonsil hypertrophy, RFS, and respiratory effort-related arousal (RERA) were associated with epiglottic subtypes. Laryngopharyngeal reflux patients confirmed by RFS (t(25) = −1.32, p = 0.197) tended to suffer PEC; LTH was significantly associated (X2(1) = 2.5, p = 0.012) with PEC (odds ratio [OR] value = 44) in grades II and III LTH patients; 11 of 16 TDEC patients had grade I LTH. Pushed epiglottic collapse was more prevalent among multilevel airway obstruction patients. A single additional collapse site was found only in TDEC patients. Conclusion Laryngopharyngeal reflux causes repetitive acid stress toward lingual tonsils causing LTH, resulting in PEC with grade II or III LTH. Trap door epiglottic collapse requires one additional structural collapse, while at least two additional collapse sites were necessary to develop PEC. Respiratory effort-related arousal values may indicate EC.

Predictors of Success of Pharyngeal Surgery in the Treatment of Obstructive Sleep Apnea: A Narrative Review.

(1) Background: This narrative review aims to explore the predictors of success for pharyngeal surgery in the treatment of obstructive sleep apnea (OSA). An extensive literature search was conducted, identifying relevant studies published up to June 2023, utilizing various databases and key search terms related to OSA, surgical interventions, and predictors of success. The review encompasses both retrospective and prospective studies, case series, and cohort studies to provide a broad understanding of the topic; (2) Methods: Review of English scientific literature on phenotypes of OSA related to predictors of success of pharyngeal surgery; (3) Results: Of 75 articles, 21 were included, in these the following were determined to be factors for surgical success: body mass index (BMI) (8 articles), apnea/hypopnea index (AHI) (8 articles), cephalometry (8 articles), palatine tonsil size (7 articles), Modified Mallampati score (2 articles), genioglossus electromyography (2 articles), Friedman score or upper airway anatomy (3 articles), nasopharyngolaryngoscopy (2 articles), drug-induced sleep endoscopy (DISE) (1 article), oral cavity anatomy (1 article) and oxygen desaturation index (ODI) (1 article); (4) Conclusions: The lack of standardized protocols for the indication of pharyngeal surgery is a reality, however identifying known predictors of surgical success may facilitate homogenizing indications.

The Effect of Tonsillectomy and Adenoidectomy on Upper Airway Obstruction Patterns in Children with Obstructive Sleep Apnea

Abstract Introduction Alterations in upper airway flow dynamics and sites of airway obstruction immediately after tonsillectomy and adenoidectomy (TA) have not been assessed. Identification of the changes in airway obstruction patterns after TA potentially improves the surgical management of children with obstructive sleep apnea (OSA). Objectives To evaluate the effect of TA on upper airway obstruction patterns detected with drug-induced sleep endoscopy (DISE). Methods The medical records of patients who underwent pre-TA DISE during the induction of anesthesia and post-TA DISE at the end of TA were reviewed. Data pertaining to polysomnography and DISE findings were analyzed. Results Twenty-seven patients (15 male and 12 females aged between 2 and 18 years old) were identified. All patients had obstruction at multiple sites of the upper airway. Prior to TA, airway obstruction was at the level of the velum in 27 patients, of the oropharynx/lateral walls in 27, of the tongue in 7, and of the epiglottis in 4. After TA, airway obstruction was at the level of the velum in 24 patients, of the oropharynx/lateral walls in 16, of the tongue in 6, and of the epiglottis in 4. The degree of obstruction at the levels of the velum and oropharynx/lateral walls after TA was significantly decreased. Conclusions Drug-induced sleep endoscopy performed prior to TA revealed that most of the sites of airway obstruction persisted after TA in OSA children with multiple sites of airway obstruction. Further studies in larger group of children with OSA are needed to establish the value of DISE findings in predicting residual OSA after TA, surgical planning, determining the need for post TA sleep study, and counseling caregivers.

The Effect of Tonsillectomy and Adenoidectomy on Upper Airway Obstruction Patterns in Children with Obstructive Sleep Apnea.

Introduction Alterations in upper airway flow dynamics and sites of airway obstruction immediately after tonsillectomy and adenoidectomy (TA) have not been assessed. Identification of the changes in airway obstruction patterns after TA potentially improves the surgical management of children with obstructive sleep apnea (OSA). Objective To evaluate the effect of TA on upper airway obstruction patterns detected with drug-induced sleep endoscopy (DISE). Methods The medical records of patients who underwent pre-TA DISE during the induction of anesthesia and post-TA DISE at the end of TA were reviewed. Data pertaining to polysomnography and DISE findings were analyzed. Results Twenty-seven patients (15 male and 12 females aged between 2 and 18 years old) were identified. All patients had obstruction at multiple sites of the upper airway. Prior to TA, airway obstruction was at the level of the velum in 27 patients, of the oropharynx/lateral walls in 27, of the tongue in 7, and of the epiglottis in 4. After TA, airway obstruction was at the level of the velum in 24 patients, of the oropharynx/lateral walls in 16, of the tongue in 6, and of the epiglottis in 4. The degree of obstruction at the levels of the velum and oropharynx/lateral walls after TA was significantly decreased. Conclusions Drug-induced sleep endoscopy performed prior to TA revealed that most of the sites of airway obstruction persisted after TA in OSA children with multiple sites of airway obstruction. Further studies in larger group of children with OSA are needed to establish the value of DISE findings in predicting residual OSA after TA, surgical planning, determining the need for post TA sleep study, and counseling caregivers.

Relationship between level CPAP titration, anthropometric variables, and drug-induced sleep endoscopy DISE.

INTRODUCTION: Subjects with palatal obstruction alone vs. multilevel obstruction on DISE had better outcomes after palate surgery. We asked ourselves if the therapeutic level positive airway pressure (PAP) titration could predict the level of airway obstruction and its complexity. PURPOSE: The aim of this study was to identify possible relationships between therapeutic level of positive airway pressure initial titration and levels of collapse in drug-induced sleep endoscopy (DISE). A secondary objective was to establish the relationship the other variables and DISE. METHODS: We analyzed retrospective clinical histories between March 2020 to March 2022 of 37 patients with polysomnography or cardiorespiratory polygraphy studies and PAP initial titration who were taken to drug-induced sleep endoscopy. Sleep study data, anthropometric variables, and patterns of airway collapse during DISE were analyzed with PAP initial titration levels. RESULTS: Most of the patients with complex collapse had concentric velum collapse (p < 0.006). A significant association was found between the apnea-hypopnea index (AHI) and oropharyngeal collapse; (p < 0.0030) and finally we demonstrated relationship between neck circumference and gender with epiglottis collapse (p < 0.046), (p < 0.037), respectively. CONCLUSIONS: Our findings show a strong relationship between that complex collapses and concentric velum collapse; patients with greater oropharyngeal collapse have a higher mean AHI. Patients without epiglottic collapse have a higher mean neck circumference. An association between mean pressure initial titration and complex collapse could not be established.

The clinical application progress and potential of drug-induced sleep endoscopy in obstructive sleep apnea.

Background and Objective: Obstructive sleep apnoea (OSA) is characterized by nocturnal repetitive upper airway (UA) collapse. For sleep physicians, the recognition of UA collapse characteristics is critical for understanding OSA mechanisms and developing individualized treatment plans. Drug-induced sleep endoscopy (DISE) is an exam during simulated sleep that allows the dynamic assessment of the UA of individuals with OSA. The initial recognition of DISE was to locate the sites of UA obstruction and direct the surgical selection of OSA since it was introduced in the 1990s. After approximately 30 years of studies, based on advances in endoscopic operative techniques and innovative treatments of OSA, DISE had been performed to explore mechanisms and comprehensive treatments related to UA collapse. Methods: This article reviewed contemporary DISE advances, including indications and contraindications, technique of induced sleep, endoscopic operation, UA characteristics classification.Results and Conclusions: Precise selection based on the association between collapse patterns and treatment modalities, such as continuous positive airway pressure, oral appliance, positional therapy, robotic surgery and neurostimulator implanting, is the future research prospect based on DISE.Key messagesDISE provides sleep physicians with valuable information about the upper airway collapse characteristics and dynamic changes during sleep.The studies based on DISE findings improve the selectivity and efficiency of treatment modalities, including classical therapies such as continuous positive airway pressure, oral appliance, positional therapy, and innovative therapies such as neurostimulator implanting and robotic surgery, promote the advancement of OSA precision medicine.

Drug-induced Sleep Endoscopy: Are there Predictors for Failure of Oral Appliance Treatment?

Abstract Introduction In the literature, evidence is lacking on the predictive value of druginduced sleep endoscopy (DISE) for oral appliance treatment (OAT). Objectives The aim of the present study is to evaluate whether DISE with concomitant mandibular advancement maneuver can predict failure of OAT. Methods An observational retrospective study including patients diagnosed with obstructive sleep apnea (OSA) who previously received OAT. Results of DISE were analyzed in a group with documented OAT failure (apnea-hypopnea index [AHI] >10 events/hour or < 50% reduction) and a group with OAT benefit (AHI <10 events/hour or >50% reduction). The upper airway was assessed using the velum, oropharynx, tongue base, epiglottis (VOTE) classification. Additionally, a mandibular advancement maneuver, manually protruding the mandible by performing a jaw thrust, was performed to mimic the effect of OAT. Results The present study included 50 patients with OAT failure and 20 patients with OAT benefit. A subgroup analysis of patients with OAT failure and an AHI <30events/hour included 26 patients. In the OAT failure group, 74% had a negative jaw thrust maneuver. In the subgroup with an AHI <30 events/hour, 76.9% had a negative jaw thrust maneuver. In the OAT benefit group, 25% had a negative jaw thrust maneuver (p< 0.001). Conclusions A negative jaw thrust maneuver during DISE can be a valuable predictor for OAT failure, independent of AHI. Drug-induced sleep endoscopy should be considered as a diagnostic evaluation tool before starting OAT.

Drug-induced Sleep Endoscopy: Are there Predictors for Failure of Oral Appliance Treatment?

Introduction In the literature, evidence is lacking on the predictive value of drug-induced sleep endoscopy (DISE) for oral appliance treatment (OAT). Objectives The aim of the present study is to evaluate whether DISE with concomitant mandibular advancement maneuver can predict failure of OAT. Methods An observational retrospective study including patients diagnosed with obstructive sleep apnea (OSA) who previously received OAT. Results of DISE were analyzed in a group with documented OAT failure (apnea-hypopnea index [AHI] > 10 events/hour or < 50% reduction) and a group with OAT benefit (AHI <10 events/hour or > 50% reduction). The upper airway was assessed using the velum, oropharynx, tongue base, epiglottis (VOTE) classification. Additionally, a mandibular advancement maneuver, manually protruding the mandible by performing a jaw thrust, was performed to mimic the effect of OAT. Results The present study included 50 patients with OAT failure and 20 patients with OAT benefit. A subgroup analysis of patients with OAT failure and an AHI < 30 events/hour included 26 patients. In the OAT failure group, 74% had a negative jaw thrust maneuver. In the subgroup with an AHI < 30 events/hour, 76.9% had a negative jaw thrust maneuver. In the OAT benefit group, 25% had a negative jaw thrust maneuver ( p < 0.001). Conclusions A negative jaw thrust maneuver during DISE can be a valuable predictor for OAT failure, independent of AHI. Drug-induced sleep endoscopy should be considered as a diagnostic evaluation tool before starting OAT.

Can drug-induced sleep endoscopy (DISE) predict compliance with positive airway pressure therapy? A pilot study.

PURPOSE: Drug-induced sleep endoscopy (DISE) has been poorly explored as an examination to assess positive airway pressure (PAP) therapy in patients with obstructive sleep apnea (OSA). The present study aimed to identify by DISE possible characteristics related to low compliance with PAP therapy due to respiratory complaints. METHODS: Patients using PAP for OSA underwent DISE in two conditions: (1) baseline (without PAP) and (2) PAP (with the same mask and airway pressure used at home). We compared patients reporting low compliance to PAP due to respiratory complaints to those well-adapted to therapy. VOTE classification (assessment of velopharynx, oropharynx, tongue base, and epiglottis) and TOTAL VOTE score (the sum of VOTE scores at each anatomical site) were assessed. ROC curve analyzed the accuracy of TOTAL VOTE to predict low compliance due to persistent pharyngeal obstruction in both conditions. RESULTS: Of 19 patients enrolled, all presented multilevel pharyngeal obstruction at baseline condition, with no difference between groups at this study point. When PAP was added, the median VOTE value was higher in the epiglottis (P value=0.02) and tended to be higher at the velum and tongue base in the poorly adapted group; TOTAL VOTE score was also significantly increased in patients with low compliance (P value<0.001). ROC curve demonstrated that patients with TOTAL VOTE scored 2.5 or more during DISE with PAP presented a 4.6-fold higher risk for low compliance with PAP therapy due to pharyngeal obstruction (AUC: 0.88±0.07; P value<0.01; sensitivity: 77%; specificity: 83%). CONCLUSIONS: Adding PAP during a DISE examination may help to predict persistent pharyngeal obstruction during PAP therapy.

Nasal vs. oronasal mask during PAP treatment: a comparative DISE study.

PURPOSE: The present study evaluated the upper airway pattern of obstruction in individuals undergoing drug-induced sleep endoscopy (DISE) exam with positive airway pressure (PAP), and compared this effect through a nasal or oronasal mask. METHODS: Prospective study. Patients requiring PAP due to obstructive sleep apnea (OSA) were evaluated through DISE at three different moments: (1) a baseline condition (without PAP); (2) PAP treatment with a nasal mask; and (3) PAP with an oronasal mask at the same pressure. The conditions were compared intra-individually, following VOTE classification. A TOTAL VOTE score (the sum of VOTE scores observed for each anatomical site) was also applied to compare intra-individual results. RESULTS: Thirteen patients were enrolled in the study. All patients presented multi-level pharyngeal obstruction at baseline condition. In six patients, the pattern of obstruction differed according to the mask. Nasal mask significantly decreased the obstruction score when compared with baseline condition both in velum (P value < 0.05) and oropharynx regions (P value < 0.005). TOTAL VOTE score was also significantly lower during nasal mask evaluation when compared with basal condition (P value < 0.005). Remarkably, oronasal mask with the same pressure was not as effective as nasal masks. Obstruction levels observed at the tongue base or epiglottis levels were more resistant to PAP treatment. CONCLUSIONS: Collapse in velum and oropharyngeal sites is more compliant to PAP than obstruction at lower levels of the pharynx, either with nasal or oronasal masks. Nasal mask is superior to prevent pharyngeal collapse than oronasal devices under the same pressure.

The Effect of Sedating Agents on Drug-Induced Sleep Endoscopy Findings.

OBJECTIVE: Drug-induced sleep endoscopy (DISE) has gained interest for upper airway evaluation in patients with snoring and obstructive sleep apnea (OSA), and different drugs have been used to induce sedation. Nevertheless, all drugs have presented specific advantages and disadvantages with differential effects on respiratory physiology. This study evaluated and compared the effects of midazolam, propofol and dexmedetomidine on DISE findings, O2 nadir, and bispectral index (BIS) in the same sample of patients. STUDY DESIGN: Case series prospective study. METHODS: Consecutive patients who elected to undergo surgery for OSA treatment and were intolerant to conservative therapies underwent DISE with propofol, dexmedetomidine, and midazolam between July 2015 and July 2016. RESULTS: Fifty-two patients were analyzed, and 43 (82.7%) were men. Agreement among drugs for both degree and patterns of obstruction was excellent at all sites (velum, oropharynx, and epiglottis) except for the tongue base. Dexmedetomidine had the least complete collapse sites and highest O2 nadir and was the only drug for which apnea severity and obstruction levels (upper, lower, or combined) were correlated. The variability among drug treatments for the BIS index was considerable, and propofol had the lowest variability and average value. CONCLUSION: Drug selection had a relevant influence in DISE findings. Compared with dexmedetomidine, midazolam and propofol presented higher incidence of tongue base collapse, lower O2 levels, and lower BIS index values. Propofol resulted in an O2 nadir that most resembled that observed during polysomnography. The BIS index variability differed among drugs, and its use was considered relevant for sedation orientation. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:506-513, 2019.

Comparison of drug-induced sleep endoscopy and Müller's maneuver in diagnosing obstructive sleep apnea using the VOTE classification system / Comparação entre endoscopia com sono induzido por fármacos e manobra de Müller no diagnóstico de apneia obstrutiva do sono usando o sistema de classificação VOTE

Abstract Introduction: Knowledge of the site of obstruction and the pattern of airway collapse is essential for determining correct surgical and medical management of patients with Obstructive Sleep Apnea Syndrome (OSAS). To this end, several diagnostic tests and procedures have been developed. Objective: To determine whether drug-induced sleep endoscopy (DISE) or Müller's maneuver (MM) would be more successful at identifying the site of obstruction and the pattern of upper airway collapse in patients with OSAS. Methods: The study included 63 patients (52 male and 11 female) who were diagnosed with OSAS at our clinic. Ages ranged from 30 to 66 years old and the average age was 48.5 years. All patients underwent DISE and MM and the results of these examinations were characterized according to the region/degree of obstruction as well as the VOTE classification. The results of each test were analyzed per upper airway level and compared using statistical analysis (Cohen's kappa statistic test). Results: There was statistically significant concordance between the results from DISE and MM for procedures involving the anteroposterior (73%), lateral (92.1%), and concentric (74.6%) configuration of the velum. Results from the lateral part of the oropharynx were also in concordance between the tests (58.7%). Results from the lateral configuration of the epiglottis were in concordance between the tests (87.3%). There was no statistically significant concordance between the two examinations for procedures involving the anteroposterior of the tongue (23.8%) and epiglottis (42.9%). Conclusion: We suggest that DISE has several advantages including safety, ease of use, and reliability, which outweigh MM in terms of the ability to diagnose sites of obstruction and the pattern of upper airway collapse. Also, MM can provide some knowledge of the pattern of pharyngeal collapse. Furthermore, we also recommend using the VOTE classification in combination with DISE.

Resumo Introdução: O conhecimento do local da obstrução e do padrão de colapso das vias respiratórias é essencial para determinar o tratamento cirúrgico e clínico corretos de pacientes com Síndrome de Apneia Obstrutiva do Sono (SAOS). Para este fim, vários testes e procedimentos de diagnóstico foram desenvolvidos. Objetivo: Determinar se a Endoscopia de Sono Induzido por Fármacos (DISE) ou Manobra de Müller (MM) seria mais bem-sucedida na identificação do local de obstrução e do padrão de colapso das vias respiratórias superiores em pacientes com SAOS. Método: O estudo incluiu 63 pacientes (52 do sexo masculino e 11 do sexo feminino) que foram diagnosticados com SAOS em nossa clínica. As idades variaram de 30 a 66 anos e a idade média foi de 48,5 anos. Todos os pacientes foram submetidos a DISE e MM e os resultados destes exames foram caracterizados de acordo com a região/grau de obstrução, bem como a classificação VOTE. Os resultados de cada teste foram analisados de acordo com o nível das vias respiratórias superiores e comparados por análise estatística (teste estatístico kappa de Cohen). Resultados: Houve concordância estatisticamente significativa entre os resultados da DISE e MM para os procedimentos que envolvem configuração anteroposterior (73%), lateral (92,1%) e concêntrica (74,6%) do véu palatino. Os resultados da parte lateral da orofaringe também estavam em concordância entre os testes (58,7%). Os resultados da configuração lateral da epiglote estavam em concordância entre os testes (87,3%). Não houve concordância estatisticamente significativa entre os dois exames para os procedimentos que envolvem a parte anteroposterior da língua (23,8%) e epiglote (42,9%). Conclusão: Sugere-se que a DISE apresenta várias vantagens, como segurança, facilidade de uso e confiabilidade, que superam a MM em termos da capacidade de diagnosticar locais de obstrução e o padrão de colapso da via respiratória superior. O MM pode também fornecer algum conhecimento sobre o padrão de colapso da faringe. Além disso, recomendamos o uso da classificação VOTE em combinação com DISE.

Comparison of drug-induced sleep endoscopy and Müller's maneuver in diagnosing obstructive sleep apnea using the VOTE classification system.

INTRODUCTION: Knowledge of the site of obstruction and the pattern of airway collapse is essential for determining correct surgical and medical management of patients with Obstructive Sleep Apnea Syndrome (OSAS). To this end, several diagnostic tests and procedures have been developed. OBJECTIVE: To determine whether drug-induced sleep endoscopy (DISE) or Müller's maneuver (MM) would be more successful at identifying the site of obstruction and the pattern of upper airway collapse in patients with OSAS. METHODS: The study included 63 patients (52 male and 11 female) who were diagnosed with OSAS at our clinic. Ages ranged from 30 to 66 years old and the average age was 48.5 years. All patients underwent DISE and MM and the results of these examinations were characterized according to the region/degree of obstruction as well as the VOTE classification. The results of each test were analyzed per upper airway level and compared using statistical analysis (Cohen's kappa statistic test). RESULTS: There was statistically significant concordance between the results from DISE and MM for procedures involving the anteroposterior (73%), lateral (92.1%), and concentric (74.6%) configuration of the velum. Results from the lateral part of the oropharynx were also in concordance between the tests (58.7%). Results from the lateral configuration of the epiglottis were in concordance between the tests (87.3%). There was no statistically significant concordance between the two examinations for procedures involving the anteroposterior of the tongue (23.8%) and epiglottis (42.9%). CONCLUSION: We suggest that DISE has several advantages including safety, ease of use, and reliability, which outweigh MM in terms of the ability to diagnose sites of obstruction and the pattern of upper airway collapse. Also, MM can provide some knowledge of the pattern of pharyngeal collapse. Furthermore, we also recommend using the VOTE classification in combination with DISE.

Polysomnographic evaluation of propofol-induced sleep in patients with respiratory sleep disorders and controls.

OBJECTIVES/HYPOTHESIS: The treatment for obstructive sleep apnea syndrome (OSAS) depends on correct localization of upper airway obstruction, exception made for continuous positive airway pressure (CPAP). Drug-induced sleep endoscopy (DISE) with propofol allows this evaluation, but the drug effects on sleep parameters are not yet well established. Our objective was to study by polysomnography (PSG) whether propofol would change sleep parameters by means of a prospective cross-sectional clinical study in a tertiary hospital. STUDY DESIGN: Thirty non-obese subjects (6 controls and 24 OSAS patients) underwent two daytime PSGs, one with DISE and the other without DISE. METHODS: During DISE exam, propofol was administered intravenously in continuous infusion using a target-controlled infusion pump. The parameters evaluated were: presence of snoring, apnea-hypopnea index (AHI), oxyhemoglobin saturation (SaO2), and sleep macroarchitecture. RESULTS: Snoring was absent in all healthy subjects during DISE sleep with propofol, and present in all OSAS patients (100%). AHI and mean SaO2 showed no statistical difference between the two tests, with and without propofol. However, minimum SaO2 was significantly lower during propofol infusion (88.64 for without vs. 85.04 for with propofol; P < 0.01). Regarding sleep macroarchitecture, the tests with propofol significantly increased N3 sleep and totally extinguished REM sleep (P < 0.005). CONCLUSIONS: The results demonstrate that propofol significantly changes sleep macroarchitecture. However, the main respiratory parameters, AHI and mean SaO2 , remained unaffected. Thus, in order to determine the sites of obstruction, propofol DISE used with target-controlled infusion proved to be an effective drug for endoscopic evaluation of patients with OSAS.