Average Respiratory Disturbance Index Research Articles

0470 Factors Associated with Discordant Initial Home Sleep Apnea Testing and Polysomnography

Abstract Introduction Nocturnal polysomnography (PSG) is the gold standard for diagnosing obstructive sleep apnea (OSA). Home sleep apnea tests (HSAT) have been incorporated in the diagnostic algorithm in patients with a high pre-test suspicion of OSA. While many studies have compared HSATs with PSGs, it is not well understood what factors may be responsible for inconclusive HSAT results. Methods We performed a retrospective chart review of adult patients who underwent a non-diagnostic HSAT evaluation, who subsequently tested positive for OSA (on PSG) between 1/1/2022 and 11/1/2022. We collected demographic and sleep study data. Patients who did not have a follow up PSG were excluded. Results A total of 20 patients were reviewed. 80% had a negative HSAT with a positive subsequent PSG. The average age was 33.9 years (SD +/- 11.3 years). 43% were male and 50% were Caucasian. The average BMI was 29 kg/m2 (SD +/- 5.3 kg/m2). The average Epworth Sleepiness Scale score (ESS) was 8 (median 6.5) with only 31% reporting an ESS >10. The average HSAT recording time was 449.1 minutes. The average respiratory disturbance index (RDI) on the follow up PSG was 17.7 events/hour of sleep (SD +/- 12). Only 1 patient was diagnosed with severe OSA. 38% were diagnosed with anxiety in this cohort. Other co-morbidities were insignificant. Of all the HSATs performed, 40% were denied for an initial PSG evaluation and converted to an HSAT evaluation. Conclusion HSATs are validated in patients with a high pretest probability of OSA. Anxiety was found in one third of patients included (possibly contributing to a negative initial HSAT). Patient demographics however were also not remarkable for a high risk of OSA in this group (e.g. non-obese, < 55 years, female). The subsequent diagnosis for OSA was also only mild or moderate (93.8%) in this lower risk cohort. Hence, another explanation for the initial negative HSAT evaluation may have been the insurance denial of the initial PSG request (40%). Denials of low risk patients for PSG may contribute to a misuse of resources. We also need to educate referring physicians to follow appropriate HSAT ordering criteria (based on high OSA risk factors). Support (if any)

0558 Sleep Bruxism and Sleep Breathing Disorder

Abstract Introduction Sleep bruxism (SB) is reported by 8-9% of the adult population and is mainly associated with rhythmic masticatory muscle activity (RMMA) characterized by repetitive jaw muscle contractions (3 bursts or more at a frequency of 1 Hz). The purpose of this study was to evaluate the relationship between the nature of sleep bruxism and the sleep breathing disoredr. Methods We prospectively studied 32 patients who were referred to the clinical sleep apnea laboratory for study. They underwent standard nocturnal polysomnographic examination; in addition, masticatory activity was measured with a masseter electromyogram. Patients slept in the supine and lateral decubitus positions. Results Nocturnal clenching was higher in patients with higher respiratory disturbance index. 28 among 32 patients were included in the criteria of obstructive sleep apnea; average respiratory disturbance index (RDI) was 12.7 280 clenches demonstrated in all patients. Conclusion We conclude that there is an association between sleep related breathing disorder and bruxisms that sleep position affects the incidence of both sleep disordered breathing and bruxisms, and that analysis of apneas and hypopneas and clenching events in both supine and lateral decubitus sleeping positions may be helpful. Support (if any)

Influence of obesity and overweight on the association between sleep-disordered breathing and atrial fibrillation: the DASAP-HF study

Abstract Background The association between sleep apnea (SA) and atrial fibrillation (AF) has been well described. However, it remains unclear whether the association is causative or primarily dependent on shared comorbidities such as obesity. The Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe SA, whether central or obstructive in origin. Purpose In the present analysis we studied in patients with heart failure the contribution of obesity in the relationship between SA, measured by RDI, and AF. Methods Patients with ejection fraction ≤35% implanted with an ICD endowed with an algorithm (ApneaScan) that calculates the RDI each night, were enrolled and followed-up for 24 months. The weekly mean RDI value was considered, as calculated during the entire follow-up period. The endpoint was daily AF burden of ≥6 hours. Results 164 patients (age 67±10 years, 75% male, ejection fraction 29±5%) had usable RDI values during the entire follow-up period. Body mass index (BMI) was <25 kg/m2 in 62 patients (normal), 25.0–29.9 kg/m2 in 66 patients (overweight), ≥ 30 kg/m2 in 36 patients (obese). When compared with normal patients (31±11 episodes/h), the average RDI value calculated during the entire follow-up period did not differ in overweight patients (35±13 episodes/h, p=0.114), but was significantly higher in obese patients (39±12 episodes/h, p=0.002). During follow-up, AF burden ≥6 hours/day was documented in 48 (29%) patients (BMI ≥ versus <25 kg/m2; HR: 1.47, 95% CI: 0.83–2.60, p=0.197; BMI ≥ versus <30 kg/m2; HR: 0.98, 95% CI: 0.46–2.09, p=0.963). Based on the ROC curve analysis, average RDI ≥37 episodes/h maximized sensitivity and specificity for the prediction of AF (Area under the curve: 0.63, 95% CI: 0.55–0.70, p=0.011). Device-detected RDI ≥37 episodes/h was associated with the occurrence of AF on univariate analysis (HR: 3.88, 95% CI: 2.02–7.44, p<0.001), as well as after correction for either BMI ≥25 kg/m2 (HR: 3.76, 95% CI: 1.94–7.26, p<0.001), or BMI ≥30 kg/m2 (HR: 4.15, 95% CI: 2.15–8.04, p<0.001). Conclusions In heart failure patients, we confirmed the association between ICD-detected SA and AF, an association that persisted independent of patient body habitus. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): The study is supported by a research grant from Boston Scientific

0786 Assessing the Adequacy of Auto Titrating Positive Airway Pressure Treatment in Patients with Severe Obstructive Sleep Apnea Diagnosed on Home Sleep Testing

Abstract Introduction Auto titrating positive airway pressure (Auto-PAP) therapy has been increasingly prescribed to treat obstructive sleep apnea (OSA) without reliance on in-laboratory PAP titration studies. Given the current pandemic and the limited use of in laboratory titrations, Auto-PAPs have been prescribed increasingly. The ability to achieve optimal control of obstructive events with Auto-PAP for patients with severe OSA (respiratory disturbance index (RDI) >30/hour of recording) on home sleep apnea testing (HSAT) has not been systematically investigated. Our study looks at the success of treatment on Auto-PAP in patients diagnosed with severe OSA on HSAT. Methods We retrospectively reviewed charts of patients who were diagnosed with severe OSA on HSAT and were prescribed an Auto-PAP at the Memorial Hermann – Texas Medical Center Sleep Disorders Center between September 2019 and May 2020. The usage data, residual AHI and adherence was assessed. Successful treatment was determined as a residual AHI (rAHI) <15. We excluded patients those who were non-adherent to PAP therapy. This study was conducted as a quality improvement initiative at our institution. Results We identified 24 patients diagnosed with severe OSA on HSAT and prescribed Auto-PAP. Nine patients were excluded due to non-adherence to Auto-PAP (37%). Of the remaining 15 patients, 80% were male, the average age was 53.7 years (range 36-69) and the average RDI on HSAT was 51.4 events/hour (SD 17.1). The average usage >4 hours was 76% in the adherent patients. The median pressure on Auto-PAP was 9 cm H2O (range 5.3-16.3). The average rAHI of 1.8 events/hour (range 0.3- 6.1). Usage data revealed only 1 patient with rAHI>5 and central apnea index of 3.9, who was then referred for an in-lab PAP titration study. Conclusion Sensors in the airway circuit of PAP devices measure airflow, vibration, and flattening of the airflow profile. Auto-adjusting PAP devices use this feedback to make online adjustments in pressure to maintain upper airway patency. Our study suggests that Auto-PAP is an effective initial therapy even for severe OSA, permitting both timely and adequate control of OSA especially when in laboratory titrations are limited. Close monitoring is however recommended to ensure adherence, and also to assess the potential emergence of central events. Support (If Any)

Implantable defibrillator-computed respiratory disturbance index predicts new-onset atrial fibrillation: the DASAP-HF study

Abstract Introduction Sleep apnea (SA), as measured by polysomnography, is a risk factor for atrial fibrillation (AF). The DASAP-HF study previously demonstrated that the Respiratory Disturbance Index (RDI) computed by an implantable cardioverter defibrillator (ICD) algorithm accurately identifies severe SA, is associated with cardiovascular events, and independently predicts death. Purpose In the present analysis we tested the hypothesis that device-detected RDI could also predict AF burden. Methods Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed-up for 24 months. One month after implantation, patients underwent a polysomnographic study. The weekly average RDI value was considered, as calculated by the algorithm during the entire follow-up period and over a 1 week period preceding the sleep study, and patients were stratified according to an RDI value ≥ or <30 episodes/hour. The endpoints were: daily AF burden of ≥5 minutes, ≥6 hours, ≥23 hours. Results 164 enrolled patients had usable RDI values during the entire follow-up period. Severe SA (RDI≥30 episodes/h) was diagnosed in 92 (56%) patients at the time of the polysomnographic study. During a median follow-up of 25 months, AF burden ≥5 minutes/day was documented in 70 (43%), ≥6 hours/day in 48 (29%), and ≥23 hours/day in 33 (20%) patients. Device-detected RDI≥30 episodes/h at the time of the polysomnographic study, as well as the polysomnography-measured apnea hypopnea index ≥30 episodes/h, were not associated with the occurrence of the endpoints, using a Cox regression model. However, using time-dependent Cox model continuously measured weekly average RDI≥30episodes/h was independently associated with AF burden ≥5 minutes/day (HR: 2.13, 95% CI: 1.24–3.65, p=0.006), ≥6 hours/day (HR: 2.75, 95% CI: 1.37–5.49, p=0.004), and ≥23 hours/day (HR: 2.26, 95% CI: 1.05–4.86, p=0.037), after correction for history of AF, left atrial diameter, and gender. Conclusions In heart failure patients implanted with an ICD, device-diagnosed severe SA is associated with a higher risk of AF. In particular, severe SA on follow-up data review identifies patients who are from two- to three-fold more likely to experience an AF episode, according to various thresholds of daily AF burden. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Promoted by the Italian Heart Rhythm Society (AIAC).Supported by a research grant from Boston Scientific.

ICD-detected respiratory disturbance index: accuracy for sleep apnea detection and prognostic value

Abstract Purpose In patients affected by heart failure an association exists between sleep apnea (SA) measured by polysomnography and adverse outcome. Impedance-based implantable cardioverter defibrillator (ICD) algorithms have been designed to compute the Respiratory Disturbance Index (RDI) to identify severe SA. The purpose of the DASAP-HF study was to evaluate the accuracy of RDI for the prediction of severe SA, and investigate the prognostic value of device-detected RDI values. Methods Patients with left ventricular ejection fraction ≤35% implanted with an ICD were enrolled and followed for 24 months. One month after implantation, patients underwent a polysomnographic study (PS) for assessing the apnea-hypopnea index (AHI). The average RDI value was calculated over a 1-week period preceding the sleep study and compared with the assessment of severe SA at PS (AHI ≥30 episodes/h). The endpoint was all-cause death after 24 months. Results 224 out of 265 enrolled patients had usable RDI values. Patients characteristics: 79% male, 67±10 years, BMI 27±7kg/m2, ejection fraction 29±5%, 54% ischemic cardiomyopathy, 50% CRT-D. The mean AHI value at PS was 21±15 episodes/h. The mean RDI value recorded during the week preceding PS was 30±16 episodes/h. RDI values accurately identified severe SA diagnosed at PS (AUC 0.77; 95% CI 0.70–0.83; P=0.001). Based on the ROC curve analysis, RDI ≥29 episodes/h and AHI ≥17 episodes/h maximized sensitivity and specificity for the prediction of death. Both indexes were independently associated with all-cause death but, after correction for the other independent significant prognostic variables, RDI≥29episodes/h yielded stronger prediction (HR: 12.22, 95% CI:1.64–91.37, p=0.015) as compared to AHI ≥17episodes/h (HR: 4.14, 95% CI:1.17–14.66, p=0.028). Moreover, severe SA diagnosed at PS (AHI ≥30episodes/h) was not associated with death (HR: 1.20, 95% CI:0.3817–3.8266, p=0.761). Conclusions In heart failure patients indicated to ICD, severe SA was confirmed to be associated with survival. The ICD-measured RDI accurately identified severe SA detected at PS, and was associated with the risk of death at long-term. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Boston Scientific

Incidence of sleep apnea and association with atrial fibrillation in an unselected pacemaker population: Results of the observational RESPIRE study

Patients with atrial fibrillation (AF) often have sleep apnea (SA), but diagnosis of SA with polysomnography is costly. SA monitoring is a pacemaker feature that measures respiratory disturbance index, the sum of abnormal respiratory events divided by sleep duration. The purpose of this study was to evaluate the incidence and severity of SA and its association with AF in an unselected population fitted with pacemakers. RESPIRE (REgistry of Sleep APnea monItoring and Atrial Fibrillation in pacemakeR patients) was a multicenter, international, observational, open-label study following adult subjects for 18 months after implantation with an SA monitoring-enabled dual-chamber pacemaker. Severe SA was defined as average respiratory disturbance index ≥20 from implantation to follow-up visit. The first co-primary end point was the difference in significant AF (cumulative AF episodes lasting ≥24 hours over 2 consecutive days) between subjects with severe and those nonsevere SA at 12 months in the full analysis set (N = 553). The second co-primary end point was the rate of major serious adverse events at 18 months in the modified intention-to-treat set (N = 1024). Severe SA was detected in 31.1% (172 of 553). A higher incidence of significant AF was reported in patients with severe SA than in patients with nonsevere SA (25.0% vs 13.9%; difference 11.1%; 95% confidence interval 3.7%-18.4%; P = .002). Significant AF increased with time in both groups, but at a faster rate in the severe SA group. No intergroup difference in the overall rate of major serious adverse events was observed (P = .065). SA screening over 12 months identified severe SA in almost one-third of unselected patients fitted with pacemakers. Severe SA was associated with a higher incidence of significant AF.

Variability of Sleep Apnea Severity and Risk of Atrial Fibrillation: The VARIOSA-AF Study.

This study sought to determine night-to-night variability in the severity of sleep-disordered breathing (SDB) and the dynamic intraindividual relationship to daily risk of incident atrial fibrillation (AF) by using simultaneous long-term day-by-day SDB and AF monitoring. Night-to-night variability in SDB severity may result in a dynamic exposure to SDB related conditions impacting the timing and extent of cardiovascular responses. This study was an observational cohort study. Daily data for AF burden and average respiratory disturbance index (RDI) were extracted from pacemakers capable of monitoring nightly SDB and daily AF burden in 72 patients. Nightly RDI values were grouped into quartiles of severity within each patient. AF burdens of >5 min, >1 h, and >12 h were the outcome variables. A total of 32% of patients had a mean RDI of≥20/h, indicative of overall severe SDB. There was significant night-to-night variation in RDI reflected by an absolute SD of ±6.3 events/h (range 2 to 14 events/h) within any givenpatient. Within each patient, the nights with the highest RDI (in their highest quartile) conferred a 1.7-fold (1.2to2.2; p<0.001), 2.3-fold (1.6 to 3.5; p< 0.001), and 10.2-fold (3.5 to 29.9; p< 0.001) increase risk of having atleast 5 min, 1h, and 12 h, respectively, of AF during the same day compared with the best sleep nights (in their lowestquartiles). There is considerable night-to-night variability in SDB severity which cannot be detected by 1 single overnight sleep study. SDB burden may be a better metric with which to assess the extent of dynamic SDB related cardiovascular responses such as daily AF risk than the categorical diagnosis of SDB. (Night-to-Night Variability in Severity of Sleep Apnea and Daily Dynamic Atrial Fibrillation Risk [VARIOSA-AF]; ACTRN 12618000757213).

Adjustable Minimally Invasive Hyoid Myotomy and Suspension with Uvulopalatopharyngoplasty for the Treatment of Obstructive Sleep Apnea

Objectives: Examine the efficacy of minimally invasive hyoid myotomy and mandibular suspension with adjustable tensioning for hypopharyngeal obstruction in conjunction with uvulopalatopharyngoplasty in the surgical treatment of obstructive sleep apnea. Methods: Retrospective chart review in a private practice. Twenty consecutive patients with multilevel obstructive sleep apnea over a 12-month period were included. Patients underwent hyoid myotomy and suspension and uvulopalatopharyngoplasty with or without tonsillectomy either staged or performed at the same time for those patients who had not undergone uvulopalatopharyngoplasty previously. The hyoid was suspended to the posterior surface of the mandible using the Siesta Encore system and desired tension set through a single small submental incision. Patients underwent clinical examination and sleep study prior to surgery and approximately 3 months postoperatively. The primary outcome was a successful surgical result, defined as respiratory distress index lower than 20, and 50% or greater decline in respiratory distress index, and no oxygen desaturations below 85% on the postoperative sleep study. Results: Nineteen (95%) of 20 patients achieved a successful outcome. The average preoperative respiratory disturbance index (RDI) was 52.7. The average postoperative RDI was 11.8 ( P &lt; .005). The average preoperative body mass index was 27.3. The average decrease in the RDI was 78%. All patients in the study reported clinical improvement of symptoms. There were 2 minor wound complications and no major complications. Conclusions: For patients with multilevel obstructive sleep apnea, minimally-invasive mandibular hyoid suspension appears to be highly efficacious for the treatment of hypopharyngeal airway obstruction when performed in conjunction with uvulopalatopharyngoplasty.

Overlap syndrome: an indication for sleep studies?

The coexistence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary diseases (COPD) is known as overlap syndrome (OS); it occurs in 10-20% of patients with OSA. Patients with OS have a higher risk of pulmonary hypertension and worse nocturnal hypoxemia than those with either disease alone. Differences may be seen according to severity of COPD, anthropometric measures, and polysomnography (PSG) features of patients. Recent studies have suggested that long-term use of continuous positive airway pressure for OSA is associated with worsening of coexistent COPD. This stresses the importance of identifying this subgroup of patients in order to provide adequate therapy. This study aims to describe the presence of OS among subjects at our institution and study its association to daytime hypercapnia, nocturnal hypoxemia, and severity of OSA and of COPD. We reviewed the records of patients who underwent PSG and pulmonary function test (PFT) at our center since 2002. Data gathered from PSG and PFTs included respiratory disturbance index (RDI), apnea index, lowest nocturnal desaturation, forced expiratory volume in 1 s (FEV1), FEV1/forced vital capacity ratio, arterial blood gasses, and anthropometric measures. Five hundred forty-seven records were reviewed, but only 73 met all inclusion criteria for analysis. Thirty-six patients had COPD, 52 had OSA, and 29 had OS. The mean predicted FEV1 percent of all subjects was 80%, and the mean diurnal partial pressure of carbon dioxide (pCO(2)) was 39 mmHg. There were no significant differences in average pCO(2) or RDI between subjects with OSA and OS. In all subjects, hypercapnia significantly correlated with worse RDI (p = 0.01) and with worse nocturnal desaturation (p = 0.01). During rapid eye movement (REM) sleep, those with FEV1 less than 80% predicted had higher RDI than those with higher FEV1 (p = 0.010). In these preliminary results, the prevalence of OS in our population is similar to that previously reported. Daytime hypercapnia correlated with the more severe sleep-disordered breathing (SDB) and worse nocturnal hypoxemia in all subjects. Severity of obstructive ventilatory impairment is associated with worse SDB during REM sleep. Randomized trials to determine if PSGs are indicated in all patients with severe COPD should be considered. This is an ongoing study.

Mandibular Midline Bicortical Bone Screw: An Adjunct to Genioglossus Insertion Advancement

Genioglossus insertion advancement was reported by Riley et al 1 Riley R.W. Powell N.B. Guilleminault C. Obstructive sleep apnea syndrome: A surgical protocol for dynamic upper airway reconstruction. J Oral Maxillofac Surg. 1993; 51: 742 Abstract Full Text PDF PubMed Scopus (178) Google Scholar in 1993 to be 70% to 80% successful in treating mild to moderate obstructive sleep apnea syndrome. To date, we have performed 17 genioglossus insertion advancements in our office. The average preoperative respiratory disturbance index (RDI) was 33.5, and the average postoperative RDI was 16.7, for an average decrease of 16.8.

Reduced renal function and sleep-disordered breathing in community-dwelling elderly men

Background Sleep-disordered breathing (SDB) may increase the risk of cardiovascular disease (CVD) and death in chronic kidney disease (CKD). However, the association between mild reductions in renal function and SDB is uncertain. Methods We studied 508 community-dwelling men aged ⩾67 years (mean 76.0 ± 5.3) who were enrolled at the Minnesota site for the Minneapolis center of the Outcomes of Sleep Disorders in Older Men (MrOS) sleep study and had serum cystatin-C and creatinine measured coincident with overnight polysomnography. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m 2 using Cockcroft–Gault (CG), modification of diet in renal disease (MDRD) and Mayo Clinic formulae. SDB was defined by a respiratory disturbance index (RDI) ⩾15 events/h. Results Mean cystatin-C was 1.21 ± 0.30 mg/L, and mean creatinine was 1.09 ± 0.23 mg/dL. Median RDI was 7.0 events/h (range 0–73). Higher quartiles of cystatin-C were associated with higher mean RDI ( p for trend = 0.007). This association persisted after adjustment for age and race ( p for trend = 0.03), but not after adjustment for body mass index (BMI, p for trend = 0.34). After adjusting for age, race, BMI, diabetes, hypertension, and CVD, CKD defined by the Mayo Clinic formula, but not CG or MDRD, was associated with a higher odds of SDB [odds ratio (OR) 1.95, 95% confidence interval (CI) 1.04–3.65, p = 0.04]. Conclusions Older men with reduced renal function as defined by higher cystatin-C concentration have higher average RDI. This effect is explained by higher BMI in men with higher cystatin-C. CKD defined by the Mayo Clinic formula is independently associated with twofold higher odds for SDB. Therefore, reduced renal function may be associated with SDB in older men.

Bariatric surgery for treatment of sleep apnea syndrome in 15 morbidly obese patients: Long-term results

Objective: To evaluate the long-term outcomes of bariatric surgery with respect to respiratory disturbance index (RDI) in sleep apnea syndrome (SAS). Design: Case series with long-term follow-up (1 to 12 years). Setting: Private clinic in an academic tertiary referral center. Patients: Fifteen morbidly obese patients (10 men, 5 women) who were referred for the treatment of severe SAS. Intervention: For all 15 patients who presented with severe SAS, nasal positive airway pressure breathing was either not available or was not tolerated by the patient; therefore, bariatric surgery was performed as a means of treatment for SAS. Main outcome measures: RDIs and minimum oxygen saturation were measured both preoperatively and postoperatively (1 to 12 years after surgery). Results: Weight loss ranged from 60 to 220 pounds (27 to 100 kg). RDI decreased by at least 55% in each patient, and all patients with tracheostomies (8 of 15) had their tracheostomy tubes removed. Average RDI preoperatively was 96.9 and average RDI postoperatively was 11.3. Results were similar for all 15 patients in that minimum oxygen saturation increased during sleep from an average preoperative minimum oxygen saturation of 58.7% to an average postoperative minimum oxygen saturation of 85.2%. Conclusions: Bariatric surgery as a means of treating SAS in the morbidly obese provides effective long-term reduction in RDI. Bariatric surgery also significantly improves minimum oxygen saturation in morbidly obese patients with SAS. Biliopancreatic bypass is more effective in reducing RDI to normal values than vertical banded gastroplasty. (Otolaryngol Head Neck Surg 2001;125:299-302.)

Postoperative treatment of the patient with obstructive sleep apnea

Objective: The postoperative management of patients with obstructive sleep apnea syndrome (OSAS) has been based primarily on the potential loss of the airway. Our hypothesis is that not all patients with OSAS require placement in the intensive care unit after surgery. Methods: We undertook a prospective, nonrandomized study (N = 38). Data included demographics, polysomnograms, body mass index (BMI), and postoperative course, including any complications within 72 hours. Results: The average respiratory disturbance index was 66, and the average BMI was 29. The average preoperative and postoperative maximal arterial oxygen desaturation values were 82% and 94%, respectively. Patients with BMIs less than 35 did not have desaturation values below 90%. No complications occurred. Discussion: Within the first 72 hours after surgery, no complications were observed in our study groups. Patients with BMIs greater than 35 were at increased risk for postoperative desaturations. The uncomplicated OSAS patient, one without significant comorbid factors, can be treated in a safe and prudent fashion outside of an intensive care unit. (Otolaryngol Head Neck Surg 2000;122:233-6.)