Faculty Bibliography

STUDY OBJECTIVE: A one-way nasal resistor has recently been shown to reduce sleep disordered breathing (SDB) in a subset of patients with Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS). The purpose of this study was to examine characteristics predictive of therapeutic response to the device and provide pilot data as to its potential mechanisms of action. PATIENTS, INTERVENTIONS, AND MEASUREMENTS: 20 subjects (15M/5F, age 54 +/- 12 years, BMI 33.5 +/- 5.6 kg/m(2)) with OSAHS underwent 3 nocturnal polysomnograms (NPSG) including diagnostic, therapeutic (with a Provent(R) nasal valve device), and CPAP. Additional measurements included intranasal pressures and PCO(2), closing pressures (Pcrit), and awake lung volumes in different body positions. RESULTS: In 19/20 patients who slept with the device, RDI was significantly reduced with the nasal valve device compared to the diagnostic NPSG (27 +/- 29/h vs 49 +/- 28/h), with 50% of patients having an acceptable therapeutic response. Among demographic, lung volume, or diagnostic NPSG measures or markers of collapsibility, no significant predictors of therapeutic response were found. There was a suggestion that patients with position-dependent SDB (supine RDI > lateral RDI) were more likely to have an acceptable therapeutic response to the device. Successful elimination of SDB was associated with generation and maintenance of an elevated end expiratory pressure. No single definitive mechanism of action was elucidated. CONCLUSIONS: The present study shows that the nasal valve device can alter SDB across the full spectrum of SDB severity. There was a suggestion that subjects with positional or milder SDB in the lateral position were those most likely to respond. CITATION: Patel AV; Hwang D; Masdeu MJ; Chen GM; Rapoport DM; Ayappa I. Predictors of response to a nasal expiratory resistor device and its potential mechanisms of action for treatment of obstructive sleep apnea. J Clin Sleep Med 2011;7(1):13-22

STUDY OBJECTIVES: We examined agreement among multiple sleep clinicians when presented with clinical data plus the full tracings and data obtained from unattended limited monitoring (ULM) or a full polysomnography (PSG). METHODS: Subjects included 66 patients with complaints of sleep disordered breathing (SDB) and 19 volunteers willing to undergo 2 nights of ULM followed by PSG. Two assessment packages were created for each subject with identical clinical history (Hx) and ARES Symptom Questionnaire, plus the electronic record of signals collected on the ARES Unicorder (Hx+ULM) or on the PSG (Hx+PSG). Data were presented to 4 sleep-trained clinicians for diagnosis and treatment recommendation. For agreement on diagnosis and treatment, comparisons were made between clinicians using ULM or PSG, and within clinicians comparing both techniques. RESULTS: For diagnosis, agreement between pairs of clinicians using Hx+PSG ranged from 74% to 86% and 66% to 85% when using Hx+ULM. For treatment, agreement using Hx+PSG ranged from 74% to 86% and 58% to 77% when using Hx+ULM. Agreement between clinicians was highest in the subjects with the highest RDI and fell off markedly at the lowest RDI, irrespective of whether the clinicians used the Hx+PSG or Hx+ULM. This pattern was also seen for the decisions made by an individual clinician using Hx+ULM vs. Hx+PSG. CONCLUSION: Our data show that sleep clinicians have significant disagreements for diagnosis even when presented with the 'gold standard' of a PSG and clinical data. Agreement was high when the SDB index was elevated and lower when the SDB index was in the mild-to-moderate range, regardless of the technique used to obtain it

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased perioperative risk, but the incidence of postoperative complications and the severity of OSA associated with increased risk have not been established. We investigated the relationship between intermittent hypoxemia measured by home nocturnal oximetry with the occurrence of postoperative complications in patients with clinical signs of OSA identified during preoperative assessment for elective surgery. METHODS: This study was performed at a tertiary care hospital. Home nocturnal oximetry was performed on elective surgical patients with clinical features of OSA. The number of episodes per hour of oxygen desaturation (or oxygen desaturation index) of > or = 4% (ODI4%) was determined. Subjects with five or more desaturations per hour (ODI4% > or = 5) were compared to those with less than five desaturations per hour (ODI4% < 5). Hospital records were reviewed to assess the incidence and type of postoperative complications. RESULTS: A total of 172 patients were investigated as part of this study. No significant differences were observed between groups in terms of age, body mass index, number of medical comorbidities, or smoking history. Patients with an ODI4% > or = 5 had a significantly higher rate of postoperative complications than those with ODI4% < 5 (15.3% vs 2.7%, respectively [p < 0.01]; adjusted odds ratio, 7.2; 95% confidence interval, 1.5 to 33.3 [p = 0.012]). The complication rate also increased with increasing ODI severity (patients with an ODI4% of 5 to 15 events per hour, 13.8%; patients with an ODI4% of > or = 15 events per hour, 17.5%; p = 0.01) Complications were respiratory (nine patients), cardiovascular (five patients), GI (one patient), and bleeding (two patients). The hospital length of stay was similar in both groups. CONCLUSION: An ODI4%> or = 5, determined by home nocturnal oximetry, in patients with clinical features of OSA is associated with an increased rate of postoperative complications