Study Objectives: To evaluate the performance of a portable monitor (Nox-T3, Nox Medical Inc. Reykjavik, Iceland) used to diagnose obstructive sleep apnea in Chinese adults. Methods: Eighty Chinese adults (mean ± standard deviation age 47.6 ± 14.0 years, 77.5% males, body mass index 27.5 ± 5.4 kg/m 2 ) underwent overnight, unattended home sleep apnea testing (HSAT) with the Nox-T3 portable monitor followed by an overnight in-laboratory polysomnogram (PSG) with simultaneous portable monitor recording. The portable monitor recordings were scored using automated analysis and then manually edited using different criteria for scoring hypopneas. Polysomnography was scored based on recommended guidelines. Results: When scoring of hypopneas required a ≥ 4% oxygen desaturation event, the mean ± standard deviation apnea-hypopnea index (AHI) was 24.4 ± 20.8 events/h on HSAT, 28.0 ± 22.9 events/h on in-laboratory portable monitor recording, and 28.6 ± 23.9 events/h on PSG (P < .0001). Bland-Altman analysis of AHI on PSG versus HSAT showed a mean difference (95% confidence interval) of −4.64 (−7.15, −2.13); limits of agreement (equal to ± 2 standard deviations) was −26.62 to 17.35 events/h. Based on a threshold of AHI ≥ 5 events/h, HSAT had 95% sensitivity, 69% specificity, 94% positive predictive value, and 75% negative predictive value compared to PSG. Using an AHI ≥ 15 events/h, HSAT had 93% sensitivity, 85% specificity, 89% positive predictive value, and 91% negative predictive value. Closer agreements were present when comparing the simultaneous recordings. Similar results were obtained using different scoring criteria for hypopneas. Conclusions: Despite known differences between HSAT and PSG, the results show close agreement between the two diagnostic tests in Chinese adults, especially when controlling for night-to-night variability and changes in sleeping environment.

Study Objectives: Clinical practice guidelines recommend polysomnography (PSG) for diagnosis of obstructive sleep apnea (OSA) in patients with major comorbidities. We evaluated home sleep apnea testing (HSAT) using a type 3 portable monitor (PM, Nox-T3, Nox Medical, Reykjavik, Iceland) to diagnose OSA in adults with chronic obstructive pulmonary disease (COPD). Methods: Ninety adults with COPD (89.0% males, mean ± standard deviation age 66.5 ± 7.8 years, body mass index 27.5 ± 5.8 kg/m 2 , forced expiratory volume in the first second/forced vital capacity [FEV1/ FVC] 53.5 ± 12.4%, FEV1 54.0 ± 18.4% predicted) underwent unattended HSAT followed by an in-laboratory PSG with simultaneous PM recording. Results: Scoring hypopneas with a ≥ 4% oxygen desaturation, the apnea-hypopnea index (AHI) was 16.7 ± 20.6 events/h on HSAT, 20.0 ± 23.3 events/h on in-laboratory PM, and 21.2 ± 26.2 events/h on PSG (P < .0001). Bland-Altman analysis of AHI on HSAT versus PSG showed a mean difference (95% confidence interval) of −5.08 (−7.73, −2.42) events/h (P = .0003) and limits of agreement (± 2 standard deviations) of −30.00 to 19.85 events/h; HSAT underestimated AHI to a greater extent for more severe values (rho = −.529, P < .0001). Using an AHI ≥ 5 events/h to diagnose OSA, HSAT had 95% sensitivity, 78% specificity, 88% positive predictive value, and 89% negative predictive value compared to PSG. Mean oxygen saturation was 93.2 ± 3.7% on PSG, 91.0 ± 3.3% on in-laboratory PM, and 90.8 ± 4.0% on HSAT (P < .0001). Percentage time oxygen saturation ≤ 88% was 17.9 ± 26.4% on HSAT, 17.4 ± 25.5% on in-laboratory PM, and 10.0 ± 21.1% on PSG (P < .0001). Conclusions:The Nox-T3 PM can be used to diagnose OSA in patients with COPD but, most likely due to differences among pulse oximeters, a greater number of patients with COPD and without OSA qualified for nocturnal oxygen treatment using this PM than PSG.

Obstructive sleep apnea (OSA) is highly prevalent in patients undergoing total joint arthroplasty (TJA) and is a major risk factor for postoperative cardiovascular complications and death. Recognizing this, the American Society of Anesthesiologists urges clinicians to implement special considerations in the perioperative care of OSA patients. However, as the volume of patients presenting for TJA increases, resources to implement these recommendations are limited. This necessitates mechanisms to efficiently risk stratify patients having OSA who may be susceptible to post-TJA cardiovascular complications. We explore the role of perioperative measurement of cardiac troponins (cTns) and brain natriuretic peptides (BNPs) in helping determine which OSA patients are at increased risk for post-TJA cardiovascular-related morbidity.