A pilot study: portable out-of-center sleep testing as an early sleep apnea screening tool in acute ischemic stroke

Abstract

IntroductionPrompt diagnosis of obstructive sleep apnea (OSA) after acute ischemic stroke (AIS) is critical for optimal clinical outcomes, but in-laboratory conventional polysomnograms (PSG) are not routinely practical. Though portable out-of-center type III cardiopulmonary sleep studies (out-of-center cardiopulmonary sleep testing [OCST]) are widely available, these studies have not been validated in patients who have recently suffered from AIS. We hypothesized that OCST in patients with AIS would yield similar results when compared to conventional PSG.MethodsPatients with AIS had simultaneous type III OCST and PSG studies performed within 72 hours from symptom onset. The accuracy of OCST was compared to PSG using: chi-square tests, receiver operatory characteristic curves, Bland–Altman plot, paired Student’s t-test/Wilcoxon signed-rank test, and calculation of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).ResultsTwenty-one out of 23 subjects with AIS (age 61±9.4 years; 52% male; 58% African-American) successfully completed both studies (9% technical failure). Nearly all (95%) had Mallampati IV posterior oropharynx; the mean neck circumference was 16.8±1.6 in. and the mean body mass index (BMI) was 30±7 kg/m2. The apnea hypopnea index (AHI) provided by OCST was similar to that provided by PSG (19.8±18.0 vs 22.0±22.7, respectively; P=0.49). On identifying subjects by OCST with an AHI ≥5 on PSG, OCST had the following parameters: sensitivity 100%, specificity 85.7%, PPV 93%, and NPV 100%. On identifying subjects with an AHI ≥15 on PSG, OCST parameters were as follows: sensitivity 100%, specificity 83.3%, PPV 81.8%, and NPV 100%. Bland–Altman plotting showed an overall diagnostic agreement between OCST and PSG modalities for an AHI cutoff >5, despite fine-grained differences in estimated AHIs.ConclusionCompared with PSG, OCST provides similar diagnostic information when run simultaneously in AIS patients. OCST is a reliable screening tool for early diagnosis of OSA in AIS patients.

Prevalence and Determinants of Sleep Apnea in Patients with Stroke: A Meta-Analysis

“…49 Recent studies reporting the feasibility of portable PSG screening in patients with stroke/TIA also support the recommendation of quick OSA screening in both inpatient and outpatient settings. 20,50,51 In this study, we were unable to elucidate the pathological mechanisms to account for the differences in sleep apnea prevalence across different stroke subtypes, etiology, and location. Future studies reporting the prevalence of sleep apnea in stroke patients should also consider reporting details of the etiological subtypes and location of stroke.…”

Oximetry as an Accurate Tool for Identifying Moderate to Severe Sleep Apnea in Patients With Acute Stroke

“…23 Although prior studies have proposed HSAT as a reliable screening tool for acute ischemic stroke, widespread implementation of HSAT would require significant resources that smaller community facilities may not have access to. 24 As demonstrated in our study, oximetry offers an attractive and accurate alternative to HSAT. Because of its cost effectiveness and lack of extensive training required for acquisition of reliable data, nocturnal oximetry may be more practical to implement on a wider scale.…”

Sleep for Stroke Management and Recovery Trial (Sleep SMART): Rationale and methods

“…For example, the gold standard of in-laboratory polysomnography is not used in Sleep SMART to identify obstructive sleep apnea, as this approach is often poorly tolerated in the AIS setting, may be logistically challenging during hospitalization, and is not necessary to identify AIS patients with obstructive sleep apnea. 15 Home sleep apnea tests effectively identify obstructive sleep apnea after stroke 16,17 ; moreover, these devices have been commonly used in post-stroke research. The Nox T3 TM device used in Sleep SMART has been validated against full polysomnography 10,11 and has advantages over some other portable sleep apnea tests in that it has both abdominal and thoracic abdominal effort belts, and uses respiratory inductance plethysmograph technology.…”