title: A pilot study: portable out-of-center sleep testing as an early sleep apnea screening tool in acute ischemic stroke.
abstract: BACKGROUND
  Prompt 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.
  
  
  METHODS
  Patients 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).
  
  
  RESULTS
  Twenty-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/m(2). 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.
  
  
  CONCLUSIONS
  Compared 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.
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: Oleg Y
authors.initials: OY
authors.lastname: Chernyshev
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: McCarty
authors.affiliation: Sleep Disorders Center, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Moul
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: Cesar
authors.initials: C
authors.lastname: Liendo
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: Gloria C
authors.initials: GC
authors.lastname: Caldito
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: Sai K
authors.initials: SK
authors.lastname: Munjampalli
authors.affiliation: Department of Neurology, Tulane University, New Orleans, LA, USA.
authors.forename: Roger E
authors.initials: RE
authors.lastname: Kelley
authors.affiliation: Division of Sleep Medicine, Department of Neurology, Louisiana State University Health Sciences Center at Shreveport, LA, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Chesson
keywords: acute ischemic stroke; acute sleep medicine; obstructive sleep apnea diagnosis; portable clinical screening; sleep testing in stroke