University of Oulu

Huhtakangas, J. K., Saaresranta, T., Vähänikkilä, H., & Huhtakangas, J. (2022). Nocturnal hypoxemia and central apneas increase mortality, but not recurrent ischemic events after ischemic stroke. Sleep Medicine, 97, 1–9.

Nocturnal hypoxemia and central apneas increase mortality, but not recurrent ischemic events after ischemic stroke

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Author: Huhtakangas, Jaana K.1; Saaresranta, Tarja2; Vähänikkilä, Hannu3;
Organizations: 1Oulu University Hospital, Finland
2Division of Medicine, Dept of Pulmonary Diseases, Turku University Hospital and Sleep Research Centre, Dept of Pulmonary Diseases and Clinical Allergology, University of Turku, Turku, Finland
3Northern Finland Birth Cohorts, Arctic Biobank, Infrastructure for Population Studies, Faculty of Medicine, University of Oulu, Oulu, Finland
4Medical Research Center Oulu Brain Health, Oulu University Hospital, Research Unit of Clinical Neuroscience, Oulu University of Oulu, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.3 MB)
Persistent link:
Language: English
Published: Elsevier, 2022
Publish Date: 2022-12-07


Background: The aim of the study was to investigate whether findings in cardiorespiratory polygraphy had an association with stroke mortality or ischemic event recurrence after ischemic stroke.

Methods: We prospectively studied 204 ischemic stroke patients who underwent cardiorespiratory polygraphy within the first 48 h after the symptom onset. We followed all these patients for a median of 6.2 years. We evaluated mortality, time of survival, causes of death and new ischemic events.

Results: Of 204 ischemic stroke patients, 43 died and 48 had a new ischemic event during the follow-up. The lowest arterial oxyhemoglobin saturation (min SaO₂) (P = 0.007) was lower, the percentage of time spent below arterial oxyhemoglobin saturation less than 90% (T90) (P = 0.005) was higher, and central apnea index per hour (CAI/h) (P = 0.04) was higher among the deceased. Male gender, older age, diabetes mellitus, elevated modified Rankin scale (mRS) score, lower Glasgow Coma Scale (GCS) score and CAI/h independently predicted higher mortality. Peripheral arterial disease (PAD) and higher National Institutes of Health Stroke Scale (NIHSS) score were independent predictors for a recurrent ischemic event. Among those having respiratory event index (REI) at least 30, older age and lower GCS score independently predicted higher mortality. Only 21 stroke patients initiated continuous positive airway pressure (CPAP) treatment; of those, only one had a new ischemic event.

Conclusions: The non-survivors had more severe nocturnal hypoxemia and more central apneas than survivors. Among patients with REI at least 30/h, increased CAI predicted higher mortality, but not independently.

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Series: Sleep medicine
ISSN: 1389-9457
ISSN-E: 1878-5506
ISSN-L: 1389-9457
Volume: 97
Pages: 1 - 9
DOI: 10.1016/j.sleep.2022.05.014
Type of Publication: A1 Journal article – refereed
Field of Science: 3121 General medicine, internal medicine and other clinical medicine
Copyright information: © 2022 The Authors. This is an open access article under the CC BY license (