IEEE trans. biomed. eng. IEEE trans. biomed. eng. Acute Cardiorespiratory Coupling Impairment in Worsening Sleep Apnea-Related Intermittent Hypoxemia Hietakoste Salla Armañac-Julián Pablo Universidad de Zaragoza Karhu Tuomas Bailón Raquel Universidad de Zaragoza Sillanmäki Saara Töyräs Juha Leppänen Timo Myllymaa Sami Kainulainen Samu 2023 research-article