<unk>  normally triggers a reflex which increases breathing and access to oxygen (O2), such as arousal and turning the head during sleep. A failure of this reflex can be fatal, for example as a contributory factor in sudden infant death syndrome.<unk>  can induce increased cardiac output, an elevation in arterial blood pressure (higher levels of carbon dioxide stimulate aortic and carotid chemoreceptors with afferents -CN IX and X- to medulla oblongata with following chrono- and ino-tropic effects), and a propensity toward cardiac arrhythmias.<unk>  may increase pulmonary capillary resistance.
Hypercapnia
Hypocapnia
Acidosis
Alkalosis
Metabolic alkalosis
Hypoxemia
Metabolic acidosis
Hypoventilation