Images in Sleep MedicineApnea while awake
Section snippets
Summary
A 47-year-old woman was admitted for chronic hyperventilation-related complications, including loss of consciousness, muscle cramps and tetany with normal serum calcium levels. Her medical history excluded primary cardiovascular, endocrine, neurological or metabolic disorders. The resting arterial blood gases showed chronic respiratory alkalosis with metabolic compensation (pH=7.47, PaCO2=26.4 mm Hg, PaO2 =85.4 mm Hg, Base excess=−4.4 mmol/L, HCO3−=21.5 mmol/L). Polysomnography was performed, which
Image analysis
Fig. 1, Fig. 2.
Discussion
- 1.
Extreme hyperventilation can cause wake apneas secondary to severe hypocapnia. Another mechanism is seizures from cortical hypoperfusion [1].
- 2.
Hypocapnia can cause glottic closure during sleep, especially during the use of timed ventilatory support. In this subject, the airway seemed open at least during part of the apneas.
- 3.
The resolution of respiratory abnormality even during stage 1 sleep suggests a resetting of the apnea threshold. If this was not the case, sleep onset would have been
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- et al.
Apnea following hyperventilation in man
J Neurol Sci
(1982) The pathophysiology of hyperventilation syndrome
Monaldi Arch Chest Dis
(1999)