CHEST August 2001 vol. 120 no. 2 625-633
With helpful figures:
http://www.chestjournal.org/content/120/2/625.full#F1
Respiratory patterns during a 3-min time period for a patient with OSA syndrome showing obstructive apneas with typical saw-tooth morphology of the pulse oximetry curve. Flowna = nasal and oral airflow; Respth = thoracic respiratory effort; Respabd = abdominal respiratory effort; Respsum = sum signal of thoracic and abdominal respiratory effort; O = obstructive apnea.
Respiratory patterns during a 3-min time period for a patient with OSA syndrome showing obstructive hypopneas with a more regular up-and-down waveform of the pulse oximetry curve. H = hypopnea; see Figure 1 legend for definition of abbreviations.