At this point we decided to treat this patient with adaptive support ventilation (ASV), with positive expiratory pressure (PEP) support of 3–10 cm H₂O and an automatic positive airway pressure (APAP) of 8.0 cmH₂O.  Since this patient had an OSA before, only 8.0 cmH₂O would be expected to result in normal breathing, as shown in the improvement in his oximeter tracing on ASV (blue line) compared with his oximetry result when breathing room air (green line).