Figure 2

Waveform examples. Top, capnography; bottom, nasal pressure monitoring. Arrows (black) indicate the point of SpO2 < 90% in Patient #35 and SpO2 < 95% in Patient #37. Arrows (white) indicate obstructive respiratory disorder, revealing a flattened waveform pattern. No desaturation occurred after the second short period of apnea in patients #35.