Most patients with sleep apnea who have had a diagnosis and a whistler pressure test done at a regular hospital and wear the whistler as prescribed by their doctor do well in over 90% of cases. However, some patients have poorly adjusted initial whistler pressure titration and need to repeatedly redo the manual titration before wearing the whistler. It is also important to check the airway of the patient wearing the whistler. Some patients have a heavy whistle pause, but his own airway is wide and just collapses into a completely airtight lumen at night when he sleeps; some patients have a narrow airway that collapses to airtightness even when they sleep. Monitoring these two types of patients will reveal that the severity of the whistling pause is the same, but who is better suited to wear the whistler? Obviously the patient with the wide airway. In patients with wide airways, the collapsed tissues are loose and the air pressure of the whistler can displace these tissues; in patients with narrow airways, there is little room for tissue displacement and only a small amount of swelling can be squeezed out of the blood vessels after congestion, which may also interfere with the venous return to the head, so such patients are not suitable for wearing a whistler and are more suitable for surgery to widen the narrow airway. Patients with severe airway obstruction but easily displaced tissues are best suited to wear a whistler.