sighsmometer
A pneumatic-bellows-type device that is attached to a patient’s chest with Velcro straps, and is used to measure how deeply/evenly the patient is breathing.
If Ethan Couch had to lie still on a doctor’s exam-table for more than a few minutes, he would probably wear out the sighsmometer with all of his impatient wheezing and moaning about having to remain immobile for that long.