Comparison of two methods of measuring tracheal mucous velocity in anesthetized beagle dogs

Tracheal mucous velocity measurements were made in 6 beagle dogs using both Sackner's method of radiographing teflon discs and Chopra's method using a gamma camera to detect the movement of instilled labeled material. Dogs were anesthetized by intravenous injection of 30 mg of sodium pentobarbital/kg of body weight in case 1 after pretreatment with atropine and Innovar-Vet; in case 2, without the pretreatment. The mean velocities measured using the 2 techniques were significantly different in both cases: case 1, 3.7 +/- 3.3 mm/min for Sackner's methods and 7.5 +/- 3.7 mm/min for Chopra's method (p less than 0.001); case 2. 3.7 +/- 3.1 mm/min for Sackner's method, and 5.5 +/- 2.1 mm/min for Chopra's method (p less than 0.05). Systematic differences in velocities should be considered when comparing data from investigators using different techniques.