An improvement in whole body plethysmography

A simple method for greatly reducing thermal drift and acoustic noise in constant-volume, whole body plethysmography is described. Evaluation and adjustment for any particular clinical application can be carried out in a few moments. The device itself consists of a 20- to 25-gauge needle, a "Y" tube, and a 1-liter or more vessel, and may be assembled in 30 minutes from parts readily available in any hospital laboratory.