Use of the Air Plethysmograph in the Evaluation and Treatment of Patients with Venous Stasis Disease

BACKGROUND: Some patients with venous stasis disease require physiologic testing of venous function for complete evaluation prior to and/or after treatment. OBJECTIVE: To review basic uses of the air plethysmograph in evaluating patients with venous stasis disease. METHODS: The air plethysmograph can be used to quantitate obstruction, reflux, and the effectiveness of the calf muscle pump. RESULTS: Significant outflow obstruction is indicated by an outflow fraction of less than 35%. A venous filling index of 2 ml/second or greater indicates significant reflux. An ejection fraction of less than 40% is associated with poor calf muscle pump function. CONCLUSIONS: The air plethysmograph can be used in the evaluation of patients with venous stasis disease to quantify venous abnormalities of obstruction, reflux, and poor muscle calf pump function.