UPPER EXTREMITY IMPEDANCE PLETHYSMOGRAPHY IN PATIENTS WITH VENOUS ACCESS DEVICES

Central venous access devices (VADs) are often associated with thrombo tic obstruction of the axillary-subclavian venous system. To explore t he accuracy of impedance plethysmography (IPG) in identifying this com plication we performed IPG on 35 adult cancer patients before their VA Ds were placed and approximately 6 weeks later. At the time of the sec ond IPG the patients also underwent contrast venography of the axillar y-subclavian system. The venograms revealed partial venous obstruction in 12 patients (34%) and complete obstruction in two (5.7%). Although the IPG results from venographically normal and abnormal patients ove rlapped extensively, mean measurements of venous outflow were signific antly lower in the patient population with abnormal venograms (P = 0.0 52 for Vo; P = 0.0036 for Vo/Vc). In our hands, therefore, upper extre mity IPG cannot be used to make clinical decisions about individual pa tients with VADs, but it can distinguish venographically normal and ab normal populations.