Impedance plethysmography as a screening procedure for asymptomatic deep venous thrombosis in a rehabilitation hospital.

Abstract

Patients admitted for an inpatient rehabilitation treatment program almost uniformly have an elevated risk of deep venous thrombosis (DVT) and pulmonary embolism (PE). We assessed the value of impedance plethysmography (IPG) as a screening procedure for asymptomatic deep venous thrombosis in a series of patients admitted to our institution. Using a prospective observational study design, consecutive admissions to our facility for a period of almost one year were subjected to IPG within several days of admission. The study site was a 60-bed hospital-based rehabilitation center. Four hundred eighty-three consecutive patients were studied prospectively within several days of admission. Diagnoses included a variety of neurological disorders that resulted in significant weakness, intracranial surgery, orthopedic surgical procedures and fractures, joint replacements, and nonorthopedic postsurgical deconditioning. Three hundred eighteen patients were available for three-month follow-up. IPG was successfully completed in 301 patients. If IPG was positive, DVT was further assessed by duplex ultrasound (DU). When IPG and DU confirmed the presence of a DVT, administration of heparin and Coumadin was begun. Thirteen of 416 attempted IPG studies were positive for DVT, whereas DU confirmed the diagnosis in only 3 patients. Follow-up found that six patients developed DVT or PE before discharge from our institution; five patients developed DVT or PE after discharge. IPG has a poor yield as a screening tool for asymptomatic DVT on admission to an inpatient rehabilitation facility. The sensitivity and positive predictive value of IPG was too low to advocate its routine use in this setting.