Unanticipated variations between expected and delivered pneumatic compression therapy after elective hip surgery - A possible source of variation in reported patient outcomes

The differences between the pneumatic compression thromboprophylaxis delive red after elective total hip arthroplasties and that was expected were quan tified before (49 patients) and after a concerted nursing education program (30 patients) that was designed to ensure maximum compliance and to verify the correct application or the devices. The expected therapy was not deliv ered to any of the patients monitored. Therapy was delivered only an averag e of 77.8% of the time during the expected treatment periods. During 99.9% of the expected therapy times, values of key outcomes-related parameters of the therapy delivered to the patients varied by >10% from expected values. These variations were not reduced significantly by medical and nursing edu cation. This variation may be a significant confounding factor in comparati vely evaluating thromboembolic disease outcome reports.