On the dynamic performance of the Abbott Safeset blood-conserving arterial line system

Objective. Critically ill patients frequently have indwelling arterial lines placed during their Intensive Care Unit stay. The lines are used to monitor blood pressure continuously, administer drugs and to draw blood for a variety of physiologic tests. Several blood-conserving arterial line systems have been developed to eliminate the need to discard blood in the process of obtaining undiluted and uncontaminated blood samples. The purpose of this study was to evaluate the dynamic performance of one such system – the Abbott Clinical Care System Safeset blood conserving arterial line system – in comparison to a conventional arterial line system. Methods. We studied ninety-nine patients who had indwelling arterial lines placed during surgery and who were admitted to our Surgical Intensive Care Unit (SICU). The patients were randomly placed into one of two groups. The control group received a conventional indwelling arterial line system; the experimental group received the Abbott Safeset system. We measured the damping coefficient and resonant frequency daily in order to evaluate and compare the dynamic performance of the two systems. We also measured discard volumes (in the control group) and blood sample sizes during the patients stays in the SICU. Results. The two patient groups were similar in regards to demographics and baseline clinical characteristics. A median 3 ml of blood per draw and 17.5 ml of blood per patient was discarded in purging the conventional arterial line system while, by design, no blood was discarded with the experimental system. There was no difference between the two groups with regard to damping coefficient. Both systems were underdamped. However, the conventional arterial line system had a significantly higher resonant frequency (16.7 Hz) compared to the Safeset system (12.5 Hz). Conclusions. Because the Abbott Safeset blood-conserving arterial line system is underdamped and has a lower resonant frequency compared to the traditional arterial system, it may overestimate systolic blood pressure, particularly in patients with high heart rates.