Objective: To evaluate blood samples obtained from a new blood-conserving arterial line system for the presence of hemodilution or heparin contamination.
Design: Prospective, clinical trial.
Setting: A coronary intensive care unit in a tertiary-care teaching hospital.
Patients: Cardiovascular patients in whom invasive arterial blood pressure monitoring was indicated.
Interventions: Paired blood samples were obtained from a conventional arterial line system and a new blood-conserving arterial line system for the measurement of hematocrit and partial thromboplastin time, and compared to evaluate for the presence of either hemodilution or heparin contamination.
Measurements and main results: A Bland-Altman bias analysis of the variability between the two blood draw methods was performed. The analysis indicated that a) a randomly determined partial thromboplastin time obtained from the blood-conserving arterial line would lie between 3.32 and -5.11 of the partial thromboplastin time taken from the conventional arterial line value with 95% confidence; and b) a randomly determined hematocrit obtained from the blood-conserving arterial line would lie between 1.97 and -1.85 of the hematocrit taken from the conventional arterial line value with 95% confidence.
Conclusions: We concluded that a) blood samples obtained with the blood-conserving arterial line demonstrate no evidence of hemodilution or heparin contamination; b) the blood-conserving arterial line provides blood samples without the need for an initial volume of blood to be discarded; c) the blood-conserving arterial line provides a means for blood conservation in the intensive care setting.