Time course of beat-by-beat error measurement associated with continuous non invasive monitoring of arterial blood pressure by the Finapres device, has been analyzed during short-term (up to 7 min) recordings either at rest (stationary conditions) or after phenylephrine injection (dynamic conditions) in 22 post-myocardial infarction patients. The equipment set point Self-Adjustment was deactivated during recordings. The systematic and random components of the error have been estimated over one min consecutive intervals for systolic and diastolic pressure. Long-term (> 20 min) reproducibility has been assessed as well. Quite a stable performance has been found during short-term stationary conditions associated to a high interpatients variability of systematic error and to a not negligible random error. A slight drift of systematic error, either for systolic or diastolic pressure, has been detected in long-term analysis. During dynamic conditions a significant difference in accuracy, between the first and second min after phenylephrine injection associated with a global loss of stability, has been observed during short term recordings consistent over the long-term period.

Thus, while effective in stationary recordings despite Self-Adjustment disconnection, Finapres performance should be considered cautiously during dynamic evaluation.