Abstract
Clinically, most recorded blood pressure waves are spiky. Then the blood pressure values are misread (high systoric blood pressure). Usually accepted main reason of this is due to feature of the catheter. But we demonstrated small air bubbles in the catheter change the pressure wave more than catheter itself. We analized direct blood pressure monitoring kits, long (for operating room) and short (for ICU) one with indwelling catheter. The latter had good frequency characteristics and less probability of air mingling, so we should select short catheter kit. Frequency characteristics of flush devices were good exept Cutter's one (count for little clinically).
