Zero Arterial Catheters with Every Change in the Height Difference of Pressure Transducer and Catheter Insertion Site

After successful insertion, the arterial catheter must be zeroed before initiating hemodynamic monitoring.[1] This zeroing is performed by opening the pressure transducer stopcock to the atmosphere, allowing for measurement relative to atmospheric pressure.[1] During and after zeroing, the pressure transducer is positioned at the level of phlebostatic axis when measuring arterial pressure at the aortic root and at the level of the external auditory meatus when measuring arterial pressure at the circle of Willis.[1-4] It is essential to maintain the pressure transducer at the same level as the artery intended for pressure measurement. However, after zeroing, importance of keeping the transducer aligned with the level of the inserted artery is often overlooked. This practice should be avoided because zeroing the arterial catheter to atmospheric pressure may also inadvertently zero the height difference between the pressure transducer and catheter insertion site. Therefore, even when the pressure transducer is correctly positioned at the level of the target artery (such as aortic root or the circle of Willis), any changes in the angle or inclination of perioperative stretchers, intraoperative tables, or critical care beds may alter the height relationship between the pressure transducer and catheter insertion site (such as the radial artery or femoral artery). Consequently, measured arterial pressure may fluctuate, reflecting not only changes in transducer height but also in the height of catheter insertion site. Manufacturers also recommend maintaining a consistent angle for accurate trending of measured arterial pressures.[5] Therefore, it is essential not to overlook the need to re-zero arterial catheters whenever there is a change in the height difference between the pressure transducer and catheter insertion site; this re-zeroing can be easily performed by providers, immediately following any adjustment to the angle or inclination of perioperative stretchers, intraoperative tables, or critical care beds. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.