Fig. 2

TP group. Step 1: Advance the needle 0.5 cm post-flashback to penetrate the posterior wall. Withdraw the inner needle. Step 2: Connect the catheter to the sensor tube. Open the 3-way stopcock collar to align the cannula with atmospheric pressure. Step 3: Withdraw slowly until arterial blood reflux. Immediately close the stopcock to atmosphere. Step 4: Lower the catheter to a 15° angle and advance it fully into the arterial lumen. Connect the IBPM module.