Invasive arterial pressure monitoring and frequent blood gas analysis have become essential components for physiologic optimization and anesthesia management of emergency surgical procedures in patients presenting with major blood loss or sepsis. Radial artery is used commonly for cannulation as it is easily accessible and associated with less incidence of post-cannulation complications (1). Various techniques exist for arterial cannulation like the direct over-the-needle cannulation(2,3,4), guide-wire assisted catheterization(2,3,4), liquid stylet technique(5), and ultrasound-guided catheterization(6).

              Previous studies have shown that radial artery cannulation with guide-wire assistance was more successful compared to the direct technique in patients undergoing various cardiovascular and neurosurgical procedures in the elective set-up, done by staff anesthesiologists (3, 4). In the emergency surgical suite the arterial cannulations are mostly done by residents with limited experience and the direct cannulation is the most common technique employed. However the direct cannulation technique may be difficult in patients with low arterial pressure, requiring multiple attempts and causing considerable delay. The purpose of this study is to assess whether arterial cannulation can be achieved faster, with fewer attempts, using the guide-wire assisted technique.