Arterial cannulation is commonly required in perioperative settings for continuous blood pressure monitoring and arterial blood gas analysis. The radial artery is most commonly used however alternative sites may be required when radial artery cannulation is not feasible or contraindicated. Posterior tibial artery is an established alternative site. The first dorsal metatarsal artery is another potential site with good collateral circulation but has not been well studied.

This prospective randomized controlled trial aims to compare ultrasound guided cannulation of the first dorsal metatarsal artery versus the posterior tibial artery in adult patients undergoing elective surgeries. Adult patients aged eighteen years or older requiring arterial cannulation will be randomized into two groups. One group will undergo ultrasound guided first dorsal metatarsal artery cannulation and the other group will undergo ultrasound guided posterior tibial artery cannulation.

The primary outcome is first attempt success rate of arterial cannulation. Secondary outcomes include number of attempts to cannulate cannulation failure rate total procedure time and incidence of complications such as ischemia bleeding thrombosis and hematoma. The study aims to evaluate whether first dorsal metatarsal artery can be a reliable alternative to posterior tibial artery for arterial cannulation in adult patients.