This prospective randomized study was designed to compare ultrasound guided technique with Doppler assisted technique for radial arterial cannulation in infant and small children.

In infants, percutaneous cannulation of radial artery requires considerable expertise. People have been using Doppler guided radial artery cannulation technique to improve success rate for more than 20 years. Recently, Ultrasound sonography has been utilized for central line placement in pediatrics. The purpose of this study is whether ultrasound guided radial artery cannulation technique improves the success rate compared to traditional doppler guided technique.

Inclusion Criteria:

• Inclusion criteria

  1. Pediatric patient undergoing scheduled major surgery which require continuous arterial pressure monitoring
  2. Term neonates and children < 4 years old weighing >/= 3 kg and < 12 kg

Exclusion Criteria:

• Exclusion criteria

  1. Patients with a skin wound or infection around puncture site
  2. Abnormal circulation in the hand (known vascular compromise, mottling, cool skin temp relative to other hand, poor capillary refill)
  3. Recent radial arterial puncture (less than 1 month)
  4. Any emergency surgery or profound hemodynamic instability requiring urgent arterial cannulation.