Ultrasound Guided Ulnar Versus Radial Artery in Pediatrics Undergoing Major Non Cardiac Surgery

"Ultrasound examination will be performed using a hockey stick, high frequency (5-10 MHz) ultrasound probe (S-NerveTM; SonoSite Inc., Bothell, WA, USA).~. Arterial cannulation will be performed using the long axis view (in-plane) technique with a 24 or 22-gauge canulae according to the operator preference. Cannulation will be considered complete when the arterial waveform is confirmed on the monitor. If cannulation is unsuccessful within the third attempt or within 10 min, the case will be considered a failure at the chosen artery. After the failure, an alternative site will be used for cannulation and the case will be excluded from the study."