This is the first level one systematic review to demonstrate strong evidence for the use of ultrasound guidance in radial artery cannulation in adult and paediatric populations. In the adult population, ultrasound use significantly increased first-attempt success rate, which subsequently resulted in a significant reduction in the number of attempts. The benefits of ultrasound were also shown in the paediatric population, with a significant increase in first-attempt success rate and reduction in the number of attempts. The use of ultrasound as an adjunct to radial arterial cannulation should now be considered best practice.

Abstract. A 2D box model of the cochlea has been used to predict the basilar membrane, BM, velocity and the fluid flow caused by two components of bone conduction: due to inertia of the middle ear and due to inertia of the cochlear fluids. A finite difference approach has been used with asymmetric fluid chambers, that enables an investigation of the effect of varying window stiffness, due to otosclerosis for example. The BM is represented as a series of locally reacting single degree of freedom systems, with graded stiffness along the cochlea to represent the distribution of natural frequencies and with a damping representative of the passive cochlea. The velocity distributions along the passive BM are similar for harmonic excitation via the middle ear inertia or via the fluid inertia, but the variation of the BM velocity magnitude with excitation frequency is different in the two cases. Excitation via the middle ear is suppressed if the oval window is assumed to be blocked, but the excitation via the cochlear fluids is still possible. By assuming a combined excitation due to both middle ear and fluid excitation, the difference between the overall response can be calculated with a flexible and a blocked oval window, which gives a reasonable prediction of Carhart's notch.