Monitoring low blood pressure. A non-invasive technique

Surgical procedures frequently warrant the use of hypotensive anaesthesia, yet the nature of the surgical procedure may not require intra-arterial monitoring of blood-pressure which is associated with a significant incidence of hazards. An ultrasonic technique is described which is convenient and without complication and which may be employed when intra-arterial cannulation is difficult or undesirable as, for example, in the neonatal case.