One of the complications of catheterizations of the femoral artery for cerebral angiography is occlusion of this artery at the puncture site or the production of distal emboli and Jacobsson et al., (1969) quote the incidence of these as 0.2% to 8% with an amputation rate of between 0.003% to 0.0002%. One of the ways of reducing femoral artery morbidity is by monitoring the pulse distal to the puncture site. The technique of photople-thysmography has been known for over 30 years (Evans, 1944; Brown, 1967; Weinman, 1967, 1972) and although not widely accepted as a quantitative measure of blood pressure or volume, the method is useful when it is required to know the relative volume of blood present at any given time. We have used this technique to monitor peripheral circulation in the catheterized leg, using the non-catheterized leg as a control and our preliminary results indicate the value of this technique. The principle exploits the fact that living tissues are translucent to light, particularly in the i...
