Cutaneous and subcutaneous blood flow rates in paraplegic humans investigated by 133Xenon wash‐out. Methodological considerations

Abstract

In a methodological study including 14 paraplegics and seven normal controls cutaneous and subcutaneous blood flow rates were investigated by 133Xenon wash-out after atraumatic labelling. In paraplegics, areas suffering pressure sores were included. The method was found applicable for the authors' purposes. In seven paraplegics median (95% confidence limits) cutaneous blood flow was 5.2 (2.4-8.5) ml (100 g min)-1 and subcutaneous 4.3 (2.0-13.2) ml (100 g min)-1. This did not differ from normal controls. In seven paraplegics with ischial pressure sores a trend for increased cutaneous blood-flow rates from areas adjacent to sores was obvious (P = 0.06). During 70 degrees head-up tilt, elimination-rate constants were reduced by a factor of 0.54 (0.50-0.70). A proximal blockade or infiltration of the 133Xenon depots with lidocaine did not inhibit employment of the method. The proximal block did not alter the local blood flow rate, but infiltration increased it in both paraplegics and normal individuals. Intra- and interdepot coefficients of variation were about 11% and 40% respectively. Interindividual coefficients of variation varied between 25% and 46%.