Evaluation of unaccountable phlebitis with the long arm silastic catheter

This study was initiated to identify the causal factor responsible for the development of "unaccountable phlebitis" when using the long arm silastic catheter. Use of computerized axial tomography has provided a means of analyzing veins containing indwelling silastic catheters of the upper arm. Physical data of diameters of the veins are limited to inaccuracies of the machine and must only be regarded as relative. We have been able to detect a great variability of cross-sectional vein diameter and area within any one patient. This narrowing tends to occur in the mid-upper arm region and may explain the occurrence of "unaccountable" phlebitis in this area. It appears that laminar blood flow and flotation of the catheter in the vein is inhibited in these areas of narrowing.