Forearm Blood Flow Measured by Venous Occlusion Plethysmography in Healthy Subjects and in Women with Postmastectomy Oedema

A chronic swelling of the arm may develop following damage to axillary lymph vessels during breast cancer treatment. Certain unusual pathophysiological features of postmastectomy oedema indicate that factors additional to lymphatic damage are important. One factor postulated previously is a haemodynamic abnormality. Forearm blood flow was therefore measured by venous occlusion plethysmography using both a conventional mercury strain gauge and a newer optical volumeter (Perometer). The latter was initially assessed in healthy subjects. When forearm blood flow was measured using the two methods simultaneously, the strain gauge and Perometer did not differ significantly for healthy or oedematous arms. Dominant and non-dominant arm blood flow in healthy subjects was similar but with greater variation between sides with the Perometer. Using the strain gauge, blood flow in the oedematous arm (2.51 +/- 1.33 ml/100 ml per min) was significantly lower than in the opposite unaffected arm (3.77 +/- 2.29 ml/100 ml per min; p = 0.026). The Perometer results showed a similar but nonsignificant trend (p = 0.105). Taking into account the greater limb volume on the affected side, total forearm blood flow was essentially the same in each arm (unaffected: 40.72 +/- 28.70 micromilligrams/min; oedematous: 41.78 +/- 22.11 ml/min). The reduced blood flow per unit volume of arm was therefore likely to be due to a simple 'dilution' effect of the increase in volume. The results indicate that it is unlikely that raised blood flow contributes to oedema formation, contrary to the haemodynamic concept.