No vasodilator response to low-dose heparin in the forearm skeletal-muscle vascular bed.

OBJECTIVE

Recent reports show that heparin induces vasodilation. This heparin-induced vasodilation might interfere with the results of vascular studies using the perfused-forearm technique because the arterial catheter is often flushed with a heparin solution in those experiments. Therefore, we investigated the vascular effects of flushing an arterial catheter with a heparin solution compared with a placebo solution (NaCl 0.9%) in six healthy volunteers.

METHODS

During the first half of each experiment, the arterial catheter was flushed several times with the placebo solution. In the second half, identical flushes were performed with a solution of heparin diluted in NaCl 0.9% (4U x ml(-1)).

RESULTS

Forearm blood flow (venous occlusion plethysmography) response was similar with heparin and placebo after all flushes.

CONCLUSION

We conclude that low-dose heparin in the solution to flush an arterial catheter has no short-term vasodilator effect in the human forearm vascular bed. Therefore, the results of studies using the perfused-forearm technique are not confounded by flushes with a low-dose heparin solution.