Venous flow dynamics during spinal block in normotensive and hypertensive elderly patients: a duplex ultrasonographic study

Abstract

BACKGROUND: Spinal block induces hyperkinetic change in lower extremity blood flow. We compared the venous flow dynamic responses to spinal block in normotensive and hypertensive elderly patients. METHODS: Following spinal block using 10 mg 0.5% (w/v) bupivacaine, we measured changes in blood pressure, heart rate, and venous flow dynamics of the popliteal vein by duplex ultrasonography in 20 normotensive (NBP group) and 18 hypertensive (HIBP group) patients. RESULTS: Spinal block caused significant decreases in blood pressure in both groups; similar rates of hypotension were observed. At baseline, peak velocity, time-averaged maximum velocity, and time-averaged mean velocity were higher in the HIBP than in the NBP group. During spinal block, peak velocity increased in both groups, and the between-group differences were no longer significant. At baseline, volume flow in the two groups was similar and increased by 141.5% in the NBP and 131.7% in the HIBP group during spinal block. CONCLUSIONS: Blood pressure and flow dynamics in the popliteal vein showed similar changes during spinal anaesthesia in elderly patients taking antihypertensive medication and normotensive patients, despite differences in baseline values.