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.

Trial registration: ClinicalTrials.gov NCT01091779.