Abstract

The hypotensive effects of spinal anesthesia were investigated in 60 patients aged 75 years or older and divided into two groups: 30 normotensive patients (group 1) and 30 treated hypertensive patients (group 2). In both groups, spinal anesthesia was performed in lateral decubitus position with 3 ml 0.5% isobaric bupivacaine. Hemodynamic measurements were performed before the establishment of spinal blockade and repeated during the 60 minutes following intrathecal injection. Median cephalad level (T10) and ranges of sensory blockade were similar in the two groups. Changes from baseline to lowest blood pressures showed significant decreases in group 2 compared with group 1 : 10.7% in SBP, 11.2% in MBP, and 14.8% in DBP. Hypotension was observed in three group 1 patients and ten group 2 patients. Five patients in group 2 (but none in group 1) had a SBP decrease of 40% from baseline or more. The decreases in MBP and DBP were persistent after 60 minutes. These results suggest that pre-existing hypertension can be recognized as an important factor to explain blood pressures changes during isobaric bupivacaine spinal anesthesia in elderly patients.