Comparison of the immediate hemodynamic changes induced by unilateral and bilateral spinal anesthesia in hypertensive elderly patients

ABSTRACT

BACKGROUND: The objective of this study was to compare the frequency of hypotension and immediate hemodynamic changes induced by unilateral and bilateral spinal anesthesia in hypertensive elderly patients. METHODS: Forty hypertensive elderly patients undergoing lower leg surgery were randomly allocated into unilateral (group US) and bilateral spinal anesthesia (group BS). After intrathecal bupivacaine injection, patients in group US were kept in the lateral position for 10 min while patients in group BS were immediately placed in the supine position. Hemodynamic parameters were measured for 20 min by non-invasive cardiac output monitor based on bioreactance. RESULTS: In both groups, mean arterial pressure was significantly decreased after spinal anesthesia compared to the baseline value. However, frequency of hypotension requiring vasoactive drug was significantly lower in group US (5%) than in group BS (35%) (P = 0.044). The dermatom of sensory block on the operated limb was significantly lower in group US [T10 (10–10)] than in group BS [T8 (7.5–10)] (P = 0.013). In comparison within the group, changes of cardiac index were similar as the baseline value in both groups, although total peripheral resistance index was constant in group US but significantly decreased in group BS. CONCLUSIONS: Unilateral spinal anesthesia effectively reduced the frequency of hypotension requiring vasoactive drug and affected hemodynamic performance less than bilateral spinal anesthesia.