Clinical characteristics of spinal levobupivacaine: hyperbaric compared with isobaric solution

Abstract

We performed a prospective, double-blinded study in 20 patients undergoing gynecologic surgery with lower abdominal incision, to investigate characteristics of intrathecal hyperbaric levobupivacaine compared with isobaric levobupivacaine. We randomly assigned them to receive 3 mL of either isobaric or hyperbaric 0.42% levobupivacaine intrathecally. We found that hyperbaric levobupivacaine, compared with isobaric levobupivacaine, spread faster to T10 level (2.8 ± 1.1 versus 6.6 ± 4.7 minutes, P = 0.039), reached higher sensory block levels at 5 and 15 minutes after injection (T8 versus L1, P = 0.011, and T4 versus T7, P = 0.027, resp.), and had a higher peak level (T4 versus T8, P = 0.040). Isobaric levobupivacaine caused a wider range of peak levels (L1 to C8) compared with hyperbaric form (T7 to T2). The level of T4 or higher reached 90% in the hyperbaric group compared with 20% in the isobaric group (P = 0.005). Our results suggest that hyperbaric levobupivacaine was more predictable for sensory block level and more effective for surgical procedures with lower abdominal approach. Hyperbaric levobupivacaine seems to be suitable, but the optimal dosage needs further investigation.

Figure 1

CONSORT flow diagram.

Figure 2

Sensory block levels at 5 and 15 minutes after spinal block, and peak levels of sensory block in patients receiving isobaric (blue bars) or hyperbaric levobupivacaine (red bars). Hyperbaric levobupivacaine reached higher sensory block levels at all periods of time (*P = 0.011, ^† P = 0.027, and ^‡ P = 0.040, resp.). More patients in hyperbaric group reached T10 or higher at 5 minutes, T4 or higher at 15 minutes, and higher peak levels of sensory block than in isobaric group (*P = 0.011, ^† P = 0.005, and ^‡ P = 0.005, resp.).

Figure 3

Comparison of time to T4 after isobaric (dotted line) and hyperbaric (dashed line) levobupivacaine (P = 0.002).