Effects of programmed intermittent thoracic paravertebral bolus of levobupivacaine on the spread of sensory block: a randomized, controlled, double-blind study

Abstract

Background and objectives This randomized, controlled, double-blind trial compared the effectiveness of levobupivacaine delivery of a programmed intermittent paravertebral bolus with a continuous paravertebral infusion. Methods Thirty-two consecutively enrolled patients who underwent unilateral video-assisted thoracic surgery were randomized to receive either a programmed intermittent paravertebral bolus of 10 mL of 0.2% levobupivacaine every 2 hours (Bolus group, n=16) or a continuous paravertebral infusion of 0.2% levobupivacaine at 5 mL/hour (Infusion group, n=16) after the operation. Postoperatively, after injection of 20 mL of 0.25% levobupivacaine through the paravertebral catheter, a mechanical infusion pump was set depending on the assigned group. The primary efficacy outcome was the number of anesthetized dermatomes 24 hours after the initial bolus of levobupivacaine. The secondary efficacy outcomes included the number of anesthetized dermatomes at other time points, pain at rest and coughing, additional analgesic use and patient acceptance of the analgesic technique. Arterial levobupivacaine concentration was measured to ensure safety. P<0.05 was considered statistically significant. Results The mean (95% CI) number of anesthetized dermatomes 24 hours after the initial bolus of levobupivacaine was significantly larger among subjects receiving programmed intermittent bolus (n=16) compared with those receiving continuous infusion (n=16; 6.8 (5.7–7.9) vs 3.1 (2.0–4.2); p<0.001). The arterial levobupivacaine concentration did not reach a toxic level. Conclusions The programmed intermittent paravertebral bolus of levobupivacaine provided a wider dermatomal spread of sensory block than continuous paravertebral infusion with an identical hourly dose of levobupivacaine. Trial registration number NCT000022532.