Comparison of continuous thoracic epidural with paravertebral block on perioperative analgesia and hemodynamic stability in patients having open lung surgery.

BACKGROUND

Epidural analgesia can result in perioperative hypotension in patients having thoracotomy. This randomized prospective study assessed the effects of epidural and paravertebral analgesia on hemodynamics during thoracotomy.

METHODS

Thirty-two patients were randomized to receive either epidural analgesia (n = 16, 0.25% levobupivacaine and 30 μg/kg morphine) or paravertebral block (n = 16; 0.5% levobupivacaine and 30 μg/kg morphine). Oxygen delivery, stroke volume and systemic vascular resistance indices, heart rate, and mean arterial pressure measurements were performed before administration of local anesthetic, after induction of general anesthesia, institution of 1-lung ventilation, first skin incision, retractor placement, lung-inflation maneuver, and at last skin suture. The primary end point was the volume of the colloid infusion necessary to maintain oxygen delivery index of 500 mL/min per squared meter or higher. Postoperative analgesia was provided immediately after surgery by an infusion of 0.125% levobupivacaine and 20 μg/mL morphine in epidural/paravertebral infusion. Pain, rescue-analgesia consumption, arterial pressure, and heart rate were recorded at 6, 24, and 48 hrs after surgery. Administration of anesthesia and data collection were done by research staff blinded to the regional analgesia technique.

RESULTS

The groups did not differ significantly in heart rate, mean arterial blood pressure, or systemic vascular resistance indices. However, to maintain the targeted oxygen delivery index, a greater volume of colloid infusion and phenylephrine were required, respectively, in the epidural than in the paravertebral group (554 ± 50 vs 196 ± 75 mL, P = 0.04; and 40 ± 10 vs 17 ± 4 μg, P = 0.04). Pain intensity before and after respiratory physiotherapy as well as 24 hr rescue piritramide consumption was similar in the epidural (4.1 ± 3.1 mg) and the paravertebral (2.5 ± 1.5 mg) groups (P = 0.14). Systolic blood pressure after 24 and 48 hrs was lower in the epidural group.

CONCLUSIONS

Under the conditions of our study, continuous paravertebral block resulted in similar analgesia but greater hemodynamic stability than epidural analgesia in patients having thoracotomy. Paravertebral block also required smaller volume of colloids and vasopressors to maintain the target oxygen delivery index (DO2I).