[Feasibility study of bilateral thoracic paravertebral block for postoperative analgesia in patients after off-pump coronary artery bypass grafting].

OBJECTIVE To investigate the feasibility of bilateral thoracic paravertebral block for postoperative analgesia in patients after off-pump coronary artery bypass grafting (OPCABG). METHODS Upon the approval of institutional Ethics Committee and informed consent, forty patients ASAII or III aged 52-77 yr with BMI (body mass index) < 30 kg/m(2), undergoing OPCABG, were randomly divided by random numbers into two groups(n = 20 each):thoracic paravertebral block for postoperative analgesia group (group P) and patient-controlled intravenous analgesia (PCIA) group (group I). Bilateral thoracic paravertebral block and insertion epidural catheter were performed at T3, 4 interspace prior to induction of anesthesia in group P. At the end of the operation , an infusion of 0.375% ropivacaine was injected at the rate of 5 ml/h up to 48 h.Group I received PCIA with morphine. Dermatomes of hypoalgesia in group P were recorded. The following indexes were recorded at 12, 24, 36 and 48 hours after postoperative analgesia beginning: VAS scores of rest pain, cough pain and sedation score. To evaluate stability of circulation. Cycle time, complications and side effects after operation were recorded. RESULTS Dermatomes of hypoalgesia was 5.1 ± 1.0 segments in group P. VAS scores of rest pain (2.4 ± 0.4, 2.6 ± 0.5, 2.4 ± 0.4, 2.2 ± 0.3 vs 3.7 ± 0.7, 3.6 ± 0.8, 3.4 ± 0.6, 3.1 ± 0.6, all P < 0.01), cough pain (3.7 ± 0.8, 3.9 ± 1.0, 3.8 ± 1.1, 3.8 ± 0.9 vs 4.4 ± 1.1, 4.9 ± 1.3, 4.8 ± 1.3, 4.3 ± 1.2, P < 0.05, <0.01) and sedation scores (2.2 ± 0.4, 2.0 ± 0.4, 1.9 ± 0.3, 1.8 ± 0.3, 2.6 ± 0.5, 2.5 ± 0.4, 2.4 ± 0.5, 2.2 ± 0.4, P < 0.05) in group P were significantly lower than in group I at the four points. The incidences of sinus tachycardia (5% vs 25%) and hypertension (0 vs 30%) in group P were significantly reduced than in group I (P < 0.05), and there were no significant difference in the incidences of sinus brachycardia (30% vs 15%) and hypotension (20% vs 10%) (P > 0.05) . Compared with group I, extubation time (5.5 ± 1.4 vs 7.1 ± 1.7) and residence time in ICU (17.3 ± 4.2 vs 21.4 ± 5.8) were shortened significantly in group P (P < 0.05), and there were no significant difference in length of stay after operation (10.5 ± 2.6 vs 11.7 ± 2.8, P > 0.05). The incidence rate of nausea in group P was significantly lower than in group I (5% vs 25%, P < 0.05), and there were no significant difference in the other complications and side effects after operation (P > 0.05). CONCLUSION Bilateral thoracic paravertebral block for postoperative analgesia could be used safely and efficiently and accelerate the cycle time in patients after OPCABG.