Introduction: Preoperative respiratory dysfunction is a significant risk factor for increased post-cardiac surgery morbidity and mortality . We evaluated the effects of HTEA on the postoperative course of patients with preoperative respiratory disease undergoing elective cardiac surgery.
Method: Between March 2001 and November 2003, 270 patients scheduled for cardiac surgery at our institution were enrolled in a prospective randomized trial comparing an opioid-based balanced general anaesthetic (GA, 130 patients) with a HTEA plus general anaesthesia technique (140 patients). Patients with the following criteria were included: COPD (GOLD stage I-III), obesity (BMI > 30kg/m2), smoking (>30 packs-years), any other clinically significant pulmonary disease. On the day of surgery, a thoracic (C7-T4) epidural catheter was inserted in the HTEA patients. Epidural anaesthesia was induced with bupivacaine or levobupivacaine 0.25% 10 mL + morphine 2.5mg and maintained with bupivacaine or levobupivacaine 0.5% + morphine 0.02% 1-5mL/hour. HTEA patients received epidural bupivacaine or levobupivacaine 0.125% + morphine 0.012% 1-5 mL/hour for postoperative analgesia. GA patients were given an iv. opioid (morphine, tramadol) bolus when needed. Patient and surgical characteristics, postoperative course, complications and mortality data were collected. Statistical analysis was performed with the ANOVA and chi-squared test.
Results: There were no differences in patients and surgical characteristics. HTEA patients had shorter awakening (16 vs. 84 minutes) and intubation (11 vs. 23 hours) times (P < 0.001). In the GA group, there was a higher incidence of postoperative sinus tachycardia (20% vs. 9%, P < 0.05) and anti-arrhythmic drugs use (48% vs. 28%, P < 0.05). GA group patients had a higher incidence of atelectasis (segmental or plate-like) on the post-extubation chest X-ray (16% vs. 6%, P < 0.05). Postoperative PaO2/FiO2 ratio was higher in the HTEA group before (299 vs. 265 mmHg, P < 0.05) and soon after extubation (333 vs. 278 mmHg, P < 0.01). VAS scores after extubation were significantly lower in the HTEA group (0.5 vs. 4.5, P < 0.001) as well as the need for iv. opioids (2 vs. 89%, P < 0.001). There were 3 dural punctures and 1 bloody tap without any immediate or delayed neurological signs and symptoms.
Discussion: HTEA is a technique that can benefit cardiac surgery patients. In our study, HTEA provided excellent pain control, allowed earlier extubation, decreased the incidence of supraventricular tachyarrhythmias and better preserved respiratory function. Patients with respiratory disease undergoing cardiac surgery can benefit from HTEA with no significant catheter-related complications.
1 Samuels LE, Kaufman MS, Morris RJ, et al. Coronary artery bypass grafting in patients with COPD. Chest