Original article: cardiovascular
Prospective randomized trial of high thoracic epidural analgesia for coronary artery bypass surgery

https://doi.org/10.1016/S0003-4975(02)04074-2Get rights and content

Abstract

Background

Postoperative pain may be severe after coronary artery bypass surgery. High thoracic epidural analgesia (HTEA) provides intense analgesia.

Methods

Eighty patients were randomized to HTEA or intravenous morphine analgesia (control). Patients received coronary artery bypass surgery (CABG) with cardiopulmonary bypass. Pain was measured by visual analogue scale 0 to 10. Psychologic morbidity, intraoperative hemodynamics, ventricular function, lung function, and physiotherapy cooperation were also assessed. On the third postoperative day HTEA and morphine were ceased and only oral medications were used. Acetaminophen, indomethacin, and tramadol were allowed as supplemental analgesics in both groups.

Results

The primary endpoint of pain scores was significantly less with HTEA on postoperative days 1 and 2 at rest, 0.02 ± 0.2 versus 0.8 ± 1.8 (p = 0.008) and 0.1 ± 0.4 versus 1.2 ± 2.7 (p = 0.022), respectively, and with coughing 1.2 ± 1.7 versus 4.4 ± 3.1 (p < 0.001) and 1.5 ± 2.0 versus 3.6 ± 3.1 (p = 0.001), respectively. When HTEA and morphine were ceased on day 3, there were no significant differences. The secondary endpoints of postoperative depression (p = 0.033) and posttraumatic stress subscales (p = 0.021) of the Minnesota Multiphasic Personality Inventory were lower with HTEA. Extubation occurred earlier with HTEA, 2.6 versus 5.4 hours (p < 0.001). HTEA showed improved physiotherapy cooperation (p < 0.001), arterial oxygen tension (p = 0.041), and peak expiratory flow rate (p = 0.001). Mean arterial pressure was lower with HTEA (p = 0.036), otherwise there were no differences in intraoperative hemodynamics or ventricular function.

Conclusions

Epidural analgesia reduces pain after coronary operation and is associated with improved physiotherapy cooperation, earlier extubation, and reduced risk of depression and posttraumatic stress.

Section snippets

Material and methods

Institutional ethics committee approval and informed written consent were obtained. A single surgeon performed all operations, completed between 1998 and 2001. Eighty patients undergoing elective CABG were randomized to receive high thoracic epidural analgesia (HTEA) or a patient controlled intravenous morphine analgesic (control). Acetaminophen, indomethacin, and tramadol were allowed as supplemental analgesia in both groups.

Results

Eighty patients were randomized, and 3 patients from the HTEA group were withdrawn (1 patient withdrew themself from the study after randomization, deciding not to participate in research, and 2 patients failed epidurals prior to induction), and 1 patient from the control group withdrew from the study after randomization and requested the epidural instead. Hence, analysis was performed on 37 HTEA and 39 control patients. There were no differences in demographic variables or the number of grafts

Primary endpoint

The primary reason for using an epidural analgesic technique is to provide optimal pain relief. Our study found a significant reduction in the pain experienced after coronary surgery (Table 3).

Sixty-three percent of the HTEA patients experienced no pain or only mild pain at all times postoperatively. Conversely, the pain experienced by patients who received intravenous opioid infusions (with supplementary agents) was far more varied. Their pain ranged from mild to severe, and more so when

Acknowledgements

We thank Karen Groves, Dr Michael Barrington, the Department of Biomedical Engineering, Royal Melbourne Hospital for technical support, and the cardiothoracic and operating suite nursing staff for their support. Prof John Ludbrook performed the statistical analysis (Biomedical Statistical Consulting Pty, Ltd). We thank Prof John Ludbrook and Prof James Angus for manuscript review. The study is supported by grants from the National Heart Foundation of Australia; Australian Society of

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