Lumbar versus thoracic epidural buprenorphine for postoperative analgesia following coronary artery bypass graft surgery

Pulmonary Complications After Cardiac Surgery

Over the past two decades there has been a steady evolution in the practice of adult cardiac surgery with the introduction of “off-pump” surgery. However, respiratory complications remain a leading cause of postcardiac surgical morbidity and can prolong hospital stays and increase costs. The high incidence of pulmonary complications is in part due to the disruption of normal ventilatory function that is inherent to surgery in the thoracic region. Furthermore, patients undergoing such surgery often have underlying illnesses such as intrinsic lung disease (e.g., chronic obstructive pulmonary disease) and pulmonary dysfunction secondary to cardiac disease (e.g., congestive heart failure) that increase their susceptibility to postoperative respiratory problems. Given that many patients undergoing cardiac surgery are thus susceptiple to pulmonary complications, it is remarkable that more patients do not suffer from them during and after cardiac surgery. This is to a large degree because of advances in anesthetic, surgical and critical care that, for example, have reduced the physiological insults of surgery (e.g., better myocardial preservation techniques) and streamlined care in the immediate postoperative period (e.g., early extubation). Moreover, the development of minimally invasive surgery and nonbypass techniques are further evidence of the attempts at reducing the homeostatic disruptions of cardiac surgery. This review examines the available information on the incidences, consequences, and treatments of postcardiac surgery respiratory complications.

A comparison of thoracic or lumbar patient-controlled epidural analgesia methods after thoracic surgery

Background

We aimed to compare patient-controlled thoracic or lumbar epidural analgesia methods after thoracotomy operations.

Methods

One hundred and twenty patients were prospectively randomized to receive either thoracic epidural analgesia (TEA group) or lumbar epidural analgesia (LEA group). In both groups, epidural catheters were administered. Hemodynamic measurements, visual analog scale scores at rest (VAS-R) and after coughing (VAS-C), analgesic consumption, and side effects were compared at 0, 2, 4, 8, 16, and 24 hours postoperatively.

Results

The VAS-R and VAS-C values were lower in the TEA group in comparison to the LEA group at 2, 4, 8, and 16 hours after surgery (for VAS-R, P = 0.001, P = 0.01, P = 0.008, and P = 0.029, respectively; and for VAS-C, P = 0.035, P = 0.023, P = 0.002, and P = 0.037, respectively). Total 24-hour analgesic consumption was different between groups (175 +/- 20 mL versus 185 +/- 31 mL; P = 0.034). The comparison of postoperative complications revealed that the incidence of hypotension (21/57, 36.8% versus 8/63, 12.7%; P = 0.002), bradycardia (9/57, 15.8% versus 2/63, 3.2%; P = 0.017), atelectasis (1/57, 1.8% versus 7/63, 11.1%; P = 0.04), and the need for intensive care unit (ICU) treatment (0/57, 0% versus 5/63, 7.9%; P = 0.03) were lower in the TEA group in comparison to the LEA group.

Conclusions

TEA has beneficial hemostatic effects in comparison to LEA after thoracotomies along with more satisfactory pain relief profile.

Buprenorphine in postoperative pain management

Several decades ago, the analgesic properties of buprenorphine were discovered. Its approval for the use as an agent for the treatment of opioid abuse has led to increasing numbers of patients presenting for surgery on buprenorphine. This article describes the challenges, advantages, and disadvantages of the use of buprenorphine as an analgesic for postoperative pain in patients with and without preoperative maintenance therapy.

Improved pain control after cardiac surgery: results of a randomized, double-blind, clinical trial

OBJECTIVE

We sought to determine whether a continuous regional infusion of a local anesthetic delivered to the operative site would result in decreased levels of postoperative pain and narcotic requirements for patients who undergo a standard median sternotomy for cardiac surgery.

METHODS

A double-blind, randomized, controlled trial was conducted at a single center. Patients who were undergoing elective coronary artery bypass graft surgery alone or combined with laser transmyocardial revascularization received bilateral intercostal nerve blocks with either ropivacaine or saline. At wound closure, 2 catheters with multiple side openings were inserted percutaneously and placed directly over the sternum. The same agent (ropivacaine vs saline) was then administered as a continuous regional infusion for 48 hours through an elastomeric pump. Requirements for postoperative systemic narcotic analgesics and pain assessment scores were recorded for 72 hours after the operation. Secondary outcome measures were hospital length of stay and pulmonary function test results. Pain scores and narcotic use on the second postoperative day were also compared to avoid the confounding influence of anesthesia administered at the time of the operation.

RESULTS

The total amount of narcotic analgesia required by the ropivacaine group was significantly less than that of the control group (47.3 vs 78.7 mg, respectively; P =.038). The ropivacaine group required less narcotics on postoperative day 2 as well (15.5 vs 29.4 mg, P =.025). The mean overall pain scores for the ropivacaine group were significantly less than the mean overall scores for the normal saline group (1.6 vs 2.6, respectively; P =.005). Patients receiving ropivacaine had a mean length of stay of 5.2 days compared with 8.2 days for patients in the normal saline group (P =.001). Excluding the data from outliers (length of stay = 39 days), the normal saline group mean length of stay was 6.3 days (P <.01). There was no difference in assessment of pulmonary function.

CONCLUSION

Continuous delivery of local anesthetics significantly improved postoperative pain control while decreasing the amount of narcotic analgesia required in patients who underwent standard median sternotomy. There was also a significant decrease in hospital length of stay, which is likely to result in significant cost reductions.

Comparison of continuous thoracic epidural and paravertebral blocks for postoperative analgesia after minimally invasive direct coronary artery bypass surgery

OBJECTIVE

To compare continuous thoracic epidural analgesia (TEA) and paravertebral block (PVB) for postoperative analgesia in patients undergoing minimally invasive direct coronary artery bypass (MIDCAB) surgery for quality of analgesia, complications, compliance to chest physiotherapy, hemodynamics, and respiratory effects.

DESIGN

Prospective, randomized study.

SETTING

Specialty research hospital.

PARTICIPANTS

Forty-one consenting patients undergoing MIDCAB surgery.

INTERVENTIONS

Patients in the TEA group had an epidural catheter inserted at the T4-5 interspace, whereas patients in the PVB group had a catheter inserted in the paravertebral space on the left side at the T4-5 level.

MEASUREMENTS AND MAIN RESULTS

Parameters evaluated included visual analog scale pain scores at rest and while coughing, supplemental analgesic requirement, complications, hemodynamics, and respiratory parameters. Measurements were made at 2-hour intervals for 12 hours beginning at 10 minutes after endotracheal extubation. There was no statistically significant difference in visual analog scale scores and requirement of supplemental analgesia between the 2 groups. Cardiac index at 4 hours and 6 hours was significantly higher in the TEA group. Patients in the PVB group had significantly lower respiratory rates at 8, 10, and 12 hours. All other parameters were comparable. In 1 patient, the epidural space could not be catheterized. One patient in the TEA group had transient hypotension, and 1 patient complained of backache at the site of the epidural catheter insertion.

CONCLUSION

PVB is as effective as TEA for postoperative analgesia after MIDCAB surgery. PVB is technically easier than TEA and may be safer than TEA because no complications were seen in the PVB group.

Epidural analgesia with a combination of bupivacaine and buprenorphine in rats

We determined the analgesic effects of epidural administration of either bupivacaine at 62.5, 125, 250, and 500 micrograms/kg; buprenorphine at 5 and 10 micrograms/kg; and the combination of bupivacaine at 125 micrograms/kg and buprenorphine at 5 or 10 micrograms/kg, using the tail flick (TF) and colorectal distension (CD) tests in rats and compared the results with those obtained using morphine at 100 micrograms/kg. In both the TF and CD tests, all doses of bupivacaine alone produced potent anti-nociceptive effects, although the effect rapidly diminished after 20-30 min of administration. The administration of buprenorphine at 10 and 5 micrograms/kg produced mild to moderate anti-nociceptive effects in both the TF and CD tests, and the effects were relatively constant throughout the 2-h experimental period. Combinations of 5 or 10 micrograms/kg of buprenorphine with 125 mg/kg of bupivacaine produced a significantly higher percentage of maximum possible analgesic effect (%MPE) than that of the calculated additive effect of each drug alone in the TF and CD tests. The analgesic effect of this combination was similar to that of morphine. Minimal ataxia was observed in rats administered this combination.