Abstract ID: A12
Abstract Title: Analgesic effectiveness of perioperative, single-dose, extended-release epidural morphine after hip arthroplasty
Poster Type: Either
ABSTRACT BODY
Introduction: Recent meta-analyses indicate that epidural analgesia is superior to intravenous patient-controlled analgesia (IV PCA). Previously, we presented significant opioid-sparing effects of an extended-release (ER), perioperative epidural morphine (DepoDur™) following hip arthroplasty. This single-dose ER epidural morphine (EREM) was recently approved but within a narrower recommended dose range than that used in our previous studies. Therefore, we have retrospectively assessed patient ratings of pain intensity for indicated doses only.
Materials and Methods: Two multicenter, randomized, double-blind trials were conducted in patients undergoing hip arthroplasty. Patients signed informed consent; investigative sites were approved by the appropriate institutional review board and conformed to the Declaration of Helsinki. Thirty minutes before anesthesia and the start of surgery, patients received a single epidural injection of placebo or EREM at 10, 15, or 20 mg. In the postoperative period, patients had access to IV PCA only. Pain intensity evaluations through 48 hours were recorded via a 100-mm Visual Analog Scale (VAS) and categorical scale (CAT) at rest (R) and during activity (A).
Results: Patients receiving EREM 10 mg (n=35), EREM 15 mg (n=50), EREM 20 mg (n=81), or placebo (n=76) were assessed. Clinically meaningful differences in the percentage of patients reporting moderate to severe pain throughout the first 24 h were observed. At 4, 8, 12, 18, and 24 h, the percentage of patients reporting moderate to severe pain on the CAT-R was 59%, 44%, 48%, 41%, and 26% for placebo and 12%, 9%, 6%, 14%, and 29% for EREM 10-mg–treated patients, respectively. Similarly, the percentage of patients reporting moderate to severe pain on the CAT-A was 59%, 70%, 59%, 44%, and 48% of placebo-treated patients and 11%, 12%, 14%, 20%, and 40% of EREM 10-mg–treated patients at 4, 8, 12, 18, and 24 h, respectively. Similar results were observed when comparing placebo with the 15-mg dose for CAT-R (P≤0.0004 for all times through 24 h), and there was a significant difference between EREM 15 mg and placebo at 24 h for CAT-A (P=0.0052). Mean differences in VAS-R scores at 4, 8, 12, 18, and 24 h were 40, 30, 25, 19, and 3 mm between placebo and EREM 10 mg (P<0.001 for treatment effect through 18 h) and 25, 31, 25, 21, and 15 mm (P<0.01 for all time points) between placebo and EREM 15 mg. Clinically meaningful improvements were also observed for both EREM groups on the VAS-A. In both studies the EREM 20-mg group was comparable to the 10- and 15-mg groups and superior to placebo during the first 24 h. Significantly greater consumption of supplemental opioids by the placebo group (P<0.05) was associated with decreased pain after 24 h that was generally comparable to the EREM groups. Adverse events were typical of opioid therapy (eg, pruritus, nausea, and vomiting).
Discussion: In 2 independent studies in hip arthroplasty, treatment with conventional IV PCA alone was more likely to result in the undertreatment of postoperative pain compared with a recommended epidural dose of ER morphine. Single-dose ER morphine may help to bridge the analgesic gap frequently observed in the immediate postoperative period.
Funding Source: Supported by Endo
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A12