Korean J Anesthesiol.  2009 Oct;57(4):466-471. 10.4097/kjae.2009.57.4.466.

The effects of epidural magnesium on postoperative pain management in patients with patient-controlled epidural analgesia after a thoracotomy

• Kim SM
• Cho SH
• Kim SH
• Lee DG
• Chae WS
• Jin HC

• KMID: 1765451
• DOI: http://doi.org/10.4097/kjae.2009.57.4.466

Abstract

BACKGROUND
Magnesium presents analgesic effects by blocking the non-competitive N-methyl-D-aspartate receptor in the spinal cord. The purpose of this study was to evaluate the effects of epidural magnesium on cumulative dose of ropivacaine in patients with patient-controlled epidural analgesia (PCEA) after a thoracotomy.
METHODS
In a randomized, prospective, double-blind trial, we enrolled 40 patients undergoing PCEA after a thoracotomy. Control group (n = 20) received an initial dose of 0.375% ropivacaine 0.1 ml/kg, and following demand doses of 0.2% ropivacaine 2 ml with 15 min lockout interval on the patient demand. Magnesium group (n = 20) additionally received MgSO4 100 mg in the initial dose and 4 mg in the demand doses. Cumulative dose of ropivacaine, the resting and coughing visual analog scale (VAS) score were measured at 3, 6, 12, 24, and 48 hours after surgery.
RESULTS
Magnesium group showed lower cumulative dose of ropivacaine than control group at 12, 24, and 48 hours after the surgery (P<0.05), but not at 3 and 6 hours (P < 0.05). The VAS score was not different between 2 groups (P < 0.05).
CONCLUSIONS
Epidural magnesium may be useful as an adjuvant to ropivacaine after a thoracotomy. However, because magnesium showed no beneficial effect at the early period after the surgery, more investigation about proper initial dose is required.

Keyword

Magnesium; Patient-controlled analgesia; Ropivacaine; Thoracotomy

MeSH Terms

Amides
Analgesia, Epidural
Analgesia, Patient-Controlled
Cough
Humans
Magnesium
N-Methylaspartate
Pain, Postoperative
Prospective Studies
Spinal Cord
Thoracotomy
Amides
Magnesium
N-Methylaspartate