(S-283) Gershon, R.Y., Saturday 9:15
TITLE: REMOVAL OF EDTA FROM 2-CHLOROPROCAINE INCREASES THE EFFICACY OF EPIDURAL MORPHINE ANALGESIA
AUTHORS: Raphael Y. Gershon, Medical Doctor, Audrey S. Alleyne, MD, Kenneth M. Mims, MD, Dawn M. Williams, MD, Thanayi Barone, MD
AFFILIATION: Emory University School of Medicine, Atlanta, GA.
INTRODUCTION: 2-chloroprocaine (2-CP) is a commonly used local anesthetic for epidural anesthesia. While epidural morphine (EM) is highly popular for post caesarean section (c/s) analgesia, the prior use of 2-CP adversely affects subsequent EM administration.1 One proposed mechanism for this antagonism is the presence of ethylenediamine tetracetic acid (EDTA), a calcium chelating preservative.2 We investigated whether reformulated 2-CP, now EDTA free, would have a diminished antagonism of EM.
METHODS: With institutional approval and patient informed consent, 40 ASA I and II parturients scheduled for cesarean section were randomly assigned to receive either 3% 2-CP EDTA free, or 2% lidocaine in epinephrine 1:200,000 (LE) and subsequently studied in a prospective double-blinded fashion. After delivery, 2.5mg Duramorph was injected in the epidural space, and the patient postoperatively was placed on a PCA devise using intravenous morphine. Visual analog pain scores (VAPS) and PCA dose was assessed at 8, 16 and 24 hours after c/ s. Statistical analysis was by ANOVA and student's t-test. A p value of .05 was considered significant.
RESULTS: All parturients achieved a bilateral T2 sensory level or higher and Bromage score of 2 or 3, with either 23.1±2.7 ml (LE) or 24.1±4.5 ml (2-CP) (p=.40). VAPS preincision and upon incision was 0 for both groups. Time until first PCA usage was 226±177 min (LE) and 203±148 min (2-CP) (P=.67). Post c/s analgesia assessment is depicted in figure I.
Figure I.
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8 hours |
16 hours |
24 hours |
Total |
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|
VAPS |
PCA |
VAPS |
PCA |
VAPS |
PCA |
PCA |
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|
LE |
19.6+ 27.9 |
2.2+ 2.3 |
11.3+ 21.1 |
1.4+ 1.4 |
24.2+ 31.9 |
2.3+ 2.2 |
5.9+ 5.1 |
|
CP |
19.0+ 16.2 |
4.1+ 3.7 |
23.7+ 21.2 |
3.4+ 3.2 |
24.1+ 23.9 |
4.9+ 4.5 |
11.6+ 8.0 |
|
P |
.93 |
.05 |
.07 |
.01 |
1.0 |
.03 |
.01 |
DISCUSSION: We found a statistically significant difference in PCA usage between LE and 2-CP at all times. However, VAPS were not significantly different between the two groups at any point. We believe this shows comparable postoperative analgesia with a somewhat increased intravenous morphine usage for 2-CP. While our LE data are near identical to a recent study1, our 2-CP parturients required 1/3 the PCA morphine dose as compared to their parturients, at only 1/2 of their Duramorph dose (2.5mg vs. 5.0mg). We believe the removal of EDTA from 2-CP is the main difference between studies.
REFERENCES:
1Acta Anesth Scand 41:774-778, 1997.
2Reg Anesth 22 (1):43-52, 1997.
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