Extradural Pressure Following the Injection of Two Volumes of Bupivacaine

Abstract

We investigated the influence of the pressure generated by low lumbar extradural injection of bupivacaine on the development of block in a randomized double-blind study. Thirty patients (aged 17-66 yr) received one of two volumes of 0.75% bupivacaine. Group I (n = 15) received 10 ml (75 mg) and group II (n = 15) 15 ml (112.5 mg). Injection of the larger volume resulted in a greater pressure at the end of injection, but within 1 min this decayed to the same plateau pressure that was produced by the smaller volume. Mean maximum cephalad spread of block was the same in each group (group I, T9.5; group II, T8.4) and there was no correlation between individual level of block and maximum or plateau extradural pressure, or with patient characteristics.

Epidural saline solution prior to local anaesthetic produces differential nerve block

“…Park et aL s also reported that there were only small differences in spread with 10, 15, 20 ml lidocaine. In addition, no correlation between the volume and the effect was reported by Duggan et trL 1 or Paul et al 2 Our finding of no difference in cold sensation block among three groups was consistent with these reports. The relationship between epidural saline and spread of the subsequent anaesthetic has been reported by Iwama 6 who showed that a larger volume of saline using LOR caused a greater extent of hypaesthesia.…”

Saline volume and local anesthetic concentration modify the spread of epidural anesthesia

“…There were no differences in age, height or weight among the two groups (Table). The number of spinal segments with hypesthesia to cold in the i ml, 5 rnl and 10 ml saline groups in the mepivacaine 1% group were 12.5 [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] (Figure 2). The number of segments with hypesthesia for coldness in the 5 ml and 10 ml saline groups in the 1.5 % mepivacaine group was greater than that in the 1 ml saline group (P< 0.05) (Figure 2).…”

“…Fifteen minutes after the injection of I0 ml mepivacaine, the dermatome levels of hypesthesia to cold and pinprick were determined by an individual blinded to the saline volume. ~tdts: The number of spinal segments with hypesthesia to cold in the three subgroups in the mepivacaine 1% group were 12.5 [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] .5], respectively. Saline volume did not alter the anesthetic level of the mepivacaine 1%, although it did affect the anesthetic spread of the mepivacaine 1.5%.…”

“…Quinze minutes apr~s l'injection de I 0 ml de m~pivacai'ne, le niveau du dermatome touch~ d'hypoesth&ie au froid et ~ la piqfire a ~t~ d~termin~ par une personne ignorant le volume de solution sal~e donn& 1~.su[tats 9 Le hombre de segments m~dullaires atteints d'hypoesth&ie au froid a ~t~, dans les trois sous-groupes qui ont re~su la m~pivaca'ine 1%, de 12,5 [6-20], 13 [8,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]5] et de 12,5 [6,5-22], respectivement (m~diane [~tendue]). Dans le groupe qui a rec;u la m~pivacaTne 1,5 %, les segments ont ~t~ : 12 [7][8][9][10][11][12][13][14][15][16][17][18]5], 14 i-8,5-19]* et 15 [6-23]*, respectivement (*P < 0,05 vs le groupe I ml). Le hombre de segments atteints d'hypoesth&ie ~ la piq0re a &~, dans les trois sous-groupes de m~pivaca~ine 1%, de 10,5 [2-22], I 0,5 [4][5][6][7][8][9][10][11][12][13][14][15][16][17] ...…”

“…Le hombre de segments atteints d'hypoesth&ie ~ la piq0re a &~, dans les trois sous-groupes de m~pivaca~ine 1%, de 10,5 [2-22], I 0,5 [4][5][6][7][8][9][10][11][12][13][14][15][16][17] et I I [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], respectivement. Les segments du groupe de m~pivaca'ine 1,5 % ont ~t~ de 12 [7,[5][6][7][8][9][10][11][12][13][14][15][16]], 12 [-1,5-17] et de I 1,5 [5][6][7][8][9][10][11][12][13][14][15]…”