Canadian Journal of Anaesthesia

, Volume 46, Issue 10, pp 930–934 | Cite as

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

  • Toshiyuki Okutomi
  • Makiko Minakawa
  • Sumio Hoka
Reports of Investigation



To examine the effects of the volume of saline and the concentration of local anesthetic on the quality of anesthetic level.


One hundred and fifty two patients received thoracic epidural anesthesia were allocated into two groups; mepivacaine 1% (75 patients) and 1.5% (77 patients). Each group was randomly divided into three sub-groups depending on epidural saline volumes of 1 ml, 5 ml, or 10 ml. Fifteen minutes after the injection of 10 ml mepivacaine, the dermatome levels of hypesthesia to cold and pinprick were determined by an individual blinded to the saline volume.


The number of spinal segments with hypesthesia to cold in the three subgroups in the mepivacaine 1% group were 12.5 [6–20], 13 [8.5–20.5] and 12.5 [6.5–22], respectively (median [range]). The segments in the mepivacaine 1.5% group were 12 [7–18.5], 14 [8.5–19]* and 15 [6–23]*, respectively (*P < 0.05vs 1 -ml group). The number of spinal segments with hypesthesia for pinprick in the three subgroups in the 1% mepivacaine group were 10.5 [2–22], 10.5 [4–17] and 11 [4–19], respectively. The segments in the mepivacaine 1.5% group were 12 [7.5–16], 12 [7.5–17] and 11.5 [5–22.5], 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%. In both groups, a differential nerve block was elicited in the 5 ml and 10 ml saline subgroups.


When a large volume of saline is administered prior to local anesthetic, more differential blockade and a greater extent of anesthesia may be elicited.


Epidural Catheter Epidural Space Spinal Segment Mepivacaine Thoracic Epidural Anesthesia 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



Examiner les effets du volume de solution salée et de la concentration d’anesthésique local sur la qualité de l’anesthésie.


Cent cinquante-deux patients qui ont reçu une anesthésie péridurale thoracique ont été répartis en deux groupes: mépivacaïne 1% (75 patients) et 1,5% (77 patients). Chaque groupe a été divisé au hasard en trois sous-groupes selon les volumes de solution salée péridurale administrée, 1, 5 ou 10 ml. Quinze minutes après l’injection de 10 ml de mépivacaïne, le niveau du dermatome touché d’hypoesthésie au froid et à la piqûre a été déterminé par une personne ignorant le volume de solution salée donné.


Le nombre de segments médullaires atteints d’hypoesthésie au froid a été, dans les trois sous-groupes qui ont reçu la mépivacaïne 1%, de 12,5 [6–20], 13 [8,5–20,5] et de 12,5 [6,5–22], respectivement (médiane [étendue]). Dans le groupe qui a reçu la mépivacaïne 1,5%, les segments ont été: 12 [7–18,5], 14 [8,5–19]* et 15 [6–23]*, respectivement (*P < 0,05vs le groupe 1 ml). Le nombre de segments atteints d’hypoesthésie à la piqûre a été, dans les trois sous-groupes de mépivacaïne 1%, de 10,5 [2–22], 10,5 [4–17] et 11 [4–19], respectivement. Les segments du groupe de mépivacaïne 1,5% ont été de 12 [7,5–16], 12 [7,5–17] et de 11,5 [5–22,5], respectivement. Le volume de solution salée n’a pas changé le niveau anesthésique de la mépivacaïne 1%, mais il a eu un effet sur l’étendue anesthésique de mépivacaïne 1,5%. Dans les deux groupes, un blocage nerveux différentiel a été provoqué dans les sous-groupes de patients qui ont reçu 5 et 10 ml de solution salée.


Lorsqu’on administre un grand volume de solution salée avant l’anesthésique local, on peut obtenir davantage de blocage différentiel et une plus grande étendue de l’anesthésie.


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Copyright information

© Canadian Anesthesiologists 1999

Authors and Affiliations

  • Toshiyuki Okutomi
    • 1
  • Makiko Minakawa
    • 1
  • Sumio Hoka
    • 1
  1. 1.Department of AnesthesiologyKitasato University School of MedicineSagamihara KanagawaJapan

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