Spinal Cord and Cerebral Blood Flow Responses to Subarachnoid Injection of Local Anesthetics with and without Epinephrine

S. S. Porter, M. S. Albin, W. A. Watson, L. Bunegin, G. Pantoja

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46 Scopus citations


Subarachnoid anesthesia with lidocaine, mepivacaine, or tetracaine with and without added epinephrine (1:100000) produced no demonstrable changes in average cerebral (CBF) or segmental spinal cord blood flow (SCBF) in 38 cats anesthetized with pentobarbital. Blood flow was measured by the injection of radioactive microspheres. Seven groups of cats received either lidocaine 15 mg, lidocaine 15 mg with epinephrine, mepivacaine 10 mg, mepivacaine 10 mg with epinephrine, tetracaine 5 mg, tetracaine 5 mg with epinephrine, or saline with epinephrine 1:100000. Mean arterial pressure (MAP) decreased significantly (P<0.05) in Groups I‐VI. Added epinephrine had no effect on the decrease in MAP. Amplitude of the somatosensory cortical evoked response decreased significantly in Groups I‐VI, but did not change from control in Group VII. No significant change in CBF or SCBF was demonstrated in any group at any time. Plasma lidocaine and mepivacaine levels were significantly less at 5 min after subarachnoid injection in the groups receiving epinephrine compared to those not receiving epinephrine (P<0.05). The data appear to support the hypothesis of a vasoconstrictive reduction in systemic absorption of intrathecal local anesthetics, but suggest that significant segmental spinal cord ischemia does not occur. Maintenance of total flow in the face of a decrease in MAP suggests that autoregulation in brain and spinal cord may be maintained. Changes in regional SCBF or CBF may have been present but were not examined in this study. Further studies of brain and spinal cord blood flow dynamics, regional flow changes, and regulation of flow after intrathecal agents are necessary.

Original languageEnglish (US)
Pages (from-to)330-338
Number of pages9
JournalActa Anaesthesiologica Scandinavica
Issue number3
StatePublished - Apr 1985


  • Anesthesia
  • blood flow
  • spinal
  • spinal cord
  • vasoconstrictors

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine


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