Korean J Anesthesiol.  2005 Dec;49(6):793-797. 10.4097/kjae.2005.49.6.793.

The Effect of Injection Speed of Local Anesthetic on Success Rate of Unilateral Spinal Anesthesia

• Cho HS
• Son YS
• Chung KD
• Lee WH
• Park JM
• Chung JH
• Lee SM

• KMID: 1894316
• DOI: http://doi.org/10.4097/kjae.2005.49.6.793

Abstract

BACKGROUND: The relationship between the injection speed of a local anesthetic and the success rate of unilateral spinal anesthesia has been a controversial issue. The aim of this thesis was to identify any significant effects of the drug injection speed on the success rate of unilateral spinal anesthesia.
METHODS
Forty patients were randomly allocated into 2 groups, group R and S. The injection speed was 4 ml/min in group R (n = 20) and 1 ml/min in group S (n = 20). Hyperbaric 0.5% bupivacaine 10 mg was injected via a syringe pump. The drug was administered at the L3-4 intervertebral space with the patient in the lateral decubitus position, which was maintained for 20 minutes after the injection. A spinal sensory block was assessed by examining the temperature sensation using an alcohol-sponge. The motor block was evaluated using the modified Bromage scale and the dependent and non-dependent sides were compared.
RESULTS
Significant differences (P<0.05) were observed in the success rate of unilateral motor paralysis (45% in group R vs 90% in group S). There were no significant blood pressure differences between the two groups 5, 10, 15, 30 and 60 minutes after injecting the hyperbaric 0.5% bupivacaine.
CONCLUSIONS
The injection speed of local anesthetics is one of the crucial factors for achieving a unilateral spinal anesthesia. Therefore, it is important to maintain a slow injection speed of a local anesthetic in unilateral spinal anesthesia.

Keyword

injection speed; success rate; unilateral spinal anesthesia

MeSH Terms

Anesthesia, Spinal*
Anesthetics, Local
Blood Pressure
Bupivacaine
Humans
Paralysis
Sensation
Syringes
Anesthetics, Local
Bupivacaine