Spec Grav of Local anesthetics

mwbeah · Feb 1, 2005

Can anyone tell me where I can find (or just tell me) the specific gravities of the local anesthetics ie. marcaine .75%, lidocaine 5%, tetracaine 1% in their solutions with dextrose? I was asked this in clinical and have not been able to track down an answer. I know that they are hyperbaric and more than 1.009 or whatever but can anyone tell me their exact spec gravs?

This formula will work for marcaine:

The formula [sG = 1.006 + .038 (%bupivacaine concentration)] may be used to predict the SG; however, for simplicity each 10mcg of fentanyl added to 1.2mL of 0.75% spinal bupivacaine causes a 0.0020--0.0040 decrease in SG. It is important to understand that fentanyl added to enhance a spinal anesthetic lowers its baricity, and thus possibly may increase the height of blockade.

Table 1. SG of spinal bupivacaine solutionsSpinal bupivPlain Fent1.2ml+10mcg1.2ml+20mcg1.2ml+30mcg%bupiv0.75%0.0%0.64%0.56%0.50%11.03400.98001.03101.02721.024821.03400.98001.03151.02701.024231.03470.98101.02991.02681.025041.03400.98511.03001.02721.025551.03400.98501.03011.02701.025861.03400.98001.31301.02651.0250Average1.03410.98101.03121.02691.0249+/-SD0.00030.00200.00070.00030.0006

Reference:

Addition of Fentanyl Alters the Baricity of Hyperbaric Spinal Bupivacaine

Clinton Z. Kakazu, M.D., Chingmuh Lee, M.D., John S. McDonald, M.D.

Department of Anesthesiology, Harbor-UCLA Medical Center, Torrance, California

athomas91 · Feb 1, 2005

morgan and mikhail has it all listed in a chart as well...good luck

apaisRN, RN, CRNA · Feb 3, 2005

Wow, that was an intimidating cluster of numbers! Can't believe I'll be learning stuff like this soon.