Why can't spinal anaesthesia work from chest down?

[scilearner]

Hello everyone

 

Here are some questions I have about spinal anaesthesia

 

1. I know it is usually done below L3 because that is where spinal cord ends and not done above that because spinal cord can get damaged. But can't a really skilled person give it above L3, because subarachnoid space ends before spinal cord? So if he stops at the right time wouldn't it work giving anaesthesia from a higher level.

 

2. Why does the spinal anaesthetic agent only act below the point it was administered. Can't it diffuse up and affect the whole spinal cord?

 

3. Why can you achieve higher level anaestheisa (Meaning from chest to toe) from epidural anaesthesia?

 

4. What is the difference between paraesthesia and numbness. Don't they both mean lack of senastion?

 

Thanks

Edited February 8, 2014 by scilearner

[DogLady]

Spinal anesthesia can be placed higher, but the risk for paralyzing the muscles of respiration (the diaphragm and intercostal muscles) increases. The anesthesia used can also diffuse higher (usually no more than 1 or 2 vertebral segments). To allow for some leeway, the spinal is placed no higher than absolutely necessary. Sometimes the patient is kept in a seated position for a minute or two after the spinal has been placed so the anesthetic will settle lower and not diffuse upward.

 

Spinal anesthesia is done so the patient doesn't have to be completely sedated and paralyzed, and placed on a breathing machine, so avoiding that paralysis is essential.

 

Paresthesias is a general term referring to abnormal sensation, including numbness, but also tingling, burning pain, lancinating pain, other sensations.

 

FWIW,

Clarissa

[scilearner]

Thanks a lot for the response Clarissa That did clear up most of my questions. Hope you are around the forum, if I have more anaesthesia questionsv

I have more questions

 

 

3) Since in epidural anesthesia, you only go to epidural space and there is less chance of damaging spinal cord, can't you give it above L1 (Not too high to block resp centre) to achieve anaesthesia in a greater region of the body. Why isn't this done regularly?

4)Is epidural also given at spinal level (meaning below L1) in normal setup? If so what is the basic difference in action between them. I understand the difference in procedure (spinal is just one shot, epidural you can continuosuly administer drugs via catheter), what I'm asking is differenc e in action?

5) If mothers in labour are given epidural, wouldn't the epidural catheter get dislodged when they are moving in pain? Sort of stupid question but just asking.