Why can't spinal anaesthesia work from chest down?

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In summary: 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. Women are given epidurals while in labor and it stops
  • #1
sameeralord
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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 :smile:
 
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  • #2
If the entire spinal cord becomes anaesthetised, what do you think will happen to the patient's respiration?
 
  • #3
SteamKing said:
If the entire spinal cord becomes anaesthetised, what do you think will happen to the patient's respiration?

Thanks for the response :) Yeah respiratory centre would not work. But I mean not that high, why can't you give spinal from like T2 level, so only shoulder down will get paralysed. Isn't respiratory centre located in medulla oblongota, so why can't you give it a bit below that? What are the answers for my other questions.
 
  • #4
What about the diaphragm?
 
  • #5
Yanick said:
What about the diaphragm?

"C3, C4, C5 keep the diaphragm alive " :biggrin:

sameeralord said:
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 :smile:

You can do it at high levels, but like you mentioned there are increased complications the high up you go. High spinal or total spinal blocks are avoided because, like mentioned, you get respiratory effects. I suppose you could mechanically ventilate the patient but if going to this extreme then general anesthesia is safer and better anyway--so why not use that? Especially because with general, you don't run the risk of damaging the cord--a not so great complication of spinal blocks. So above the level of L1 it is not longer the preferred method.

To answer your second question, yes it can diffuse upward. Though not much, but again this is a reason why high spinal blocks aren't preferred.

I'm not sure by what you mean here "high level anasthesia". Do you have a source or can you explain better what you are asking here>?
 
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Thanks a lot for all the responses, especially Bobze :smile:

The replies cleared most of my doubts.

What I mean from the 3rd question is

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.

Thanks :smile:
 
  • #7
sameeralord said:
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?
Why would this be needed?

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.
Women are given epidurals while in labor and it stops the pain. I don't know what you mean here either.
 
  • #8
sameeralord said:
Thanks a lot for all the responses, especially Bobze :smile:

The replies cleared most of my doubts.

What I mean from the 3rd question is

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?

Yes, you can but for the same reasons mentioned before general anesthesia is preferred. Its really operator dependent, hospital policy, drug availability, anesthesiologist dependent etc. Epidurals take more training and skill to administer than spinal blocks.

sameeralord said:
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?

There isn't much difference. They can even use the same drugs. However, spinals typically tend to work faster and are easier to do, but would require repositioning the patient to readminister anesthetic during the procedure. Therefore, in longer procedures epidurals are preferred, because the catheter (soft) in place allows easy redosing. When both are placed correctly spinals also tend to cause more hypotension that requires intervention than epidurals. Epidurals can cause hypotension as well, but less so than spinals when done correctly.

sameeralord said:
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.

Thanks :smile:

No. If the epidural is done correctly she shouldn't be moving in pain :). The catheters are soft, but are generally held in place with something like tegaderm.
 
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  • #9
Thanks Bobze :smile:
 

Related to Why can't spinal anaesthesia work from chest down?

1. Why can't spinal anaesthesia work from chest down?

Spinal anaesthesia works by injecting numbing medication into the fluid surrounding the spinal cord, which then blocks nerve signals and causes numbness. However, since the nerves that control sensation in the chest and abdomen originate from higher levels of the spinal cord, the medication injected into the lower spine will not reach these nerves and therefore cannot produce numbness in these areas.

2. Can spinal anaesthesia be used for surgeries below the chest?

No, spinal anaesthesia is not effective for surgeries below the chest because it cannot produce numbness in the lower body. This type of anaesthesia is typically used for surgeries on the lower limbs, pelvic region, and lower abdomen.

3. Are there any alternatives to spinal anaesthesia for surgeries below the chest?

Yes, there are other forms of anaesthesia that can be used for surgeries below the chest, such as epidural anaesthesia or general anaesthesia. Your healthcare provider will determine the most appropriate type of anaesthesia based on your individual needs and the type of surgery being performed.

4. Why is spinal anaesthesia only effective for surgeries on the lower body?

As mentioned before, spinal anaesthesia works by blocking nerve signals from the lower spine. Since the nerves that control sensation in the upper body originate from higher levels of the spinal cord, the medication injected into the lower spine will not reach these nerves and therefore cannot produce numbness in these areas.

5. Can spinal anaesthesia cause paralysis?

There is a small risk of paralysis with any type of anaesthesia, including spinal anaesthesia. However, this risk is extremely rare and typically only occurs when there are complications during the injection. Your healthcare provider will carefully monitor you during the procedure to minimize this risk.

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