How long to wait for unilateral spinal?

[soorg]

With any hyperbaric LA, how long do you keep your patient operative side down for before positioning them for surgery? I've heard various answers from two minutes to ten minutes. I usually wait a bit five minutes, but still sometimes get a pretty dense bilateral block...

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[Planktonmd]

With any hyperbaric LA, how long do you keep your patient operative side down for before positioning them for surgery? I've heard various answers from two minutes to ten minutes. I usually wait a bit five minutes, but still sometimes get a pretty dense bilateral block...

That whole unilateral block thing is very unpredictable and most of the time you end up with a bilateral block regardless of how long you wait.
Waiting 5 minutes could feel like hours when everyone in the room is standing there waiting for your permission to position the patient and move on. So I would say a couple of minutes is good enough and if you get a unilateral block it's great, if not, maybe next time.

 

[leaverus]

if you get a unilateral block it's great, if not, maybe next time.

never even heard of such a thing. why is it great? what's the advantage of specifically aiming for a unilateral block? does it last longer? is it more dense? and what kind of procedures - hips and knees? seems more a waste of time than anything but please educate me if i'm wrong.

 

[ZzzPlz]

never even heard of such a thing. why is it great? what's the advantage of specifically aiming for a unilateral block? does it last longer? is it more dense? and what kind of procedures - hips and knees? seems more a waste of time than anything but please educate me if i'm wrong.

For C Sections I'll have the ladies lie prone for a few minutes to really get the incision site covered

 

[twoliter]

never even heard of such a thing. why is it great? what's the advantage of specifically aiming for a unilateral block? does it last longer? is it more dense? and what kind of procedures - hips and knees? seems more a waste of time than anything but please educate me if i'm wrong.

Should be less undesired side effect (HoTN, urinary retention, etc.) theoretically. May not be a huge factor, but can't hurt, right? Also, I'm sure it's less a desire for a unilateral block as it is a desire to ensure an effective block on the operative side.

 

[psychbender]

Use isobaric bupi with the patient positioned for surgery, and you won't have to worry about the block not being dense enough on the operative side.

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[pgg]

Use isobaric bupi with the patient positioned for surgery, and you won't have to worry about the block not being dense enough on the operative side.

It's also a kindness to not put hip fx patients broken-side-down for their spinals.

 

[facted]

It's also a kindness to not put hip fx patients broken-side-down for their spinals.

Broken side is usually less painful than the other, but a Little ketamine makes that a moot point. Agree with the isobaric though.

 

[Planktonmd]

never even heard of such a thing. why is it great? what's the advantage of specifically aiming for a unilateral block? does it last longer? is it more dense? and what kind of procedures - hips and knees? seems more a waste of time than anything but please educate me if i'm wrong.

A unilateral block is supposed to theoretically cause less sympathetic blockade and as a result less hypotension for procedures that require only unilateral anesthesia (hips, knees...).
You never heard of this?

 

[d9sccr]

A unilateral block is supposed to theoretically cause less sympathetic blockade and as a result less hypotension for procedures that require only unilateral anesthesia (hips, knees...).
You never heard of this?

Is that dependent on which side you're measuring BP?
Do you use less total dose of spinal medication to prevent cephalad spread?
I don't know anyone that uses a unilateral spinal, although there aren't many cases in residency that the surgeons would complete before it wore off

 

[Planktonmd]

Is that dependent on which side you're measuring BP?
Do you use less total dose of spinal medication to prevent cephalad spread?
I don't know anyone that uses a unilateral spinal, although there aren't many cases in residency that the surgeons would complete before it wore off

The sympathetic blockade on one side should theoretically cause vasodilation and fluid pooling in one side as opposed to 2 sides when the block is bilateral, which could explain why you have less hypotension. notice I am saying (theoretically).
Look at this old study that suggests waiting 10 minutes:

Unilateral spinal anaesthesia with hyperbaric bupivacaine. - PubMed - NCBI

 

[twoliter]

Is that dependent on which side you're measuring BP?
Do you use less total dose of spinal medication to prevent cephalad spread?
I don't know anyone that uses a unilateral spinal, although there aren't many cases in residency that the surgeons would complete before it wore off

Would you expect the blood pressure to be lower on one side than the other?

 

[deleted162650]

Ya know what else causes less hypotension?

An isobaric spinal.

 

[Planktonmd]

Ya know what else causes less hypotension?

An isobaric spinal.

True... but sometimes it might last longer than you want.

 

[facted]

True... but sometimes it might last longer than you want.

Depends on how much bupi you use. You can use as low as 1-1.2ml of 0.5. lasts a little more than an hour and a half to two hours in my experience. Height is fine for hip surgery.

 

[Scotty_G]

Most people are not going to wait ten min in the OR in pp setting. Use isobaric if your concerned and be done with it.

 

[leaverus]

A unilateral block is supposed to theoretically cause less sympathetic blockade and as a result less hypotension for procedures that require only unilateral anesthesia (hips, knees...).
You never heard of this?

Nope, never once saw it in residency nor in 10yrs of pp. Must be a geographic thing. And honestly i dont care about theoretical; does it work?

 

[OneFellSwoop]

I've attempted a few. The unilaterality is unpredictable and it's a good way to waste time and piss off surgeons who are waiting to get started. Do your spinal, run a neo gtt if needed and be done with it.


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[soorg]

Have done a few-sort of stupid, but I just wanted to see if it really worked while waiting longer for the block to set in. Usually end up with some element of a bilateral block.

 

[deleted59964]

while i accept that waiting for a unilateral block may not be practical / good business.... having a sound knowledge of spinal anaesthesia, and the behaviour of different local anaesthetics -- is kinda key to our specialty IMHO.

 

[dhb]

Nope, never once saw it in residency nor in 10yrs of pp. Must be a geographic thing. And honestly i dont care about theoretical; does it work?

Yes it works: i turn the needle with the eye down, inject slowly a lower volume than for a bilateral and wait 5min.
It's a nice trick to have in your bag , of course you can do a 3cc isobaric spinal for 99% of cases but i like to be a little more elegant.

 

[Planktonmd]

Nope, never once saw it in residency nor in 10yrs of pp. Must be a geographic thing. And honestly i dont care about theoretical; does it work?

It does work when done right! Why do you sound upset?

 

[facted]

It does work when done right! Why do you sound upset?

Therev is no doubt this can work. I tried it once on residency. It was fun and then I realized this is one of the most useless techniques in anesthesia. You have to wait longer and the benefit is.....???

Use a 1.5-2ml of 0.5% and call it a day.

 

[Planktonmd]

Therev is no doubt this can work. I tried it once on residency. It was fun and then I realized this is one of the most useless techniques in anesthesia. You have to wait longer and the benefit is.....???

Use a 1.5-2ml of 0.5% and call it a day.

It does produce less hypotension, and possibly less urinary retention. So it's worth trying in certain situations where no one is breathing down your neck.
But I agree, in most cases it's not very practical.

 

[fakin' the funk]

Ya know what else causes less hypotension?

An isobaric spinal.

Isobaric spinals were shockingly undertaught/underused in residency. And incredibly useful.

For hip fx cases I like to (first, have spinal tray plus a 22g needle open and ready) pop em with about 20 prop 20 ketamine, roll fracture side up, and do the spinal. My success rate is not that great - the positioning is never perfect vs sitting, and there is usually a wall of bone - but it's my best shot.

 

[deleted162650]

Isobaric spinals were shockingly undertaught/underused in residency.

That's because our surgeons were too slow for neuraxial.

 

[d9sccr]

Would you expect the blood pressure to be lower on one side than the other?

If you had a high enough spinal, I'd think that's possible. A unilateral sympathectomy would reduce vascular tone to that side, leading to a difference in BP on the two sides, no?

 

[dhb]

this is one of the most useless techniques in anesthesia.

Disagree

 

[Arch Guillotti]

For hip fx cases I like to (first, have spinal tray plus a 22g needle open and ready) pop em with about 20 prop 20 ketamine, roll fracture side up, and do the spinal. My success rate is not that great - the positioning is never perfect vs sitting, and there is usually a wall of bone - but it's my best shot.

Do you ever try a paramedian approach with the 22 gauge?

 

[facted]

Disagree

Why? What's the utility? With 1.5 of 0.5% I don't really get hypotension usually in the elderly. What problem are you solving?

 

[facted]

Isobaric spinals were shockingly undertaught/underused in residency. And incredibly useful.

For hip fx cases I like to (first, have spinal tray plus a 22g needle open and ready) pop em with about 20 prop 20 ketamine, roll fracture side up, and do the spinal. My success rate is not that great - the positioning is never perfect vs sitting, and there is usually a wall of bone - but it's my best shot.

Hard to believe, but the fracture side down is actually less painful because the bone isn't just flying on the wind. You might be able to improve position though I agree with the ketamine which makes the pain somewhat of a moot point.

 

[pgg]

Hard to believe, but the fracture side down is actually less painful because the bone isn't just flying on the wind. You might be able to improve position though I agree with the ketamine which makes the pain somewhat of a moot point.

My experience differs. Having started out my anesthesia life doing hyperbaric spinals on broken-side-down patients, and later switching to isobaric spinals on broken-side-up patients ... the difference has seemed pretty clear to me. A little ketamine helps but the iso/broken-up group seems to need it less.

 

[Arch Guillotti]

Hard to believe, but the fracture side down is actually less painful because the bone isn't just flying on the wind. You might be able to improve position though I agree with the ketamine which makes the pain somewhat of a moot point.

Disagree.

 

[fakin' the funk]

Do you ever try a paramedian approach with the 22 gauge?

Half the time the patient is sunk into one of those ****ty inpatient beds and I don't know whats midline, paramedian, parasagittal, axial, etc etc.

 

[dhb]

Why? What's the utility? With 1.5 of 0.5% I don't really get hypotension usually in the elderly. What problem are you solving?

1.5ml of iso in an old lady can last more than 2h easily.
I like to mix it up, i leave the cookie cutter anesthesia to other "providers"