To Propofol or Not to Propofol?

[Peak]

Inotropes should be titrated to markers of perfusion, which (unless there is a Swann or non-invasive cardiac output monitor) is usually a thoughtful gestalt of the clinical exam, echo, labs, etc. While I recognize that nurses are capable of being thoughtful, it's a different matter from just responding to an isolated bedside variable like the blood pressure.

Titrating vasopressin is controversial. I don't usually do it, although I wouldn't argue if someone wanted to. In any case it's not exactly a model of fine-tuning; usually people just move between .04 and 0 in two or three clicks at most.

We predominantly use LA (left atrial), RA (right atrial), PA (far less common), peripheral art lines as well as calculating hemodynamics based on central venous and arterial gasses on our kids.

 

[E tank]

That's a bit like saying you can't titrate milrinone or vaso.

"Titration" is a concept that is interwoven into a vast and complex pattern of pharmacodynamics and pharmacokinetics. To conflate milrinone and vasopressin in the context of titration, is, at the most charitable, naive...

 

[E tank]

Many, but certainly not all. Definitely not in the last glenn I took care of.

Do tell...what was the role of vasopressin in the last glenn shunt you took care of?

 

[Peak]

Do tell...what was the role of vasopressin in the last glenn shunt you took care of?

It helped out their hypotension related to their post OP infection.

 

[CWATT]

@CWATT Are you carrying propofol or are you only allowed to maintain it during transfers?.

We carry it.

 

[Carlos Danger]

@Remi — how does this apply to Ketamine which does not interact with GABA receptors? My understanding is Ketamine offers mild analgesia but it is strongly recommended -and I always did- add Fentanyl for patient comfort.

As an aside, there are some references that implicate ketamine in both GABA and opioid receptor agonism. Really just depends on what you read. Lots that we don't know about the drug still, but it seems pretty good at almost everything that people try to use it for. Which is everything from acute pain, to procedural sedation, to status epilepticus, to treating chronic pain and addictions and depression and suicidal ideation. Pretty impressive.

IME, ketamine is not a good drug for use as a primary analgesic. A small dose of ketamine (10-20mg) is a great adjunct to a healthy dose of opioid for someone who is having a lot of pain. But by itself, you need a higher dose of ketamine (50mg+) than you probably want to use, in order to get serious pain under control. Once you get above about 0.5mg/kg, the analgesic effects will still increase, bu so do the psych effects.

First line IMO for severe acute pain (esp out-of-hospital) should still be be fentanyl, followed by small doses of ketamine if needed. Much higher doses of opioids and non-opioid adjuncts (ketamine, a-agonists) might be needed in a very opioid-tolerant patient, but opioids are still where it's at, generally speaking.

 

[Tigger]

As an aside, there are some references that implicate ketamine in both GABA and opioid receptor agonism. Really just depends on what you read. Lots that we don't know about the drug still, but it seems pretty good at almost everything that people try to use it for. Which is everything from acute pain, to procedural sedation, to status epilepticus, to treating chronic pain and addictions and depression and suicidal ideation. Pretty impressive.

IME, ketamine is not a good drug for use as a primary analgesic. A small dose of ketamine (10-20mg) is a great adjunct to a healthy dose of opioid for someone who is having a lot of pain. But by itself, you need a higher dose of ketamine (50mg+) than you probably want to use, in order to get serious pain under control. Once you get above about 0.5mg/kg, the analgesic effects will still increase, bu so do the psych effects.

First line IMO for severe acute pain (esp out-of-hospital) should still be be fentanyl, followed by small doses of ketamine if needed. Much higher doses of opioids and non-opioid adjuncts (ketamine, a-agonists) might be needed in a very opioid-tolerant patient, but opioids are still where it's at, generally speaking.

For whatever reasons, one of the systems I work in trialled Ketamine as the first-line analgesic and boy was that an exciting time. I agree that a combination therapy is nearly always successful though I generally find that 0.3mg/kg seems to provide all the analgesia the patient could ever want and more.

 

[SpecialK]

I'd stay away from propofol for induction of general anaesthesia in the patients tending to need it pre-hospital. You cannot extrapolate what is used in elective anaesthesia to the patients seen pre-hospital; or at least the majority who need to sent to sleep. Somebody who needs a munted femur realigned and has no other problems then perhaps ....

I've never heard of ketamine as a first-up pain relief; except in burns or the patient is trapped and the fire brigade are needing to do painful things to free them. A great example recently is a bloke who was trapped in his smashed car. He had a whole bunch of fractures and was screaming in agony. The fireys needed to turn his car into pieces to get him out and it was going to take a while. Aliquots of intravenous morphine just weren't going to cut it so he got a big dose of ketamine to settle him down, provide analgesia, and a bit of forgetting and got him out fine.

First-up pain relief is generally methoxyflurane (since don't have entonox anymore, grrr) and either a combination of oral paracetamol, ibuprofen, and tramadol if the pain is not severe, or if they are in bad pain then intravenous morphine. Take for example somebody who has an isolated radius and ulna fracture and it's painful but not my femur is in two halves painful; methoxyflurane, and oral PIT in combination is generally all that is needed.

With the new CPGs coming soon are fascia illicia blocks with 0.75% somethingacaine (I forget which). This is going to be great for people with NOFs and femur fractures so their leg can get taken out rather than having to load them up on opiates or ketamine. I can also see this coming for median, ulna or radial nerves in the arm too.

 

[Brandon O]

You guys are doing blocks in the field?

 

[Scott33]

I believe that Paramedic Practitioners in SECAMB (UK, NHS) have, or had, the ability to do digital nerve blocks for wound care to the fingers in the field. Not sure if anyone other than doctors are doing femoral nerve blocks for lower extremity fractures, but I believe it was at least considered. The difference being is that one of the above conditions will always still need an ambulance and hospital, the other won’t....necessarily.

 

[SpecialK]

Digital nerve blocks with SQ lignocaine have been in for a couple of years now for Paramedics and ICPs. Fascia illicia blocks are a logical extension, as would be wrist and arm blocks and perhaps costal blocks.

 

[Carlos Danger]

Digital nerve blocks with SQ lignocaine have been in for a couple of years now for Paramedics and ICPs. Fascia illicia blocks are a logical extension, as would be wrist and arm blocks and perhaps costal blocks.

I don't see how that is a logical extension at all, because digital blocks and fascia iliaca blocks couldn't be more different.

A digital block isn't really a nerve block, it's just infiltration of some tissue with a small amount of local anesthetic. It doesn't require any special equipment or skill at all. Precise placement is unimportant and spread of the local isn't an issue. The volume of local is very small and there are no important organs or vessels in the area, so safety is of little concern. You could literally show a layperson one time how to do these and they'd probably have nearly 100% success rate in doing them on their own, with virtually no risk to the patient.

A FICB, on the other hand, requires special equipment (ultrasound and block needles - it can be done by landmark and feel, but rates of success with that method are inconsistent even among anesthesia providers who are adept at regional anesthesia and are doing the procedure in ideal conditions), and a fair amount of training and experience to achieve any consistent rate of success and safety for the patient. You need precise needle placement and proper spread in order to get a good block. You are injecting a very high volume of local (40ml is common) in the region of some critical organs, so the potential safety implications are not at all trivial. They aren't a hard block to learn by any means, but learning any kind of nerve block certainly takes practice.

The biggest problems with doing a FICB (or most other nerve blocks) in the field are practical. Like most blocks, patient positioning is important both for visualization and proper spread of the local. It would be very difficult if not impossible to do a successful FICB in a patient trapped in a car in a seated position, for instance, even for someone with a lot of experience doing nerve blocks. Also, these blocks take time to set up. You don't just place the needle, inject, pull the needle out and immediately do whatever painful procedure you are preparing for. It generally take at least 10, often 20 minutes or so for the local to spread and soak into the nerves and provide the anesthesia you are looking for. Finally, these blocks don't provide the type of dense anesthesia that you might be envisioning. It isn't like a spinal where the entirety of the lower extremity is completely insensate, or a supraclavicular block that does the same thing to the arm. A FICB that is working well covers the hip, femur, and lateral thigh pretty consistently, but beyond that, coverage and block density is quite variable, especially below the knee. Nine times out of ten you will still be giving these patients a fair amount of analgesics, even if the block works pretty well.

I did HEMS for over ten years and was present on countless MVC extrications, and now I do nerve blocks every day in the hospital. I can envision very little utility for these in the field. These scenarios are what versed and ketamine are made for. My prediction is that there will pretty rarely be attempted in the field, and when they are they will result in much longer scene times and low success rates, and will ultimately have little if any impact on patient outcomes or on the amount of drugs you have to give.