Category Archives: Analgesia

Analgesia

Look Back at Analgesia

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It seems like a simple thing that’s a given – delivery of good analgesia. Except for the bit where good clinicians fail over and over at this. Here’s Dr Alan Garner checking out a recent study from the Swiss that looks at some of the holes. 

As prehospital clinicians I think we all aim to provide as technically sound and evidence-based management as we can.  This is a given but when I think about what I would like for my own family or myself I also want “care”.  This is what makes health care interactions more than just an exchange of services for money. And this is what sends me crazy when I hear patients described as “clients”.

But I am digressing.  A major component of care is the relief of suffering and the most common form of suffering we see in the prehospital world is pain.  Good pain relief early might not change the patient’s probability of death in the longer term but it might well change functional outcomes such as symptoms of post traumatic stress disorder.  But most of all we should do it, and do it well because we care.

There have been a lot of studies published about management of pain in emergency departments and it almost always looks bad.  People with obviously painful conditions either not getting analgesia, getting it late or not getting enough.  Given that the most common single presenting complaint to emergency departments is pain of some kind, I would argue that a fundamental KPI of good emergency care should be time to adequate pain relief and this should be reported above the 4 hour rule, access block and any other process indicator.  Waiting for a bed for hours is regrettable but waiting for hours in agony is simply barbaric.

If EDs are doing it badly you can be reasonably confident that prehospital is worse given all the additional constraints.  A new study has just been published by the guys from REGA (Swiss Air Ambulance) building on some work they have done previously around the prehospital analgesia question.  The work arose from a quality assurance project on analgesia that they have been conducting across their organisation to try and improve pain management and they are much to be commended for sharing their work on this.  They have allowed us a view into their struggle so we can learn from them.

And it has been a struggle.  In this new study they documented that one in six patients with moderate to severe pain (defined as >3 on a 0-10 numerical rating scale as reported by the patient) did not get any prehospital analgesia at all!  This is even more noteworthy given that the physician documented the pain score of >3 at the scene but apparently did not act on it for some reason.  One clue might be that a predictor of inadequate analgesia was shorter scene times and more severe injury (higher NACA score).  I was wondering if hypotension therefore might be one of the drivers for no analgesia but “circulation insufficient” was pretty uncommon being present in only 13 of the 778 conscious patients in this study (this stuff is in Table 1 in the paper).

 

Local Stories

Several years ago we audited the analgesia given to children by our own service.  In some cases we did not give analgesia for clearly painful injuries (like bent long bones) but there was evidence that the road paramedics who had been there ahead of us had done so.  There is no mention of this occurring in the Swiss study.  Perhaps this might partially explain the lack of analgesia given if this is also occurring in their system.  Although even if this did occur the physicians still documented pain scores >3 whilst the patient was in their care which you would have thought would prompt further analgesia.

I am not meaning to be too critical here.  In the audit of our own service that I mentioned we also found cases with clearly painful injuries and no record of analgesia given by road paramedics or our doctors.  This prompted a major rethink for us in our approach to analgesia in the field including formally recording pain scores on our observations chart to prompt our teams to keep this front of mind.  Analgesia is also included as an item in all our Carebundles for traumatic conditions, and for intubated patients regardless of the underlying pathology.  One of the risks for inadequate analgesia identified in this new study was that the patient had a non-trauma problem.  It might be timely for us to review our Carebundles for non-trauma conditions too.

Digging Deeper

Another risk factor for inadequate analgesia was severe pain from the outset (score 8 or more).  In this situation it seemed a single agent just was not enough.  Judicious use of small amounts of ketamine in addition to the opioid appeared really useful here.  And it appeared the combination was better in severe pain rather than just ketamine as a single agent.

I am also a little surprised about the narrow modes of delivery utilised with all analgesia given IV.  In our system the nasal route for fentanyl is used frequently particularly for children and it works a treat.  I also think that regional blocks have a place, particularly where the injury mechanism and your exam indicate that the injury is confined to a limb and the situation is not time critical (the time it takes is probably the major contraindication prehospital).

We have recently formally introduced fascia iliaca blocks to our service.  There are lots of other blocks you can utilise , particularly if your service carries an ultrasound machine with an appropriate probe for nerve localisation.  This is a skill you are unlikely to learn prehospital (except perhaps for femoral or fascia iliaca blocks) as you will never do enough of the other types to develop any skill.  If part of your practice is in the hospital context where you can get lots of practice however, these are well worth learning.  Done well they can completely remove the need for parenteral opiates.  The context that we have used regional blocks (other than femoral or fascia iliaca) is in limbs trapped in machinery.  Not a common circumstance but a useful tool to have in the box when it occurs.

The Other Bits We Rarely Look At…

I don’t think this was the aim of this study but it would also have been nice to see some attention paid to non-pharmacological methods of pain management.  Good splinting and packaging is the obvious first line for prehospital services and is one of the basics that is worth doing well.  We don’t carry hot or cold packs in our service due to the weight, but they are available from our local ground ambulances.  These can also help in the right patient.

Plus a Slightly Unexpected Elephant

And lastly they claim a slightly unexpected elephant is in the room.  Treatment by a female physician is reported as being associated with a higher likelihood of arriving at hospital with inadequate analgesia.  To be honest I’m not quite sure what made them look at the gender of the practitioner but there it is, written up. Before anyone assumes this was some situation induced by most of the patients being middle-aged blokes, it wasn’t about the patient gender at all.

IMG_5815
An actual elephant not in a room as opposed to the elephant in the study that is probably not an elephant. 

So what is going on? I can’t quite figure out why this would be the case although the Swiss group has documented this previously in their own system.  Is this a Swiss peculiarity or is it more wide spread?

Well to me it looks like there are a few holes in the information provided that make me wonder if it’s a blip rather than an actual pachyderm. For example non-trauma patients were more likely to arrive at hospital with insufficient analgesia than trauma patients. I can’t construct what proportion of those patients got a physician of a particular gender by chance from this report though. Could it be that the real issue is that clinicians interpret the significance of pain differently based on the context or mechanism? If it’s “medical” pain rather than traumatic pain do we tend to wait for the medicine to fix the medical, rather than treating pain separately? There’s at least one confounder for you without even trying so I’m not convinced a strong case is made that provider gender is a crucial determinant of analgesia efficacy.

A question the physician gender stat does raise that is beyond the scope of this study is the need to consider the particularities of the provider in the mix. Beyond breaking things into much larger groups (like physician vs paramedic) I don’t recall seeing much on what characteristics of a clinician make them more or less likely to provide the good juice. If we don’t understand biases that might be in play I’m not sure we can do the most effective job of changing practice.

 

The bottom line – be obsessed with good analgesia.  It’s easy to get obsessed with all those interventions we think of as advanced, but the long-term quality of life of patients will probably be equally influenced by getting this bit right. Use a multimodal approach rather than just the parenteral one.  Combine agents if severe pain requires it.  Consider local and regional blocks if you have the skill.

And if anyone can figure out if the physician gender difference in this study is a blip or a real thing of some other sort hidden somewhere in the unreported elements, I’d like to know.  It’d be good to show that elephant the door.

 

Notes:

Yes. That’s a real elephant and the photo is via @AndyDW_

Oberholzer N, Kaserer A, Albrecht R, et al. Factors Influencing Quality of Pain Management in a Physician Staffed Helicopter Emergency Medical Service. Anesth. Analg. 2017. 

 

Analgesia

Things We Say We Love But Never Do

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We haven’t had that many chances to chat about something that really matters – analgesia. Here’s a post on things to do with needles by Andrew Weatherall. No acupuncture involved. 

I like drugs. I like the ones that make people drift into their own special ether world. I like the ways they bend light right or left. I like the ones that make vessels open, myocytes contract and gates stay open.

I particularly like the ones that find ways to interrupt pain pathways. Whether they antagonise or agonise (not the best derivation of that word, granted) I am a fan of most of them. This is at least in part because so much of the time we could do better with analgesia. For all the techniques at our disposal and all the agents we have, most often the literature I read on the actual delivery of pain relief would be marked with a “Could do better”.

Despite my broad ranging endorsement of pharmacological agents, when it comes to analgesia, I actually think the best option is sometimes the one that lets you use less drugs.

Which is where regional analgesic techniques really stand out from the bunch.

Providing Clarity

I should really specify a bit. Not all regional techniques seem apt for the prehospital or retrieval environment. For starters I really mean peripheral nerve blockade because the neuraxis just isn’t a place for  a needle in the great outdoors.

And not all techniques are quick enough to make the administration feasible, particularly once you consider the positioning and preparation required.

If there is one block that should be right at the top of everyone’s list though it is the fascia iliaca block to make mute a firing femoral nerve.

Of all the blocks I can think of it is the one that should be a ready-grab technique for most prehospital providers. It is quick to perform. It is reliably effective. It takes away big pain. And I’ve heard people mention it as a great technique lots of times in the cosy space of bases in all sorts of spots.

Yet, whichever way I cut my Medline searches, I get < 50 entries in the literature for prehospital care and fascia iliaca block. And when I mention I’ve used it, I sometimes draw quizzical looks. As if I’d suggested a pot of green tea to the kids at a birthday party.

Yet a well performed peripheral nerve block can mean less of all those other drugs we use for analgesia (particularly the opioids or ketamine) and those agents can have their own issues on occasion.

It tends to provide a better quality of analgesia, along with a patient who has an entirely unclouded sensorium. That super lucid patient can now become a really crucial agent in clinical assessment. At the same time they can be more aware of what’s going on without the distress of pain. I’m inclined to think that a patient who can be reassured and coached effectively through each step probably has a better journey in the long run than the one dozing in and out a bit. I’ve seen patients with both femurs smashed up cracking jokes in the emergency department with their doctors and nurses thanks to functioning nerve blocks.

So is the issue that the technique seems too forbidding? That hardly seems possible.

The Nuts and Bolts

The fascia iliaca technique was first described in the literature by Bernard Dalens, a paediatric anaesthetist. He and his colleagues had gone back to the anatomical drawing board in search of a better femoral nerve block than the ‘3-in-1’ technique. It arose from paeds anaesthesia for a pretty good reason – Dalens was after a block that would work in patients who couldn’t give you good feedback about experiencing paraesthesia, or for whom rationalising the sensation of nerve stimulation might be a bit much.

It’s a while back that this work appeared too – 1989. At the start of 1989, Milli Vanilli were still thought to be a legitimate music act and Rain Man won big at the Oscars. This is not a new technique.

In a comprehensive description of the anatomy involved (complete with radiographic demonstration of local anaesthetic spread) Dalens and crew also report success compared to the ‘3-in-1’ technique – 55 of 59 patients with a successful block of all the nerves they were aiming for (vs only 11 of 51 having block of all the nerve branches in the ‘3-in-1’ group).

They also reported higher first time success rates and less motor blockade. Sounds perfect.

It also just seems more sensible than looking for the femoral nerve. Why approach the nerve with a needle when you can produce the same block with the needle away from the nerve? Why be any closer to the vascular bundle than you need to be? I can’t figure out why you’d bother.

So what are the key points in the technique? (I start with an assumption that as much monitoring as possible is on the patient.)

1. Define the spot for the ‘X’ that marks the spot.

Join the anterior superior iliac spine and the pubic symphysis (draw a line if necessary). Divide it into 3 parts. The mark for where the outer third starts is your staging point. Now drop down a couple of centimetres. There’s your ‘X’. Want a double check? Feel for the femoral pulse. You should be at least a couple of centimetres closer to the edge of your (probably imaginary) bed.

2. Prepare the skin

You still have to be clean. It’s also nice to put a little bit of quick-acting local under the skin to make the rest more pleasant. So wait 1 minute.

3. Use the right needles

I think it helps to make a hole in the skin for the subsequent needle to work through. Sometimes the force required with the short bevel needle makes you really dive through the first ‘pop’ just by the effort to get through the skin. Everything is easier if that resistance at skin level is gone by using a standard needle first.

For the actual procedure, something with a short bevel. It’s the short bevel that lets you feel the two pops. The whole technique (when doing it by feel) relies on the two pops. The first is when you pop through the fascia late. The second is when you pop through fascia iliaca.

My other tips here – once the short bevel needle is through the skin, come right back to almost skin level. You don’t want any doubt as to which is the first pop. Second tip – steady pressure on the needle once you start. Steady pressure leads you to distort the fascia until you suddenly pop through. Then you rest for a second, start your steady pressure again and you’ll feel the sudden give more obviously. If you make short, sharp moves you can fool yourself into thinking you’ve had a pop.

4. Mix the drugs

This one isn’t from Bernard. For prehospital use you do want that block working quickly (that might be less relevant in theatres and maybe even ED). You also have that nagging worry about using solid doses of long-acting agents that might be a bit intractable if they find the heart and cause mischief.

There’s nothing that says you have to use the one agent. I tend to mix in some lignocaine with something longer acting in low concentrations. The longer-acting drug is worth it too – I’ve had patients with a fractured femur get all the way to their operation later in the day without any need for ongoing analgesia.

I'd choose 11 if I could.
I’d choose 11 if I could.

5. Turn up the volume

In the original paper, Dalens used 0.7 mL/kg for the under 20 kg child, working up to 15 mL for those in the 20-30 kg range, 20 mL for 30-40 kg kids, 25 mL for 40-50 kg and 27.5 mL for those over 50 kg (using 1% lignocaine with some adrenaline). The whole idea is spread through a plane, so more is better. I commonly think up to 1 mL/kg, with the local anaesthetic diluted to allow that volume. More volume guarantees spread without dropping speed of onset too much.

 

Things I don’t do? Well I don’t think using ultrasound adds anything in the prehospital or retrieval context. So I don’t do it. That said the description right here from NYSORA is pretty good.

I do still use it in some patients with other injuries – a block that works and takes away the pain of a femoral fracture, apart from being inherently good for the patient, will still decrease the overall need for analgesia because it’s like one big painful injury didn’t happen.

But What About the Prehospital Space

Well why wouldn’t we do it? Worried about local anaesthetic toxicity? Then use less of the drug. Worried about compartment syndrome? There’s no evidence that having a block changes how often that occurs or causes problems. What I think is pretty clear is that it’s entirely feasible for the prehospital environment.

It’s been described in the care of a 6 year old. Back in 2003 Lopez et al reported use in 27 patients prospectively and saw a big drop in pain scores by the 10 minute mark. 1 block didn’t work. A French group (well, in the abstract as my French isn’t quite that good) report   63 successful blocks in a total series of 107 (other techniques were on the table).

More recently, a group in the Netherlands looked at a process for training the local EMS-nurses in this technique. Their results? 96 of 100 patients had a perfectly working block.

So why isn’t everyone doing it? I couldn’t find good research on that. So maybe it’s just that we spend so much time talking about other options, we forget what is, at its heart,

Or maybe it’s just habit and we need to people to remember there’s nothing about being able to block rapidly firing signals along sensory nerves with drugs in the same loose family as cocaine that shouldn’t be considered sort of astonishing.

Maybe next time there’s a patient with a badly bent femur you could start with a simple question: can I block this pain?

(Pssst … you know the answer already.)

Notes: 

I did a second edit to add a little more description (paragraphs 2 and 3) in the “Use the Right Needle” section. I also added a paragraph to clarify why I’d choose it over the femoral nerve block just before launching into the list of technique tips. It’s the paragraph that starts with “It also just seems more sensible …”

The original Dalens paper is sort of a joy.

Here’s that letter regarding use in a 6 year old.

Here’s the Pubmed link for the Lopez paper.

Here’s the Pubmed link for the French paper.

And here’s the SJTREM paper where they trained up EMS-nurses.

Oh, and to really understand how much can be offered by good regional techniques in retrieval medicine, it’s worth looking up this account of a soldier injured in Iraq. They had most of a calf blown away. With the addition of two nerve catheters (lumbar plexus and sciatic) they had initial debridement and subsequent operations interspersed with multiple long flights to finally make it back to Washington via Germany. All with good pain relief.

The image in this piece is in the Flickr Creative Commons section and is unaltered from the image posted by amp.