PHARM in Review 2013

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Alex Tzannes reviews the latest developments and contention in pre-hospital and retrieval medicine for the past year.

Alex Tzannes reviews the latest developments and contention in pre-hospital and retrieval medicine for the past year.

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  • the other day i found this book kicking around at the base: it recounts in a proud if somewhat breathless style the history and the heroics of nsw ambulance officers back in the 70s and 80s. amidst the carnage and the handlebar moustaches one finds reference to MAST suits, bicarb, lignocaine and litres of haemaccel. what struck me was that so much of what comprised the “standard of care” only 20yrs ago has now been shown to be useless or even dangerous, and subsequently abandoned. it got me reflecting once again about prehospital medicine in the modern era: what evidence do we have for what we do? what will stand the test of time and what will be largely discredited when we look back a couple of decades from now?
  • the other day i found this book kicking around at the base: it recounts in a proud if somewhat breathless style the history and the heroics of nsw ambulance officers back in the 70s and 80s. amidst the carnage and the handlebar moustaches one finds reference to MAST suits, bicarb, lignocaine and litres of haemaccel. what struck me was that so much of what comprised the “standard of care” only 20yrs ago has now been shown to be useless or even dangerous, and subsequently abandoned. it got me wondering about prehospital medicine in the modern era: what evidence do we have for what we do? what will stand the test of time and what will be largely discredited when we look back a couple of decades from now?
  • the other day i found this book kicking around at the base: it recounts in a proud if somewhat breathless style the history and the heroics of nsw ambulance officers back in the 70s and 80s. amidst the carnage and the handlebar moustaches one finds reference to MAST suits, bicarb, lignocaine and litres of haemaccel. what struck me was that so much of what comprised the “standard of care” only 20yrs ago has now been shown to be useless or even dangerous, and subsequently abandoned. it got me wondering about prehospital medicine in the modern era: what evidence do we have for what we do? what will stand the test of time and what will be largely discredited when we look back a couple of decades from now?
  • the other day i found this book kicking around at the base: it recounts in a proud if somewhat breathless style the history and the heroics of nsw ambulance officers back in the 70s and 80s. amidst the carnage and the handlebar moustaches one finds reference to MAST suits, bicarb, lignocaine and litres of haemaccel. what struck me was that so much of what comprised the “standard of care” only 20yrs ago has now been shown to be useless or even dangerous, and subsequently abandoned. it got me wondering about prehospital medicine in the modern era: what evidence do we have for what we do? what will stand the test of time and what will be largely discredited when we look back a couple of decades from now?
  • the other day i found this book kicking around at the base: it recounts in a proud if somewhat breathless style the history and the heroics of nsw ambulance officers back in the 70s and 80s. amidst the carnage and the handlebar moustaches one finds reference to MAST suits, bicarb, lignocaine and litres of haemaccel. what struck me was that so much of what comprised the “standard of care” only 20yrs ago has now been shown to be useless or even dangerous, and subsequently abandoned. it got me reflecting once more on prehospital medicine in the modern era: what evidence do we have for what we do? what will stand the test of time and what will be largely discredited when we look back a couple of decades from now?
  • from that perspective, lets see what’s hot and what’s not in prehospital and retrieval medicine.
  • first cab off the rank is adrenaline for OHCA. im sure you all recall this scene from pulp fiction protocols from the 80s called for atropine, lignocaine, bicarb, calcium, all of these are out. What have we got left? compression only CPR, and electricity, and adrenaline. Show of hands for adrenaline in CA? of course you do....
  • because its in all the protocols.
  • turns out in japan they haven’t been using Adrenaline all that long, allowing this paramedic study of all OHCA. JAMA march 2012 Prospective, registry 2005-2008; huge numbers 417 000 of which 15 030 got adrenaline under instruction from physician almost complete follow up
  • the results were interesting. as usual the patients who received adrenaline had higher rates of ROSC, but they also had significantly poorer 1 month survival and poorer neurologic outcomes. of course not a RCT, but they did perform all sorts of regression analyses and propensity matching. which ever way they sliced and diced the data, the results remained similar.
  • the journal editorials and on line commentary came thick and fast: there were limitations of course: overall survival was pretty low compared to some other trials, and it was in the pre hypothermia era our pathophysiologic understanding was far from complete: we knew adrenaline increased aortic root pressure, but decreased cerebral microcirculation, and probably contributed to post ROSC myocardial necrosis and arrhythmogenesis. other wondered whether the traditional dose of 1mg q 3-5min, unchallenged since the original studies on dogs in the 60s, was simply too much of a good thing?
  • what was needed was the definitive randomised controlled trial. all agreed the question had reached a state of clinical equipoise its a shame most of the ambulance services in australia were not familiar with the term when ian jacobs performed this important study.
  • the PACA trial was supposed to be definitive. you probably recall the results. but its the back story that i think carries the important message for us. the study had been planned to recruit about 4000 pts. despite ethics approval and initial commitment across australia four of the five states pulled out, following criticism in the lay press about witholding from patients the accepted “standard of care”. it seemed too nuanced an argument that their was no evidence to support this standard. Jacobs study therefore was left significantly underpowered with 535pt; and it too showed improved ROSC, and only a NON sig trend to improved survival at one month. this was in contrast to a Norwegian RCT published in JAMA around the same time of IV therapy vs no IV in OHCA that again showed improved survival to hospital, but a not quite significant trend AGAINST survival to discharge. a post hoc analysis by adrenaline actually given reached significance for a worse outcome. (Olasveengen) i think that the PACA trial was a stirling example of politics and media prevailing over science, which i think is a great MISSED opportunity. i put it to you that because prehosptial and particularly aeromedical medicine has such a high political profile, this is a recurrent barrier to conducting unbiased research in our field. next lets look at spinal immobilisation
  • nice rv article neurosurgery journal 2013. although the recommendations are pretty conventional, it reminds us just how poor the evidence base is for various facets of spinal immobilisation, if you’ll pardon the pun.
  • this is a particular hobby horse of mine. several reports of neurologic deterioration whilst in medical care, historical before and after comparisons, lesser rates of complete cord lesions after the introduction of immobilisation. experts in the field question this assumption. Mark Hauswald, a EM professor, New Mexico, radical rethink of spinal care last year in EMJ. i’m not sure i follow all his reasoning, but he has some very interesting and iconoclastic ideas. what we do know is that the chances of further harm in the context of inadequate immobilisation is stunningly rare: one study of admissions to 8 level one trauma centres found a secondary deterioration rate after “missed” spinal injury of 1 in 500 with fractures, and about 1 in 4000 of all trauma patients.
  • the neurosurgeons remind us constantly that even one spinal injury missed is a devastating outcome, and i agree. but is it possible that we are doing potential harm to the vast majority of patients without an unstable fracture? the obvious example here is prolonging scene time. this guy is getting cold and might be slowly exsanguinating while the rescue agencies meticulously dismantle his car to get him out.
  • no matter where you work we’ve all met this patient. he’s got a 1 in 4000 chance of deterioration if we miss a spine fracture, but what are we assuredly offering him? decubitus ulcers discomfort and agitation respiratory compromise difficult laryngoscopy, critical hypoxia. all the guidelines talk about maintaining a “neutral position” when intubating a patient like this
  • but i’d argue neutrality is a hard concept to define.
  • this 77yo man came through my ED the other day. he’d had a few drinks, fell from standing height and hit his head, no neuro deficits but agitated; intubated for control. have a look at scout film flat back board take a look at his neck thats not neutral
  • same patient he now has a screw in his type 2 PEG fracture. post op, the neurosurgeons have put an 11cm pillow under his head.
  • different patient, same message: if he were standing up he’d be looking up at the sky. the point is we need to have a critical approach to “neutral” not just the elderly kyphotic patient. one older study showed that 80% of adults attain their neutral position with between 1.3 and 5cm of post occipital padding. if you don’t believe me, stand up against a wall and relax. another study MRI’d volunteers with their head immobilised with various amounts of padding and actually demonstrated that 2cm led to the optimal cross sectional area of the vertebral canal at all cervical levels.
  • there are a number of studies using volunteers or cadaver models and either radiography or some sort of external motion sensor that show that collars are at best pretty useless and may in fact cause significant longitudinal distraction at the site of unstable injuries. log rolling is demonstrably bad for thoracolumbar injury, especially if the patient is a woman with big hips. case 40yo MTB in the middle of nowhere in kosc .NP his injuries were a nasty lac down his leg and a sore neck. his riding companions included an intensive care paramedic and a doctor who had dressed his wound, applied a collar and thoughtfully immobilised him on a camp bed inside this old hut. problem was he was build like a brick shit house and this door was about five foot high and two foot wide. thus it was going to be an absolute pain in the ass to stretcher him out to the aircraft.
  • luckily, jeffrey shafer from washington university published this fascinating pilot study, western journal EM 2009 small number of healthy volunteers it compared various means of extrication from the drivers seat of a wrecked car, and measured the resultant movement across the c spine.
  • but at least we all agree to keep them supine right? it turns out norwegian paramedics have been using the lateral trauma position in transit in 2005, arguing that in their system, without the capacity for drug assisted intubation, it was safer in obtunded patients than keeping them on their back. as far as i can tell to date there have been no reports of deterioration as a result.
  • small steps, but challenging conventional wisdom, and generating hypotheses regarding an important topic. so what do i take away from all this? i am happy to clear the neck prehospitally when appropriate. i always use an modest occipital pad in adults particularly for intubation, i am happy for alert patients with potential neck injury to optimise their position of cervical immobilisation, and i am happy for alert patients without lower back pain to get out of a vehicle with a collar on but under their own steam if there are no safe alternatives.
  • anyone know who this is? ken mattox. he said this in 2002, and here we are 10yrs later. hypotensive resuscitation is in, hallelujah, even the latest version of the ATLS says so. and i think that the jury is in on this.... especially if you are a young fit male standing on a corner in downtown houston minding your own business and you get shot or stabbed and you’re in theatre 45min later. but you know, i haven’t gone to a lot of these patients recently.
  • i go to these sorts of patients instead. this was a man in his late seventies, a grey nomad we call them, driving his bus around australia when he fell asleep and plunged into a creek. he was trapped up to his neck in cold swampy water while the rescue guys figured out how to get him out. all the furniture and crap in the bus had slid forward and crushed his seat, folding him around the big old steeering wheel. he had a closed pelvis and bilateral open femurs. for the first couple of hours he was conscious. he told me he was on b blockers and warfarinized for AF. by the time he was hauled out the back window he had a HR of 25 and a temp of 33 degrees. i can’t remember his BP but i don’t think i believed it anyway. say you’re on the spot: what is the optimum resuscitation strategy for this guy?
  • if you decide to shoot for a blood pressure it would be nice to know your measurements were accurate.this neat little study in anaesthesia last year of showed that non invasive BP had a hopeless correlation to IABP in patients being transported by air. this bland altman plot shows confidence intervals for systolic pressure of -40 to +33mmHg; MAPs were a little better but not much. one of our registrars is currently running a similar trial at GSA HEMS.
  • there’s very little good evidence to guide our choices for some of these individuals, but like the fable of Buridan’s ass, our patients require us to make a choice. i don’t really want to get into a discussion about FFP to packed cell ratios and the like, because other speakers at SMACC will do the topic greater justice. i think the exciting developments in prehospital resuscitation will come from the gradual extension into the field of haemostatic agents that until now have been largely confined to hospital use.
  • first up, we’re all aware of the 2010 CRASH 2 study, and what’s not to like? this was a well conducted RCT of a cheap widely available and easy to administer drug that appeared safe and effective at reducing mortality, with a NNT of about 66 it probably doesn’t matter how banged up you are: ian roberts in last september’s BMJ found improved mortality in all subgroups stratified by risk of death. Of particular relevance to us was this this sub group analysis from the lancet suggesting an even greater benefit of TXA if given within 1hr of injury, with an NNT down to 40 for death due to bleeding. conversely after 3hrs it seemed to increase mortality. So this puts TXA2 firmly in the domain of the prehospital clinician.
  • in the recent MATTERS trial the british and us military reported on its use in southern afghanistan. in a retrospective study of almost 900 consecutive combat injuries and confirmed that TXA was associated with a decrease in mortality particularly in the patients who received more than 10 units of blood. back in the civilian world keep an eye out for an upcoming multicentre trial of prehospital TXA led by monash university. we’ve included it in our kit by the way.
  • GSA hems are now one of many civilian EMS in australia that carry o neg packed cells. recent literature in this area has simply been descriptive and focussing on logistic issues of storage and waste minimisation.
  • given the evidence borne out of the combined iraq and afghani conflicts, the inhospital emphasis has definitely shifted to the early provision of clotting factors. a couple of prehospital organisations have reported their early experiences. Prothrombin complex concentrates are an obvious candidate; lightweight and much easier to store than prethawed FFP. london HEMS have been using octaplex (which is a four factor PCC) for patients on warfarin with a head injury if the on scene point of care INR is over 2. other recent work has demonstrated a reduction in acquired coagulopathy and blood transfusion requirements of brain injured patients even if they are not on warfarin, making PCC an interesting possibility for future prehospital study.
  • prehospital thawed plasma is another attractive option. the mayo clinic in minnesota have just published two cohort studies of massive transfusion in their ED and aeromedical retrieval service. since 2009 their HEMS has carried two units of prethawed FFP which they give before packed cells in their MTP. they use A rather than the far rarer AB plasma as the universal donor type, and this seems to be a safe practice. we’ve looked into this but unfortunately at this point we have not been able to source prethawed FFP in NSW. the french military have been using freeze dried lyophilised plasma for almost 30yr but this too is not approved for civilian practice.
  • last year one of our registrars did this fixed wing transfer of a warfarinised patient with a contained aortic endo leak following a previous graft. en route you can see the patient dropped his bundle and was unresponsive to multiple units of blood and products. the retrieval team arranged to meet the vascular surgeons in theatre, where they gained proximal control with an intra aortic balloon deployed via his femoral artery. the patient promptly went from periarrest to talking and had an unremarkable repair. the term for this is resuscitative endovascular balloon occlusion of the aorta, or REBOA. in many centres it’s being used as first line haemostasis for ruptured AAA and the vascular surgeons i’ve spoken to think it has made a big difference.
  • like a heavily laden 145 on a hot still day however, it has pretty much failed to take off in trauma. i think this paper is a potential game changer, describing the experience of a french trauma centre using REBOA in critically unstable patients with pelvic fracture. the numbers are small: 9yrs, 74pts requiring emergent angioembolisation, and 13 of these undergoing REBOA to gain control. patients were impressively unwell, either arrested or about to, but 12 of the 13 got to the angio suite alive. systolic BPs rose from a mean of 40 to 110. what was most exciting was that all of these balloons were inserted blind, and then pulled back to the bifurcation, with good position subsequently demonstrated at angio. other studies have demonstrated its superiority to thoracotomy and cross clamping in animal models of abdominopelvic exsanguination.
  • another job last year: a pedestrian vs truck. when we got to him he was conscious, but with his pelvis and legs crushed under the wheel, and as you can see a fair amount of external haemorrhage from these areas. within seconds of the trucks weight being lifted off he arrested, and was unsalvageable. as with any “talk and die” patient, i found this one tough, and i’ve spent a fair bit of time wondering what else we might have done for him. it’s early days, but i predict that combined with the development of ultrasound guided techniques and new more compliant balloons there will be a role for REBOA for a group of patients like this who would otherwise almost certainly die.
  • if i’m up here in a decade from now, what else might i be talking to you about? with increasing minaturisation of technology, it is inevitable that many diagnostic and therapeutic modalities that were previously the domain of hospital medicine will find a place in PHARM. as usual the crazy germans have taken things to the next level. thus we have seen preliminary studies in the last year or two on CT and prehospital stroke thrombolysis (which depending on your point of view might be a good or a bad thing). ED ECMO is now being used as an adjunct for OHCA; several case series report relatively good outcomes even after prolonged arrest. you might have heard of the CHEER study currently recruiting patients at the alfred hospital in melbourne. but two case reports recently appeared in resuscitation describing the prehospital initiation of ECMO, one in a paediatric drowning and one in an adult marathon runner. as telecommunication becomes more sophisticated, it is likely that we will see some amazing leaps forward in remote monitoring and patient tracking. Anyone involved in mass casualty incidents know how easy it is to lose track of patient flow from the scene and will see the value in this innovative bar coder based system being developed by Ian Norton and his colleagues up in Darwin. but whatever tools we have at our disposal in prehospital and retrieval medicine in the future, one thing is certain.

Transcript

  • 1. • [slide show of old asnsw pics]
  • 2. PHARM: the year in review AlexTzannes Sydney HEMS
  • 3. equipoise | ekwə poiz|ˈ ˌ noun balance of forces or interests: this temporary equipoise of power.
  • 4. • "Please mark my word. Within no less than 10 years, probably even less than 5 years, any[one] that raises the blood pressure to higher than 3/4 the pre injury level, especially if using crystalloid solutions will be severely criticized...... Also mark this down on this date. The final target for a prehospital or EC measured BP will be that greater than 80 SYSTOLIC will be the level that the QA moral police will cite ..... as causing unnecessary complications, deaths, and costs."
  • 5. Fluid strategies in trauma •
  • 6. “During my eighty-seven years I have witnessed a whole succession of technological revolutions. But none of them have done away with the need for character in the individual or the ability to think.” Bernard M. Baruch 1870-1965