Some Facts About Fasting & Aspiration Risk with Sedation

By | May 9, 2014

The approach taken by anaesthetists to a patient with a potentially full stomach requiring sedation seems to differ widely from that of some emergency physicians. I must qualify this statement by saying that this is not true of  many emergency physicians with whom I work  clinically. It has been a perspective I’ve largely been exposed to by emergency physicians I’ve had contact with through social media. As such it may be that the real distinction to be made is not between the specialties but between those clinicians who inform their decisions based on  opinions expressed in social media and those who don’t. I’m not sure whether this is the case and these are clearly generalisations as it’s unlikely all the emergency physicians using social media share a homogenous view either. Regardless of the reason for this difference of opinion I think its worthwhile stating a few facts on the issue.

For those of you who have access I had a great & detailed discussion with Andy Buck about fasting, airway management & procedural sedation recently on the May Aussie Edition of EMRAP.

The following are facts about fasting and aspiration risk.

FACT 1 – Aspiration Is A Real Risk: aspiration is not theoretical – whilst uncommon, it happens and patients occasionally suffer serious morbidity or mortality from it. It is certainly more common in anaesthetic practice than other potentially lethal events like “Can’t Intubate, Can’t Oxygenate” which we expend considerable effort on adopting strategies to avoid. The seriousness of lung damage produced by aspiration is dependent on the volume & composition of the aspirate with low pH material producing a higher risk of aspiration pneumonia and with aspiration of solid material being much more likely to result in mortality.

How do we know this?: clinical experience & published literature.

Conclusion: It would seem reasonable that we take reasonable precautions to mimimise the risk of aspiration in our patients. In particular avoiding the risk of aspiration of solid material decreases the risk of mortality from aspiration.


FACT 2 – The Risk of Aspiration of Solid Material Is Lower if the Stomach is Empty: having an empty stomach does not eliminate the risk of aspiration of acidic gastric secretions but it does drastically reduce the chance of potentially fatal aspiration of particulate gastric content.

How do we know this?: Common sense. You can’t aspirate something that isn’t there. Whilst the  baseline risk of a patient aspirating a burger during sedation if their airway is not protected may be low, it’s infinitely lower if there’s not a burger in the stomach in the first place. Those of you who  somehow don’t believe this should have no problem letting your patients snack on nachos right up to the time you administer sedation. Conversely if you adopt sensible strategies to avoid placing solid material into the stomach that might not otherwise be there,  immediately prior to sedating a patient sufficiently to potentially impair their airway protective reflexes, you are acknowledging this principle.

Conclusion: In attempting to minimise the risk of aspiration in sedated patients, it would be safer if there was no food in the stomach.


FACT 3 – The Stomach Empties With Time: given enough time all food leaves the stomach. The question is how much time is enough for the stomach to empty? The time required for gastric emptying varies according to the nature of the food (fatty foods empty much slower) and patient factors (pain, nausea, opioids, intra-abdominal “mischief”, pregnancy, sepsis, etc). Many of the factors that delay gastric emptying are present in the patient population presenting for emergency procedures, both in the ED and the operating theatre. As such many of these patients may not ever be able to be considered “fasted” within the time frame that clinical urgency dictates their procedure must be done. This means that looking at studies of ED patients which determine that standard 6 hour fasting doesn’t influence the risk of aspiration doesn’t allow you to conclude that there is no increased risk of aspiration from having a full stomach. Such studies aren’t necessarily comparing full stomach with empty stomach, it is likely they are often comparing full stomach at time zero with full stomach at 6 hours – and as such a difference in the aspiration rate wouldn’t be expected. Thus it’s important that we keep the terminology in relation to “fasted” versus “empty stomach” clear when discussing this issue . The salient point is whether the patient has a full/empty stomach, not whether they are fasted/unfasted. Fasting is only one mechanism by which we can assess whether a patient might have an empty stomach, but it is often of limited use in the ED patient population. This is by no means meant to imply that there is no value in ever fasting ED patients. There are many who may have normal gastric emptying and who may benefit from fasting where this is clinically appropriate. Even patients in whom gastric emptying may be delayed should still be given the opportunity to fast where this does not expose them to unnecessary suffering or clinical risk – as gastric emptying might still occur. Clinical urgency determines the timing of the procedure/sedation, the likelihood of an empty stomach at that time determines the strategies required to minimise the risk of aspiration with sedation. The important point is that saying that fasting doesn’t always decrease aspiration risk is not the same as saying having a full stomach doesn’t always increase aspiration risk.

“The salient point is whether the patient has a full/empty stomach, not whether they are fasted/unfasted… saying that fasting doesn’t always decrease aspiration risk is not the same as saying having a full stomach doesn’t always increase aspiration risk”

“Clinical urgency determines the timing of the procedure/sedation, the likelihood of an empty stomach at that time determines the strategies required to minimise the risk of aspiration with sedation”

How do we know this?  From looking in the stomach of fasted patients. Patients coming for elective gastroscopies following a standard anaesthetic fast of 6 hours for food, 2 hours for water typically have empty stomachs (there may be varying amounts of residual liquid but solid food is very rare). Whilst that establishes that a 6 hour fast seems generally effective it is possible that a shorter fasting time would be equally effective. It’s important to note, however, that a 6 hour fast is not universally effective and that rarely patients who would be expected to have normal gastric emptying, have solid food matter in their stomachs at gastroscopy, despite reporting having fasted for an appropriate duration. Whether this represents a failure of gastric emptying within the 6 hour period or the fact that the patient did not actually fast for 6 hours is unknown. From an ED perspective it is also important to note that this 6 hour fast is from a “light meal” and any margin for error it provides may not be true of large volume fatty meals & alcohol which may be in the stomachs of some of the ED patient population (some fasting guidelines advocate longer fasting periods of 8-10 hours following fatty meals). Given the above, and the fact that a 6 hour fast from food is unlikely to do harm, especially when water is continued up until 2 hours prior to the procedure, I can’t see a particular value in trying to shave the fasting time down further. One final point to note is that  patients having gastroscopy who are judged to be at risk of delayed gastric emptying and intubated via RSI despite having been fasted, frequently (though again not universally) have large residual gastric volumes and solid food material in their stomachs, reinforcing the fact that the time taken for the stomach to empty is genuinely impacted upon by the factors listed above.

Conclusion: Fasting for minimum 6 hours for food and 2 hours for water should be routinely undertaken for patients having sedation where clinically feasible in order to promote gastric emptying and achieve an empty stomach. Patients at risk of delayed gastric emptying may continue to have a full stomach despite fasting for the requisite time periods.



The above  points are facts. Proof of them via large randomised controlled trials is not required. These are things we already know from direct observation & unassailable logic. Any study that fails to validate these facts must be flawed. Aspiration is real and is worse when it involves particulate matter. The risk of aspirating solid material is infinitely higher when there is solid matter in the stomach to aspirate and the likelihood of there being solid matter in the stomach to aspirate diminishes with increased fasting time. Whilst the baseline risk of aspiration may be small, it’s sequelae may be serious. Taking these facts together one can only conclude that, where clinically feasible, in order to minimise risk of (especially particulate) aspiration, all patients should be fasted before receiving any sedation likely to impair their protective airway reflexes. Similarly where patients are judged likely to be at risk of not having an empty stomach either because of delayed gastric emptying or where the clinical urgency of the sedation/procedure precludes fasting, the patient is at increased risk of aspiration.

Only now do we get into an area where clinical evidence is required. In  patients who are judged to be at increased risk of aspiration, what is the best strategy to mitigate this risk in patients requiring  sedation for short, painful procedures that can be performed in the ED such as reduction of fractures & disclocations? The predominant anaesthetic perspective (and that of many emergency physicians) is that RSI with a cuffed ETT should be used. Another group of emergency physicians advocate sedation with an unprotected airway.

Certainly I don’t think many would dispute that once the cuffed ETT is in place, the risk of the patient aspirating is drastically reduced.The questions to be addressed are what risks of aspiration does the process of intubation & extubation during RSI pose and what other additional risks is the patient exposed to during the process of RSI (eg. anaphylaxis from muscle relaxants – you’d then have to weight this according to risk of serious permanent morbidity/mortality versus that from particulate aspiration). I’m not sure that these risks of RSI are well known or easy to quantify. If these risks are less than those of aspiration during sedation with an unprotected airway, then RSI is the answer. Conversely if they are higher then sedation with an unprotected airway is the safer option. I don’t know the stats on these issues but I’d be keen to hear from those of you that do. There may be other factors like the drugs used for procedural sedation that influence this equation. I will say of the often touted statement that “ketamine doesn’t impair airway protective reflexes” that I’m yet to be shown a legitimate reference for this. Whilst I have seen this statement made in a journal article, when the antecedent references were traced back they lead to an erroneous interpretation by a non-clinical pharmacology journal of what “airway protection” meant, using it to describe findings of unchanged pharyngeal muscle tone in patients receiving ketamine. Anecdotally I’ve noticed that patients induced with ketamine tend to retain a coordinated swallow which seems encouraging to me that they might also retain their airway reflexes better – I wouldn’t be counting on this on that basis though.

This issue of the risks of RSI versus unprotected airway is the only one we should be debating though – not the efficacy of fasting, the significance of having a full stomach or whether the ED has the resources to do RSI’s even if they are required – simply what is the lowest risk approach to sedating patients judged to be at increased risk of aspiration for these procedures. We have to decide what is best practice for our patients, then manage resources appropriately. It is also important to note that for a given subset of procedures, assuming that intubation & extubation are performed appropriately, there should only be one answer to this issue. Those advocating RSI & those advocating sedation with an unprotected airway can’t both be right. This shouldn’t be an anaesthetic versus ED issue, nor a conventional resources versus online learning issue – this is a question of fact not opinion. Now that we’ve defined the question, show me the answer.

“We have to decide what is best practice for our patients, then manage resources appropriately”


40 thoughts on “Some Facts About Fasting & Aspiration Risk with Sedation

  1. Minh Le Cong

    thankyou Nick. I sincerely hope you are feeling better today by the way.

    I will address your last point of debate : RSI with cuffed ETT vs unprotected airway. I take it that your main concern is that unfasted patients are being sedated to point of unprotected airway and loss of airway protective reflexes, in the ED and that this is a significant unaddressed risk to patient safety in your opinion.

    Firstly you claim there is risk in unfasted sedation of ED patients yet you provide no citation of the nature and magnitude of risk. You simply say it must be increased risk. You do admit that you are unaware of the published statistics. Well let me provide you with some!
    this Cape Town ED study shows little difference in complications between fasted and unfasted patients with ED sedation. None were intubated! Combined complications between the groups showed only a 5.4% complication rate with no aspiration events.

    this Australian ED study of 2623 patients undergoing ED sedation showed only 1 silent aspiration event in an elderly patient. The patient recovered in hospital and went home.

    I must contest your assertion that RSI with cuffed ETT is superior to sedation with a spontaneous ventilating patient in terms of overall patient safety. RSI carries major risks and is not to be undertaken lightly. A patient who can protect their own airway and keep breathing is far safer than one who cannot and RSI removes any control of the airway from that very patient relying upon it.

    The Gordon Ewing case in the Scottish Coroners court was of a man who was having elective RSI for a fractured finger repair. What ensued lead to his death for an elective procedure. This must highlight that concerns about aspiration need to be seriously balanced with risks of RSI and removing a patients protective airway reflexes.

    Every weekend millions of people get intoxicated to point that they can no longer obey commands and certainly have very full stomachs but I see no epidemic of aspiration related deaths weekly as a result. EDs do not intubate every drunk person who cannot obey commands. The cuffed plastic is not fantastic for all!

    In my prehospital and retrieval medicine work, we have moved from a policy of mandatory intubation of all agitated patients to now one of ketamine based sedation using infusion for aeromedical retrieval sedation. In our 7 yr experience of this we have never had an aspiration event but have had 3 vomiting events. Each time the patient was able to protect their own airway and manage the vomitus. I strongly feel that RSI of all agitated patients requiring retrieval should be a last resort in general and there are multiple ethical, legal and logistical issues why RSI of such patients is NOT in anyones best interests.

    The idea that RSI is simple belies the fact that difficult airways are encountered, expected and unexpected and for a given procedure, the concept to RSI a difficult airway merely for the concern of aspiration risk, seems excessive and certainly in Mr Ewings case, lethal.

    You seem to not address at all the nature of the ED procedures required and that simply all ED procedures are the same and if unfasted all patients require RSI.
    Your suggestion is that a dislocated shoulder requires a RSI in unfasted patient . This is counter to all the published ED research on the matter! For example

    thankyou once again

    1. Nicholas Chrimes Post author

      Hi Minh,

      Firstly, as I said in the post, you need to stop talking about the impact of fasting and talk about the impact of empty stomach. I don’t know all the stats but I do know the risk of aspiration for emergency anaesthesia has been quoted at around 1:1000 which means that both the of the first 2 studies you cited (I haven’t had a chance to look at the others) are phenomenally underpowered to show any difference – on top of which they likely compare patients with delayed gastric emptying due to pain/opioids and thus compare unfasted patients with full stomachs to fasted patients with full stomachs and find no differences in aspiration risk because they all have full stomachs!

      Secondly, I don’t make an assertion that RSI is superior to sedation with an unprotected airway. That is precisely the question that I ask at the end of the post. The only assertion I’ve made is that patients with full stomachs are at higher risk of aspiration than patients with empty stomachs which is uncontestably true for all the reasons stated in the post.

      Thirdly, as always, I don’t accept that ED is somehow fundamentally different from the operating theatre with regards to the technical aspects of safe patient care. At the moment we have a sub-group of ED physicians acting contrary to accepted standard practice of the specialty that sedates people & manages their airways for a living with the sole justification that “those OT rules don’t apply to us in ED”. Anaesthetists apply these rules to sedation patients who aren’t having airway manipulation, as do many ED physicians working in ED. I’m not asserting that anyone in particular is right, I’m simply saying we can’t both be right. My desire is to find some facts and unite divergent practice.


      1. Minh Le Cong

        I don’t understand your disbelief that divergent practices exist . Perhaps both ways are appropriate and safe ? Why do you feel need to demonise one method simply because it differs to yours ?

        It’s ok for doctors to have different ways of doing same thing . In fact most of anaesthesia is exactly that ! You claim RSI is standard but you know that term is very loosely based as a standard even amongst anaesthetists !

        1. Nicholas Chrimes Post author

          I’m not disbelieving that divergent practices exist. I do think that two such different approaches are unlikely to have identical risks. It is more likely that there is a “right answer” here (within the confines of a particular level of sedation for specific procedures). I’d like to know what that is.

          When did I “demonise” any method? I said I’m not aware of any statistics on the relative risks of either approach. There is a level of melodrama & defensiveness to your response to this which is unhelpful. I’m perfectly prepared to accept that current “standard practice” in anaesthesia may be wrong (in fact being able to demonstrate that would delight me!). We need to have evidence though before we start to act contrary to standard anaesthetic practice for fasting before procedures – or at least have a compelling rationale . Absence of evidence for the benefit of RSI over other techniques is not in it’s own sufficient to justify acting contrary to the routine practice of the specialty whose area of expertise is sedation & airway management.

          There may be variations in what technically constitutes RSI but I maintain that implementing the principles of RSI in patients judged to be at risk of aspiration is overwhelmingly the usual practice of anaesthetists in Australia & New Zealand. Conversely it’s not clear to me that the views espoused on Twitter regarding aspiration risk during procedural sedation are necessarily representative of a equivalent proportion of emergency physicians. A number of ED physicians I work with clinically have not appreciated me characterising the views on aspiration expressed on this topic on social media as being representative of their practice.

          1. Minh Le Cong

            ok enough of the rhetoric!
            show me any evidence of a non RSI/anaesthetic approach to unfasted patients in ED undergoing procedural sedation, leading to worse outcomes than a predominantly RSI approach.

          2. Nicholas Chrimes Post author

            For some reason you seem to be responding to this post as if I’m pushing an answer rather than asking a question. I’m not saying you’re doing it wrong. I’m saying you’re doing it differently to usual anaesthetic practice. I don’t know which approach is higher risk. That is the question my post asks.

            As I said to Lana though, I think that, given you are advocating acting contrary the longstanding expert advice of the specialty who perform sedation & airway management for a living, the onus of proof rests with you. So why don’t you show me evidence of RSI leading to worse outcomes than a non-RSI approach. Then you might have grounds to make an argument for going against conventional practice and a sound rationale.

    1. Nicholas Chrimes Post author

      Yes, that was the citation I mentioned in the post that I traced back to the pharmacology journal misinterpreting what is meant by airway protection. I’m confident ketamine is more likely to maintain airway reflexes than propofol but I wouldn’t rely on that absolutely at sedative doses – and I’ve not seen any literature to support it either.

  2. Kath Woolfield

    I agree with almost all of your points Nick.
    I only take issue with the absolute black and white way in which you frame your discussion.
    Decisions regarding the best way to provide analgesia/sedation for a patient undergoing a painful procedure need to be done on a case by case basis (taking in to account all the points you have mentioned).
    But stating nobody should receive procedural sedation unless fasted for 6 hours I think oversimplifies things. Equally fasted for 6 hours does not necessarily equal safe for sedation.

    1. Nicholas Chrimes Post author


      At no point did I say “no one should receive procedural sedation unless fasted for 6 hours”. I said where clinically feasible fasting should be undertaken prior to procedural sedation to avoid increased risk of aspiration. Where fasting is not clinically feasible procedural sedation needs to be undertaken with attention to the fact that the patient is at increased risk of aspiration. I conclude by saying that I don’t have the statistics to quantify the risks involved with RSI vs sedation with unprotected airway for procedural sedation (and we would need to better define the exact procedure & level of sedation in order to do this). It concerns me however that we have such divergent practice between anaesthetists and a sub-group of ED physicians.

      You mentioned in a post on Twitter that you hadn’t seen evidence that “not fasting” (which I will broaden to mean, proceeding with a potentially full stomach) causes harm. Given that the practice of sedating patients with potentially full stomachs without using RSI to facilitate airway protection is contrary to the established standard practice of the specialty that sedates & manages airway for a living, I would have thought the burden of proof to establish this practice as safe rested with those undertaking it rather than the other way round. If there’s evidence out there that procedural sedation on a full stomach is safer than RSI, I’m very happy to take it back and challenge the anaesthetists – but I haven’t seen it yet.

      1. Minh Le Cong

        I am working on a publication of our aeromedical experience of ketamine retrieval sedation over 7 yrs in unfasted unintubated patients . So stay tuned . Evidence coming ! And it lyses the dogma!

  3. reuben

    nick you are making most of your assertions about the dangers of aspiration contrary to published evidence. you also do not seem to consider the harms of fasting, which are substantial and important. I work in a variety of north american emergency departments and have never seen anyone wait to fast a patient prior to PSA, ever. there are a number of very large case series attesting to the safety of this practice, and our largest organization (ACEP) just published a guideline finally acknowledging this. [ ]

    the most recent anesthesia guideline on this topic [ ], which addresses fasting prior to an operation, not PSA, states:

    “The literature is insufficient to evaluate the effect of the timing of ingestion of solids and nonhuman milk and the perioperative incidence of emesis/reflux or pulmonary aspiration.”

    they make the same summary statement about the risk of aspiration following clear liquids, breast milk, and infant formula.

    as your countryman mel herbert said in this months’ EMRAP, the appropriate amount of time to wait after eating to perform procedural sedation is until the patient has finished chewing.


    1. Nicholas Chrimes Post author


      Can you specify which statements I’m making that are contrary to the published evidence and provide the references which contradict them? I would be very interested to see this.

      You seem to be ignoring the central tenant of my post that is that the issue is not one of simply “fasting” but of whether the “stomach is empty”. Studies which compare two groups of patients, one of which is fasted & one of which is not – but neither of which are likely to have empty stomachs, do not add much to this discussion. From the perspective of the risks I’ve identified the two groups are identical, so it is not surprising that their aspiration risk would also be identical. In any case the number of patients in these studies is too small to detect such a difference even if it did exist. The ACEP guidelines seem to be based on these studies.

      You’ve been a bit disingenuous in your selective quoting of the of the ASA fasting guidelines as the following sentence states “the consultants agree and the ASA members strongly agree that fasting from the intake of a light meal… 6 hours or more before elective procedures requiring general anaesthesia, regional anaesthesia or sedation/analgesia should be maintained”. They go on to extend this fasting recommendation to 8 hours for fatty meals. The absence of evidence to support a particular recommendation should not be used as a reason to disregard expert opinion and a sound physiological rationale based on information such as the three facts in my post.

      In any case the issue under discussion is not so much about HOW WE DECIDE who is at increased risk of having residual gastric content but rather WHAT WE DO to address this once it has been identified as an issue. We are still left with vastly divergent practice from two groups of clinicians in patients identified as being at increased risk of having solid food in their stomach without good evidence on either side. What we can say based on the facts outlined in my post is that there is an increased risk of potentially significant aspiration if the stomach is not empty when airway protective reflexes are suppressed. We don’t need a trial to prove this, the three facts in the post clearly demonstrate it. What I am yet to see is evidence as to whether the overall risk of RSI is greater or less than the risk of sedating patients with residual gastric content without airway protection. If the data exists to make this assessment I would love to see it. I’m very happy to concede that RSI is not the best response to the patient with residual gastric content if presented with data that supports that contention.

      Finally with regards to the risks of fasting, you aren’t seriously telling me that there’s “substantial & important” harm arising from a 6 hour fast from solids. Let’s put this in perspective, this is the time interval between having lunch at noon and dinner at 7pm and a fraction of the usual daily interval between dinner and breakfast. Complications such as effects on immunity, gastric mucosal repair, metabolism and nutrition result from protracted & inappropriate fasting due to poorly orchestrated organisational issues surrounding fasting in healthcare institutions. If these are the issue the answer is to address them, not expose the patient to an increased risk of aspiration. I can only assume you don’t wake your children during the night for a snack to prevent them falling victim to these “substantial and important” harms.

      1. Minh Le Cong

        well clearly as per my previous citations, the answer to what we do once we know there is increased risk of aspiration, depends on the patient and problem, but in general in the EDs I have worked in and take patients to, procedural sedation in this patient group is done safely without recourse to RSI! In fact we do it in prehospital setting all the time!

        Anthony Bells study of over 2000 ED patients shows the sedation in ED without RSI is safe and aspiration is less than 1/2000 incidence.

        My aeromedical series which will near a full decade of data soon, shows in full stomach, unfasted patients, ketamine sedation can be provided efficaciously and safely. We have had no aspiration events, ever! I am working on the current draft paper as we debate this!

        combined with multiple ED studies showing the similar safety profile in increased aspiration risk patients , the overall conclusion is that in patients presenting to ED or retrieval service, careful selection of patients by EM and retrieval docs, can provide safe and effective sedation without recourse to RSI.

        The reason why I know this specifically is that when I started retrieval medicine almost a decade ago, we did RSI to all agitated patients for aeromedical transfer. This was basically policy, albeit with no safety data or evidence that this was best practice.

        With the ketamine sedation protocol we have almost reduced the use of RSI as method of restraint in aeromedical retrieval of agitated patients to zero. In one base it has not been used for the last 3 yrs!
        other services have adopted our protocol with similar results. Alice Springs and MedSTAR in Adelaide are notable partners in pioneering this retrieval sedation practice.

  4. Minh Le Cong

    the risks of RSI you ask?
    well there was the Gordon Ewing Case
    also in Oz retrieval I know of the following

    One case of aspiration during extubation in ED, when a patient intubated for agitation was retrieved from a rural hospital.

    Two cases of awareness during RSI and subsequent mechanical ventilation during aeromedical transfer.

    Alice Springs Retrieval have data on this
    difficult airway encountered in RSI including failed intubation
    VAP from intubation

    Now conversely I am aware of cases where sedation was performed when RSI should have been done instead, and deaths occurred. Notably the Port Hedland coroners case of Mr Lees.

    But like any anaesthetic a risk assessment and airway planning need to be done for any sedation. This is the difference I believe that makes a difference, not using RSI as a hammer

  5. MJ Slabbert

    It always comes down to Risk vs Benefit and first do no harm. As an experienced clinician you should take into account the EBM but also consider your specific patient as n=1.
    Guidelines are guidelines.
    Don’t put a patient at risk (either way) never believe it “never happens” or “try and get away with it”.

    Sometimes procedural sedation takes clinical priority (at risk limb etc), sometimes fasting takes priority and it is a balance of perceived risks and benefits. Whether we admit it or not, our practice is shaped by prior experience and you only need to see one person vomit / regurgitate and aspirate to not want to “wing it”…ever.

    Will we always get it right? Well maybe not.

    Should we plan and prepare for getting it wrong? Absolutely .

    Risk vs Benefit
    Clinical Prioritising
    First do no harm


  6. Luke Regan

    What a fantastic and sophisticated debate. Thanks to all parties for their considered and qualified contributions, great to hear real experts in the field giving up their experience to the ether (NPI) free of charge.

    Disclosure of interest= uk EM doc, longstanding user and advocate of safe procedural sedation, wherever it is employed.

    Points of personal opinion:
    1. Nick you repeatedly describe “divergent practice between anaesthetists and a sub-group of ED physicians.” I’m going to say this is the other way round in the uk, ed physicians in all of the depts I’ve worked in for last 9 years over here have a uniform approach to this that is college mandated, supported and backed by that most woeful (but at least tangible and ever growing) of evidence – years of multi site registry data showing no harm. 7 years ago international meetings were swamped with posters and presentations from around Europe and the states reporting case series of hundreds from varied sites, all showing no harm. This was necessary to collate due to the local and idiosyncratic response of anaesthetic depts to the emergence of this ‘by necessity’ practice. Fasting for up to eight hours quite rightly was not the starting point for any of these. Why examine something that will beer be relevant to the patient an undeliverable by your institution? Decent, safe, timely, governed and reviewed sedation and analgesia needed to be done for these patients. RCOA has weighed in as an expert opinion late in the day, which is welcome as a group of experts giving an opinion. I give that weight, but the weight it deserves, and weigh it against aforementioned data collected by people actually performing this function on a daily basis. So whilst I do love all the ‘non-contestable’ facts about how our stomachs might be working in a given emergency context it doesn’t shift my desire to head for the process that gets the job done and has enthusiastic review of actual practice behind it.

    2. I absolutely have to agree with Minh on the many many reasons why intubation is not the instant no brainer solution for these patients. The enthusiasm for plastic vs gastric is what sees a prehospital anaesthetist meet a drunk, walking talking head injured patient with facial bleeding and decide that the ‘safe’ thing to do is anaesthetise, paralyse and intubate. Only they don’t, the subsequent LMA fails to properly ventilate, the bleeding which was no problem is now partially obstructing the supine anaesthetised paralysed airway and on arrival to ED the only plan proposed is to continue attempts at intubation either orally or via the neck. This happens, it shouldn’t, and the desire to avoid aspiration (or protect against it after your anaesthetic has caused it..) shouldn’t induce such tunnel vision, but it does!

    3. The procedural sedation I’ve been taught and have taught is patient tailored, titrated, run to checklist. The only anaesthetic guide I’ve had to this group of patients is in the ’emergency dept list’, a possibly quaint remnant of uk practice that nonetheless deals with minor procedures that require a max of 5 mins operative analgesia/sedation/ anaesthesia. With precious few exceptions I got to see years of 200mg of propofol delivered to all of gods creatures with the wonderful variety of haemodynamic compromise, ventilation difficulties, prolonged wake up, laryngospasm etc that one size fits all anaesthesia brings. Again agreeing with Minh here, sorry, but I’m unconvinced that there is a body of opinion on procedural sedation amongst anaesthetists let alone experience. I think you’re a rare find Nick in that you care enough about the process to even think through how to do it safely…and these patients need something done…I have many many great anaesthetist colleagues who want the airway in theatres to be managed safely, but don’t want to be involved with the many daily sedation events in a busy ED and they’ve appreciated the decade long efforts at establishing safe practice and governance in the ED so they don’t feel obliged to have an opinion on something they neither do, nor want to do…


  7. reuben

    Nick – the notion that, during PSA, aspiration causes clinically important harm with an appreciable frequency, or that this frequency can be reduced by fasting, is contrary to the outcomes reported in these registries, and contrary to the opinion presented in these reviews, which can all be found, along with other relevant papers, in this folder:

    Smally 2011
    Thorpe 2010
    Molina 2010
    Roback 2004
    Agrawal 2003
    Ghaffar 2002
    Treston 2004
    Bell 2007
    Babl 2005
    McKee 2008

    There are over 20,000 ED PSA cases reported in the literature, and, to my knowledge, 2 reported clinically consequential aspiration events. In one case, the patient was NPO for 6 hours prior to the procedure (Cheung 2007), in the second, NPO for 24 hours (Taylor 2011). There is also theoretical evidence that fasting, which increases the volume and acidity of gastric secretions, makes aspiration events more dangerous (Maltby 1986).

    The suggestion that we might expose a non-fasted patient with a shoulder dislocation to the risks of RSI so that an endotracheal tube can be placed for the three minutes it takes perform a propofol-facilitated joint relocation, for the purposes of reducing aspiration risk, a risk that has been demonstrated to be trivially small and not reduced by fasting, is, in my view, a dangerous, almost irresponsible suggestion. Attempting to view this from your perspective, I will stipulate that anesthesiologists are better than emergency physicians at routine intubation, and the situation described is much closer to routine intubation than a usual emergency department intubation.

    I certainly recognize that the anesthesia guideline I quoted concluded with a strong recommendation for fasting and did not mean to imply otherwise; my point was that the authors of that guideline explicitly acknowledge that their recommendation is not evidence-based. The physiologic arguments you confidently assert as support of a fasting recommendation seem to me academic when compared to the overwhelming evidence that performing PSA on non-fasted patients is safe and effective, especially when viewed in light of the harms of fasting.

    The harms of fasting are very important and are a source of considerable morbidity; that you trivialize them is a powerful testament to the occasional chasms between EM and anesthesia. I think as groups we agree on most issues that come up in the areas where our expertise overlaps, but there is no greater exception to this than how we view fasting and aspiration risk.

    Every time a patient in the emergency department who requires a procedure is fasted, there is harm. The procedure they need usually involves a painful condition; by delaying the procedure, you prolong the length of time the patient is in pain (and hungry and, more distressingly, thirsty). The lesion that needs to be addressed progresses–the fracture swells, the dislocation stiffens, the heart becomes more content to be in atrial fibrillation–the procedure therefore is harder or less effective. The patient remains in a bed in the ED, taking up geographic and nursing resources that could be diverted to others.

    There are more insidious harms. Because of the fasting culture in medicine and the unfortunate policies that have arisen around them, in many emergency departments, the default nursing position is that patients are NPO until specifically authorized to eat by a provider. In practice this means most patients in the department are deprived of food and drink on the chance that someone is going to get upset because the patient has eaten. It gets even worse: radiologists have somehow jumped on this train and now, in some centers, will not accept patients for IV-contrast CT unless they have been fasted for 4 or 6 hours. This on the chance that the patient will have an allergic reaction to the contrast, then somehow as a result vomit and aspirate. So we wait hours to get pulmonary embolism diagnosed, for a baseless, senseless, defensive policy that directly harms patients.

    Fortunately, like so many other things that stand in the way of our providing the best care we can, we have learned how to overcome fasting/aspiration insanity. As I mentioned, nobody delays PSA in the ED for fasting, at least not in the regions I’ve practiced. The culture of fasting in the ED is, in some departments at least, being reversed (I have a slogan for this that is slowly catching on: *everyone eats*). When radiology asks about last PO, we tell them 6 hours, regardless–respond to bullshit with bullshit.

    I just got off an airplane. As we begun our descent, the flight attendant passed by my aisle, looked sternly at the passenger seated next to me who was reading a Kindle, and said, sir, please turn off all electronic devices for landing, in the usual tone that suggests the safety of other passengers was imperiled by his operating a Kindle. We looked at each other and shook our heads.


    1. Nicholas Chrimes Post author

      Thanks Reuben,

      Frustratingly a discussion on the best way to manage patients with residual gastric content is again being diverted into a debate on the merits of fasting. These are completely separate issues: one is about how to get the stomach to empty, the other is about what to do if it’s not. As I’ve said many times previously, due to pain &/or pathology, a significant proportion of ED patients will not have an empty stomach regardless of how long they are fasted. Thus saying that there is no decrease in aspiration risk with fasting these patients is very different to saying there is no increase in aspiration risk resulting from them having residual gastric content.

      The primary issue I’m interested in exploring is not whether ED patients should be fasted but what is the best way to manage those requiring sedation who are judged at risk of having residual gastric content. All the harms of fasting you outline are specifically targeted at patient groups in whom there is little likelihood of gastric emptying anyway. If the patient is in pain that cannot be adequately managed without the procedure for which they require sedation, they should not have their procedure delayed for fasting as it is both inhumane & pointless, as their stomach is unlikely to empty during that period anyway. Similarly I would not suggest fasting a patient at the expense of worsening the pathology for which they require the procedure. Conversely a patient who is suitable for fasting and, given they require it, has eaten within the last 6 hours and consumed water up until the last 2 hours is unlikely to become hungry or thirsty (and could easily have their intake supplemented with IV fluid if necessary) or suffer any harm from the process – provided that the logistic/cultural issues you identify do not result in inappropriate fasting. Fasting for IV contrast because of the possibility of anaphylaxis is clearly ludicrous – by extension we would be fasting for antibiotics, latex exposure or proximity to bees! In anaesthetic practice the proceduralist typically determines the clinical urgency and the anaesthetist then manages the airway based on the likelihood of residual gastric content being present at that time. The question is what is the best way.

      I will take a look at the data you’ve provided. I don’t claim to be up on the stats but I’m concerned that there’s a significant reporting bias involved here. Just anecdotally I’m aware of aspiration events occurring at a much greater rate than you’ve quoted. As I’ve said previously, I’m not advocating that RSI is necessarily the safer option, I’m just trying to find some data to compare it with “unfasted general anaesthesia” (which is what sedation to the point of impairment of airway reflexes amounts to). The difficulty is that the complication rate from both are low (though the complication severity potentially high) so this data may not exist – in which case we have to look to the physiological principles I’ve outlined (ie. “common sense”) and expert opinion, both of which would suggest performing RSI in these patients.

  8. Minh Le Cong

    Nick, we both know unfasted general anaesthesia is self induced in millions of folks around the world daily by ETOH!

    That is essentially a natural ongoing experiment as to the risks of sedation/GA to point of loss of obeying verbal commands! How many times have we nursed comrades/friends after they were well and truly beyond loss of command of anything! Did we feel need to RSI em all? Maybe but not very often I suspect!

    ED sedation is done to titrated sedation targets and yes sometimes it meets point of a GA but I would hope none of my ED colleagues nor my trainees think that that is the goal to maintain the sedation depth at a GA level for prolonged periods of time!

    You are right I couldnt find much on risks of unfasted unintubated GA but there are some
    here is a letter that supports your concerns

    I think you can do both ; RSI or procedural sedation in ED. I know what is done safely thousands of times = both! the complications of RSI in my opinion are far worse and more frequent than the complications of procedural sedation in ED. The advantages of PSA in ED is that the patient maintains spont ventilation,and their own airway. The drugs given are short acting. A risk assessment is done as part of any ED sedation planning.

    I appreciate your concern but I fail to see what is the crisis you are worried about. If you have proof of major safety issues please cite them here.
    I have tried to research looking at your viewpoint but cannot find major safety concerns of ED procedural sedation. yes this might be biased so please independently provide your own proof of your concerns!

    1. Nicholas Chrimes Post author

      Firstly I would hope the standard of care we apply to ourselves as highly trained specialist clinicians taking responsibility for preventing aspiration during sedation is higher than that which the average drunk might expose them to on a Saturday night. Furthermore we do know that drunks regurgitate, aspirate and die in bed. So the risk is real and whilst low, the question is is it preventable. In any case, if my friend was unconscious from alcohol to the point of not being rouseable and not obeying commands, I would take them to hospital and, yes I would intubate them if they seemed likely to stay in that state for any significant period of time.

      I’m not sure why you get a significant sense of security from the duration of general anaesthesia being brief. Regurgitation & aspiration takes a couple of seconds. Unless the duration of sedation is less than the time taken to aspirate, I’m not sure what protection that is offering. Sure, the risk probably increases slightly with time – but the time at which they are going to be at the greatest risk of aspiration is immediately following “induction” (or a bolus of anaesthetic) due to the changes in muscle tone it induces and at the time of painful stimulation (as this is a potential precipitant for vomiting) – with “procedural sedation” in ED as it’s been described in this discussion (ie. to the point of the patient not obeying commands) both these events will happen whilst the patient is unable to protect their airway. If they make it past this point without regurgitation, any cumulative risk from remaining sedated for a prolonged period whilst they are unstimulated is probably low (but I concede prolonged sedation would logically increase the risk slightly by increasing the duration for which the airway is unprotected).

      One thing that concerns me is the apparent lack of recognition that the level of “procedural sedation” being discussed (patients not obeying commands but responding to stimuli) is potentially the highest risk for aspiration events. At deep levels of sedation, barring significantly increased intra-gastric pressure, the patient is very unlikely to regurgitate (as in the presence of profound muscle relaxation there’s no gradient for gastric material to move up into the pharynx) but very likely to aspirate if they do (as they won’t be protecting their airway at all). At light levels of sedation the risk of regurgitation/vomiting is higher (as there are likely to be changes in muscle tone & intragastric pressure that predispose to gastric content moving into the pharynx) but the risk of aspiration lower (as the patient is more likely to protect their airway from the reguritant material). The zone of sedation that has been described for procedural sedation is the “worst of both worlds” – more likely to regurgitate/vomit in response to a painful stimulus & unlikely to protect their airway.

      The arguments that “we do a lot of these and rarely see trouble” and “patients aspirate even if they have been fasted” are flawed. Only a very small percentage of people who drink drive will ever have a car accident, and many people who don’t drink drive still cause accidents. Yet none of us would accept the argument that “I drink drive all the time and I’ve never had an accident and I know heaps of other people who can say the same. In any case my neighbour is NEVER drinks and died in a car accident last week”.

      Though most people in Australia wear seatbelts, only a minority will ever need them. I don’t think I’ve ever been in a situation in my life where whether I was wearing a seatbelt would have made any difference to my safety. Regardless, I wear one every time I get into a car because I know that if the right circumstances arise it will be lifesaving. I wouldn’t buy a car without a full set of airbags for the same reason. Just as it doesn’t matter to most motorists whether they have seatbelts/airbags most of the time because they won’t be in a car accident, it won’t matter whether most patients have a cuffed ETT in situ when their airway reflexes get ablated because they won’t regurgitate. In both those situations though, if the rare event of car accident/regurgitation does occur, the restraints/cuffed ETT are lifesaving. We don’t ignore the need to take safety precautions simply because the risk of the situation arising in which they will benefit us, is low.

      It is just the sheer number of drink drivers & motor vehicle accidents and the fact that all the data is collected that allows us to recognise the increased likelihood of a low risk event with drink driving. Surely you realise that many aspiration events would never get reported to internal hospital risk management systems, let alone make it into external databases or peer reviewed literature. You are undoubtedly assessing risk subject to a considerable reporting bias.

      The problem is that there is no data to support RSI vs sedation with an unprotected airway, but in the absence of this I don’t think your opinion that “the complications of RSI in my opinion are far worse and more frequent than the complications of procedural sedation in ED” is adequate grounds to go against a sound physiological rationale and the opinion of specialists who sedate patients for a living.

      There is also a false sense of security from the intention to maintain spontaneous ventilation. We all know that it’s easy to overshoot and cause apnoea and when that occurs in the presence of an unanticipated difficult airway, the issues in management are identical to those faced if that difficult airway were encountered during RSI – except that your situational awareness is much lower (for the exact reasons on which you base your argument that it makes procedural sedation safer) and you are therefore considerably less likely to be prepared to deal with it. The mantra “If you think the patient might be difficult to intubate, then they need to be intubated” is often used (and is one to which I subscribe) with regard to patients with an anticipated difficult airway having the level of sedation we are discussing. I presume you wouldn’t embark on deep sedation of a patient with a known difficult airway for these sorts of procedures. Such a patient is clearly no better off when sedated simply because their difficult airway is unanticipated, in fact they are likely to be worse off. The issue of difficult airway with respect to this debate simply doesn’t hold water.

      I don’t know what you’re getting at when you say the drugs used for procedural sedation are short acting. Beyond the addition of sux, they’re the same drugs. There’s no reason for any patient having a procedure under RSI to be asleep for any longer than with an unprotected airway. The delay comes from needing to extubate them appropriately – and this is the real issue for implementing this in ED. Extubation is taught extremely badly (= sometimes not taught at all) even in anaesthetics. If ED physicians were to adopt a policy of RSI’ing patients for these sort of procedures they would certainly need to be appropriately trained in extubation, as I presume this is something you currently get little exposure to.

      I’m not worried about any sort of crisis. I’m worried about a patient who might aspirate and die because they didn’t have a cuffed ETT in situ when they regurgitated. This is not a hypothetical circumstance, this happens. The question still remains, is the risk of RSI itself higher than the risk of sedation with an unprotected airway. What astonishes me is that having acknowledged that you have no data on this you are prepared to state that RSI is more dangerous in your opinion. At least I’m saying I don’t know the answer.

      What I am saying is that on the basis of having no data to support either approach, the burden of proof must be on those who are going against conventional wisdom and the widespread opinion of experts who perform procedural sedation, anaesthesia and airway management on a daily basis, to demonstrate that their approach is safer – not for anaesthetists to demonstrate that it is unsafe. I’m happy to ditch RSI if you can show me unfasted sedation is safer but until then I’m going to go with guidelines produced on the basis of common sense and expert opinion, rather than on the basis of grossly underpowered studies citing unchanged relative aspiration risks in two groups of patients, both of whom likely have full stomachs.

      Once again, I’m not pushing RSI, I’m asking for evidence to change from accepted and well reasoned practice. I’m not seeing any.

  9. Minh Le Cong

    Your last paragraph contradicts itself . Of course you are pushing RSI ! What’s your alternative if you aren’t ?

    Your car and seatbelt analogy is weird but let me use it in response . Do you always need to use a car to get where you want to go? If you just need to go down the street , why not walk ? Should you walk with a helmet on ? Maybe but generally if you are careful , walking is fine !should you look both ways crossing the street ? Yes of course …take due care !

    Both RSI and sedation have risks , no denying this!

    ED docs give sedation daily and it is generally safe . The data comes from large registries that number over 100000 across several countries

    I am not sure what point you are trying to make as this is all reality . Are you suggesting this is irresponsible practice ? Anaesthetists do what they do. ED docs do what they do . What’s the issue?
    Once again you seem to say you have evidence of bad sedation cases in ED . But you remain nonspecific on details That seems to be the crux of your arguement : a vague generic fear of aspiration. But Equally there are bad RSI cases in ED and OT !

    Can ED sedation be done badly ? Of course ! No one is perfect ‘! But RsI by anaesthetist can be not great either ! Ewing case in point ! Bromiley too!

  10. Tim Leeuwenburg

    Nick’s argument is cogent…and the seatbelt analogy seems reasonable

    I’m off to re-read that classic paper “if nothing goes wrong, is everything alright?” – seems pertinent to the question Nick asks.

  11. Tim Leeuwenburg

    …actually, just one more thought

    The pertinent question would appear to be ‘is the stomach empty or not’ regardless of fasted/nonfasted combinations.

    How reliable is ultrasound in this? Can it reliably confirm presence or absence of gastric contents, cross-correlated with aspiration risk? Then shape ones approach around that…

    Probably a huge degree of inter-operator variability?

  12. Minh Le Cong

    Thanks Tim! How bout you and Nick run a study of RSI of all patients with acute shoulder dislocation on KI and report your results ? Would be far more useful than that other paper you are going to reread !

  13. Minh Le Cong

    Nick, you say you are asking for evidence and yet you unfairly reject what Reuben and I have offered you.

    This makes me think you have another agenda apart from “seeking the truth”!

  14. Tim Leeuwenburg


    The paper I mention is a classic. It highlights the folly which we sometimes see, viz :

    “I did a three year survey of N patients undergoing procedure X with Y anaesthetic and there were no occurrences of Z”

    Doesn’t mean Y is safe…it may well be, but need to understand zero numerators.

    Which is why a study of RSI for shoulder dislocations on KI would be a waste of my time…

    (Anyhow, who uses sedation for shoulder dislocation nowadays? I Cunningham mine)

    1. Luke Regan

      Hi Tim!

      As a friendly and coincidental aside to an otherwise brilliant discussion rich in metaphor and poetic and occasionally allegedly syllogistic analogy…great to hear of your use of Cunningham! Do you play Enya or Gregorian Chants to up your success rate??

      My first great inspiration, friend and mentor in EM was the author of the technique back when we both worked at the John Hunter…interestingly he was also the first person to show me safely performed unintubated propofol assisted reduction of a dislocated hip…as I recall not long after he’d come from anaesthetics/ITU…they must have forgotten to graft on the unspoken, untested but universally known truths we are discussing…or perhaps like most of us he had good experience and teaching in both clinical areas and awareness of the risks and benefits both proven and postulated and had made a considered decision on what was best for the patient in front of him.

      I think all on here debating the grey do the same with their patients and different conclusions come from the greyness of the area rather than wilful treading in the dark/light. Good luck navigating:).


  15. Michaela Cartner

    The primary issue I’m interested in exploring is not whether ED patients should be fasted but what is the best way to manage those requiring sedation who are judged at risk of having residual gastric content.

    Hi All
    Using the above quote from the website authour as my starting point , and reading the above pasionate posts I would like to hesitantly advance alternative strategies

    I have sedated a fasted (12 hr) lady for elective cardioversion and then kept her in my ICU for a week with aspiration. Resp failure and rapid development of septic shock.

    I have accepted to ICU many complications of entirely appropriate RSI (airway trauma, aspiration despite every effort of the treating teams both ED and in OT.)

    In short, There is no one way to treat the at risk patient. Neither option will save you. therefore all options are both valid and invalid.
    Schrödinger’s cat if you will.
    It will depend on the skill mix of the hospital, the treating team and the geography.
    Re patient factors:
    pain, limb threat, neurovascular compromise. electrolyte and haemodynamic factors all play a role.

    RSI vs Sedation have been explored above with all thier shortcomings above.
    Other methods
    – local infiltration (pretty wussy and not sexy, limited scope)
    – regional anaesthesia rocks. I am lucky, I work with a number of enthusiastic practitioners. we have started high epidurals in the ED before, shoulder blocks, femoral nerve blocks. one shot or catheter left behind.

    To use the seatbelt analogy on ludicrous step further, instead of using the seatbelt in your car….. take the bus and use regional techniques!

    The onset of sophisticated regional techniques has widened the scope but of course in a TBI or unco-operative patient you are checkmated!

    a short vigette to close.
    a young man was admitted to a tertiary centre with a TBI after a failed attempt at ute-surfing in regional Australia.
    Whilst waiting for the retrieval team the treating medical team managed a cerebrally iritated, inebriated young man with intermittant aloquots of midazolam untill the flying retrieval team arrived in 3 hours.

    On arrival to the tertiary institution the (now intubated ) patient had a tough few days as most of his XXXX and bundy and cokes were now in his lungs.
    The ICU did the usual ABCD approach (Accuse, Blame, Criticise, Denigrate) but actually the initial management was correct.

    the initial Doc thought the risk of him intubating when the retreival team with a more comprehensive skill set were on the way was greater than sedation, left lateral and suction. Hard to argue with a practitioner with insight into his skill set choosing potential future aspiration risk over potential instant death!
    Mind you if he was a locum with advanced airway skills a different standard is required!
    Thats my piont really

    Thanks for the papers references

    1. Nicholas Chrimes Post author

      Thanks for your perspective Michaela.

      I agree where regional techniques are feasible, this if often the best way to go. This is an approach we would adopt in OT also.

      Clearly there are incidents of aspiration occurring and the number of incidents Michaela cites suggests they are occurring at a higher rate than has been reported in the literature (for both PSA & RSI). This is my experience also.

      Undoubtedly no approach to sedating the patient with a full stomach is going to eliminate all risk. Both RSI & PSA will have complications and it will sometimes be possible to say in hindsight that the alternate technique was preferable. That doesn’t mean that the wrong decision was made prospectively on the available information at the time. Hindsight bias often leads us to evaluate process based on outcome, which is not necessarily appropriate. It is possible to adopt the right process and still have a bad outcome and vice versa. As such, I don’t think it follows that because both techniques have complications, both techniques are equally valid or safe. Just as we can’t say both techniques are equally safe because both have no complications, we can’t say they are equally safe because the both have some complications. To make a judgment about relative safety, we need data about the relative risk of both techniques when used for comparable cases. Unfortunately I don’t think such data exists – in which case we have to look to common sense to make a decision.

      I take your point about working within you scope of practice and agree, that in the case you’ve presented, the practitioner involved should most definitely not have tried to intubate the patient if that was outside their skill set. Whether the deep level of sedation which lead to aspiration occurring could have been avoided is impossible to say from the available information (the alteration in conscious state may well have been due to the head injury itself). We can only assume that the clinician involved did their best for the patient within the limitations of their skill set.

      With regards to in hospital sedation, however, I would say that no one should be sedating patients to the degree that we have been discussing without the requisite skill set to manage the complications – which would include RSI & intubation. Thus I would assume any clinicians performing PSA to this degree have advanced airway skills and are competent with RSI & intubation – which as Michaela points out, mandates a different standard of care.


      1. Michaela cartner

        One of the other things to weigh up in the decision making process of these difficult patients (apart from patient, proceedure, pathology , mode of sedation and skill set of the treating team) is the gestalt of the unit.

        There will never be data on this it’s too nebulous.

        What may be appropriate in business hours may not be advisable out of hours/ weekends / whatever.

        I remember being challenged once by my registrar on a Sunday afternoon as to my decision to re sedate the patient instead of extubating. He was quite forcefully vocal in his advocacy for the patient (I’m being tactful here)

        I heard him out and explained the non textbook non academic reason. I was 3/4 thru a 72 hour on call weekend shift and I was so fatigued I doubted I had the skills to react quickly anymore. There was no one else in the unit with advanced skills untill Monday morning and the unit had too much flux. Incoming, discharges, the usual bed bingo with no ICU beds in the hospital or the state and making quasi HDUs in the wards whilst the clipboard brigade screams at you.

        In ED its resuses, psych emergencies, patient overload,
        in theatre it’s a simultaneous AAA, twin crash ceaser and the 6 hour elective gallbladder the surg regs still haven’t been able to mobilise yet.

        Unit gestalt will dictate your choice to some extent and no-ones going to publish any data on that except generalist “out of hours ” observational stuff. Its a different aspect to situational awareness.

        If it was easy it wouldn’t be the absorbing discipline of critical care that it is.

  16. Minh Le Cong

    thanks Michaela for taking the time to make a thoughtful comment!

    Nick, you accept , as Michaela suggests. that there are no risk free options in the emergency pt with full stomach. RSI or PSA have risks. Dont deny this as you clearly state you accept that statement!

    You go on then to state that you have observed aspiration events and believe they are more frequent than is reported in the literature.

    Well surely then this is a training issue , not an inherent inferiority of PSA to RSI.
    It is an illogical conclusion to say, I observe aspiration from PSA, therefore the PSA is the problem , therefore we must replacd it with RSI?!?

    RSI has problems but I dont here you saying, oh we should get rid of RSI?!

    I can apply the same equation that TIm used to RSI!

    I know you are going to bring up the “well since we are the sedation experts, our opinion should count more” but I think that is unfair stance given the wealth of ED research documented. I would be more than happy to compare my sedation data from retrieval and ED in regard to ketamine use with yours! equally I would concede you would use propofol far in excess of my entire career experience.

    No one is disrespecting your expertise as an anesthetist, certainly I know you deal with emergencies and critical cAre in your work++++++

    But I find it disturbingly arrogant that you ignore the ED research that is offered and the clear expertise of ED physicians in this officially credentialled scope of practice in Australian emergency medicine.

    I dont think its black or white. it is exactly as Michaela says : you can do both. Both have risks. be careful.

    1. Nicholas Chrimes Post author

      Minh I have never said RSI is safer. I’ve said repeatedly said that I don’t know what’s safer and asked if anyone has any comparative data. That hasn’t been provided – presumably because it doesn’t exist. I have said that in the absence of such data it seems hard to justify a change from decades of convention and practice recommendations from specialists who do nothing but this.

      Aspiration with either RSI or PSA is not necessarily a training issue. It’s may be merely a reflection that every technique has a complication rate. The question is which has the LOWER complication rate?

      You can and should apply Tim’s equation to RSI. The whole point is that doesn’t mean the overall risks of both techniques are equal. You seem emphatic, however, that this is the case. I can’t see the basis for this conclusion though in the absence of comparative data from studies that are sufficiently powered to detect a difference in such low risk events.

  17. Minh Le Cong

    Nick you said that you subscribe to the maxim, if it looks like a difficult intubation, then they should be intubated! I assume that means you believe RSI is safer…than not RSI!?

    you also imply that as anaesthetists choose RSI in aspiration risk patients then choosing this approach is preferable because of the vast experience gradient of that specialty.

    that sounds awfully like the implied superior safety of RSI!

    the complication rate is not an inherent property of the techniques as we both admit RSI or PSA are non standard techniques . any studies are in fact comparisons of different providers skill and the sedation cases. therefore unless you completely standardise everything, you will never be able to find the truly lower COMPLICATION RATE !!

    you ask for impossible, impractical data!

    of course we should always try to improve quality and safety of care. we need to look at training and supervision, audit and review. but to get into this artificial examination of RSI vs PSA when both are acceptable and supported by large registry safety data is misguided. the techniques are not the true issue, its the providers and the system they operate in that should be the true focus of your attention.

    to say that two groups doing same thing cant both be right is a DISTRACTION from the true heart of the matter!

    1. Nicholas Chrimes Post author

      Minh, you’ve clearly misunderstood several statements I’ve made. I can’t be any clearer than I already have.

  18. Minh Le Cong

    Nick, do you unconditionally accept the statement that in the emergency patient with a likely full stomach, the risks of doing RSI or PSA in the ED for a given procedure, depend upon the provider, patient and condition?

    1. Nicholas Chrimes Post author

      Do you uncondiitonally accept the statement that in a motorist, the risk of wearing or not wearing a seatbelt for a given drive depends on the car, the driver & the road conditions? The answer surely depends on what exactly the question means. Do those factors affect both the risk of wearing & not wearing a seatbelt – yes. Do they affect the risk of wearing a seatbelt relative to not wearing a seatbelt – yes. Do they ever make the risk of wearing a seatbelt greater than not wearing a seatbelt – no.

      I’m not saying that RSI is of proven benefit like a seatbelt (once again, I acknowledge we don’t know this). I’m merely pointing out that even if it was, the question you’ve asked is too imprecise, and the answer to any interpretation of it, irrelevant.

      Let’s leave further discussion of this topic to the podcast. I don’t think there’s much more we can achieve here. So that the podcast doesn’t degenerate into tribal ED vs anaesthetics posturing, I’ve given you the names of some local ED physicians who are well known to the FOAM community and see the merits of the RSI rationale. It would be great if you could also find an Australian/NZ anaesthetist who sees the merit in the unfasted PSA line of reasoning so that we could have a purely intellectual debate rather than that is seen to be along specialty lines.

      In the meantime I’ll have a close look at the literature Reuben has provided. Hopefully we can then have a discussion that gets closer to finding the best answer to this question – or at least improves our understanding of one another’s perspectives rather than perpetuating the division between specialties, as this thread unfortunately seems to be doing.

  19. Minh Le Cong

    well since you asked the question I will respond
    Yes I do accept the statement you put forward! Therefore I must assume you accept mine!

    therefore this debate is over!

    I only know of one Australian anaesthetist who I could ask who can offer a counter viewpoint to yours. He helped me co-author my first paper on ketamine retrieval sedation! that is a bit unfair as you know more ED physicians who take your view!

    However we are certainly prepared to be the underdog in this and I will ask him!

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