Sunday, September 21, 2014

The Bougie Review Part I: By the Numbers

First let me say thank you to everyone on Twitter or Facebook or carrier pigeon who heard about the Bougie survey, filled it out and shared it with others.  Only by the goodness of people like you, and a little help from technology, was I able to collect so much information in such a short period of time.

As I said before, the review of bougie usage for intubation is being released in two parts. This article deals strictly with a breakdown of the numbers collected from the survey, which mainly dealt with attitudes, training and experience using the bougie. Part two will be a more extensive literature review that will most likely reference these numbers and relate them to the broader evidence for and against using the bougie in clinical practice. 

The Survey
Using Survey Monkey (www.surveymonkey.com), I constructed a very simple 10 question survey using the questions and answer choices below:
1.       Have you received formal education on how to use a bougie to facilitate intubation?
Yes/No
2.       Have you used/trained with a bougie on an airway manikin?
Yes/No
3.       Please rate your level of comfort in using a bougie to facilitate endotracheal intubation on a live patient.
Very Comfortable/More Comfortable/Neutral/More Uncomfortable/Very Uncomfortable
4.       Have you ever used a bougie to facilitate a live intubation, and if so was it successful?
Yes, successful/Yes, unsuccessful/No, I have never used a bougie for a live intubation
5.       If you have used a bougie to facilitate intubation, did you use it:
Two-person railroad technique (place the bougie, then have an assistant guide the tube onto the bougie
Pre-loaded into tube, similar to technique used with malleable stylet.
I have used both of these techniques
I have never used a bougie on a live patient
6.       When performing orotracheal intubation on the first attempt, what device do you prefer to shape and guide the ET tube?
Malleable stylet/Bougie/No device/Something else
7.       Would you find more airway education, especially related to using the bougie, useful to your practice and professional development?
Yes/No
8.       Please rate your level of comfort in performing endotracheal intubation on a live patient
Very Comfortable/More Comfortable/Comfortable/More Uncomfortable/Very Uncomfortable
9.       Please select your credential under which you practice intubation:
Physician/CRNA/Anesthesia Assistant/Nurse Practitioner/Physician Assistant/RN/Paramedic/Other
10.   How many years have you been performing live intubations under any credential?
0-1/1-3/3-5/5-10/More than 10

As you can see, this is a pretty blunt little tool, and not at all meant to divine scientific data about usage or success rates with and without the bougie. Rather, my hope here was to develop some ideas about current attitudes to help guide the current article and shape further research. 
Some of the admitted weaknesses with the survey are:

·         It asks about years of intubation experience, not how many intubations.  A physician in a busy, urban ED could intubate hundreds of patients during his residency and many more in his first couple of years as an attending. Conversely, a less taxing stint in a small community ED may see 10-20 intubations per year. The same can be said for practice environments across all the credentials collected here.
·         Speaking of practice environments, there was no question about that either.  Not specifying “EMS” or “Air Medical” or “Acute Care” led almost 9.5% of respondents to select “Other” for their credential and specify that they were flight/CCT paramedics or nurses.  Asking this question could very likely have provided another way to sort the data.
·         One question asked if the clinician had ever used a bougie, and if so whether or not it was successful.  This is valuable, but not as valuable as knowing how many intubations had been tried with the bougie, and how many of the total attempts had been fruitful.  Of 322 respondents that have used a bougie clinically, only five people responded that their bougie experience had been unsuccessful.  I suspect two things about this: 1) Those five people have never had a successful experience, as they probably would have reported their best result, and 2) The remaining 317 people probably had some failures, but the structure of the questions led them to report that they had been successful at least once. Or, more optimistically, that they had succeeded more often than they failed.
·         The question about how they used the bougie (railroad, preloaded or both) should have asked their preference.  I make a small leap in the analysis that this was the respondent’s intent, but that supposition is not supported by science.

The survey was distributed via the web, primarily on social media groups populated mostly with critical care transport clinicians, acute care practitioners and prehospital EMS personnel.  Responses came from all over the world, most commonly the USA, Australia and Europe.

The Respondents

A total of 380 clinicians responded to the survey, and they were further separated for study by credential and years of experience.
 


 








For simplicity’s sake, clinicians that identified as “other” and listed a credential that contained “nurse” or “paramedic” were classified as one of those things.  If they self-identified as both, I classified them as whichever one they listed first. No one identified as an anesthesia assistant or physician assistant, so they are not included.  The only “Other” responses that were completely unique were respiratory therapist (there were several varieties of RT that got simplified) and one student nurse anesthetist.  Years of experience required no adjustment though it may have been useful to break the largest group, “More than 10 years” down a little further since it made up nearly half of the sample population.  The survey specifically asked how many years under any credential and not the current one since many providers begin their careers in one discipline and move either laterally or upward in terms of licensure and practice environment. 

Training: Past and Future
Not surprisingly, nearly everyone (98.7%) who responded has had some sort of training in using the bougie, either a formal education session, manikin practice or both.  That translated across all credentials and experience levels with the lowest incidence of training occurring in paramedics and those providers with less than one year of experience, though neither of these reached statistical significance.  Training, success and comfort level appear to be linked, at least negatively, as three of the five respondents who have had no training, have never tried to use the bougie and feel very uncomfortable about the prospect of doing so.  The other two without formal training reported they had been successful at least once and they were at least comfortable with using the bougie.  I can only imagine how confident I might be with something at which I had succeeded without ever being trained. 

What is a little quizzical is how many providers don’t believe that further training with the bougie would be beneficial to their practice or professional development (24.4%).  As you can see, the numbers are distributed fairly evenly across the years of experience with predictably fewer respondents in favor of more training as experience levels rise.


 Looking at credentials makes it a little less clear. Slightly more than half the physicians don’t want more educations, which may not be unusual given the length of initial medical education. The largest number of providers who want more training is the paramedics, while nurses come in about the same as the overall average. Of all the clinicians who did not want more training, 31% prefer using the bougie on a first attempt, and all but one of those have at least three years of experience, perhaps indicating a self-perceived level of competence among this group in using their tool of choice. I found it a little distressing and somewhat hard to believe that anyone who intubates, or performs any invasive skill for a living for that matter, would not find value in at least some ongoing education and training. 

One response made me wonder if I should have asked the question “Have you ever heard of a bougie before?” A physician with less than one year of experience reported that he had no formal bougie education, had never used one, was uncomfortable with using one and didn't want any education about using one.  I had to wonder if the word Bougie means something else, and something bad, where he is from.

Success and Failure
This is the part you were waiting for, right?  Of the 380 respondents, 322 stated that they had used the bougie on a live patient and 317 of those responded that they had been successful.  As stated above, I believe there are probably some failures hidden in that number, but the question was not sufficiently powered to find them and providers, rightly so, answered with their best performance.  Training and comfort level with the bougie and with intubation overall appear to be linked to success. The numbers lead me to conclude that training is inextricably linked to success (quick, call the Nobel Foundation). It is well documented that muscle memory, identification of landmarks and manipulation skills are enhanced by experience and reinforced by successes (1).
 
There were only five failures reported and again I surmise that those clinicians have never had a success when using the bougie or that’s the experience they would have reported. The table below lists the details of each respondent who reported an unsuccessful bougie experience:




 As you can see, the clinicians that reported failure were all educated, very experienced and comfortable with both intubation and bougie usage.  One possible explanation for this lives within the nature of airways themselves.  Several sources report the true incidence of difficult airway, depending on definition, at between 3%-11% of all cases (2).  Further classification of truly bad airways that cannot be rescued by means other than surgical, referred to as “Cannot intubate, cannot ventilate” (CICV) can be found in 0.01-0.03% of cases(3).  The failure rate reported in the survey is 1.5%, higher than the incidence of CICV but below average of reported airway difficulty. Thus I contend it is very plausible that the airways encountered by these trained, experienced providers were difficult, maybe impossible airways for which there was little hope short of a scalpel.

See One, Do One, Teach One, BE ONE!
Most of the clinicians who have used the bougie are comfortable with both its use (95%) and intubation in general (97.89%).  Only five people reported being uncomfortable with both, even though four of those claimed a successful bougie experience. To their credit, all five would find more education beneficial.
These findings seem to suggest that using the bougie improves the comfort level, or at least that an elevated comfort level from adequate training increases the likelihood that a provider will use the bougie. But with training levels, successful use and confidence levels all being above 95%, discerning which has the most positive effect is beyond the reach of the survey.

Choices
The survey looked at two different preferences: what providers choose to shape the tube on first attempt and what technique they used when they employed the bougie. One the first question, a majority of providers across all credentials surveyed prefer a malleable stylet over a bougie on their first attempt. This wasn't especially surprising since, even though the bougie was first introduced in 1949(4), its widespread use in acute care, transport and prehospital medicine has peaked only in the last ten years.  The same preference is true across all measured experience levels.  Paramedics had the greatest affinity for the bougie on first attempt (42.97%) among the credential groups and the 3-5 year experience group had the greatest bougie preference (44%). It is worth noting that an overwhelming majority of that group is made up of paramedics.

Summary
The survey, though not very powerful, did seem to affirm some widely held beliefs. Training in use of the bougie is widespread across all credentials and experience levels.  Though it would have been beneficial to know where the providers practice intubation, the primary distribution of the survey link suggest that it was mostly completed by clinicians involved in air/ground critical care transport, acute care and EMS.  Among these populations, success rates and confidence levels in use of the bougie and intubation in general are very high.  The reported failure rate falls well within the generally accepted percentage of difficult airways and comes close to the minute number of airway cases that cannot be managed effectively without surgical intervention.  Preference for the malleable stylet over the bougie for a first attempt remains greater than 50% overall and in every single credential group. This suggests that most providers still consider the bougie a difficult airway or rescue airway tool and have not adopted it as a first pass device. This is further supported by the 3 to 1 preference for using the bougie with the two person “railroad” technique rather than preloaded, suggesting that bougie is employed only after a difficult view is encountered. 

Part II of the Bougie review will examine the evidence of airway success rates when using the bougie and present the cases for and against using the bougie as a first attempt adjunct on every intubation attempt.

Thanks again for reading. Feel free to comment here or on Twitter @Crit_Care_Excel, and visit the website, www.critical-care-excellence.pro.

References
1.       Garza AG, Gratton MC, Coontz D, Noble E, Ma OJ. Effect of paramedic experience on orotracheal intubation success rates. J Emerg Med. 2003;25(3):251-6.
2.       Law JA, Broemling N, Cooper RM, et al. The difficult airway with recommendations for management--part 1--difficult tracheal intubation encountered in an unconscious/induced patient. Can J Anaesth. 2013;60(11):1089-118.
3.       TNATC Provider Manual 5th Ed ASTNA 2010

4.       Gataure PS, Vaughan RS, Latto IP. Simulated difficult intubation. Comparison of the gum elastic bougie and the stylet. Anaesthesia 1996; 51: 935-8.

Wednesday, September 10, 2014

#3: What's the best way to relax?


Prepared by Michael. C Berrier, NRP, FP-C, C-NPT, AAS

Something that is never in short supply in medicine, especially acute and critical care medicine, is opinion. Even in the burgeoning age of evidence based practice, opinion and dogma still make up a surprising portion of what we do at the bedside. From this meld of evidence and anecdote flows a river of options in just about every procedure or treatment plan we have. Tubes: cuffed or uncuffed? Tourniquets: good or bad? Trauma resuscitation: Blood or fluid? Drink: Coke or Pepsi?  The choices are endless. But, many of these options have been proven, at least we think, good or bad.  Cuffed tubes for (almost) everyone, yay tourniquets and blood out needs blood in.  The drink question is beyond the scope of this article.  But so many other choices still exist, for good or for ill, and most of these are almost solely at the discretion of the provider.  One of these choices that folks in acute/critical care and transport make regularly is what combination of drugs they will use to carry out a rapid sequence induction and intubation (RSII).

The history: RSII provides for optimal intubation conditions by inducing a state of unconsciousness followed immediately by paralysis to minimize patient movement and, more importantly, allow free movement of the mandible to facilitate laryngoscopy and tracheal tube placement(1).  The originally stated purpose of the RSII as opposed to traditional general anesthesia was to secure the airway for patients in whom an NPO period could not be documented or confirmed. This was first used in cases of emergency obstetrics in 1946 (2) but quickly migrated to emergency departments and acute care areas and finally outside into EMS and CCT.  The choice of medications was traditionally dictated by anesthesiologists because they were the ones locally who controlled the medication and did the training.  This has relaxed quite a bit today so that physicians and mid-level providers can choose their cocktail in the hospital, while EMS and CCT medical directors dictate what their employees will use in the field and write protocols accordingly. Some of the most commonly used induction drugs for this procedure are etomidate and ketamine, while the most common drugs used for neuromuscular blockade are succinylcholine (sux) and rocuronium (roc). This review will be limited to these four drugs.

Science and evidence: When we consider the appropriateness of a medical intervention, we should always consider the efficacy, the utility and above all the safety of that intervention.  Fortunately, when it comes to the medications used for rapid sequence induction and intubation, there is a trove of evidence available about all three.

First, let's consider efficacy.  When we perform an induction, we ask our medications to do two simple things: make our patients sleep and relax.  In this department, all four of our drugs perform just about exactly as we want. 

Etomidate is a sedative hypnotic that depresses the reticular activating system (RAS), inhibiting excitatory stimulation at the GABA-receptor complex.  Or, more simply stated, it's the pharmacological equivalent of a right hook to the jaw...a knockout.  It produces a state of complete unconsciousness in as little as 15 seconds, maybe shorter in a hypermetabolic patient, and usually lasts less than 10 minutes(3).

  Ketamine exerts its effects on the GABA-receptor complex and opioid receptors, producing profound dissociative anesthesia and analgesia in about 45 seconds. The duration is a little longer than etomidate, sometimes lasting as long as 20 minutes (4). 

For relaxation, both Sux and Roc produce complete neuromuscular blockade in almost all patients when dosed appropriately, though by different mechanisms (5). Sux is a depolarizing muscle relaxant, acting on the cholinergic receptors of the motor end plates to stimulate total myocyte depolarization. The relaxation is rapid, often less than a minute and remarkably short-lived at less than 10 minutes (6).  Roc instead competitively blocks the uptake of acetylcholine at the motor end plate, causing relaxation by preventing depolarization.  This results in a longer onset of action, about a minute, and a much longer duration of action at between 30-60 minutes, depending on your reference (7).  So, efficacy is covered by any of the current available choices.

Secondly, thinking about the utility of these drugs provides the first inkling that a choice may not be necessary, or at the very least superfluous.  In the world of critical care transport, space is at a premium because, well, ambulances and helicopters are only so big.  So the more we can consolidate and combine our drugs and equipment for multiple purposes, the fewer specific things we have to carry.   Said another way, it would be nice if our drugs had more than one job, allowing us to use them more and waste them less.  It is here that two of our four drugs begin to distinguish themselves.  
Let’s begin with the simple chart below:















Etomidate and Sux have but one job in emergency and critical care transport medicine, and that job is RSII.  Neither are appropriate for long term maintenance of anesthesia because of their fiercely short durations of action and well documented negative effects from repeat dosing (8,9). Furthermore, the muscle fasciculations caused by massive muscle depolarization following Sux administration have prompted many services to premedicate patients with a non-depolarizing NMBA at 1/10th the intubation dose prior to induction (10).

You know, a non-depolarizing agent…like Roc. 

This process actually contributes to the argument that Sux has only one job, and adds the idea that it can’t even do that job by itself.

Conversely, ketamine and Roc both have multiple jobs, most completely independent of one another.  Roc is not only suitable for induction but also for long term maintenance of neuromuscular blockade should the clinical situation warrant that.  Evidence suggests that the dose can be manipulated within the effective range of 0.6 -1.2 mg/kg to achieve varying durations of action without affecting onset.  One study found that Roc dosing at 0.6 mg/kg based on ideal body weight in obese patients produced a significantly shorter duration of action (11), somewhat alleviating the fears of a prolonged “can’t intubate, can’t ventilate” situation in the event of a failed airway.

As far as ketamine goes, the utility is vast and wide.  Obviously, it performs well as an induction agent with only a slightly longer onset that etomidate (9), and it can also be used for prolonged sedation of the intubated and unintubated patient alike.  It is very useful for procedural sedation, agitation and concomitantly or alone for pain control as well (12). There is even some recent anecdotal cases of physicians using ketamine and BiPAP in the emergency department for patients with impending respiratory failure who were able to avoid intubation altogether by allowing them to calm down and oxygenate effectively (13). To succinctly summarize the utility of ketamine, here is a tongue-in-cheek graphic from Dr. Steve Carroll about his thoughts on ketamine, aptly dubbed the Carroll Emergency Treatment Algorithm, or CETA:





Finally, we look at safety, and this is where the picture clears and muddies all at once.  First we must acknowledge that RSII carries with it a certain amount of risk, even when performed under the most controlled conditions by experienced providers.  By administering sedatives and paralytics, you are taking away a patient’s ability to protect his airway and breathe (2) so the utmost priority rests with your expedience and certainty in taking over those functions through intubation and mechanical ventilation.  Beyond that, it is incumbent upon you as a clinician and the medical community at large to use the safest adjuncts available to facilitate this risky procedure. Looking to the evidence, there is no shortage of study on the proper drug combination to produce optimal intubating conditions at the least expense of patient safety.  A Medline search of “Roc + Sux” produces 304 results, while a similar search of “ketamine + etomidate” yields 282.  Granted, you can narrow these results by adding the term “versus”, but it is clear that these medications are frequently reviewed together, often in comparison or contrast.  What is more telling; however, is the literature that looks at each agent individually through the lens of side effects and general safety.  Some of the biggest issues noted with each medicine were:


Sux: The good news is that Sux is usually pretty safe for almost all patients. The bad news is that when it is unsafe, mortality can reach up to 70%. This is further complicated by the relative absence of indication of the worst of these mortal side effects and the nearly absolute absence of appropriate treatment during transport (14). Of greater concern are the findings of a 2011 study that Sux administration for RSII was associated with significantly more rapid desaturation than a dose of Roc (15). This difference is thought be caused by widespread muscular depolarization as evidenced by the fasciculations often seen with Sux administration and the resultant increased oxygen consumption. As focused as we are on maintaining optimal oxygenation (1,2) during the requisite apneic period during RSII, using a medication thought to increase oxygen demand raises important concerns.

Roc has been the subject of scrutiny for a couple of reasons outside of the operating room, and one of those is related to its duration of action being prolonged. This is a known and intended effect of the medication, though measurably shorter than other medications in its class.  The other stated concern has been Roc induced anaphylaxis (16). This condition is particularly troublesome because it is refractory to normal anaphylaxis care, namely injected epinephrine. One case demonstrated a profound grade IV anaphylaxis that failed to respond to 0.7 mg of epi 1:1000 administered IM (17). The only effective treatment for this particular case was sugammadex, the reversal agent for Roc which is both very expensive and virtually absent from emergency departments and critical care transport vehicles. Fortunately, one study found the incidence of Roc allergy to be literally one in a million (1,008,000 to be precise) (18), making it not more prone to anaphylaxis than other non-depolarizing NMBA.

Etomidate, once the darling of emergency and operative medicine alike for its relatively neutral hemodynamic profile has come under fire in the last ten years for association with post induction adrenal suppression.  This is evidenced by a drop in serum cortisol levels and refractory hypotension and bradycardia in the ICU as much as 24 hours after RSII with etomidate.  While most studies confirm that the cortisol reduction and adrenal suppression is real, they also state that these events are seldom clinically significant and almost always self-correcting (19), though a few did show a link between single etomidate bolus and mortality (20).

Ketamine has been extensively studied for perceived increases in intracranial pressure (8), apnea (4), and the so-called emergence reactions characterized by dreams and hallucinations (9).  The latter two of these are of much greater concern when the drug is used for procedural sedation, but has little bearing when ketamine is used for RSII as the patient will become apneic by design and remain sedated long after that effect has passed (9). However, in either case, emergence can be mitigated with subsequent doses of benzodiazepines (1). The issue of increased ICP after treatment with ketamine has been theorized because of the drug’s well documented increasing of mean arterial pressure which will, by extension, elevate ICP.  Several direct studies have since shown that ketamine does not raise ICP directly and may actually contribute to stabilization of cerebral perfusion by maintaining cerebral perfusion pressure (21). 

Clinical considerations:  Logistically, the main considerations about any of these drugs is proper labeling and storage of paralytic agents. Obviously, NMBAs are deadly if misused or mistaken for other drugs, so great care must be taken to ensure the drugs are properly labeled, kept secure and any unused volume wasted promptly after use.  Both Roc and Sux are temperature sensitive and will begin to lose potency at room temperature.  Both of these medications should be bulk stored in a refrigerator until ready for deployment and then rotated and discarded according to a schedule recommended by a pharmacist.  There are no significant medication compatibility issues with any of the four drugs discussed and no special administration equipment required (i.e. filters, pumps, etc).

Discussion: Anecdotally, RSII is a procedure commonly found in critical care transport and EMS agency protocols, but the frequency of performance is not very high.  For this reason, vigorous training and drills are necessary to maintain muscle memory and adequate knowledge of the required skills and medications.  To further this goal, agencies can possibly increase the success of the process by adding tools like video laryngoscopes (this topic will be discussed at a later date), adjuncts (gum elastic bougie, etc) and appropriate airway rescue devices (i.e. supraglottic devices, cric kits, etc).  But another possible avenue to reduce complexity would be to find the most appropriate, widely accepted combination of induction agent and NMBA and mandate their use for every procedure.
One way to decide if a mandated single cocktail is the answer is to ask the question backwards: Is a choice the answer? Or, at least, is the choice beneficial? Based on the evidence above, I'm inclined to say no.  Though one or two studies find that one drug or the other produces better intubating conditions, the evidence is a long way from declaring a winner at either induction or muscle relaxation. However, the facts and the literature do suggest that two of these drugs, etomidate and sux, are adequate at one job while being unsuited for any other. Even without calling their safety into question, this lack of utility hurts their case. 

Protocols are written to be guidelines combined with sound judgment to provide the best care, and evidence seems to suggest that doesn't necessarily include a choice of RSII cocktail. Further, the literature seems to favor making the single combination ketamine and rocuronium.

Our bags are pretty full. Let's make some room.

Refernces:
1.       Bryan E. Bledsoe, Randall W. Benner. Critical Care Paramedic. Harlow : Prentice Hall, 2006.: 142
2.       American Academy of Orthopaedic Surgeons (AAOS), UMBC. Critical Care Transport. Jones & Bartlett Learning; 2011: 166-167
3.       Etomidate Drug Information. Available at: http://www.drugs.com/pro/etomidate.html. Accessed August 9, 2014.
4.       Ketamine Drug Information. Available at: http://www.rxlist.com/ketamine-hydrochloride-drug.htm. Accessed August 9, 2014.
5.       Mallon WK, Keim SM, Shoenberger JM, Walls RM. Rocuronium vs. succinylcholine in the emergency department: a critical appraisal. J Emerg Med. 2009;37(2):183-8.
6.       Anectine Drug Information. Available at: http://www.rxlist.com/anectine-drug.htm. Accessed August 9, 2014.
7.       Zemuron Drug Information. Available at: http://www.rxlist.com/zemuron-drug.htm. Accessed August 9, 2014.
8.       Walls RM, Murphy MF. Manual of Emergency Airway Management. Lippincott Williams & Wilkins; 2012
9.       Caro, D. Sedation or induction agents for rapid sequence intubation in adults. Available at: http://www.uptodate.com/contents/sedation-or-induction-agents-for-rapid-sequence-intubation-in- adults?source=search_result&search=Sedation or induction agents for rapid sequence intubation in adults&selectedTitle=1~150. Accessed September 9, 2014.
10.   Shreiber J, Lysakowski C, Fuchs-Buder T, Tramer R. Prevention of succinylcholine-induced fasciculations and myalgia. Anesthesiology. 2005;103: 877-84
11.   Meyhoff C. Should dosing of rocuronium in obese patients be based on ideal or corrected body weight? Anesthesia and analgesia. 2009; 109: 787-92
12.   Birrer K. Ketamine sedation for adult burn dressing changes. Available at: http://www.surgicalcriticalcare.net/Guidelines/Ketamine for Burn Dressings 2013. Accessed August 9, 2014.
13.   Carrol S. Airway update screencast. Available at: http://embasic.org/airway-update/. Accessed August 9, 2014.
14.   Martyn JA, Richtsfeld M. Succinylcholine-induced hyperkalemia in acquired pathologic states: etiologic factors and molecular mechanisms. Anesthesiology. 2006;104(1):158-69.
15.   Tang L, Li S, Huang S, Ma H, Wang Z. Desaturation following rapid sequence induction using succinylcholine vs. rocuronium in overweight patients. Acta Anaesthesiol Scand. 2011;55(2):203-8.
16.   Rose M, Fisher M. Rocuronium: high risk for anaphylaxis?. Br J Anaesth. 2001;86(5):678-82.
17.   Conte B, Zoric L, Bonada G, Debaene B, Ripart J. Reversal of a rocuronium-induced grade IV anaphylaxis via early injection of a large dose of sugammadex. Can J Anaesth. 2014;61(6):558-62.
18.   Bhananker SM, O'donnell JT, Salemi JR, Bishop MJ. The risk of anaphylactic reactions to rocuronium in the United States is comparable to that of vecuronium: an analysis of food and drug administration reporting of adverse events. Anesth Analg. 2005;101(3):819-22
19.   Schenarts CL, Burton JH, Riker RR. Adrenocortical dysfunction following etomidate induction in emergency department patients. Acad Emerg Med. 2001;8(1):1-7.
20.   Den brinker M, Joosten KF, Liem O, et al. Adrenal insufficiency in meningococcal sepsis: bioavailable cortisol levels and impact of interleukin-6 levels and intubation with etomidate on adrenal function and mortality. J Clin Endocrinol Metab. 2005;90(9):5110-7.
21.   Wang X, Ding X, Tong Y, et al. Ketamine does not increase intracranial pressure compared with opioids: meta-analysis of randomized controlled trials. J Anesth. 2014;


Friday, September 5, 2014

HOT salted...plastic?

The debut post for Critical Caring, “Hypertonic Saline: Worth its salt?”, was well if not widely received, but it did turn a few heads. Hyperosmolar therapy (HOT) was concurrently the subject of the Emergency Medicine EMS journal club meeting our trauma center, and the response was favorable enough among the EM physicians (our transport medical director one of them) to write a protocol for our air/ground CCT service to guide administration of hypertonic saline (HTS) to patients with significant intracranial hypertension. 
In search of inspiration, I asked Dr. Bill Hinckley from University of Cincinnati Air Care (tweeting as @UCAirCareDoc) for his HOT protocol1, and he graciously agreed.  While reading his protocol, I came across something I hadn’t considered:


It had not honestly occurred to me that a patient could have such severe intracranial hypertension as to warrant HOT but still not meet clinical criteria for intubation.  Though I had never transported or seen a patient who fit this description, I conceded there are many things I haven’t seen and don’t know and gladly counted this among them.  So I included this box in the first draft of our protocol:







to which the medical director replied  I wonder about managing intracranial hypertension…in a patient who is not intubated.  Makes sense. I probably should have asked that question myself.

He also said “It might make more sense to make intubation a requirement – not as a means of management, but as a marker of severity.”  Again, incredibly sound logic.  If someone is sick enough, by the criteria (posturing, hypertensive, unilaterally blown pupil, seizure, coma), to need HOT, would they not also need definitive airway control?  This has been my own experience as well as that of many intensivists I had polled on the issue before, leaving me to wonder how often do we manage intracranial hypertension WITHOUT an advanced airway? To begin, I tossed the question to Twitter.

Twitter rarely disappoints.

Dr. Hinckley answered “rarely” and put the questions to a few of his colleagues and followers.  Here is some of the discussion:

Dr. Chris Zammit (@cgzammit) said “I advocate for HOT if there is neurodeterioration (GCS drop by 2 or more points)”  This seems sounds, even if the GCS D doesn’t meet the magic threshold of 8 to intubate (which, by the way, I’ve always though was a little suspect).  It has been my experience that GCS in the setting of significant brain insult doesn’t spontaneously improve, but rather declines over time, seemingly falling faster the further it declines. So even if the patient goes from GCS 15 to 13 between neruo assessments, it is conceivable that 11 and then 9 are fast approaching.  

This line of thought was echoed by Wendy Chang (@EM_NCC), a neurointensivist who adds that HOT in non-intubated patients is “not common, since those who need HOT are critical and likely need ETT but possible as HOT may reduce ICP/reverse herniation and pt would not need ETT.”  She and others (Brian Burns, @HawkmoonHEMS; Taylor Zhou, @canibagthat) mostly agree that these are critical patients who are not only comatose enough to warrant intubation, but also need to have oxygenation and ventilation strictly controlled to prevent hypoxia and maintain normal ventilation or provide mild hyperventilation in the case of acute herniation. 

A few things worth remembering about HOT:
  • · Both 3% Saline and Mannitol can be given safely via peripheral IV, though mannitol requires a filter.2,3
  •   They can both be given IO, but make sure your access is patent prior to bolus.4
  • · Mannitol should be avoided in the profoundly hypotensive or poorly resuscitated patient due to massive osmotic shift and diuresis.5
  • ·  HOT therapy doesn’t take place in a vacuum.  Sedation, analgesia, hemodynamic support, oxygenation and ventilatory regulation are all crucial to good outcomes in these patients.6

HOT is rare intervention in our service, and instituted almost universally in the intubated patient, so our protocol will read that way, at least for now. 

Thanks for reading Critical Caring.  Feel free to comment here or on twitter, @Crit_Care_Excel

References
  1. Hinckley B. Management of Intracranial Hemorrhage (SAH, ICH In: University of Cincinnati UC Health AirCare Policy #CLIN24 January 2013
  2. Mannitol injection, USP. (2014, July 2014). Retrieved from hospira.com: www.hsopira.com/products_and_service/drugs/mannitol
  3. Luu, J. (n.d.). Three percent saline administration during pediatric critical care transport. Pediatric Emergency Care, 1113-1117.
  4. Intraosseous(IO) Vascular Access and the EZ-IO Frequently asked questions. (2014, july 25). Retrieved from vitaid.com: www.vitaid.com/files
  5. Managment of patients with severe head trauma. (2012). Joint Theater trauma system clinical practice guidelines. United States.
  6. Prehospital TBI-Beyond the “Code”. Taming the SRU website. http://www.tamingthesru.com/blog/acmc/prehospital-tbi-beyond-the-code?q=tbi Published 5/20/2014. Accessed 9/5/14