Environmental & Toxicology (August 2015)
Review: Brown et al. Accidental Hypothermia. NEJM 2012
Research: Ali et al. Lack of Coagulopathy After Copperhead Snakebites. Annals of EM 2015
AIR: Toxicology
Review: Brown et al. Accidental Hypothermia. NEJM 2012
Research: Ali et al. Lack of Coagulopathy After Copperhead Snakebites. Annals of EM 2015
AIR: Toxicology
16 comments
Ali et al.
– Really nice retrospective study (as good as many toxicology-related studies can get)
– Perhaps coagulopathy is not such a concern with copperhead snakebites
– Keep in mind that this applies only to copperheads. The crotalidae subfamily also includes rattlesnakes and cottonmouths, which I hear has higher risk of coagulopathy, though I’ve never been bitten myself.
Brown et al.
– Table 2 summarizes the severity of accidental hypothermia and its treatments very well.
– When are we getting ECMO?
■How has reading the article changed your practice?
Luckily- I have never treated a pt with a copperhead bite, nor have I been a victim. Suprised at how common these bites are in certain regions. I guess I would maybe try to aim my practice at looking for clinically signifcant bleeds, and likely avoid serial coags/labs if no bleeding present in clinically stable pt. –> however, I’m at at the Poison Control Center at Children’s currently- and micromedex and their recommendation is to pull labs (coags/CBC) after the antivenom is given, and every 4-6 hours afterwards…
■What information had you believed in previously that were debunked by reading this article?
laboratory proven coagulaopathy may not necessary to monitor… esp if there is no clinically significant bleeding or edema.
■What new information did you learn from reading this article?
I learned that CroFab is also referred to as FabAV (initially confused me). Also only mentioned in only 1 sentence, but that treatment for compartment syndrome induced by snakebite by copperheads is with antidote alone- not surgery.
■What are current areas of uncertainty on this topic that can be potential areas for research?
– does bite location have an effect on coagulopathy? (i.e. extremity v. truck v. proximity to blood vessels)
– how long do pt’s need to be observed after a copperhead snakebite if there is no need for serial laboratory work?
did i answer the wrong question set? haha.
It’s all good. I can tell you definitely read the articles and have thoughtful responses. The bite location and observation time questions are really interesting. I wish there were more snakes to go around to study.
Perhaps if there was a plane full of em…
maybe we should have a group viewing of this movie or something. for educational purposes only…
■How has reading the article changed your practice?
consider ECMO or transferring pt to a facility who may offer this option with temps survival is very very low, and CPR and resus may be useless.
■What new information did you learn from reading this article?
In all-by-myself-hospital- there is utility in checking a serum K, and if it is >12mmol/L, can consider termination, even if core temp is not >32C (90F)
■What are current areas of uncertainty on this topic that can be potential areas for research?
– need for maintaining hypothermia in pt’s who cardiac arrested b/c of severe hypothermia–> i’m not sure I understand what the goal temp should be in this case, and for how long…
Ali et al article: Copperhead Snakebites
~ What are some strengths of the study?
This is actually a pretty impressive retrospective study from two hospitals that spanned over 10 years, and enrolled a fair number of patients, especially considering it looks at a topic that I did not believe to be that common. For almost all confirmed or highly suspected copperhead bites, they were also able to find the coagulation studies for the patients.
~ What are the limitations?
One major limitation is the nature of being a retrospective study. The other is that over half of the bites were only “presumed” to be copperhead bites, although they argue that these were highly likely. I would be interested to know the prevalence of coagulopathies in all snakebites of unknown species, rather than just copperheads, because I would imagine that often people are not sure by what species they were bit.
~ What are the main outcomes of the study?
The main outcomes of this study showed that there were no clinically significant alterations in clotting ability in the patients found to have copperhead bites. They argue that this means that there should not be a need to get serial coagulation studies on these patients.
~ Does reading this article change your practice? If so, how?
It does not really change my practice, because I don’t think we see a lot of these patients in our population. But it does make me a little more aware of the, albeit possibly more theoretical than actual, complications of these bites in case I do encounter one eventually.
Brown et al article: Accidental Hypothermia
~ How has reading the article changed your practice?
Thinking about times when CPR should not be continued and the patient may qualify for termination was interesting. We are always taught that “a patient isn’t dead until they’re warm and dead”, but it was helpful to think of exceptions to that rule (ie trauma, possible normothermic arrest, and avalanche burial < 35 mins)
~ What information had you believed in previously that were debunked by reading this article?
I'm not sure about anything that was debunked, but the article definitely reiterated the need to rewarm patients found in cardiac arrest with hypothermia, as they may still recover with normal neurologic outcomes if they arrested after decreasing their core temp.
~ What new information did you learn from reading this article?
I found the flowsheet with a treatment algorithm for hypothermia to be very helpful. While we may not see many patients coming in from avalanches, this is probably pretty relevant in our homeless population who are sometimes found down for awhile during the winter.
~ What are current areas of uncertainty on this topic that can be potential areas for research?
I would be interested to see a retrospective review on how many homeless patients that are found down in the cold are actually ever brought back. I would bet that the number is quite low, but it would still be encouraging to see if even a few are brought back from asystole.
Copperheads!
What are some strengths of the study? They actually DID a retrospective study looking at copperhead bites. I like how they kept their focus on only copperhead bites and answering a targeted clinical question, ” do you need coagulation studies?” I also like how they wrote the paper. They included the data from the study but also individual case reports. They should do this in other research papers.
What are the limitations? Retrospective. 2 hospitals in the same region. Broke bites into copperhead and then “presumed” copperhead, meaning they had to rely on bystanders to make the call if there actually WAS a copperhead.
What are the main outcomes of the study? Coagulation studies are not needed in the absence of clinically apparent bleeding. A lot of patients in this study had abnormal levels but they were not clx significant.
Does reading this article change your practice? If so, how? As we talked about today in JC, we do not see this much, so I don’t really have a snake bite practice. This does gives ME confidence that if I got bit by a copperhead, I’d probably be OK.
– How has reading the article changed your practice?
Although I have not yet had the opportunity to treat many hypothermic patients I found it interesting that the Swiss staging system (I-IV) has proven more reliable in terms of devising treatment stragegies when recorded temperatures prove unreliable.
– What information had you belived in previously that was debunked by reading this article?
I was not aware of the large volume of warmed IVF required to treat these patients secondary to hypothermic diuresis. Previously I was aware of large volumes of warmed fluid for lavage only.
– What new information did you learn from reading this article?
I learned that when very cold, some people take their clothes off instead of piling more layers on.
– What are current ares of uncertainty on this topic that can be potential areas for research?
It seems that there is no hard evidence on whether vasopressors/epi should be administered in a patient with a temperature below 35degrees C during resuscitation or deferred until the patient is warmed to at least 35degrees C.
Ali et al. Copperhead Snakes:
– What are the strengths of the study?
This study clarified the utility of a previous clinical practice that was not supported by researched based evidence.
– What are the limitations of this study?
This study relied heavily on the subjective attestation of patients and witnesses with regards to the species of snake involved. Are there that many people out these who can distinguish a copperhead versus any other snake – particularly at night etc…
– What were the outcomes of this study?
This study revealed that clinically significant bleeding, coagulopathy or thrombocytopenia do not occur commonly following copperhead bites and that routine coagulation screens may not be required if confidence in the identification is high.
– Does reading this article change your practice?
Luckily St. Patrick rid Ireland of snakes hundreds of years ago so I have never had to deal with a snake bite. I think that in this globalized world where people keep all sorts of exotic pets I would feel more comfortable including a coagulation screen in most cases of snake bites. In the same way that we often take our patients HPIs with a grain of salt we should be wary of their ability to identify a snake
copperheads: not so bad after all?
Strengths:
retrospective review including adults and kids with thorough ID of the right snakes included only, pretty good ‘n’. I agree with travis about how having the paper be a combo of data (useful but boring) and case studies from their group made it much more pleasant to read (and therefore hopefully it will stick!)
Limitations:
adults and kids (yep, i think it’s a strength in general but a limitation because they didn’t break down the results into adults and kids – they aren’t just little grownups, right?)
limitation for my practice – it’s only 1 type of snake, and it’s 1 that I don’t see, so what does it mean for me?
Outcomes: following coag studies isn’t necessary when the patient doesn’t show signs of hemorrhage – use your clinical acumen!
Practice changing? nope…by the time I see a patient with a snake bite I’ll probably only remember this vaguely and default to uptodate for guidance :)
hypothermia
practice:
will need to actively consider sending to ECMO facility when answering radio calls – not that BEMS wouldn’t be more on top of this than I am. I’m trying to look up who has ECMO in boston…MGH, childrens, BI, anyone else?
and remember to look for signs of pre-hypothermia arrest (in the environment or the patient) and when to terminate resus efforts.
new or debunked information:
good to have a number: you don’t have to be warm and dead if your potassium is over 12
uncertanties/research areas:
drowning without vital signs: It makes sense that if you go into cold water breathing before drowning you have a decent chance of survival with neuro outcome (much better than warm water), but I’m curious why drowning in cold water without that breathing/cooling period yields worse outcomes than in warm water…
HYPOTHERMIA
How has reading the article changed your practice?
o Figure 1 does a great job of providing a tx algorithm that will guide my practice. The paragraph concerning decrease cerebral oxygen requirements allowing for a return of significant neurologic fxn even after hours of CPR suggests that I might want to consider continuing CPR longer than anticipated (only terminating based on K levels described in article).
What information had you believed in previously that were debunked by reading this article?
o That cardiac arrest for hours does not always lead to neurologic impairment in a hypothermic patient.
What new information did you learn from reading this article?
o Tons. Especially since I largely had no awareness on the issue. Things I learned from reading the article (and Wed. conference) include: unsupported and wide variance in pre-hospital management for hypothermia, what is paradoxical undressing, Swiss staging system, proper temperature measuring – lower 1/3 of esophagus if tubed and 15cm (!) via rectal, warm IV fluids up to 38-42C, save ECMO, bypass for patients who don’t respond to medical management, ECMO > CPB in cardiac arrest patients with hypothermia.
What are current areas of uncertainty on this topic that can be potential areas for research?
o Use of epi during ALS in hypothermic patients undergoing cardiac arrest. AHA and Europeans seem to differ on when to start vasopressors during cardiac arrest in hypothermic patient; difference based on body temp
SNAKES!
What are some strengths of the study?
o Can’t really do RCT with tox studies so the retrospective methodology was as good as it gets
What are the limitations?
o Reliance of patient for snake ID; lab values were post tx; copperhead venom may very b/w peds vs adults; no interrate reliability
What are the main outcomes of the study?
o Coag studies were WNL after toxicity with no bleeding complications, suggesting that copperhead venom does not induce coagulability;
Does reading this article change your practice? If so, how?