Tourniquet Device Reviews #1

As part of an ongoing project I've been looking back over the primary literature that supports the use of tourniquets for hemorrhage control. The earliest study I could find to compare various devices was a 2000 article by Calkins et al. This is a worthwhile starting point in what will become a series of posts because this was the first academically published study to directly compare devices. 

Weekly Review #20

A systematic review in the BMJ examined how well health professionals understand diagnostic tests. Using “statistics”, “healthcare”, and “accuracy” keywords the reviewers searched EMBASE, PsycINFO, and MEDLINE databases identifying 4818 hits. 74 were reviewed as potentially relevant based on title and abstract, with 28 meeting full inclusion criteria. Due to the heterogeneity of studies the systematic review was limited to presenting its findings in narrative format. The authors categorized the findings into four themes: self-rating, accuracy of definition, Bayesian reasoning, and presentation format categories. 

Two studies examined clinicians’ self-reported familiarity of statistical measures. In one study 13/50 clinicians reported understanding sensitivity, specificity, and positive predictive value; although only one was able to provide a correct definition when asked to do so. The other study found that only 58% of clinicians actually used statistical measures in their practice (although 82% claimed to do so). 

6 studies examined clinicians’ understanding of statistical definitions; they found that on average clinicians could provide a correct definition for sensitivity 76-88% of the time, specificity 80-88% of the time, but only 17% could correctly identify the correct definition for likelihood ratios.

22 studies examined how well clinicians’ were able to use pre-test probability and test accuracy to determine post-test probability (Bayesian reasoning). The studies found that in general clinicians had a poor understanding of Bayesian reasoning and were unable to determine post-test likelihood the majority of the time (0-61% success), clinicians also tended to overestimate post-test probability by 46-73%, and in one study clinicians inverted the likelihoods incorrectly interpreting patients with negative results as having a higher post-test likelihood of having a disease.

The 5 studies that examined presentation format found that healthcare providers were more accurate in their post-test estimates if the findings were expressed as natural frequencies (50 out of 100) rather than as probabilities (50%). The use of graphical aides improved clinician post-test accuracy to 73% compared to 48% when natural frequencies alone were used to communicated test power, or 23% when probabilistic language was used to describe tests.

This systematic review suggests that not only are we as healthcare providers poor at using probabilistic reasoning; but that we’re also oblivious to our weakness in this area. As a nurse I know that the preparation I received in school to interpret and use statistics was severely lacking. This research, which focused primarily on physicians, would suggest that this is a common area of weakness. This research highlights how little we all know about the tools we use on a daily basis, it may also shed some light on why so few of our colleagues engage with research, and I would suggest that most importantly it empirically shows that we could all use some brushing up on how to use statistics. I’ve covered some great resources to help with this is a few previous weekly reviews (#4 & #6) and would suggest that anyone looking for a brief intro into using Bayesian statistics take a look at the first few chapters of this online book. 

http://www.ncbi.nlm.nih.gov/pubmed/26220870

Steve Mathieu reviewed the HEAT trial of acetaminophen for fever in critically ill patients on The Bottom Line Review. This study was a double blind RCT of 700 patients that sought to determine if the administration of paracetamol to critically ill patients had any effect on: ICU free days, mortality, length of stay (LOS), number of days on organ support, and its effect on lab values and temperature. Patients were block randomized to receive either 1g IV paracetamol, or IV D5W every 6hrs for 28 days or until: ICU discharge, fever resolution, cessation of antibiotics, death, or contraindication. The study found no statistical difference in mortality, LOS, ICU free days, or organ support, although patients who received paracetamol had a lower (0.25C) average temperature. This research is contrary to a retrospective study published earlier this year that found a mortality benefit associated with paracetamol administration, it has a much higher quality design, and is one that I've been waiting to see published. Mathieu's summary of this research is concise, easy to interpret, and very timely; the summaries on this site are consistently of very high quality, this review and the site in general are a fantastic resource.

http://www.wessexics.com/The_Bottom_Line/Review/index.php?id=7257804966227311886

A retrospective analysis of tourniquet use in the pre-hospital setting was published in the Journal of Acute Care Surgery this month. Ode et al., examined the EMS use of tourniquets in a metro North Carolina ambulance service during 2012-2013. They examined patients with uncontrolled hemorrhage to determine the frequency of “correct” tourniquet (Tk) application, the efficacy of Tk as a treatment, and the frequency of Tk related adverse outcomes. 98 patients met the inclusion criteria (uncontrolled hemorrhage), 42 were excluded because they were treated outside of the metro area. Of the remaining 56 patient: 24 received a Tk (19 Combat Application Tourniquet, 5 improvised), although 5 were deemed unnecessary (the patients weren’t in shock - SBP>80mmHg) and 4 were delayed. Of the 32 who didn’t receive tourniquets three were indicated, but did not receive treatment.

The patients treated with a Tk, compared to those not, had significantly higher rates of: shock (50 vs 12.5%), vascular injury (69.6 vs 25.8%), blood transfusion (37.5 vs 9.4%), rates of admission (77.3 vs 38.7%), and mortality (8.3 vs 3.1%). None of these findings are surprising given that the protocol for application of a Tk was quiet conservative, requiring patients to be in shock, and therefore significantly sicker. Secondary analyses showed that patients who were indicated to receive a Tk but didn’t had higher incidence of shock compared to those who did (85.7 vs 60%), and that those who weren’t indicated (not in shock) but did receive a treatment by tourniquet had no adverse outcome as a result.

Due to the overly conservative treatment protocols, the small sample size, and the lack of an equivalent control arm the primary results of this study have little to contribute to the overall body of evidence for Tk use in civilian trauma. The secondary analysis does show worse outcomes for patients with missed Tk’s, and no complications associated with liberal Tk (non-indicated) use; although the numbers (n=22) are too small to reach statistical significance. From a clinical perspective this research would seem, in a small way, to support that liberal Tk use isn’t associated with worse outcomes, and that even extremely conservative (only once shock becomes apparent) Tk use imparts benefit. From a practical perspective this research provides weak evidence to support Tk use in civilian trauma, it also suggests that the current military research may be generalizable to the civilian population, and indirectly it would seem to suggest the need for a liberalization of Tk protocols among EMS services. 

http://www.ncbi.nlm.nih.gov/pubmed/26402532

Using the current VW emission scandal as a comparison piece Richard Smith offered a critique of scientific misconduct on his BMJ blog, and suggests that scientists should face criminal charges if found guilty. Criminal charges have been used to punish scientific misconduct before, as was the case with June Dong-Pyou Hon’s faking of HIV immunization results; and Smith offers three additional reasons why misconduct should be investigated criminally: Because inappropriate use of research funding is financial fraud, because universities are poorly equipped to conduct investigations, and because investigations by the university would be a conflict of interest. I would also suggest that there is a basis for criminal charge based on harm to the patient, for example the intentional non-disclosure of the increased risk for suicide when paroxetine is used to treat pediatric depression, and Andrew Wakefield's fabrication of evidence that immunizations result in autism. A thoughtful and timely piece by Smith, maybe one that will find increased traction.

http://blogs.bmj.com/bmj/2015/09/28/richard-smith-if-volkswagen-staff-can-be-criminally-charged-so-should-fraudulent-scientists/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+bmj%2Fblogs+%28Latest+BMJ+blogs%29&g=w_blogs_bmj-com

On the Trauma Professionals Blog Micheal McGonigal discusses the reflexive way that many clinicians treat low oxygen saturation readings. He discusses factors that can result in artificially low reading, patient groups where a low reading is normal, the absence of a good definition of "normal values", and suggests that if the patient is not distressed on examination they likely don't need supplemental oxygen. This is a quick reminder to treat the patient and not the number.

Mark Culver discussed the differences between intermittent and continuous PPI therapy for UGIB on Emergency Medicine PharmD. There has been a fair bit of research into this topic lately, and UpToDate had suggested changing practice from continuous to intermittent PPI therapy last year; however the practice remains widespread. This post offers a great review of the research behind the change in recommendations. The cost savings, and reduction in nurse time this practice change could result in make this post well worth the read.

There was a podcast review of fluid resuscitation in hemorrhagic shock on HEFTEMCAST. This podcast reviews the key evidence and discusses the concepts of: damage control resuscitation: permissive hypotension, hemostatic resuscitation, and damage control surgery. The review includes seminal work from the military as well as evidence from civilian trauma, it nicely summarizes the key literature, and provides links to the source research. This 16 minute review is well worth a review for anyone working in an emergency settings.

Josh Farkas offered a well balanced review of the SPLIT trial on PulmCrit. The SPLIT trial examined the differences between PlasmaLyte and Saline in patients admitted to the ICU, and found that there was no significant difference between the two fluids. Farkas acknowledges that the findings are valid among the patients reviewed, but critiques the external validity of the study; he points out that the small volumes of fluid received, the admission reason (elective post-operative), and the low illness severity observed among the patients in this cohort are not generalizable to the typical ICU population.

Weekly Review #17

This is an older post, by Micheal Douma, of a NENA presentation on abdominal-pelvic trauma. The presentation at it's core is a summary of basic hemorrhage control, and a discussion about the degree of force required to provide adequate compression to control hemorrhage. Specifically though Douma discusses controlling abdominal pelvic hemorrhage with External Aortic Compression (EAC). EAC is, in short, pressure applied to the aorta using a fist (landmarking from the umbilicus) with arms locked as though providing CPR. Effective aortic occlusion requires 80-120lbs of force, and requires constant pressure (Douma has a great graph on occlusion techniques).

Maintaining this pressure is of course difficult during transportation and resuscitation, so Douma covers some of the emerging technologies that seek to accomplish this task (REBOA, junctional clamps and tourniquets, and stasis foams). Unfortunately there is no discussion about when to use EAC, perhaps due to the research being in it's infancy, but it's something you might consider when faced with extremity or pelvic hemorrhage not controlled by binding, or tourniquet.

There are two messages here that I think are important for nurses: the first is obviously that there is a role for direct arterial pressure in hemorrhage control, which sometimes needs to be applied proximal to the injury, even if that means occluding the aorta. The second point is that controlling hemorrhage begins with basic techniques performed well, which requires a surprising amount of force - if your bandages are soaking through, you need to press harder. Douma quantifies what we would often teach in TCCC, the use of knees to provide this consistent pressure, he shows that it provides extremely effective transfer of weight, as an added benefit it frees your hands up for other tasks.

I often see hemorrhage control poorly performed (bandages aren't for absorbing blood, they're for providing pressure), I've seen the deadly consequences of pelvic trauma with overt or occult hemorrhage, and would encourage all nurses to pay attention to the messages in this post.

http://rescuescience.org/2015/06/06/nena-external-aortic-compression-presentation/




BoringEM had a post by Martin Badowski this week discussing delirium. Delirium is an acute, fluctuating change in cognition that effects ~10% of older adults in the ED, it's associated with a three fold increase in 6 month mortality and is identified in less than half of the patients (17-35%) who present with it. This post discusses the diagnostic strengths and weaknesses of different diagnostic tools (CAM, CAM-ICU, mCAM-ED, MMSE, DTS+bCAM), and offer a mnemonic to approach differentials: I WATCH DEATH

Infection - UTI, pneumonia,
Withdrawal - BZD, EtOH, hypnotics,
Acute Metabolic - Hyper/hypoglycemia, electrolyte derangement,
                           Toxins - Alcohol, recreational drugs, or prescription interactions,
                           CNS - Tumor/lesions, CVA, Infection,
                           Hypoxia - anemia, hypotension, pulmonary/cardiac failure,
                           Deficiencies - Thiamine, B12,
                           Endocrine - Adrenal, thyroid, parathyroid,
                           Acute Vascular - Shock,
                           Trauma,
                           Heavy Metals.

I have found other mnemonic a little easier to remember when it comes to assessing delirium (see AliEM post on Weekly Review 11), but this post really shines in it's discussion of the diagnostic tools, where it discusses the predictive value for each in detail. A great post for nurses working in emergency to brush up on delirium screening.

http://boringem.org/2015/09/07/medical-concept-delirium-tips-and-tools/

In an older post on Pacific Emergency Medical Training Doug Fraser discusses "big vs. small box" EMS education. The small box approach Fraser says is the classic protocol driven reductionist approach to EMS: defining your role by the "things you can do". On the other hand the "big box" approach to providing care requires that an appreciation of your role within the system as a whole, and by necessity the roles of others. This may mean building an understanding of procedures that are beyond your scope of practice, and understanding aspects of practice that you are not part of. When we do this he asserts we open the door to sharing knowledge with other professionals, we learn from them in either a direct or an indirect manner. and become better at our own job. He uses a person example of airway management, discussing how as a BLS paramedic he's learned the finer points of ventilating from anesthesiologists, while being able to bring new ideas to ALS paramedics. This idea spans all health care professions, and echos the very core message of FOAMed, as indeed upstairs care downstairs can only happen when we take an interest in what others are doing.

http://www.pacificemergencymedicaltraining.com/?page_id=15

Seth Trueger from MDAware contributed to the ongoing EM mindset series on emDocs. He discusses the role of addressing the mundane in EM, stratifying risk, and coordinating care, and his unifying theme of balancing limited time with clinical uncertainty is a great message for all healthcare providers. Truger discusses the mental process for deciding if patients need intervention, diagnostics, or transfer and suggests that if you're spending a prolonged amount of time making the decision you should probably err to the side of caution and go for it; this message I think is directly translatable to nursing. I've witnessed nurses debate calling a physician about a deteriorating patient: if there's that much question go ahead, do it, then use your mental effort and time doing something that helps the patient. His idea that the time spent doing something unimportant takes away from the you have to do something important is spot on, a great take home message.

http://www.emdocs.net/em-mindset-seth-trueger-resuscitation-risk-stratification-care-coordination/




There was a discussion on Taming the SRU by Matthew Stull about approaching the undifferentiated patient. This is a great discussion about how to perform a history and physical assessment in the ED, what he himself always does in clinical practice, and what can be omitted. I really appreciated the opening discussion about avoiding corollary information before assessing the patient. By avoiding reading too in depth into the chart Stull asserts that you're less likely to become biased toward the patient and their presentation. I think this is important because cognitive anchoring can easily lead a clinician to wrongly attribute signs and symptoms to chronic conditions and previous visits. I think this is a great message for nurses, we all have repeat patients who present with intoxication, but it doesn't mean that those people aren't presenting with acute conditions such as head injuries.

http://www.tamingthesru.com/blog/bread-and-butter/undifferentiated-patient

EMin5 discussed preparing for RSI using the SOAPME mnemonic (Suction, Oxygen, Airway, Positioning, Meds, Equipment/EtCO2). A nice succinct review of how to set up your equipment, medications, and patient.

It's been a couple of weeks since having a post on caring for obese patients. If you're needing a fix check out this EMC podcast. It has a great overview on adjusting your practice in relation to vitals, airway interventions, and medication dosing.

Check out the discussion on BIJC about the difference between hemoglobin and hematocrit values (spoiler alert: there is none).

There's some new research this week from Matthew Douma on the efficacy of "double-barreled" dual IO therapy, there's a nice review of this research on the Trauma Pro's blog.

A St.Emlyn's post discussed strategies for maximizing your sleep. It offers suggestions on sleep hygiene, discusses the negative consequences of sleep deficit, and offers tips for adjusting to rotating day night schedules. This is something many nurses may find helpful.

And finally, a 7 year prospective population study in China published in the BMJ found that those who more frequently ate spicy food had lower all cause mortality than those who did not. This study includes a large number of patients (half a million) and examined consumption of fresh or dried chili when assessing for spicy food. There are of course a number of factors (urban vs rural) that could be confounders in this study, and it's not really FOANed per-se; but hey it's a reason to eat some hot wings this weekend.

Weekly Review #10

I listened to a podcast by Dr Jason Frank presented on the International Clinical Educator Network. The discussion reviewed an article on educational strategies to improve clinical reasoning. The article in question didn't discuss how they chose their strategies, or which strategies are most effective, so I don't think that the discussion can be appreciated in a meaningfully empirical manner. However there are strategies for teaching, and learning, covered in this podcast. The discuss focuses on 7 concepts of teaching:

Dual processing Model: The rapid interpretation of information through heuristics; and the slow analysis of novel information, with strategies to help learners switch between the two.

Conscious competence model: The movement from unconsciously incompetent to differing levels of competence. There is a great discussion about how peer learning, and how being able to remember being a new learner is a valuable tool for teachers.

Knowledge Organization: Different tools to structure knowledge of illness to typical presentations and the diagnoses.

Data Gathering and Data Processing: The use of standardized approaches and mnemonics to guide history taking and physical assessment, and how to filter through information to decide what information is pertinent to the clinical presentation.

Metacognition: Different ways to approach how you're reasoning through a clinical encounter.

This is a relatively quick podcast, the strategies for teaching are easily applied to learning. I think clinical reasoning is something that is continually perfected, and that there's something here for all learners.

http://icenetblog.royalcollege.ca/2015/07/10/keylime-89-clinical-reasoning-and-the-clinician-educator/

There was a study published in the BMJ by Lyle Moncur et al., that examined the correlation between the socio-economic deprivation of a neighborhood in which a cardiac arrest occured and the rate of bystander initiated CPR. Moncur et al., did this by examining all OHCA registered with the North East Cardiac Arrest Network to determine how often bystander CPR was initiated, and the neighborhood in which the arrest occurred. The address was referenced to the Office of National Statistics to determine the level of socio-economic deprivation of the neighborhood (1 most deprived; 5 least deprived). The team was then able to compare the rates of bystander CPR by socio-economic neighborhood. 

There were 3862 OHCA calls screened for this study, 683 were excluded because of missing data. What the team determined is that as economic deprivation increase, rates of bystander CPR decrease: they found that CPR was initiated by a bystander nearly 40% as often when it occurred in an affluent neighborhood. These results are sad, but they`re certainly not new. Similar studies were performed in the US and Asia, showing similar results: as poverty increases bystander CPR decreases, they also cited differences in racial composition of neighbourhoods as a possible factor for differences in rates of bystander CPR. This study however was performed in an ethnically homogeneous region (>95% white), on a homogeneous patient population (96% white); and as such they're able to exclude race as a confounding factor. The study doesn't attempt to explain why this relationship occurs, although lack of access to training was cited as a potential cause. From a nursing perspective this will likely not impact in-hospital care of poor patients; but it may suggest that targeting CPR education to poor neighborhoods could be an effective public health mandate. 

http://emj.bmj.com/content/early/2015/06/25/emermed-2015-204643.abstract

Justin Morgenstern from First10EM posted a review of managing patients with anaphylaxis. He starts with the obligatory cry of "give the IM Epi stat!": something that still takes on average way too long. Morgenstern then discusses some possible approaches to  manage both difficult airways, as well as patients with developing angioedema. There is a good review of shock, with some links to push dose mixing charts, management tips for special populations and a "Dirty Epi Drip" set up. This is a great review for nurses, as Morgenstern makes suggestions not only on medical practice; but also on priorities of care for nursing. Great to see FOAMed that includes the whole care team!

http://first10em.com/2015/07/20/anaphylaxis/#more-614

Dr. Rebecca Schroll et al., published a study in the Journal of Trauma Acute Care Surgery earlier this year that compared the outcomes of military and civilian patients who were treated with tourniquets by pre-hospital providers for extremity trauma. This study retrospectively examined the records of patients treated with pre-hospital tourniquets from 9 level one trauma centers in the US and compared them to a prospective military study examining patients treated pre-hospitally with tourniquets during the Iraq war.

Schroll et al., reviewed the charts of patients meeting inclusion criteria (>18 years old with extremity trauma treated by tourniquet) and examined them for mortality, effectiveness of tourniquet at controlling  hemorrhage, change in SBP after tourniquet application, and complication rates. 197 patients met the inclusion criteria; the average patient was a 39.4(±1.1) year old male (85.8%) with a penetrating injury (56.3%) and ISS of 11. Tourniquets were successful for controlling hemorrhage 88.8% of the time, the overall mortality rate was 3.0%, the average complication rate was 32.4%, with 18.3% of patients requiring amputation.

The results were then compared to a seminal study of combat application tourniquets in Iraq performed by Kragh et al., in 2009, to determine how civilian tourniquet use compared to military use. Schroll et al., determined that the use of tourniquets in the civilian context tended to have better outcomes than the group from the Iraq war study; with both mortality (3 vs. 11%), and amputation rates (18.8 vs 41.8%) being lower. These are impressive statistics, and would seem to suggest that tourniquet use for extremity trauma is safe. They're especially impressive considering that 20% of the patients in the Schroll et al., review were treated with improvised tourniquets that were either self or bystander applied, with "no difference in the incidence of other complications".

There are however a few claims made by the authors that I think are overstating the level of this evidence. The study design is weak: there was no control arm to compare outcomes against, there was no discussion on which commercial tourniquets were used, or the indications for using them. The patients in this cohort have drastically different mechanisms from the military cohort; all of whom had blast injuries, tended to be more severely injured, and were being treated in an austere environment (compared to a level one trauma center). The military cohort is also missing key information about limb injury severity and time to "definitive" care, limiting the extent to which the groups can be compared. The claim that improvised tourniquet use had comparable results with no difference in complication rates is also questionable. The that total tourniquet time for this subgroup is unknown, and that the group treated with non-purposed tourniquets had a three fold rate of ischemic/reperfusion injuries (3/40 [7.5%] vs. 4/157 [2.5%]). The suggestion that improvised tourniquets were safe and effective is contrary to previous observational studies that noted higher error rates, and the need for tightening or application of commercial tourniquets when improvised tourniquets were used (see weekly review 1).

I think this research is important, it's the largest of it's type in the civilian context, and in general I think that the evidence supports the use of tourniquets in the civilian context. I don't think that the patient populations were homogeneous enough for this research to be used as a comparison to the Baghdad study by Kragh et al., and would not attempt to extrapolate their findings to the civilian context. I would also disagree with the claim that improvised tourniquets are safe and effective, there were too few patients recruited to make that claim and the outcomes (though underpowered) actually show a three fold increase in risk.

From a nursing perspective I think that this is weak evidence showing that tourniquets are safe for extremity trauma in general. It also shows that a large number of patients will present with improvised tourniquets, and these will need to be assessed as venous only tourniquet can actually speed exsanguination.

http://www.ncbi.nlm.nih.gov/pubmed/26091308

Dr. Geoff Jara-Almonte posted a review of neonatal resuscitation on emDocs this week. He touched on the major steps and take home messages you could expect to learn from an NRP course. The post discusses some of the controversy around the need to intubate, the when and hows of meconium suctioning, and the FiO2 that should be used during resuscitation. There is a quick review of resuscitation drugs and doses, as well as methods for gaining vascular access (umbilical cannulation). This is a great review for any nurse working in the ED, it certainly won't replace an NRP course nothing will replace real time simulations using the kit; but it's a succinct review of the need to know points of neonatal resuscitation.

http://www.emdocs.net/neonatal-resuscitation/ 

Weekly Review #9

ScanCrit reviewed a case report of double sequential defibrillation (DSD) published in the journal of Prehospital Emergency Care. DSD is a process of hooking a patient up to two defibrillators and providing sequential shocks. In this particular case the patient had refractory V-Fib and had received 7 unsuccessful shocks with lead placement changes. The team performed DSD using the standard anterior/apex as well as anterior/posterior placements, with the deliver shock button pressed as close to simultaneously as possible. DSD converted the patient to sinus rhythm, who went on to survive to discharge. The exact mechanism of why DSD works when standard defibrillation has failed is not known, there haven't been any good quality trials performed to date; until that happens this care report is unlikely to significantly change current practice. DSD is an exciting concept: it's a novel approach, and one that can easily be deployed without expensive new equipment. This may not be a game changer in the management of refractory arrest, but it's at least one more tool.

http://www.scancrit.com/2015/07/07/one-two-punch/#more-8222




On July 8 & 9th I participated in the inaugural Eastern Association for the Surgery of Trauma (EAST) journal club discussion. It was on an study published the Journal of Trauma and Acute Care Surgery on the use of hemostatic foam in recently deceased cadavers. The study by Mesar et al., was attempting to determine what a safe dose of foam would be. Essentially the team wanted to extend their animal models to humans to determine how much intra-abdominal pressure, and internal organ contact would be made with differing volumes of injectable foam.




The study used recently deceased cadavers (146 minutes, ± 34min), added IV fluids to the abdominal cavity to mimic blood volume, and injected foam into the cavity. Intra-abdominal pressures (IAP) where monitored and the abdomen measured every minute for 15 minutes; after 15 minutes the foam was removed to evaluate the amount of contact with internal organs.

Of the 409 patients screened 21 were recruited, 18 met inclusion criteria, 3 of the patients were excluded from the final results due to errors in administering the foam. 4 cadavers received either 45, 55, or 65mls of intra-abdominal foam using one of two purpose built delivery systems. The foam quickly reached peak volume, the resulting increase in IAP fell below the maximum threshold of 65mmHg; while the cadaveers given larger doses exceeded the IAP cutoff.

After 15 minutes the Cadavers all successfully had the foam block removed, in one piece, by laprotomy. The contact with underlying organs was noted in each case, and the average contact areas was determined. Best coverage, unsurprisingly, occurred with larger doses, and the foam didn't absorb extra fluid.

The goal of this study was to determine what a "safe" dose of intra-abdominal foam would be, and it appears that doses of 65ml will generally fall below their IAP cutoff of 65mmHg. There are some limitations to this study: the sample size is quite small, and IAP results appear to vary significantly between cadavers receiving similar doses, making predictions on average IAP by dose would be difficult. The delivery system could also use improvement, of 18 attempts there were 3 (16%) errors, one of which resulted in accidental bowel perforation. From a clinical perspective I think that this technology still needs a fair bit of refining: there is no clearly articulated target population (injury mechanism). The intent is clearly hemorrhage control, but the foam is too superficial to access major vessels (which is fine, REBOA can do that), but it also has poor contact with solid organs at doses below the IAP cutoff.

From a nursing perspective I think that this technology is exciting, abdominal bleeds account for a large number of battlefield deaths, and any tools that can increase survival for these injuries is worth investigating. I'm looking forward to additional research on this technology, and would love to see if can be used in human trials.

The moderators at the EAST journal club did an excellent job. Responses to questions were generally rapid, and they were able to offer some additional information not explicitly stated in the research article. I look forward to the next journal club discussion, this and future reviews are on twitter at #EASTjc.

http://journals.lww.com/jtrauma/Fulltext/2015/07000/Human_dose_confirmation_for_self_expanding.6.aspx







Ryan Radecki from emlitofnote had a post reviewing the specificity and sensitivity of urinalysis for UTI in febrile pediatric patients. This is a 15 year 276 patient multicenter review of infants less than three months of age with fevers, bacteremia and UTI. The goal of the study was to determine how effective urinalysis as in predicting urinary tract infection. The results are surprisingly positive, as a predictive tool urinalysis is impressively accurate: 

• Trace or greater leukocyte esterase: 97.6% (94.5-99.2) sensitive and 93.9% (87.9-97.5) specific.
• Pyuria, >3 WBC/HPF: 96% (92.5-98.1) sensitive and 91.3% (84.6-95.6) specific.
• Pyuria or any LE: 99.5% (98.5-100) sensitive and 87.8% (80.4-93.2) specific.

These results are interesting because as a screening tool UA alone is generally not effective in adult or geriatric populations. All three of these are worth a review, as the differing conclusions offer an excellent case study in Bayesian statistics and determining likelihood ratios. From a nursing perspective having a non-invasive tool with high diagnostic power is great news, taking blood from an infant is traumatic for the care team, the parents, and most importantly the patient.  

http://www.emlitofnote.com/2015/07/the-utility-of-urinalysis-in-young.html

A new study published in Critical Care by Acheampong and Vincent examined the relationship between fluid balance and mortality in ICU patients admitted with sepsis. This study was a prospective observational study of 173 patients admitted to a single Belgian ICU for sepsis in 2012. Inclusion criteria were: patients >15 years of age, admitted to ICU >48hrs for sepsis. These patients were treated using the "surviving sepsis" guidelines. Total enteral/parenteral volumes were recorded against total sensible fluid loss to determine net fluid balance; there were 225 patients enrolled, 173 met inclusion criteria. Patients with a net positive fluid balance, or in septic shock were more likely to have poor outcomes. Overall ICU mortality rate was 34%, and the results suggest that positive fluid balance was associated with an increase in mortality (HR 1.014/ml/kg: 1.008-1.027, P<0.001). Non-surviving patients however tended to be sicker (SOFA score 9.0±3.3 vs 7.7±3.3), to be in septic shock (97 vs. 68%), and to have an infection of pulmonary origin (53 vs. 30%). There were significant differences between groups; unfortunately vital sign parameters, and rates of vasopressor use were not discussed, making it impossible to determine if the relationship between fluid balance and mortality is one of cause or effect. This was a small single center study with no control arm, we know the patients who didn't survive tended to be sicker, and to be in septic shock: they likely needed more fluids to maintain BP and likely had higher rates of vascular leakage and therefore fluid retention. This study does establish that positive fluid balance is prognostic of mortality, but we knew that, from a nursing perspective this study adds little to our understanding of sepsis, or fluid resuscitation.

http://www.ccforum.com/content/19/1/251




TamingtheSRU had a discussion posted on their site by Dr. Brian Burns from Sydney HEMS. Where he was discussed the concepts of marginal gains, or aggregation of gains, and how they can be used to improve pre-hospital patient care. The talk wasn't about medical or technical skills; rather it focused on different human factor aspects of self mastery. There were several methods reviewed, but the discussion focused primarily on tools such as cognitive offloading, cognitive buildups, and cognitive rally points. Dr. Burns emphasized the usefulness of simulation, not only for difficult skills that are seldom performed, but also for common skills that need constant practice, and how to perform common skills in uncommon scenarios. This is an excellent video for all clinicians, as a nurse it's great to see some of the best clinicians around discussing simple strategies such as visualization and checklists, strategies that everyone can use to improve their everyday performance, as well as their performance in critical moments.


http://www.tamingthesru.com/blog/prehospital-medicine/when-that-1-makes-all-the-difference