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Needle Decompression Location Reviewed

We have discussed the changing thoughts regarding the sign and symptoms of Tension Pneumothorax in the past (see here: Rethinking Tension Pneumothorax). Although this study was broad, it did not address in detail the implications of different locations of one of the more popular treatments of tension pneumothorax: needle decompression. Due to an increased incidence of iatrogenic effects of improper needle placement, one of the recent topics of discussion among TCCC trainers has centered around locations (i.e., anterior vs lateral) of needle placement. Improper anterior placement in the mid-line direction can led to severe vascular injuries. Some have advocated for moving the primary location for needle insertion to the lateral location to mitigate iatrogenic effects. This location, however, raises other issues, specifically chest wall thickness in comparison to the anterior location, even as needles have increased in length.

A recent study published* in Academic Emergency Medicine seeks to answer one of the questions that have emerged from the debate by identifying the optimal site of needle insertion with respect to anterior wall thickness limitations. The results are interesting. Average chest wall thickness at the right side anterior second intercostal space, lateral forth and fifth mid-axillary locations were 46.4 mm, 53.8 mm and 63.7 mm, respectively. When considering the one factor of chest wall thickness as it relates to successful penetration of the plural space, the researchers concluded, the anterior location is superior. Furthermore, attempting to overcome the increased chest wall thickness at the lateral mid-axillary locations by using a longer catheter is risky, for it increases the risk of damaging surrounding vascular structures.

While this study does not address the larger issue of practitioners misplacement at the anterior location, it does illicit and attempt to answer an important question of impulsively changing training doctrine to emphasize the lateral location.

*Anterior Versus Lateral Needle Decompression of Tension Pneumothorax: Comparison by Computed Tomography Chest Wall Measurement by Sanchez, Leon, MD, MPH, et al. Academic Emergency Medicine 2011; 18:1022-1026 by the Society for Academic Emergency Medicine

SOFTT Added to TCCC Instructions

The SOF Tactical Tourniquet has always been TCCC approved, but until recently, it has been overlooked when it comes to official TCCC instructions and guides. Here is the link to the most recent Care Under Fire PowerPoint produced by the TCCC board that outline the instructions. Furthermore, the second link below has many other training aides for all phases of tactical medicine.

CUF Link

General TCCC Links

How to:One-handed Tourniquet Application

A principal learning objective taught in many tactical medical training programs is self-application of tourniquets. Although reports from current battlefields estimate the frequency of one-handed application at less 1/10 of 1% (o.oo1), it is still a valuable drill for those working alone (i.e., law enforcement officers). Unfortunately, the technique taught is often incorrect, as most disregard the fact that if one is applying a tourniquet to one’s limb, the limb is probably injured. Therefore, as the video demonstrates, one ought to train for real-world application.

Importance of Training Forward Life Saving Procedures and Future Blood Protocols

In a recent article published in the Journal of Trauma Injury, Infection, and Critical Care, the authors analyzed the effect of life-saving interventions (LSI) performed by combat medics and other forward providers. The medical practitioners in the study were arranged in an EMS style hierarchy under a medical director, with the majority of medics trained to the EMT-B level, in addition to supplemental training in TCCC-approved LSI procedures. Additionally, they analyzed outcomes with an eye toward the applicability of more advanced care in the form of Remote Damage Resuscitation protocols. As summarized below, they found that forward deployment of blood products would be beneficial if the logistical and scope-of-practice concerns could be addressed. In the limitations section of the study, they concede that certain biases might have affected the outcome. They note, for instance, “[t]he differential impact of transport time from point-of-injury to surgical facility arrival is worth considering.” Time from injury to point-of-injury treatment, time between request for evacuation to arrival of transportation, and time from extraction to the study facility all affected the outcomes, some of which were unknown in retrospect.

Although the authors did acknowledge in the conclusion that LSI need to be performed sooner, they unfortunately continued to argue that their notional blood protocol would have been beneficial. This is despite the fact that the majority of LSI were preformed by PA-level practitioners or higher, which is the major concern, because that indicates that urgent and priority patients were evacuated without LSI. It is difficult to surmise why LSI were not performed sooner, due to the nature of record keeping and retrospective studies. Perhaps tactical considerations dictated transport before treatment, or casualties deteriorated during evacuation. Nonetheless, early treatment is paramount, so training might possibly the more important to allocate resources to than blood protocols. Technology is an exceptional adjunct to the basics, but medics must have a foundation upon which to build.

Background: To analyze casualties from the Camp Eagle Study, focusing on
life-saving interventions (LSI) and potentially survivable deaths.

Methods: Retrospective cohort of battle casualties from a forward base engaged in urban combat in Central Iraq. Medical support included emergency medicine practitioners and combat medics with advanced training and protocols. LSI were defined as advanced airway, needle or tube thoracostomy, tourniquet, and hypotensive resuscitation with Hetastarch. Cases were assessed retrospectively for notional application of a Remote Damage Control Resuscitation protocol using blood products.

Results: Three hundred eighteen subjects were included. The case fatality rate was 7%. “Urgent” (55) or “priority” (88) medical evacuation was required for 45% of casualties. Sixty-one LSI were performed, in most cases by the physician or PA, with 80% on “urgent” and 9% on “priority” casualties, respectively. Among survivors requiring LSI, the percentage actually performed were airway 100%; thoracostomy 100%; tourniquet 100%; hetastarch 100%. Among nonsurvivors, these percentages were 78%, 50%, 100%, and 56%, respectively. Proximate causes of potentially survivable death were delays in airway placement and ventilation (40%), no thoracostomy (20%), and delayed evacuation
resulting in hemorrhagic shock (60%). The notional Remote Damage Control Resuscitation protocol would have been appropriate in 15% of “urgent” survivors
and in 26% of nonsurvivors.

Conclusion: LSI were required by most urgent casualties, and a lack or delay in their performance was associated with increased mortality. Forward deployment of blood components may represent the next addition to LSI if logistical and scope-of-practice issues can be overcome.

(J Trauma. 2011;71: S109–S113)

Risks of Rubber Band Tourniquet Use

Rubber band tourniquets (RBT) have gained popularity in the law enforcement community over the past 24 months. The compact size and nominal cost make them attractive to cash-strapped, and over loaded with respect to equipment, LEOs. Furthermore, as LEO commanders seek to outfit their personnel with live saving equipment while grappling with budget constraints, RBTs seem like a viable option. However, upon further consideration, they may not be the BEST choice due to inherit dangers of RBTs with regard to function and application.

The function of RBTs is simple: one applies it proximal to the injury, wrapping it around the limb until hemorrhage control is achieved, using the elasticity of the rubber to create greater circumferential pressure with each wrap. Initially, this seems easy and straight forward. However, due to the nature of elastic wraps one must be cautious when using one as a tourniquet, due to the difficulty in controlling the applied pressure. As noted in the Journal of Medicine and Biomedical Research, “[t]he pressure induced by the rubber bandage increases at a rate of 3 to 4 times the initial pressure when the bandage is stretched after each wrap.”(1)(3) This is dangerous due to the shearing effect generated on the underling tissues, specifically the nerves. In fact, Graham et al found that at above 300mm Hg shearing forces increased exponentially.(2)(3) With RBTs this is concerning as “[t]he pressure applied to the limb could easily exceed the safe limits and put the limb at risk of complications because the rubber bandage is capable of generating pressures in excess of 1000mmHg beneath it.” “At such extremely high pressure,” Ogbemudia continues, “neurovascular damage becomes likely and makes the use of the RBT relatively unsafe.”(1)(3) He does explain how, in a controlled environment such as a surgical suite, a RBT can be made safe by placing a BP cuff under to monitor pressure. Obviously, this is not optimal in the tactical environment.

There are also difficulties faced when applying a RBT with respect to generating adequate circumferential pressure to stop arterial hemorrhage. Applying a RBT to an extremity, especially an upper limb, mobility is required in order to wrap it around the limb a sufficient number of times. If there has been any bone involvement, this may be an excruciating affair. Furthermore, if, due to pain associated with application, the casualty does not achieve hemorrhage control, he must then un-wrap the RBT multiple times, then re-wrap it in the hopes of achieving enough pressure. Unfortunately, the reverse is true. In an attempt to generate enough pressure, one may generate too much unknowingly. Compared to a windlass-style tourniquet, for instance, one must only turn the windlass an additional 180 degrees, thereby tightening it to achieve more tension. Tourniquets issued within DOD, unlike RBTs, are difficult to over tighten when used one-handed and according to the manufacturers’ directions due to the nature of the webbing and knot interface.

Finally, when compared to standard tourniquets used by the majority of DOD and many state and local LEOs, a RBT has multiple variables that must be considered that relate to the pressure generated. In this case, variables are defined as inconsistencies between casualties and application each time a tourniquets is used. They are compared as follows:

Windlass style tourniquets have 2 variables:
1) limb circumference;
2) degrees rotated.

RBT tourniquets have 4 variables:
1) the percentage of stretch applied with each turn (composition and elasticity of the material, which affect the restoring force of the polymers);
2) the number of layers of the RBT;
3) the degree of overlap;
4) the circumference of the limb.

In the end, a RBT can be used as a field tourniquet. However, it is not the best option for LEOs. The benefits of cost savings do not outweigh the potential problems and risks associated with rubber band tourniquets.

References
[1] Ogbemudia A et al. Adaptation of the rubber bandage for the safe use as tourniquet. Journal of Medicine and biomedical Research 2006; Vol. 5 No. 2 pp-69-74.
[2] Graham B et al. Perinerual pressures under the pneumatic tourniquet in the upper and lower extremity. Journal of Hand Surgery 1992: 17B: 262-6.
[3] McEwen J. A. and Casey V. Measurement of hazardous pressure levels and gradients produced on human limbs by non-pneumatic tourniquets. Accessd at
http://www.tourniquets.org/pdf/CMBEC%2032%20McEwen%20and%20Casey%20Tourniquet%20Paper.pdf

Tourniquets and Scientific Studies

A tourniquet is a piece of  live saving equipment.  With that in mind, it is troubling to know that officers are either carrying tourniquets, or contemplating the purchasing of tourniquets, that are questionable with regard to effectiveness. What is more, they are making these decisions based on a questionable scientific study, most of which they did not completely read ( TQReport). It is not being hyperbolic to state that what it is arguing is a matter of life or death. If you question that, then please revisit the last blog entry.

One not wanting to read the entire study is understandable. It is 90 pages of dry, scientific writing. At first glance, the study is methodologically sound. It is constructed to test the effectiveness of tourniquets in an environment that simulates combat conditions. However, after one reads the study completely, there is one glaring deficiency. The study did not test which tourniquets achieved 100% occlusion. I Repeat: IT DID NOT TEST IF TOURNIQUETS ACHIEVED 100% OCCLUSION.  That should be the FIRST criterion a tourniquet must meet to continue a study.  While the ISR study (see below) tested tourniquets that could achieve 100% occlusion, the Navy study did not, so all other criteria are irrelevant.  Instead, it tested how easy it was to apply an ineffective tourniquet. As the study states:

Applications to arms were performed one-handed, but use of both hands was allowed for applications to thighs. A maximum of 5 minutes was allowed to apply the tourniquet, after which time the trial was terminated as an “application failure.” Application of the tourniquet was successful if the subject vocally declared, “Tourniquet on” — indicating that he had reached a point just before continued tightening would produce unbearable pain and had secured the device — within 5 minutes of being handed the test tourniquet. Upon such a declaration, a double event mark was recorded to mark the end of the application time period. The subject was asked to remain still throughout the remainder of the procedure.

Although the above may not seem like an issue, it is. First, applying a tourniquet until one thinks he/she has achieved hemorrhage control is not how it works. One applies a tourniquet to stop bleeding. One must continue to apply pressure until the bleeding stops. It is as simple at that. Second, using pain as indicator to cease applying pressure is not a good indicator. Doing so requires one to extrapolate the findings of a conscious, non-traumatic subject and apply them to an injured patient that has experienced enough trauma to require catastrophic-hemorrhage control.

Savvy distributors and manufacturers of different tourniquets have begun using this study to tout the effectiveness of their product. Beware. They are doing so based on the age-old assumption that consumers will not take the time to read all 90 pages. For example, they are giving potential consumers a chart that gives you a snapshot of the test that enumerates the tourniquets from best to worst. Please read the studies for yourself and make an educated decision. There are two tourniquets approved for use by the Army’s Institute for Surgical Research (ISR) (ISR Tourniquet Study). Do not let the desire to carry a tourniquet that is small–and possibly ineffective–outweigh the need to achieve hemorrhage control. Furthermore, short transport times DO NOT compensate for an ineffective tourniquet that can INCREASE bleeding. Finally, rid yourself of the disturbingly-common attitude that you will not actually need one . If that is the case, save yourself both money and weight and just don’t carry one. However, read the below post before doing so.

If you have any comments, please email them to alan@tacmedsolutions.com