Control of severe, life-threatening external bleeding in the out-of-hospital setting: Tourniquets (FA): Systematic Review

Conflict of Interest Declaration

The ILCOR Continuous Evidence Evaluation process is guided by a rigorous ILCOR Conflict of Interest policy. The following Task Force members and other authors were recused from the discussion as they declared a conflict of interest: none applicable

The following Task Force members and other authors declared an intellectual conflict of interest and this was acknowledged and managed by the Task Force Chairs and Conflict of Interest committees: none applicable

CoSTR Citation

Charlton NP, Swain JM, Nieuwlaat R, Singletary EM, Zideman DA, Epstein JL, Bendall JC, Berry DC, Borra V, Carlson JN, Cassan P, Chang WT, Hood N, Markenson DS, Meyran D, Woodin JA, Sakamoto T, Lang E: Control of severe external bleeding in the out-of-hospital setting: Tourniquets Consensus on Science with Treatment Recommendations [Internet] Brussels, Belgium: International Liaison Committee on Resuscitation (ILCOR) First Aid Task Force, 2019 December 20. Available from: http://ilcor.org

Methodological Preamble and Link to Published Systematic Review

The continuous evidence evaluation process for the production of the Consensus on Science with Treatment Recommendations (CoSTR) started with a systematic review of control of severe external bleeding in the out-of-hospital setting 22 March 2018, (PROSPERO CRD42018091326) conducted by Evidence Prime, an international Knowledge Synthesis Unit with members from the UK, Poland and Canada, and with involvement of ILCOR First Aid Task Force clinical content experts. Evidence from adult and pediatric literature was sought and considered by the First Aid Task Force. Additional scientific literature that was published after the completion of the systematic review and identified by the content experts was incorporated into the CoSTR. These data were taken into account when formulating the Treatment Recommendations.

We included all studies from the out-of-hospital setting (direct evidence), as well as studies providing indirect evidence about the effects of interventions collected in combat (military) settings, simulations (i.e. human volunteers, human cadaver or other models excluding animal models), and studies performed in the hospital setting, that clinical content experts judged as were performed in sufficiently similar conditions to still be both relative and informative. Bleeding from compressible and non-compressible external sites were included, except for epistaxis.

This CoSTR is one of four CoSTRs related to the systematic review completed on Control of Severe Bleeding in the Out-of-Hospital Setting. This CoSTR specifically addresses use of tourniquets compared with direct pressure, other styles of tourniquet or hemostatic dressings. The other CoSTRs on the Control of Severe, Life-threatening Bleeding will be published separately on ILCOR.org/costr.

Systematic Review

Nathan P. Charlton, Janel M. Swain, Jan L. Brozek, Maja Ludwikowska, Eunice Singletary, David Zideman, Jonathan Epstein, Andrea Darzi, Anna Bak, Samer Karam, Zbigniew Les, Jestin N Carlson, Eddy Lang, Robby Nieuwlaat & On behalf of the International Liaison Committee on Resuscitation (ILCOR) First Aid Task Force (2020) Control of severe, life-threatening external bleeding in the out-of-hospital setting: a systematic review, Prehospital Emergency Care, DOI: 10.1080/10903127.2020.1743801

PICOST

The PICOST (Population, Intervention, Comparator, Outcome, Study Designs and Timeframe)

Population: Adults and children with severe, life-threatening external bleeding in out-of-hospital settings. Bleeding from both compressible and non-compressible external sites were included.

Intervention: All bleeding control methods applicable for use by trained or untrained first aid providers including manufactured or improvised tourniquets, hemostatic dressings or agents, cryotherapy, direct (manual) pressure, pressure points, pressure dressings or bandages or elevation of the injured area. Manufactured tourniquets included windlass-style or elastic, with single or double application.

Comparators: Studies with comparators of bleeding control methods are included, as well as observational cohorts with a single bleeding control technique which in an observational meta-analysis may allow comparison of one technique against another.

Outcomes:

• Mortality due to bleeding (Critical)
• Cessation of bleeding / achieving hemostasis (Critical)
• Time to achieving hemostasis (Critical)
• Mortality from any cause (Important)
• Decrease in bleeding (Important)
• Complications/adverse effects (e.g. wound infection, limb loss, re-bleeding, pain related to an intervention) (Important)

Study Designs: Randomized controlled trials (RCTs) and non-randomized studies (non-randomized controlled trials, interrupted time series, controlled before-and-after studies, cohort studies) were eligible for inclusion.

Timeframe: All years and all languages were included as long as there was an English abstract; unpublished studies (e.g., conference abstracts, trial protocols) were excluded. Literature search updated to November 22, 2019.

PROSPERO Registration: CRD42018091326

Consensus on Science

Tourniquets compared with direct pressure

For the critical outcome of mortality due to bleeding, we identified very low certainty evidence (downgraded for serious risk of bias, inconsistency and imprecision) from four cohort studies{King 2015 594; Ode 2015 586; Passos 2014 573; Scerbo 2017 1165} in the prehospital civilian setting with a total of 527 participants. These studies report variable results but suggest a reduction in mortality due to bleeding with the use of tourniquets compared with the use of direct pressure alone. The mortality rate with tourniquet use for the individual studies ranged from 0 to 4%, whereas mortality with direct pressure alone ranged from 0 to 14%, however no meta-analysis could be performed due to the heterogeneity of the studies.

For the critical outcome of cessation of bleeding, we identified very low certainty evidence (downgraded for serious risk of bias and imprecision) from two cohort studies{Beekley 2008 S28; Mucciarone 2006 687} in the prehospital military setting with a total of 76 participants. Due to heterogeneity, these results were not combined for meta-analysis but results from the largest cohort study{Beekley 2008 S28} with a total of 70 participants showed a higher rate of bleeding cessation on arrival to the hospital among those with a tourniquet placed compared with those without a tourniquet; (35/42 [83.3%] compared with 17/28 [60.7%]; p = 0.033). A small cohort study{Mucciarone 2006 687} showed bleeding cessation in 2/2 participants with tourniquet and 4/4 participants with injuries that were amenable to a tourniquet but did not receive one.

For the important outcome of mortality due to all causes, we identified six cohort studies{King 2015 594; Ode 2015 586; Passos 2014 573; Scerbo 2017 1165; Smith 2019 43; Texeira 2018 769} in the prehospital civilian setting with a total of 1,811 participants. Due to heterogeneity these studies were unable to be combined for meta-analysis. The overall certainty of evidence was rated as very low primarily due to serious risk of bias, inconsistency and imprecision. In unadjusted analyses five of the six failed to demonstrate a statically significant difference in mortality between those with a tourniquet placed compared with those receiving direct pressure alone{King 2015 594; Ode 2015 586; Passos 2014 573; Scerbo 2017 1165; Smith 2019 43}. A sixth large cohort study{Texeira 2018 769} with 1,026 total participants reported a higher risk for all-cause mortality without the use of a tourniquet compared with the use of a tourniquet (5.2% compared with 3.9%; univariable OR, 1.36; 95% CI, 0.60-1.65; p = 0.452) which was significant in a multivariable analysis (adjusted OR, 5.86; 95% CI, 1.41-24.47; p = 0.015).

We identified very low certainty evidence (downgraded for serious risk of bias and inconsistency) from six cohort studies{Beekley 2008 S28; Gerhardt 2011 S109; Kragh 2015 184; Kragh 2011 590; Kragh 2015 290; Mucciarone 2006 687} in the prehospital military setting with a total of 6,163 participants. While these studies could not be combined for meta-analysis due to heterogeneity, individual studies showed no difference in all-cause mortality for the use of a tourniquet compared with use of direct pressure. Among the individual cohort studies, all-cause mortality ranged from 0% to 25% with tourniquet use and from 0% to 24% without tourniquet use, however no meta-analysis could be performed due to the heterogeneity of the studies.

For the important outcome of complications/adverse effects, we identified very low certainty evidence (downgraded for serious risk of bias and imprecision) from three cohort studies{Passos 2014 573; Smith 2019 43; Teixeira 2018 769} with a total of 1,420 participants in the prehospital civilian setting evaluating complications with use of a tourniquet compared with the use of direct pressure. Complications included compartment syndrome, nerve palsy, need for fasciotomy, or thromboembolic episodes. Due to heterogeneity these studies were unable to be combined for meta-analysis. These studies demonstrated mixed results when comparing a tourniquet compared with the use of direct pressure, with no clear increase in adverse events on one modality compared with the other.

We identified very low certainty evidence (downgraded for serious risk of bias) from five cohort studies{Passos 2014 573; Romanoff 1977 485; Scerbo 2017 1165; Smith 2019 43; Teixeira 2018 769} in the prehospital civilian setting with a total of 1686 participants reporting the complication of amputation. Due to heterogeneity, these studies could not be combined for meta-analysis, but all reported similar amputation rates with the use of tourniquets compared with the use of direct pressure.

We identified very low certainty evidence (downgraded for risk of bias and imprecision) from one cohort study{Beekley 2008 S28} in the prehospital military setting with 165 participants. This study showed no difference in the amputation rates for those who had tourniquets applied (4/67 (6.0%) compared with use of direct pressure ((9/98 (9.2%); RR, 0.65; 95% CI, 0.21-2.20; ARR, 32 fewer per 1,000 participants [95% CI, 73 fewer to 94 more]).

We did not identify evidence for the critical outcome of time to hemostasis for the comparison of the use of a tourniquet with direct pressure.

Tourniquets compared with hemostatic dressings

For the critical outcome of mortality due to bleeding, we identified very low certainty evidence (downgraded for serious risk of bias and imprecision) from one cohort study{Kotwal 2011 1350} in the prehospital military setting. Among 96 adults with external bleeding, there was no difference in mortality (0/66 deaths with use of a tourniquet compared with 0/30 deaths with use of a hemostatic dressing; RR and 95% CI not calculated).

For the important outcome of all-cause mortality, we identified very low certainty evidence (downgraded for serious risk of bias and imprecision) from one cohort study{Kotwal 2011 1350} in the prehospital military setting. Among 96 adults with out-of-hospital external bleeding, the use of a tourniquet showed a benefit compared with the use of hemostatic dressings. Tourniquet use was associated with a large all-cause mortality risk reduction; 4/66 deaths with the use of a tourniquet compared with 9/30 deaths with the use of hemostatic dressings (RR, 0.20; 95% CI, 0.07-0.60; ARR, 24 fewer per 1,000 participants [95% CI, from 12 fewer to 28 fewer). However, in this study it is important to note that the types and locations of wounds treated by each intervention was unclear (e.g. extremity, junctional, or core) and, therefore, it is unknown if the injuries were comparable.

For the important outcome of complications/adverse effects, no comparative studies were identified.

Manufactured tourniquets compared with Improvised tourniquets

We did not identify any human studies comparing manufactured tourniquets with improvised tourniquets for the management of severe, life-threatening external bleeding, however, four simulation studies were reviewed to help formulate treatment recommendations.

Windlass style manufactured tourniquets compared with other types of manufactured tourniquets

We did not identify any human studies comparing windlass style manufactured tourniquets with other types of manufactured tourniquets for the management of severe, life-threatening external bleeding, however, six simulation studies were reviewed to help formulate treatment recommendations.

Treatment Recommendations

We suggest that first aid providers use a tourniquet in comparison with direct manual pressure alone for severe, life-threatening external bleeding that is amenable to the application of a tourniquet (weak recommendation, very low certainty of evidence).

We suggest that first aid providers use a tourniquet rather than a hemostatic dressing for severe, life-threatening external bleeding that is amenable to the use of a tourniquet (weak recommendation, very low certainty of evidence).

We suggest that first aid providers use a manufactured tourniquet rather than an improvised tourniquet for severe, life threatening external bleeding (weak recommendation, very low certainty of evidence).

For the treatment of severe, life-threatening external bleeding by first aid providers, we are unable to recommend any one particular design of tourniquet compared with another.

Justification and Evidence to Decision Framework Highlights

• The Task Force recognizes that the application of pressure stops bleeding. Tourniquets represent a way of applying circumferential pressure remote from the bleeding point. Although there are few comparative studies of tourniquet use and direct pressure alone, evidence suggests that tourniquets, when applied appropriately, stop bleeding in the majority of cases. Not every area of the body is amenable to the use of a tourniquet. In general, studies included application of tourniquets to the limbs but excluding the junctional regions, such as the axillae and groin.

• No identified comparative studies included specific data on children, precluding subgroup analysis. However, in task force discussions it was felt that in the absence of specific evidence for the pediatric population that it would be reasonable for guideline groups to apply recommendations for control of life-threatening bleeding to children.

• Although this review did not address the timing of tourniquet placement, the Task Force discussed the importance of one observational study{Scerbo 2017 54} which demonstrated a greater risk of death from hemorrhagic shock when tourniquet placement was delayed until arrival at hospital as compared with tourniquet placement pre-hospital (14% compared with 3.0%, p=0.01). We also place value in a second, large observational study{Texeira 2018 769} that demonstrated a lower risk of risk for all-cause mortality with use of a tourniquet when compared to not using a tourniquet.

• This review did not evaluate the timing or order of interventions to control life-threatening bleeding. We recognize that a tourniquet may not always be immediately available for treatment, and direct manual pressure may be effective or provide some degree of haemorrhage control until such time that a tourniquet may be applied. However, in multiple casualty situations, the use of a tourniquet may free resources to attend to other life-threatening injuries.

• It is the consensus opinion of the Task Force that use of a tourniquet is preferable compared with use of a hemostatic dressing for severe, life-threatening extremity bleeding. The Task Force recognizes that there is little data that compares use of tourniquets with hemostatic dressings for similar wounds. A single study from the military setting{Kotwal 2011 1350} demonstrated a lower risk of all-cause mortality with use of a tourniquet compared with use of a hemostatic dressing, but wound locations and types may vary considerably between groups in this study. This recommendation is supported with use of the evidence to decision framework, which recognizes that most studies evaluating the use of a tourniquet without a comparator consistently demonstrate cessation of bleeding, and that simulation studies using lay providers demonstrate the ability to successfully apply a tourniquet with minimal training, while evidence to support the ability of lay providers to successfully apply hemostatic dressings is lacking. Nonetheless, if a tourniquet is not available, a hemostatic dressing can potentially be used in conjunction with direct manual pressure to treat severe, life-threatening extremity bleeding.

• The Task Force recognizes that tourniquets are not applicable in junctional or torso bleeding, and in the event of life-threatening bleeding from these areas it is reasonable to consider the use of hemostatic dressings, when available, in conjunction with direct manual pressure.

• There was no direct or human evidence comparing use of a manufactured tourniquet with use of an improvised tourniquet. In recommending the use of manufactured tourniquets the Task Force was influenced by 2 observational studies{Guo 2011 151; Lyles 2015 21} that demonstrated an improvement in simulated bleeding cessation when using manufactured tourniquets compared with the use of improvised tourniquets (85-100% with manufactured compared with 10-75% for improvised tourniquets). In addition, although manufactured tourniquets can be placed inappropriately, we feel the evidence demonstrates that there is a higher likelihood of appropriate application and effectiveness of a tourniquet when a manufactured tourniquet is used compared with an improvised tourniquet. Despite this, in task force discussions it was noted that when faced with life-threatening bleeding from a limb, and when a manufactured tourniquet is not available and bleeding cannot be controlled by direct pressure with or without a hemostatic dressings, first aid providers could consider the use of an improvised tourniquet, made to appropriate specifications (e.g. wide and tight).

• We recognize that the use of tourniquets provides added equipment and training expense that may increase healthcare disparity in some cases. We also recognize that implementation of tourniquet use, even on a small scale, may not be feasible in some areas.

• Simulation data regarding the use of a windlass tourniquet in comparison with other types of tourniquets does not appear to show a clear benefit for one type of tourniquet compared with another.

Knowledge Gaps

Current knowledge gaps include but are not limited to:

• Sufficiently powered experimental or observational studies comparing tourniquet with hemostatic dressing in individuals with severe, life-threatening bleeding in the out-of-hospital setting
• Experimental or observational studies comparing manufactured tourniquet with improvised tourniquet with hemostatic dressing in individuals with severe, life-threatening bleeding in the out-of-hospital setting
• Experimental or observational studies comparing windlass tourniquet with other types of tourniquet in individuals with severe, life-threatening bleeding in the out-of-hospital setting
• There is an urgent need for comparative studies specific to the pediatric population
• Can first aid providers recognize injuries that are amenable to tourniquet placement?
• How much education is needed to appropriately deploy tourniquets on a mass scale (e.g. just-in-time training)?

Attachments

Evidence-to-Decision Table: FA-768-Tourniquet vs.hemostatic dressing

Evidence-to-Decision Table: FA-768-Manufactured tourniquet vs. Improvised tourniquet

Evidence-to-Decision Table: FA-768-Windlass tourniquet vs. another type of tourniquet Et D

Evidence-to-Decision Table: FA-768-Tourniquet vs. direct pressure Et D

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