[Approaches to pre-hospital bleeding management : Current overview on civilian emergency medicine]

[Tourniquet use in the Helicopter Emergency Medical Service : Analysis based on data of the DRF Luftrettung (German Air Rescue) in the period 2015-2020]

BACKGROUND

In 2016 the first German recommendation for the preclinical use of tourniquets was published. Currently little is known of the frequency of the use of tourniquets in the prehospital setting in Germany. This study evaluated how often a tourniquet is used in a civilian German Helicopter Emergency Medical Service (HEMS).

METHOD

After the approval of the scientific working group of the DRF Luftrettung HEMS, the electronic database (HEMSDER) of the DRF Luftrettung HEMS was analyzed for the period 2015-2020 under the abovementioned question. All patients with a tourniquet application were included in the study and a comparison was made with the total trauma cohort and a subgroup analysis between patients who additionally required airway management and patients without additional airway management in the cohort of tourniquet patients. The analysis was mainly descriptive. Parametric test (t-tests and χ²-tests) were used for group comparison.

RESULTS

During the study period 67,321 trauma patients were treated and in 866 (1.3% of all trauma patients) a tourniquet was used. The mean age of these patients was 45.9 years (±19.5 years), 710 (84%) were male, 439 (51%) suffered a monotrauma, 296 (34%) suffered multiple trauma, 339 (38%) required a prehospital airway management and 321 (37%) of these were intubated. Significant differences between patients with tourniquet application and the rest of the trauma cohort were detected in general data (monotrauma, polytrauma and high-speed trauma, massive bleeding), vital signs at the scene of the accident (GCS, HF, S_pO₂) and necessary interventions, such as pressure bandages and use of hemostyptics, tranexamic acid, analgesia, the frequency of intubation and colloidal volume replacement. Due to limitations of the data set we could not obtain information regarding the limb used for the tourniquet, whether a conversion of the tourniquet was carried out and if the tourniquet was used according to the current German trauma guidelines.

CONCLUSION

With a frequency of 1.3% the need for a prehospital tourniquet application is low in civilian trauma patients. Monotrauma with isolated extremity injuries represent about half of the patients treated with tourniquets. The other half is represented by multiple injuries or multiple trauma patients who require significantly more invasive measures, such as airway management and more complex on-scene interventions are needed. The available data do not allow any conclusions to be drawn about the location and the quality of the tourniquet application. Future documentation systems should incorporate data on the use of tourniquets, such as the location of use, indications (tactical use/massive bleeding), bleeding control achieved (yes/no) or second tourniquet necessary, conversion (yes/no) and any obvious complications.

[Hypovolemic and hemorrhagic shock]

The term "shock" refers to a life-threatening circulatory failure caused by an imbalance between the supply and demand of cellular oxygen. Hypovolemic shock is characterized by a reduction of intravascular volume and a subsequent reduction in preload. The body compensates the loss of volume by increasing the stroke volume, heart frequency, oxygen extraction rate, and later by an increased concentration of 2,3-diphosphoglycerate with a rightward shift of the oxygen dissociation curve. Hypovolemic hemorrhagic shock impairs the macrocirculation and microcirculation and therefore affects many organ systems (e.g. kidneys, endocrine system and endothelium). For further identification of a state of shock caused by bleeding, vital functions, coagulation tests and hematopoietic procedures are implemented. Every hospital should be in possession of a specific protocol for massive transfusions. The differentiated systemic treatment of bleeding consists of maintenance of an adequate homeostasis and the administration of blood products and coagulation factors.