## 1 Introduction  
Intraoperative bleeding is a severe complication of any surgical procedure. Although surgical mortality is low in most elective surgical procedures, bleeding complications can escalate mortality rates from <1% up to 20% [1, 2]. Consequently, many scoring systems designed to assess operative morbidity and mortality risk (e.g., POSSUM, TRISS) reflect the impact of major blood loss during surgery [34]. Apart from inadequate surgical hemostasis, major risk factors include dilutional thrombocytopenia, systemic clotting factor depletion, and new oral anticoagulants (NOACs). An aging population with multiple comorbidities further contributes to the risk of intraoperative bleeding [5]. Uncontrolled bleeding contributes to a rapidly evolving vicious cycle in which the combination of hemodolution, hypothermia, the consumption of clotting factors, and acidosis further enhances the bleeding [6]. Surgical interventions to manage blood loss include, e.g., topical absorbable hemostats, conventional surgical methods, and electrocauterization, each with its own limitations [7]. In the latter, a direct or alternating current passes through an electrode wire, generating heat and thus necrotizing and profoundly destroying the tissue [8, 9]. However, the necrotized tissue can disconnect and fall off, causing secondary bleedings hours and days after surgery. This is similar to scratching of the scalp of a skin wound, causing it to bleed again, which is, however, much more severe for internal wounds. Moreover, post-operative complications, including infection, abscess formation, and hematoma, put patients at additional risk [10]. There are cost-intensive developments for intraoperative hemostasis to minimize the thermal damage caused by the heat generated. Well-known manufacturers developed energy-based surgical vessel sealing devices, e.g., the LigaSure technology from Medtronic, the Harmonic from Ethicon Johnson and Johnson, and the Thunderbeat from Olympus. The various sealing instruments have in common the fact that they try to minimize heat generation in the surrounding tissue by means of an insulating layer or structural features, and that they are often contain expensive single-use compartments, raising surgery costs significantly. Hence, an alternative process avoiding or minimizing single-use components providing intraoperative bleeding control in at least a fraction of surgical situations might support cost-effectiveness in the healthcare sector, with similar performance provided. Blood is composed of several components (Figure 1). Hemostasis is the process of blood clotting at the site of an injury [11], and its molecular mechanisms have been outlined in detail [12; 13]. Briefly, hemostasis is a complex orchestrated process that can be subdivided into primary (cellular) and secondary (plasmatic) hemostasis. During primary hemostasis, platelets become activated, involving multiple ligands and downstream signaling of various activated membrane receptors [14]. This results in versatile morphological changes enabling cross-linking of activated platelets, which form an initial white clot. In the following, the plasmatic hemostasis involves to cleavage of the protein fibrinogen to fibrin, which further stabilizes the clot [15]. Due to the many molecules involved in hemostasis, some components and their roles in this process are still not fully understood. For instance, several molecular functions in the process of hemostasis, such as integrin binding, are subject to redox control, as evident by functional disulfide bonds [16], suggesting a role of reactive oxygen and nitrogen species (ROS/RNS). In 2005, the impact of a novel technology, medical gas plasmas, on blood hemostasis was first reported [17]. Often referred to as the fourth state of matter, gas plasmas are  
Figure 1: Blood and compartments, including segmentation of the hematocrit across weight-correlated abundancies of erythrocytes, thrombocytes, and leukocytes. Created with bioreactor.com (accessed on 1 February 2022).