Hemorrhage during trauma occurred in emergency situations is a significant challenge. It may be life threatening if it is not treated swiftly. A new device which can effectively stop bleeding to save life of injured person, especially in battlefield situations and accidents, is presented. A plasma generator is designed to generate a low temperature air plasma spray for treating wounds. The spectral spike at 777.4 nm in the emission spectrum of the plasma plume and the spatial distribution of this emission line’s spectral intensity indicate that abundant atomic oxygen is generated and sprays out of the generator by about 25 mm. Atomic oxygen carried by the plasma spray can quickly activate the cascading of coagulation processes and works as dry disinfectant to advance healing. Tests on blood droplets reveal the strong dependence of blood clotting on the amount of atomic oxygen applied in the plasma treatment, which is maneuvered by increasing the plasma treatment time or decreasing the exposure distance; in both approaches, the degree of blood clotting increases. Treated smeared blood samples show that an increase of the erythrocyte concentration and a drastic decrease of the platelet count are also correlated to the increase of atomic oxygen dose applied in the plasma treatment. The results reveal the mechanisms of air plasma blood coagulation and wound healing. As animal models, pigs were used in the tests of stopping wound bleeding from a cross cut in the ham area, from a hole in an ear’s saphenous vein, and from cuts to arteries in an ear and in a real leg, all stopped swiftly. Moreover, both artery cuts were secure to remove tourniquet; downgrade of tourniquet necessary wound in under 2 minutes was demonstrated. The healing progress of cross cut wounds was observed. The healing time was shortened to about half. This battery power plasma spray can be carried to or placed at anywhere available for first aid applications. It stops bleeding swiftly to save life, and also downgrades tourniquet necessary wound to extend the golden period of saving the remaining part below tourniquet.
Bleeding, even from an external hemorrhage, may be life threatening if it is not treated swiftly [
Blood coagulation involves platelet activation and coagulation cascade. After wound is bleeding, the vasoconstriction is taken place and oxidants are released in the vascular lumen to enhance platelet agglomeration at the wound location to act on blood clotting. Moreover, oxidants fragment platelets to form a fibrin clot which keeps blood coagulation in homeostasis. Thus the treatment to speedup coagulation has to reduce the blood pressure at wound site to slow down bleeding, to clot injured blood vessels to stop bleeding, to heal the cause of bleeding and prevent complications, and to relieve symptoms [
When atomic oxygen interacted with H2O, similar oxidants to those released in the vascular lumen are generated. It suggests that atomic oxygen treatment could speedup blood clotting and clot formation and an atomic oxygen generator could serve purpose.
Plasma can effectively convert electromagnetic energy into kinetic energy of electrons, which is needed for exciting and dissociating molecular oxygen to produce chemically reactive oxygen species (ROS), including molecular oxygen in metastable states and atomic oxygen. Microwave discharge [
For medical applications, low temperature non-equilibrium air plasma would be better usage of the electron kinetic energy gained from the electromagnetic sources for producing ROS, rather than for heating the plasma effluent. One such plasma generator [
In the present work, a portable device which generates air plasma spray for first aid is described in Section 2. The coagulation and healing mechanisms of the plasma treatment are discussed in Section 3. In Section 4, the efficacy of the air plasma spray to stop bleeding is demonstrated. Summary and conclusion are presented in Section 5.
In plasma coagulation applications, it is desirable to have plasma 1) generated in open air with large spatial extent, 2) carrying a significant amount of free radicals, such as reactive oxygen species, and 3) non-equilibrium at low thermal temperature. In the following, the design of a plasma generator which produces an air plasma spray meeting these conditions is described.
Shown in
At atmospheric pressure, the air discharge is an arc mode, which generally evolves into a constricted arc and develops hot spots on the electrode surfaces. An airflow with flow rate of ~1.5 ℓ/s at gap and a nozzle are introduced to elongate and rotate the discharge path to prevent arc constriction and hot spot formation. The nozzle also works to spread out the plasma plume, as well as to cover the high voltage (HV) central electrode for safety; it increases the size of the plasma plume which expands from the exit of the nozzle by about 25 mm (i.e., about 35 mm away from the gap). A significant increase of the discharge path length works to reduce the arc temperature and the sparkling and heating of the electrodes. It also increases the generation region of the reactive species, which is particularly important to those with short lifetimes, such as atomic oxygen.
The air breakdown voltage at atmospheric pressure is about 3 kV/mm. As the discharge is initiated, the current increases rapidly to cause a sudden drop of the voltage which is the signature of arc discharge having a negative V-I characteristic. It is found that the voltage maintaining the discharge in the 1mm gap between the electrodes can be much lower than 350 V. Thus, a high voltage (HV) induction (ignition) coil can be used to trigger [
The presence of atomic oxygen in the plasma spray was examined via its emission spectroscopy [
temperature. The 777.4 nm line is attributed to the 5P state of the atomic oxygen (OI). Presented in
The thermal temperature (<320 K) of the plasma effluent is much lower than the excitation temperature of electrons channeled in the arc loop, which is estimated via emission spectroscopy to be higher than 7700 K. This plasma spray is non-equilibrium due to the following factors associated with the design and the operation, 1) the discharge is run in a periodic mode with a duty cycle less than 10%, 2) the airflow pushes the discharge along an elongated path, 3) the elongated arc loop is vibrating by the air pressure in the nozzle, 4) the triggered discharge is maintained at low voltage. Because the discharge extends to 30 to 35 mm away from the discharge gap, some of the energetic electrons and OI are generated locally in the plasma plume, rather than being conveyed from the gap region of the electrodes.
Blood is a fluid tissue that includes 60% of a liquid portion known as blood plasma, and 40% of formed elements or blood cells [
Both formed elements and blood plasma contribute to blood coagulation during hemorrhage. Blood coagulation involves platelet activation and coagulation cascade. When the platelets encounter the break situation of the blood vessel, external molecules touching the platelets trigger platelet activation; it is followed by the coagulation cascade, which is a complicated step-by-step blood clotting process. Several proteins (fibrinogen, tissue factor, calcium, etc.) and molecules, called coagulation factors, play important roles in the coagulation cascade. In the following, the role of atomic oxygen in plasma treatment to speed up blood coagulation and wound healing is explored.
Blood samples used in tests were mixed with 3.2% sodium citrate solution at 9:1 ratio (in volume). Each sample was set on a glass slide. The sodium citrate solution is a commonly used reagent to prevent premature blood coagulation, it chelates calcium ions to prolong the natural clotting time [
The effects of heat and atomic oxygen radical on blood clotting were studied and compared by tests on blood droplet samples [
The atomic oxygen flux carried by the plasma spray decreases exponentially in distance, the total amount of atomic oxygen applied to the blood droplet sample in treatment will be proportional to the total exposure time and inversely proportional to the exposure distance. Hence, the plasma treatments on blood droplet samples at different exposure distances and durations can reveal the dependency of coagulation cascade on the applied atomic oxygen flux.
Three samples treated at the same exposure distance of 25 mm for 8, 12, and 16 sec, respectively, are presented in Figures 4(b)-(d) for comparison. The sample temperatures were less than 55˚C. A shell, formed on each blood sample surface, can be clearly seen. The photos indicate that the degree of blood clotting increases with the increase of the exposure time from 8 to 16 sec. Three samples treated at three different exposure distances of 25, 30, and 40 mm for the same exposure time of 16 sec are presented in Figures 4(d)-(f). Again, the sample temperatures were less than 55˚C. As shown, the degree of blood clotting decreases as the exposure distance increases from 25 to 40 mm. These results deduce that the degree of blood clotting increases with the increase of the atomic oxygen flux delivered by the plasma spray.
Untreated (control) and plasma spray-treated smeared blood samples were prepared for cell staining and microscopy analysis, which identified cell types and performed cell counts [
The correlation between the rapid reductions of the platelet counts and clot formation time (presented in Section 3.1) of a treated sample suggests that atomic oxygen, delivered by the plasma spray, rapidly induce oxidants in blood plasma to fragment platelets for forming blood clot.
The results of the tests on blood droplet samples presented in
When interacted with H2O, atomic oxygen can generate large amount of reactive oxygen species (free radicals and hydrogen peroxides), which are expected to function similarly to those oxidants, produced or released in the vascular lumen. Several key steps in coagulation cascade are then triggered by the oxidants. These oxidants stimulate RBC- platelets and WBC interactions. The interactions influence the concentration
of cells suspended in blood; the observations of the microscope presented in
The role of atomic oxygen in wound healing process is explained as follows. Hypoxia [
The experimental results presented in this work are consistent with the published data on the effect of oxidants on blood coagulation. Therefore, the clotting process is explained to be attributed to the stimulation of RBC- platelets and/or WBC interactions by the oxidants created during the interaction of blood and atomic oxygen (as well as other likely ROS). It may be further confirmed by future studies, focusing on how the atomic oxygen (and ROS) carried by the plasma spray influences each individual cell type; the samples will be single cell type, either RBC , WBC, or platelets, as well as blood plasma, in order to verify their actual involvement in blood clotting, blood coagulation, and fibrinolysis.
Two 3-month-old male pigs weighing around 25 kg [
Row (a) of
A saphenous vein from a pig ear was first identified. As shown in Row (b) of
Before cutting an artery in an ear with a scalpel, the ear was tied with a tourniquet, shown in Row (c) of
Subsequently, a large scale test was performed by cutting an artery above the middle joint of a real leg. Tourniquet was applied to stop high-pressure arterial bleeds. The cut was treated by the plasma spray continuously for 60 s at an exposure distance of about 15 mm. Hemorrhage was controlled and tourniquet was removed. Manipulation of limbtotry to break clot was played, but wound did not re-bleed. This is the first demonstration of successful down grade of tourniquet necessary wound in under 2 minutes.
The plasma treatment time and the natural time (control) used to stop bleeding from each type of the wounds cut in the tests are recorded in
In wound healing observation, cross cut wounds were introduced in the ham area of two larger pigs; again, each cut was 10 mm in length and 5 mm in depth; one was untreated as a control and the other one was treated by the plasma spray with an intermittent exposure approach, by running the spray with 2-s on/2-s off alternately for 5 times.
The progress of the control (untreated cross cut) shown in the first row of
Wound | Treatment | |||
---|---|---|---|---|
Plasma (continuous) | Plasma (intermittent) 2-s on/4-s off On time | Plasma (intermittent) 2-s on/2-s off On time | Natural (control) | |
Straight cut (1 cm × 0.5 cm) | 18 s | 8 s | 10 s | 190 s |
Cross cut (1 cm × 1 cm × 0.5 cm) | 13 s | 8 s | 10 s | 240 s |
A hole in an ear’s saphenous vein | 15 s | 88 s | ||
Artery cut in ear (tourniquet aided) | 12 s | 60 s | ||
Artery cut in rear leg (tourniquet aided) | 60 s |
Further tests on wounds of artery cuts at different locations will be useful to establish the treatment procedure in the first aid. In future studies, it is also of interest to test the feasibility of air plasma spray to stop bleeding from artery wounds which cannot apply tourniquet. A surgical clamp may be used.
Blood coagulation and wound healing mechanisms by an air plasma spray are presented. Tests on blood droplets established a strong dependence of the blood clot on the atomic oxygen density delivered by this plasma spray. The microscope study of treated smeared blood samples correlates the decrease of the platelet count and the increase of the RBC count to the increase of the atomic oxygen flux in treatment. These correlations evidence the role of atomic oxygen flux in speeding up blood coagulation. When atomic oxygen interacts with H2O, reactive oxygen species such as OH and H2O2 are produced. These oxidants target platelets to affect several key steps of platelet function, such as enhancing platelet aggregation and fragmenting platelets to form clotting surface for the subsequent steps of the coagulation. In addition, atomic oxygen enhances superoxide (SOD) and cell metabolism and raises tissue oxygen tension in the wound healing. It also provides disinfection to shorten the period of the inflammatory phase in wound healing.
Using pigs as animal models, rapid stop of wound bleeding by this air plasma spray was demonstrated. The tests also successfully demonstrate to downgrade tourniquet necessary wound in under two minutes. The consequence of plasma treatment on wound healing was also demonstrated. A single plasma treatment to stop bleeding of a cross cut wound also reduces the wound healing time to about half.
In conclusion, this air plasma spray has demonstrated its potential as an advanced first aid device. This handheld spray is designed to be run with two types of power supplies, which are portable and light weight. One power supply employs 120 VAC input and the other one with 12 VDC input. Both can be implemented in emergency rooms, ambulances, vehicles, and buildings. Moreover, the battery power plasma spray contains its own power source. It can be carried to or placed at anywhere available for first aid applications.
The author is grateful to Drs. Olga Tarasenko, Cheng-Yen Chen, Chuan-Shun Lin, and Todd Pedersen for collaborative work, to Alessandro Betti for fabricating the air plasma spray used in the experiments, and to Prof. Heng-Chun Li for commenting on the manuscript. This work was supported in part by the Adventix Technologies Inc. and the Aceso Plasma, LLC.
Kuo, S.P. (2016) Air Plasma Spray for First Aid. Open Journal of Emergency Medicine, 4, 69-82. http://dx.doi.org/10.4236/ojem.2016.43010