Autologous Transfusion of Shed Pleural Blood in Trauma - a Register Study to Determine Applicability

Sahlgrenska academy

Autologous transfusion of shed pleural blood in trauma - a register study to determine applicability

Degree Project in Medicine

Henrik Örtenwall

Programme in Medicine, The Sahlgrenska Academy

Gothenburg, Sweden, 2021

Supervisors:

Dr. Ragnar Ang, trauma surgeon, SU

Doc. Jenny Skytte-Larsson, anesthesiologist, FömedC

Table of contents

Abbreviations ...... 3

Abstract ...... 4

Introduction ...... 5

Aim ...... 6

Background ...... 6

History ...... 6

Transfusion guidelines ...... 9

Pros and cons of allogenic blood component transfusion ...... 10

Pros and cons of autologous whole blood transfusion ...... 16

Previous research ...... 17

Blood salvage ...... 23

Material and Methods ...... 25

Results ...... 26

Prospective descriptive pilot study ...... 28

Ethics ...... 30

Discussion ...... 32

Limitations of the prospective study ...... 37

Conclusion ...... 40

Acknowledgements ...... 42

Populärvetenskaplig sammanfattning ...... 43

Appendix ...... 44

References ...... 45

Abbreviations

ABT Allogenic blood transfusion (from donor) aPTT Activated partial thromboplastin time Ca Calcium Cl Chloride CPD Citrate phosphorous dextrose CRP C-reactive protein DCR Damage Control Resuscitation DIC Disseminated Intravascular Coagulation DCS Damage Control Surgery ED Emergency Department FFP Fresh frozen plasma Hb Hemoglobin HTB Hemothorax blood HBV Hepatitis B virus HCT Hematocrit HCV Hepatitis C virus HES Hydroxyethyl starch HIV Human immunodeficiency virus HP Hemoperitoneum Il-6 Interleukin-6 INR International normalized ratio K Potassium Na Sodium NGO Non-Government Organization PCs Platelet concentrates PLT Platelets RBCs Red blood cells SU Sahlgrenska University hospital TNF Tumor necrosis factor WBC White blood cells

Abstract Background Direct autotransfusion of shed pleural blood in a trauma setting as an alternative to transfusion of banked blood in patients with (massive) traumatic hemothorax is a tested, working and well used methodology at some trauma centers throughout the world. Aim The aim of this study was to evaluate the usefulness of direct, whole blood, autotransfusion with hemothorax blood in trauma patients at Sahlgrenska University hospital (SU). Further, the aim was to summarize previous research in the field and analyze properties of blood retrieved from the pleural cavity (hemothorax) to appraise suitability for re-infusion. Method This was a register study of all patients treated with chest drain on the basis of suspected traumatic hemothorax/hemopneumothorax at the emergency department or trauma care unit at SU between 1st of January 2018 - 1st of October 2020. Inclusion criteria were chest tube insertion withing 24 hours of trauma, immediate draining >400 ml of blood followed by subsequent blood transfusion within 24h. Results A search in the journal database generated 158 hits with the ICD code GAA10 (insertion of chest drain) in combination with either S27.1 (hemothorax) or S27.2 (hemopneumothorax). 86 patients remained after excluding patients with pneumothorax, “old” hemothorax, non- trauma patients and referred out-of-county patients with tube thoracostomy already inserted. When the remaining patients were matched against the inclusion criteria, 24 patients remained that could have been treated with suggested method during the chosen time period (33 months) studied. Conclusion Less than one patient per month, admitted to SU, fulfilled the requirements necessary to utilize this technique. This low number, in combination with question marks regarding contamination and coagulation deterioration of hemothorax blood makes the technique more suitable as an emergency solution for mass-casualty situations than normal conditions until further research has clarified these uncertainties.

Key words; hemothorax , trauma , autotransfusion , autologous blood transfusion

Introduction

In Sweden, trauma is the leading cause of mortality between age 15 – 44 (1). Major bleeding in trauma constitutes an immediate threat to life. The treatment is to stop the bleeding and restore blood volume. In Swedish hospitals, the standard procedure to reestablish adequate blood volume in trauma patients is allogenic multicomponent blood transfusion. However, blood transfusion is not without risks, including those of disease transmission, incompatibility, and medical errors. One way to reduce the need of donated blood from blood banks is autotransfusion - the return of the patient’s own shed blood into the bloodstream. In the trauma setting, autotransfusion is already an established technique at trauma resuscitation centers, e.g., in South Africa, where the combination of extraordinary high rates of interpersonal violence and less than 1% active blood donors have resulted in autotransfusion becoming a lifesaving complement with the intravenous return of shed pleural and peritoneal blood (2-6).

The student course manual for Advanced Trauma Life Support (ATLS) (7), published by the

American College of Surgeons, suggest that “collection of shed blood for autotransfusion should be considered for any patient with a major hemothorax.” Furthermore, the author of the manual of Definitive Surgical Trauma Care (DSTC), Kenneth D. Boffard argues that; “In practical terms, bleeding from the chest seems ideal for immediate autotransfusion as contents of the thoracic cavity are sterile.”(5)

Insufficient blood product supply from blood banks is rarely a problem in large Swedish hospitals, and commonly trauma patients immediately receive acute blood (blood group O negative erythrocytes) pending matched blood products. However, proper evaluation of pros and cons will help to determine whether autologous transfusion of shed pleural blood is an option should there be a blood product shortage, e.g., in a mass casualty situation.

The evaluation may also be of value to organizations acting on the field, far from regular blood banks, such as the military and different NGO’s (Medicin sans Frontiers - MSF, Red

Cross etc.).

Aim

The aim of this study was to evaluate the usefulness of direct, whole blood, autotransfusion with hemothorax blood in trauma patients at Sahlgrenska University hospital (SU).

The goal was to investigate how many patients that were treated with chest tube within 24 hours of trauma, immediately draining more than 400 ml of blood and in combination with subsequent blood transfusion, to evaluate the applicability of this method.

Further, this study aimed to summarize what is known from published literature on the subject of autotransfusion with hemothorax blood (HTB) in trauma and determine unexplored areas in need of future research. As a part of this, we intended to conduct a prospective pilot study of shed pleural blood, analyzing its properties and appraise the suitability of re-infusion. The purpose is to demonstrate the risks and advantages of autologous HTB transfusion compared to allogenic transfusion in trauma patients, and in extension assess the possibility to introduce

HTB autotransfusion as a complement to allogenic transfusion in trauma resuscitation at centers in Sweden.

Background

History

The history of blood transfusion dates back to the 1667 when Richard Lower demonstrated that a dog, on the verge of dying due to hemorrhage, could be “completely restored” by receiving a blood transfusion from another dog (8).

In 1818, an English obstetrician named James Blundell performed the first transfusion of human blood to save the life of a woman with massive uterine hemorrhage using the patient’s husband as a donor (9, 10). However, it was not until the beginning of 20th century that the importance of sterile technique, the discovery of different blood types and knowledge of anticoagulants made blood transfusion a “safe” procedure (11).

Today, blood transfusion is a lifesaving procedure in severe hemorrhagic patients as well several hematologic diseases. Almost 85 000 patients received allogenic blood transfusion in

Sweden 2019 (12). WHO’s “Global Status Report on Blood Safety and Availability” from

2016 showed that Sweden has among the highest number of whole blood / red blood cell

(RBC) units transfused per 1000 population in the world (13).

In 1886, the first known human autotransfusion was performed when J. Duncan reinfused shed blood in a patient suffering from traumatic amputation. The blood from the limb was collected and returned by femoral injection without notable side effects (14).

A description of the first case of autotransfusion with blood from a traumatic hemothorax was published in 1917 by Dr. Elmendorf, but with the discovery of ABO blood typing and the institution of blood banks in the 1930s, autotransfusion technique fell into oblivion.

During the Vietnam War, combat trauma surgery generated extensive data regarding intraoperative retrieval of large quantities of blood for reinfusion, which revitalized the interest in autotransfusion (15).

Evolution of resuscitation strategies

In the past, emergency physicians, surgeons and anesthesiologists have been liberal in prescribing crystalloids and colloids to restore volume and assist systemic perfusion. Such fluids increase the intravascular volume but lack oxygen-carrying capacity as well as clotting factors. Additionally, only 30% of infused crystalloid fluid persist in the bloodstream.

Because of this, three times the volume of the lost blood must be infused, resulting in both dilution and edema. The dilution of blood decreases clotting factor concentration, which impairs hemostasis, as well as erythrocyte concentration, negatively affecting oxygen transport (16).

Colloids have osmotic activity and thus have the potential of expanding intravascular volume.

However, colloids are expensive, and when compared to crystalloids in randomized controlled trials for resuscitation of trauma patients, no evidence has been found that colloids reduce mortality compared to crystalloids (17).

One risk of colloids is that they may cause anaphylaxis (1/500 infusions), another aspect is that colloids (HES) have a negative effect on fibrin network and platelets by depletion of von

Willebrand/factor VIII complex, in combination with dilution, thereby increasing the risk of severe ongoing hemorrhage. (5, 18)

The concept of Damage Control, which implies both Damage Control Resuscitation (DCR) and Damage Control Surgery (DCS) in treating critically ill trauma patients has significantly improved outcomes. Damage Control is a temporizing measure that includes immediate arrest of ongoing hemorrhage, reduced crystalloid fluid administration, early blood product transfusion and permissive hypotension. In the concept of permissive hypotension the goal is to allow a lower than normal blood pressure (60-90mm Hg, systolic), and simultaneously strive to maintain the minimal blood pressure necessary to adequately perfuse vital organs (8).

Higher blood pressure essentially “pops” the clot off a bleeding site resulting in a resumed bleeding and increased hemorrhage. The blood loss is (partly) replaced through balanced administration of blood components (erythrocytes, plasma and platelets) from the hospital blood bank in order to re-create whole blood, complemented with fibrinogen and Ca under

TEG/ROTEM monitoring (19).

Since it is not yet possible to synthesize blood, voluntary donations are required. In 2018,

~400 000 bags of blood were donated (12). Previously blood transfusions were given as whole blood, but nowadays the blood is separated into erythrocytes, plasma, and platelets.

These have different durability and require different storing temperatures (20).

If a deficit should emerge there is a cooperation between hospitals in Sweden to buy blood products from each other. However, in emergencies this may lead to risky transfusion delays.

One way to minimize the need of blood products from a blood bank is to re-transfuse the patient’s own blood to the systemic circulation (autologous transfusion).

In elective surgery, blood may be collected from a patient 1-2 weeks prior to the operation and then be re-infused back to the same patient when needed. There are also methods to collect shed blood during surgical procedures with large, anticipated blood loss, wash it, and reinfuse the erythrocytes (CellSaver®). In a trauma setting, without time for preparations, the option is direct re-transfusion of shed pleural/peritoneal blood (6).

Transfusion guidelines

To decide who needs blood, how much, and how fast may be difficult. Hemoglobin (Hb) is a poor indicator of acute blood loss in patients with massive hemorrhage. Generally, blood volume is ~7% of the body weight in a normal adult, approximately 70 mL/Kg; thus approximately 5 L in a person that weighs 70 kg (7). It is not easy to appreciate the quantity of blood loss, but vital parameters, urine output and mental status can help in the estimation of blood volume loss, as seen in table 1, p 10.

Table 1 - Classification of hemorrhage (7)

Parameter Class I Class II Class III Class IV

Blood loss (ml) <750 750-1500 1500-2000 >2000 Blood loss (%) <15% 15-30% 30-40% >40% Rulse rate (beats/min) <100 >100 >120 >140 Blood pressure Normal Decreased Decreased Decreased Respiratory rate 14-20 20-30 30-40 >35 Urine output (ml/hour) >30 20-30 5-15 Negligible CNS symptoms Normal Anxious Confused Lethargic

Classification of hemorrhage according to American College of Surgeons; parameter variation depending on volume of lost blood. According to Swedish transfusion regulations, erythrocyte transfusion is usually not recommended if the blood loss is less than 30% [Class I and II].

RBC transfusion should be considered if more than 30% [Class III] is lost, and in case of major bleeding with more than 40% blood loss [Class IV] rapid transfusion with all components is required.

To avoid coagulopathy, RBCs, fresh frozen plasma (FFP), and platelets are generally administered in a ratio of 1:1:1. In Sweden, one platelet concentrate pack is equivalent to 4 units of platelets and allow administration in a proportion of 4:4:1 (21). If more than one

“trauma pack” (4:4:1) is necessary, administration of additional coagulation factor concentrate, fibrinogen, calcium and Tranexamic acid (Cyclokapron®) should be considered

(22).

Whole blood transfusions have been used by the military for a long time. With building evidence that whole blood transfusion may be advantageous to component therapy in trauma patients, studies are currently investigating its place in the civilian setting. (23)

Pros and cons of allogenic blood component transfusion

Even though autologous HTB transfusion has been implemented as an alternative in some countries, allogenic blood transfusion (ABT) is still the standard treatment in hemorrhagic trauma patients (24). O negative blood can be instantly administered as soon as an intravenous 10

access has been established, which may be the only option in acute situations with massive bleeding. Blood group testing must be performed before the third unit of blood has been transfused to not interfere with the result. As soon as possible the blood bank will replace the delivery of O negative “acute blood” (universal) with blood that is type-specific (ABO and

RhD compatible) and cross-matched (compatible also with other antibodies) to the recipient.

Usually, most blood banks can provide type specific blood within 10 min, while complete crossmatching requires ~1 hour (7).

Blood group distribution in the Swedish population (2019) 40%

30%

20%

10%

0% A+ 0+ B+ A- 0- AB+ B- AB- ](25) Figure 1 – Blood group distribution in Swedish population (2019). Demonstration of blood group distribution in the Sweden, with percentage in the Swedish population on the Y-axis and blood group on the X-axis.

Blood bank supply most often reflects the general population (see fig. 1) and rare blood types pose a higher risk of rapid depletion when massive transfusion is required. The situation with

O- blood is particularly problematic since these patients only can receive blood from donors with the exact same blood type (as well as O+ blood in men and postmenopausal women).

O- blood is also the “universal donor” (see fig. 2, p.12) used as a “bridge” in acute situation before testing and type-specific blood is available which further reduce the supply (26).

Autotransfusion would thus be especially advantageous in O- patients and other rare blood types.

Donor Recipient Donor Recipient

O O RhD- RhD-

A A RhD+ RhD+

B B

AB AB

Figure 2 - Illustration of transfusion compatibility between blood groups in the ABO- and Rheusus system.

Additionally, blood banks can, most often, rapidly provide large volumes of blood products in a way that is not possible through autotransfusion technique.

Most patients that undergo blood transfusion do so without complications while some endure minor adverse effects. Most commonly these are febrile non-hemolytic reactions, minor allergic reactions or formation of alloantibodies which may complicate future blood transfusions (see fig. 3) (27). However, there are some rare, but potentially fatal, adverse side effects related to transfusion of donated blood that may be avoided with autotransfusion (see fig. 4, p. 13).

8 Risk of minor blood transfusion reaction

6 % 4

0 Formation of alloantibodies Febrile non-hemolytic reaction Minor allergic reaction (28)

Figure 3 – Risk of minor blood transfusion reaction. Estimated percentage of all blood transfusions on the Y-axis and common adverse side effects on the X-axis.

Severe blood transfusion reactions

10 9 8 7 6 5

4 Nr. of cases of Nr. 3 2 1 0 Anaphylaxis TRALI AHTRs TACO TA-GVHD PTP (29) Figure 4 – Severe blood transfusion reactions. Registred number of cases in Sweden, 2019, on the Y-axis. TRALI = Transfusion-related acute lung injury, AHTRs = Acute hemolytic transfusion reactions, TACO = Transfusion-associated circulatory overload, TA-GVHD = Transfusion-associated graft-versus-host disease, PTP = Posttransfusion purpura.

Anaphylaxis

A pre-sensitized recipient may react with an anaphylactic response to different donor plasma proteins, but anaphylaxis may also be triggered by infusion of blood products containing IgA in an IgA-deficient recipient with preexisting anti-IgA antibodies (30).

Transfusion-related acute lung injury (TRALI)

TRALI is a potentially life-threatening condition that develops during, or withing 6 hours following blood transfusion. The pathogenesis of TRALI is not fully known but the main theory is that donor antibodies bind to recipient white blood cells (WBCs) in the capil1laries of the lungs resulting in degranulation and damage to pulmonary endothelium, causing leakage of fluid and inflammatory cells into the lung. Any blood containing plasma may cause

TRALI, however the incidence is higher when blood products from female donors, that has been pregnant, is transfused. (31-33)

Acute hemolytic transfusion reactions (AHTRs)

Hemolytic transfusion reactions is the result of the recipient’s immune system attacking donor

RBCs causing hemolysis, that in severe cases may lead to arrythmia or heart failure (34). The

most common cause is transfusion of ABO incompatible blood products due to human error, but other blood antigens such as Kidd, Rh, Kell and Duffy may also be involved. (31)

Transfusion-associated circulatory overload (TACO)

Just as the name implies, TACO is a circulatory overload caused by transfusion of a greater volume of blood than the recipient’s cardiovascular system can manage. This is often due to either massive infusion in patients with reduced cardiac capacity or too rapid infusion. Today, this is considered the most common severe reaction associated with blood transfusions and reported cases are likely underestimated. (31)

Transfusion-associated graft-versus-host disease (TA-GVHD)

TA-GVHD is a rare, often fatal complication (>90% mortality), which is the result of an immunocompromised patient receiving viable lymphocytes which survive in the recipient due to dysfunctional immune response. These cells instead proliferate and attack the host’s tissues. To avoid this reaction, risk patients may get irradiated blood where the DNA in all living white blood cells are inactivated. (30, 35) The incidence has been reported to 0.1-1% in immunocompromised patients. (31)

Posttransfusion purpura (PTP)

PTP usually appears in patients who have had numerous blood transfusions before, or women with several pregnancies. The reason is that the recipient’s immune system has been alloimmunized against a platelet-specific antigen. Upon re-exposure, the immune system launches an attack on the donor’s platelets that paradoxically destroy the recipients own platelets as well resulting in thrombocytopenia. (31) One case has been reported in Sweden between 2005-2019. (29)

Blood borne diseases

Another argument in favor of autologous blood transfusion is that the patient exhibits no threat of getting any blood transmitted infections. Today, the risk of getting a transfusion- 14

transmitted disease, especially in Sweden, is lower than ever. This is partly because the rate of infections such as Hepatitis B virus (HBV), Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) has declined in the general population (blood donors) since the mid 1980s, but also due to improved sensitivity of pre-donation screening tests. (31)

Only one case of transfusion-transmitted HBV and two cases of HCV has been reported in

Sweden since 2004, while no case of HIV transmission has been documented since 1985 (36).

To keep the incidence as low as possible, all prospective donors must fill out a pre-donation questionnaire with questions about general health, recent traveling, sexual habits etc.

If the form is passed without remarks the donor may proceed and donate blood for testing.

All blood is subsequently screened for HIV, HBV, HCV, Syphilis and human T-lymphotropic virus (HTLV) I and II (37). Nevertheless, these are far from all known pathogens that may cause transfusion-transmitted disease on a global level. To name a few examples, many countries are battling transmission of viruses, such as Dengue fever or West Nile virus, parasites such as Leishmania sp. or malarial Plasmodium sp. and even in rare cases prion diseases such as Creutzfeldt-Jacob’s disease (38). When it comes to bacterial transmission and transfusion-associated sepsis (TAS), it is far more common transfusing platelets (PCs) than packed RBCs. A presumptive explanation for this is the different storing conditions were PCs are kept in room temperature, favorable for bacterial growth, while RBCs are stored refrigerated (39).

Hypothermia

Donated RBCs are stored at temperatures of ~4 °C. Trauma patients with massive hemorrhage often require fast transfusion with large volumes of blood. Warming the blood before infusion, preferably to 39 °C, is thus essential to avoid cooling the patient and prevent associated undesirable effects (7). Rapid transfusion of insufficiently warmed blood will significantly drop the core temperature and result in hypothermia, decreased oxygen transport,

significant coagulopathy and will adversely affect immune and cardiovascular systems.

Hypothermia, defined as a core temperature <35°C, is common in trauma patients already upon admission and associated with increased mortality (40). A bleeding patient in combination with exposure to cold temperature is likely to be hypothermic, but also other factors such as influence of alcohol may negatively affect core temperature and blood pressure as a result of consequent vasodilation (7). In trauma patients with massive bleeding and a core temperature of 32°C and lower, the prognosis is very poor and the outcome often lethal (41).

Pros and cons of autologous whole blood transfusion

Autologous transfusion has numerous theoretical advantages compared to allogenic transfusion. The blood is known to be compatible, its normothermic on withdrawal, poses no risk of allergic reaction and will not transmit any blood borne diseases (not already present).

Furthermore, whole blood transfusion provides an optimal resuscitation solution with ideal proportions of blood cells and coagulation factors (23). Another aspect is that autologous blood may be an option for patients that refuse to receive blood transfusions from donors due to religious convictions (15).

Studies have shown blood quality deterioration over time during storage of donated RBCs including morphologic changes, hemolysis, lactic acid accumulation, decreased pH, increased oxidative damage and reduction in 2,3-diphosphoglycerate (2,3-DPG). Less 2,3-DPG effects the oxyhemoglobin dissociation curve and result in a “shift to the left”, which decreases peripheral oxygen unloading. Autologous HTB blood is reinfused soon after leaving the body and are thus far less affected by this storage lesion (42).

However, a study by Weiskopf et al. in 2006 showed that, despite lower levels of 2,3-DPG, stored blood (mean; 24 days) released sufficient quantities of oxygen to treat acute anemia, and was equally efficient as “fresh” erythrocytes, stored less than 5 h (43).

Currently, SU has no thorax drainage equipment which allows direct re-transfusion of shed whole blood. Introducing autotransfusion methods would require new equipment, but also staff training. This would be problematic in hospitals with low trauma burden and infrequent practice. Yet, blood is a limited resource and stores may rapidly decline, e.g., in case of a mass casualty situation. Reduced consumption of banked blood through autotransfusion means more blood available for other patients in need. However, it can only be introduced as a complement to allogenic transfusion in trauma since the concept of autotransfusion obviously fails if there is no blood to re-transfuse.

Previous research

Between Jan 1992 and Dec 1993, Dr. L Ansaloni from Uganda (44), in absence of other options, re-transfused blood from the abdominal cavity using a sterile soup ladle, a sterile kitchen funnel, an anticoagulant containing glass bottle, a filter made from sterile gauze and intravenous tubing with in-line micropore filter. Blood was collected from the peritoneal cavity with the soup ladle and poured through the “filter” into the bottle (illustrated in fig. 5) and then re-transfused.

Figure 5 - Illustration of blood filtration and preparation for autotransfusion; blood collected from the abdominal cavity, filtered through sterile gauze and mixed with heparin.

A total of 27 patients were included in this study, where 9 patients were not suitable for transfusion due to minimal hemoperitoneum (HP) or hemolysis. 18 patients were treated, without complications or adverse effects related to the transfusion, according to the article, claiming that direct autologous whole blood transfusion from HP is cheap, simple, and may be used even in rural areas in developing countries with very basic equipment.

Since then, several studies have investigated the safety and applicability of autologous transfusion in trauma.

A retrospective observational study, by Kothari et al. (45), was conducted in India between

1996 and 2017. 100 patients with either hemoperitoneum (60 patients) or hemothorax (40 patients), and without matched blood group available in the blood bank, were included. Blood was collected through a drainage tube into a sterile, heparinized bag. The drain was then

“clamped”, and the bag turned upside down, immediately transfusing the blood back to the patient through a micro filter. The amount transfused was between 500 – 1800 ml, and according to the results, “all patients had safe and unremarkable transfusions”.

An American multicenter, retrospective study, by Rhee et al., published in 2015, examined the safety of autologous whole blood transfusion from hemothorax, compared to allogeneic blood transfusion in 272 trauma patients. The patients were divided into two matched groups receiving either HTB or ABT. The result showed no significant difference regarding in- hospital complications or mortality. Autotransfusion was, according to the study result, found safe without excessive risk of complications. Further, both costs, and the need of RBCs and platelet transfusion was reduced in the HTB group compared to ABT group. (46)

From an economic point of view, a study by Glenngård et al. published in 2005 calculated that the expense of two units erythrocytes was estimated to 6330 SEK (in Sweden 2003) from donation to transfusion, including cost of complications.

Same calculated number for autotransfusion was lower, 5394 SEK, much due to fewer complications (47). In a trauma setting, the cost will differ significantly from the above estimated number since stated amount is calculated on collecting, ABO typing, testing for transmittable diseases, separating components, storage etc. while the setup in a trauma room will be much more primitive and instant without storage, testing or separation into subcomponents required. The total expense of consumables interconnected in our autotransfusion system described under the heading “materials and methods” was ~300 SEK

(Swedish kronor) (48).

Contraindications

The proposed list of contraindications is extensive, nevertheless, little data support many of these hazards and many proposed contraindications should be considered relative rather than absolute. Blood contamination with anything that result in haemolysis, such as sterile water, alcohol or hydrogen peroxide should be considered an absolute contraindication (49), since transfusion of hemolyzed blood may cause tubular damage and acute renal failure due to deposition of iron and hemosiderosis (50).

Bacterial contamination

There is a controversy regarding the risk of reinfusing potentially contaminated blood such as from a concomitant gastrointestinal tract injury. Contamination by bowel content was previously assumed to be an absolute contraindication of autotransfusion, however, studies have showed that the risk of re-transfusing contaminated blood with subsequent antibiotic treatment is low (6, 15, 49).

An experimental study, by Smith et al. in 1978, examined autotransfusion of contaminated blood in dogs. The animals, that were bled 40 % of their estimated blood volume, resulting in hypovolemic shock, was autotransfused with blood grossly contaminated with faeces. Only

30% of the dogs with contaminated blood transfusion survived in relation to 90% without 19

contamination. Yet, prophylactic treatment with broad spectrum antibiotics after infusion eliminated the increased risk, resulting in the same survival in both groups (90%) (51).

In a literature search no documentation of transfusion associated sepsis in humans after direct whole blood autotransfusion was found. However, contamination has been studied in patients transfused with blood from a Cell Saver device that will concentrate and wash the RBCs.

Exactly how effective this is with regards to removing bacteria is unknown and the manufacturer does not support the use of this device for contaminated blood (49, 52).

Bland et al., in 1992, showed that ~30% of the blood re-transfused after intra operative blood salvage using the Cell Saver device were contaminated with bacteria. Despite this, no adverse effects was documented in any of the 38 patients (53).

Coagulation

An American prospective descriptive study by Salhanick et al., published in 2011, investigated haematocrit, coagulation, and electrolyte profile of evacuated pleural blood in 22 patients with hemothorax. The inclusion criteria were >50ml of blood drained within 4 hours of chest tube insertion.

The following was concluded after analysis of drained pleural blood: both INR and aPTT were significantly elevated, fibrinogen was depleted with high D-dimer values and coagulation factors V and VIII were reduced. Thus, the conclusion was that “in no way can hemothorax be considered a resource for coagulation factors sufficient to resuscitate the patient” (54). With this information taken into consideration, disseminated intravascular coagulation (DIC) and coagulopathy is a major concern with HTB and should either be considered contraindicative or must be complemented with allogenic transfusion of FFP and platelets.

A study by Harrison et al. in 2014 confirmed these results when shed pleural blood was analysed from 10 patients and no thrombus was formed in any aPTT test (>180 s, reference value; 24-32). The blood was then mixed with either normal pooled plasma (NPP) or patient plasma (PP) in clinically relevant dilution and aPPT test was preformed once more. HTB +

NPP had a median value within normal range, 26.0, while the value for HTB + PP analysis was 21.7, indicating a hypercoagulable state. The authors proposed the explanation that the hypercoagulability was a consequence of high levels of activated coagulation factors in the drained plasma, but with a deficit of substrate on which to act. Once mixed with normal plasma, fibrinogen is available, and the coagulation is accelerated. The reason of why there is a difference in aPPT between HTB mixed with NPP and PP is unknown. (55)

Since coagulopathy, together with hypothermia and acidosis, constitutes “the trauma triad of death” it is vital to instantly treat it. Major bleeding result in decreased perfusion, decreased oxygen delivery and hypothermia. Hypothermia negatively affects the coagulation cascade, and the bleeding persists. Without oxygen, cells turn to anaerobic respiration, releasing lactic acid and other acidic compounds into the blood resulting in acidosis. The acidity reduces myocardial performance, further decreasing perfusion and exaggerate the hypothermia.

Uninterrupted the lethal triad reenforce in a positive feedback loop as seen in fig. 6. (56)

“The trauma triad of death”

Coagulopathy

Decreased myocardial performance Hypothermia Metabolic acidosis

Figure 6 – “The trauma triad of death”. Illustration of how coagulopathy, metabolic acidosis and hypothermia reenforce in a destructive positive feedback loop. 21

Pro-inflammatory cytokines

In 2016, Salhanick et al. (57), followed up the previously discussed study of coagulation from

2011, and examined levels of pro-inflammatory cytokines in unwashed shed hemothorax blood. The goal was to test the assumption that blood collected from a hemothorax in the chaotic setting of the trauma room is comparable to blood donated under optimal conditions at a blood bank from an inflammatory point of view.

They noticed that the level of pro-inflammatory cytokines, such as Il-6, Il-8, TNFα, and anti- inflammatory cytokines such as Il-10, was altered, and generally 10-100 times higher compared to control samples of venous blood which could stimulate transfusion reactions and inhibit healing. The exact inter-relationship between cytokines is not clarified, but it has been consistently shown that lost local control of cytokine release, as may be the case in major trauma, is associated with harmful consequences and disrupt balance of the immune system.

This could possibly lead to systemic inflammatory response syndrome (SIRS), counter anti- inflammatory response syndrome (CARS), multi-organ dysfunction syndrome (MODS) and death (58). The authors of the study thus suggest randomized trials to determine safety and investigate the potentially adverse effects of re-transfusing blood containing high levels of pro-inflammatory cytokines (57). However, in clinical trials, no increased risk of immune reactions or excess mortality has been established (46).

Malignancy

Local malignancy is sometimes declared as a contraindication for autotransfusion in the literature (15). However, the risk of reinfusing potentially contaminated, shed pleural blood is unknown. We have found no cases of metastasis due to reinfusion of autologous blood in trauma patients. Further, only 0.01%-0.000001% of eventual tumor cells is estimated to have the capacity to form metastatic lesions (49).

Embolism

A micropore in-line filter, with pore size ~40 μm, is recommended when re-transfusing the blood to reduce the risk of microembolism without requiring to increase filtration pressure. In a simple autotransfusion system, the reinfusion bag may contain air and thus there is a potential risk of air embolism upon infusion. This risk can be minimized by avoiding external pressure on the reinfusion bag, use an air bubble detector or inserting an air escape valve in the reinfusion bag (59).

Blood salvage

In trauma, blood cell salvage can be performed through two distinct separate methods.

Immediate whole blood transfusion with blood retrieved from a hollow body cavity, or reinfusion of washed RBC from a Cellsaver®. The latter contains no clotting factors, no platelets, no fibrinogen etc. and thus only improves the oxygen-carrying capacity but has no effect on coagulation. It has been suggested that trauma patients with massive hemorrhage should be transfused 1:1:1 regarding proportions of blood, plasma, and platelets (23).

The situation with Cellsaver® is 1:0:0, thus result in dilution coagulopathy if no complementary blood products are transfused (60).

In this study we have chosen to focus on re-transfusion of blood from the pleural cavities

(hemothorax). The definition of hemothorax is a collection of blood in the pleural cavity with a hematocrit of >50% of peripheral blood values (61). The far most common cause of hemothorax is penetrating or blunt trauma to the chest wall, but it may also be iatrogenically caused or appear spontaneously secondary to intrathoracic malignancy, vascular malformation, pulmonary infarction etc. Major hemothorax should be suspected in case of trauma to the chest (anamnesis, “seat belt sign”, flail chest, subcutaneous emphysema etc.), decreased breathing sounds, decreased chest movement on the affected side, dyspnea, dull percussion sounds or signs of hypovolemia. Severe cases, with major hemorrhage, is often

caused by laceration of arteries inside the chest wall such as intercostal arteries and internal mammary arteries. Each pleural cavity can contain more than 50% of a patient’s total blood volume, and thus result in respiratory failure as well as hemodynamic instability without external signs of bleeding. One useful tool to diagnose hemothorax already in the trauma room is with ultrasound equipment, where homogenously echogenic effusion, “spine sign”

(visualization of spinal bodies above the diaphragm) and “plankton sign” findings (whirling internal echoes linked to cardiac impulses) have very high sensitivity and specificity. The initial management is insertion of a chest tube drainage, primarily to re-expand the lung, but also to avoid later complications such as empyemas and fibrothorax.

Thoracotomy is indicated if >1500 ml of blood is drained immediately, or >200ml the ensuing hours as seen in fig. 7. However, most cases (85%) of hemothorax will not require surgery, and bleeding will stop spontaneously once the blood is evacuated and the lung re-expanded.

(15, 61-63)

Hemothorax management

Hemothorax

Chest tube drainage

Stable Unstable Drain production: Drain production: <1500ml (/24h) >1500ml (/24h) <200ml /hour >200ml / hour

CT-scan Surgery

Figure 7 – Hemothorax management. Flow chart demonstrating initial caretaking of a patient with suspected hemothorax.

In a healthy individual, the pleural cavity contains about 10-20 ml of clear straw-colored fluid. This fluid constitutes a physiologic function as a lubricant, decreasing friction between the layers of the pleura during respiration. The fluid is normally rich in hyaluronic acid, has a low concentration of protein (~1g/dL), pH is normally slightly higher compared to blood

(7.60-7.64), and has a glucose, triglyceride, and cholesterol proportion like plasma.

Typically, this fluid contains a smaller amount of RBCs (~40/µL) and 3-4 times more WBCs

(~150/µL), predominantly macrophages (75%). (64, 65)

Material and Methods

We conducted a register study of all patients treated with chest drain on the basis of suspected traumatic hemothorax/hemopneumothorax at the emergency department or trauma care unit at

SU between 1st of January 2018 - 1st of October 2020.

We searched the journal database of SU for patients registered with the ICD code GAA10

(insertion of chest drain) in combination with either S27.1 (hemothorax) or S27.2

(hemopneumothorax).

The journals of these patients were then screened to exclude those with mainly pneumothorax,

“old” hemothorax, referred out-of-county patients with tube thoracostomy already inserted and patients receiving chest tube on non-trauma indication (e.g. after flail chest surgery).

During the secondary screening, the journals were searched to determine time from trauma to chest drain insertion, the amount of blood immediately drained and units of blood subsequently transfused. Patients were included if chest drain were inserted within 24 hours of trauma, more than 400 ml of blood were immediately drained and the patient were transfused at least 2 units of blood within the first 24 hours. If no drained amount was defined in the journal, the patient was excluded.

Results

Patients identified through journal database Excluding patients with; search

(ICD code: GAA10 + S27.1 or S27.2) Chiefly pneumothorax [n = 158] Identification “Old” hemothorax

(n = 50) Referred out-of-county patients with tube thoracostomy already inserted Journals for primary screening

[n = 158] Non-trauma patients creening

Primary [n = 72] s

(n = 71)

Patients with traumatic Excluding patients with;

hemothorax/hemopneumothorax and chest tube insertion within 24h < 400 ml of blood immediately [n = 86] drained after chest tube insertion /

screening drained amount no registered

Secondary Secondary

No blood transfusion within 24 hours (n = 71) [n = 62] Candidates that could have been treated

with direct, whole blood, autotransfusion of hemothorax blood at SU between 1st of Jan 2018 – 1st of Oct 2020. Remaining [n = 24]

In 2018, 2019 and 2020 (until initiation of the study, 1st of October 2020) 158 patients were

registered to have been treated with chest drains on basis of suspected traumatic hemothorax

or hemopneumothorax at the emergency department or trauma care unit. After primary

screening, 72 patients could be excluded, leaving 86 to the secondary screening.

The next step was to exclude all patients with subacute drain insertion, too small amount of

blood drained and patients to whom no blood transfusion was required, leaving only 24

patients left. Thus, over the past 33 months, 24 patients could have been candidates for direct

autotransfusion after traumatic injury with the proposed technique.

As seen in fig. 8, interpersonal violence (gunshot wounds and stab wounds) constitutes a large part of possible candidates (41%), followed by falls (34%) and traffic crashes (21%).

Fig. 9 and fig. 10, page 28, illustrates that the amount of drained HTB poorly correlate with required units of transfused RBCs due to the complex injury pattern in many trauma patients involving damage to, and bleeding from several organs – not only into the thoracic cavity.

However, autotransfusion of shed HTB could possibly reduce, and in some less severe cases completely replace, ABT. The urgency of transfusion depends on speed and volume of the blood loss. Many elderly patients with minor fall trauma, in combination with anticoagulant treatment, had slowly progressing hemothorax over days-weeks. When the patients finally sought medical care, often due to pain and/or dyspnea, large amounts of pleural effusion

(even >1000 ml) could be drained without any blood transfusion required.

Traumatic hemothorax - cause

Fall trauma 4%

21% Stab wound 34%

Gunshot wound 8% Traffic crashes

Other 33%

Figure 8 – Traumatic hemothorax – cause. Pie chart showing cause of injury in patients with hemothorax at Sahlgrenska University hospital (>400ml immediately drained upon chest tube insertion, that were transfused blood) between 1st of Jan 2018 – 1st of Oct 2020.

Amount of hemothorax blood immediatly drained 1800 1600 1400 1200 1000 800 600 400 200 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Figure 9 – Amount of hemothorax blood immediately drained. Y-axis showing amount of blood (ml) immediately drained upon chest tube insertion in hemothorax patients (with subsequent blood transfusion) at Sahlgrenska University hospital between 1st of Jan 2018 – 1st of Oct 2020. Same number on the X-axis correspond to the same patient in fig. 10 and 11.

Units of RBCs transfused 30

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Figure 10 – Units of RBCs transfused. Y-axis showing units of blood transfused to hemothorax patients (where >400 ml of blood were immediately drained upon chest tube insertion) at Sahlgrenska University hospital between 1st of Jan 2018 – 1st of Oct 2020. Same number on the X-axis correspond to the same patient in fig. 10 and 11.

Prospective descriptive pilot study

Apart from the register study, we conducted a prospective descriptive pilot study of autotransfusion in trauma at the emergency department and trauma care unit, in Sahlgrenska

University hospital between 1st of Oct to 31st of Dec in 2020.

We sought to include all adult patients (>18 y) that arrived at the emergency department or trauma care unit with acute, traumatic hemothorax, where >100 ml of blood were immediately drained upon chest tube insertion.

A chest drain was inserted with sterile technique and connected to a drainage bag prepared with 11 ml of citrate phosphorous dextrose (CPD). After 100ml of blood was drained into the bag, the tube was clamped and switched over to the ordinary collecting vessel connected to an active suction device. Time of completed sampling was noted, as well as approximate time of trauma.

The blood was then filtered through a simple blood transfusion aggregate with a hydrophobic filter (Green Line B93) and subsequently separated into different test tubes depending on requested analysis. The test tubes were marked and sent to the clinical laboratory. Direct whole blood autotransfusion with hemothorax blood illustrated

Figure 11 – Direct whole blood autotransfusion with hemothorax blood illustrated. Blood is drained via a chest tube into a blood bag, containing anticoagulant solution. Once sufficient amount has been drained, the blood bag is suspended and the blood is then returned to the patient’s systemic circulation trough a filter (while the pleural drainage continues into the next blood bag).

Requested parameters were Hb, HCT, WBC, PLT, CRP, fibrinogen, electrolytes

(Na/K/Cl/Ca), pH, aPTT, INR, Il-6 and TNFα.

Test results were then compared both to reference values and the patient’s own venous blood samples extracted upon admission to evaluate how the transit through pleura, drainage system and filter affected the properties of the blood. TNFα, Il-6, fibrinogen, HCT, Cl and Ca are not standard samples for trauma patients and were thus only be compared to reference.

Ethics

Patients included in this study were not subjected to any additional risk of complications or affliction. Draining of a hemothorax is a standard procedure when suspecting blood in the pleural cavity. Samples were taken from drained blood that would otherwise have been discarded and, thus, inclusion in the study had no impact on treatment in any way. All patients had given their informed consent before they were included. The ethical aspect of the study is of integrity character only. To ensure privacy, all personal data was pseudo-anonymized with an inclusion number and the key stored in a secure computer accessible only by the authors.

The blood was destroyed after laboratory analysis and thus no samples were saved in any

Biobank. The study was granted ethical approval from the Swedish Ethical Review Authority.

Study results

Drained blood from 6 patients with traumatic hemothorax were analyzed. However, only one patient was included in the study. Two patients were excluded due to the amount drained from the chest tube being too small. One patient was excluded due to uncertainty about time of trauma/onset of bleeding (multiple fall traumas during the past week).

When drained pleural fluid was analyzed from this patient the laboratory results showed a hematocrit less than 25%, likely due to hemodilution as consequence of serous pleural effusion and long standing hemothorax (66). Similar results were obtained from another patient with iatrogenic hemothorax caused during surgery a few days earlier. One patient had to be excluded because of a misunderstanding, were laboratory staff did not approve the laboratory result (since several parameters deviated) and dismissed the samples as “sampling error” (see fig. 15, p. 38 for table of “Sampled, but excluded patients”). Ultimately, only one patient with acute, traumatic hemothorax of sufficient magnitude was included. The results obtained were as follows. (See appendix 1, p. 44.)

The most prominent difference between shed pleural blood, and venous blood was the distinct decreased hemostatic capacity. Analyzed HTB was severely thrombocytopenic, had immeasurable low fibrinogen, and very high aPTT and INR.

Oxygen carrying capacity was good with a Hb value like venous blood.

Both Il-6 and TNFα were elevated in shed pleural blood.

Interpretation of results

To test the impact of citrate and filtration on the laboratory results we analyzed double samples, both drawn directly from the drainage bag and filtered samples from blood bag

(mixed with citrate). The conclusion was that the mixed and filtered blood had lower levels of

Hb, TPK, WBC, CRP, Ca, K and Cl (likely due to dilution/filtration). Sodium was increased since it is a component of the CPD mixture and pH was decreased, probably due to the acidity of CPD. However, in vivo, it is likely to cause only minor, transient changes in the acid base balance upon transfusion due to the rapid metabolization of CPD.

For comparison, a study by Gaundry et al. in 1980, showed that the mean pH of donated blood, mixed with CPD, stored for 20 days was 6.71 (ref. 7.35-7.45) (67).

The shed pleural blood, mixed with CPD, was compared to venous blood without citrate added. Since the drained blood seems to lack hemostatic ability, the differences would be more easily visualized if CPD would had been removed from the study design. However, the goal was to determine the content and properties of the blood “returned” to the patient. An anticoagulant would be used in the autotransfusion system to avoid clotting in case of massive hemothorax, thus, to properly simulate these conditions laboratory testing was performed after

CPD mixing and filtration.

Discussion

In countries with a high trauma burden and poor blood product supply, autotransfusion is already in use and shed pleural/peritoneal blood is being re-transfused in the absence of alternative solutions (4, 6). Despite several theoretical advantages of autotransfusion, this technique has not been adopted for trauma patients in Sweden, mostly because of sufficient supply of blood products from the blood banks.

Over a 33 month period only 24 patients met the inclusion criteria (acute traumatic hemothorax treated with chest tube, draining a sufficient amount of blood to make it worth the effort and requiring subsequent blood transfusion) were identified at SU/S. Since less than one patient per month fulfilled the requirements necessary to utilize this technique, implementation will not have a massive impact on the health care of these patients during normal conditions. However, to have autotransfusion equipment available at SU could be a potentially life-saving precaution in the event of a future mass-casualty situation with blood product shortage.

Additional areas of application

Outside of Swedish hospitals, the situation is different concerning blood supply. NGOs with limited logistic possibilities have few options to restore circulation, and autotransfusion of

HTB may be a lifesaving intervention, clearly favorable compared to crystalloids/colloids.

Another possible area of use could be prehospital care. In general, ambulance paramedics in

Sweden do not have the possibility of transfusion blood in the field, with a few regional exceptions (68). In the region of Västra Götaland, a fast response car manned with an intensive care physician and nurse, equipped with 2 units of RBCs and 2 units of FFP, may be

dispatched to emergency sites such as traffic crashes, stabbings, shootings, workplace accidents etc. with anticipated life-threatening bleeding (69, 70).

The ambulance helicopter, on the other hand, is equipped with 2 units of whole blood (and 2 units of FFP), providing fast oxygen carrying and hemostatic support in bleeding patients at the expense of shorter possible storage time (exchanged every 12th h) (71). Every year the regional ambulance helicopter provide blood transfusion to ~30 patients on site and during transport (72). Both ambulatory units have staff educated in thoracostomy and a rather limited supply of donated blood. Furthermore, both soldiers from elite military units, such as the

“special operations group”, and police officers from the Swedish national task force are educated in prehospital chest drain insertion. The described autotransfusion method could be an option in prehospital care as a last resort to utilize all available blood while transporting the patient to the emergency department. CPD has a superior sustainability compared to blood products. Prepared autotransfusion kits adds little extra weight, needs no refrigerated storing, and can be kept for 2 years before the solution expires.

Supply and demand

During the study period an example of the fragility of the blood supply system, and the applicability of autotransfusion in trauma was visualized when a patient with a massive hemothorax was transfused a large amount of blood to treat hemorrhagic shock during the initial resuscitation. Blood bank stores were already low due to decreased number of blood donors during the COVID-19 pandemic (73).

Consequently, this depleted the majority of the O- and A- blood supply in the region and

Sahlgrenska University hospital had to issue a request on social media and exhort donors with the requested blood types to immediately donate blood. A- and 0- blood are rare blood groups, and virtually impossible to buy. Instead the staff was instructed to transfuse RhD+ blood to patients in acute need of transfusion with the concerned blood types, which consequently may

cause undesired sensitization against Rhesus factor. All elective surgery on A- and 0- patients had to be reconsidered until the stores were replenished (74, 75).

Coagulation of drained HBT

In line with previous studies we found that shed pleural blood has a low tendency to clot.

To avoid coagulopathy, it has been suggested that reinfusion of major amounts of blood should be complemented with FFP, PCs, fibrinogen and Ca (24).

Because of the poor hemostatic capacity, it has been proposed to use half the dose of anticoagulant, or even immediately reinfuse through a filter without any anticoagulant added.

The latter is said to have been performed during the war in Liberia in 2003 without any noticeable complications (76).

Nevertheless, massive bleeding would likely allow coagulable blood to enter, and clot, the drainage system. Thus, anticoagulation is recommended as a measure of safety, especially in a trauma setting with rapid blood loss. It is theoretically possible that patients with exsanguinating bleeding demonstrate a different coagulation profile as compared to the less urgent cases we have analyzed. The proposed underlying mechanism of the altered coagulation profile is that moderate bleeding allow time for defibrination and consumption of platelets due to “incomplete clotting” as a consequence of biochemical interaction with serosal surfaces in combination with mechanical movement of the diaphragm, lungs and heart

(61). Based on this assumption, we can speculate that major bleeding, which require immediate action and thus will be rapidly drained, may demonstrate better hemostatic properties since the pleural transit time will be shorter. Furthermore, continuous bleeding, once the chest tube has been inserted, would likely to be more like venous blood. However, since we only have data from venous blood (nr. 1 in fig. 12), and HTB drained and analyzed several hours after the trauma (nr. 2 in fig. 12), the shape of the curve in between these two points in time has not yet been clarified.

1 ?

? Sample analyzation

Coagulation capacity Coagulation ? 2 Duration in pleural cavity

Figure 12 – Possible hemostatic deterioration. 1 = Venous samples analyzed upon admission – with good hemostatic capacity 2 = Analyzed sample of hemothorax blood, drained hours later – with poor hemostatic capacity ? = Conceivable alternative graphs of coagulation deterioration of hemothorax blood over time

Anticoagulant considerations

It has been suggested in the literature that both heparin and CPD can be used as anticoagulation added to the collected blood. In an article about autotransfusion, Shawn P.

Catmull, propose a formula of either 1 ml of CPD to 7 mL of blood, or 390-450 U of heparin

(diluted in 13-15 ml of NaCl) to 100 ml of blood. (24). However, in practical terms, the anticoagulant dose of heparin used in South Africa is 1000 U in 200 ml of saline, thus the suggested figure is very high (77). The choice to go with CPD in this study was made after consultation with transfusion medicine professionals and laboratory specialists, primarily, since it interferes with test results to a lesser extent.

The formula used was 1:9, 11.1 ml of CPD mixed with 100 mL of blood. Citrates prevent conversion from fibrinogen to fibrin by binding Ca ions, necessary at several points in the coagulation cascade. CPD is quickly metabolized by the liver once the anticoagulated blood is infused. However, in case of massive transfusion with citrate containing blood products, it may accumulate. Ionized calcium thus must be monitored, and replacement therapy initiated in case of hypocalcemia to prevent coagulopathy and potentially severe consequences such as seizures or cardiac arrythmias (15, 78, 79).

One reason not to use heparin is to avoid the risk of heparin-induced thrombocytopenia, an immune mediated adverse reaction causing activation of platelets, often resulting in thrombosis (stroke, deep vein thrombosis, lung embolism, myocardial infarction) and subsequent thrombocytopenia (80).

Antibiotic prophylaxis

The question of prophylactic antibiotic treatment, and length of therapy in patients treated with tube thoracostomy has been controversial. At SU, no prophylactic antibiotics are given following tube thoracostomy. “The Eastern Association for the Surgery of Trauma” (EAST) has developed guidelines, based on several double blinded studies and meta analyses, recommending 1st generation of cephalosporins during 24 h after chest tube insertion (61).

1st gen. cephalosporins are commonly used to treat skin/soft tissue infections and are effective primarily against gram-positive cocci, such as staphylococci and streptococci (81).

No recommendation regarding prophylactic antibiotics for tube insertion and subsequent autotransfusion could be found in the literature. Logically, broad spectrum antibiotics should be used to cover not only skin flora, but also potential contamination from gram- negative/anaerobe bacteria until contemporary diaphragmic/intestinal damage can be ruled out.

Cytokines and inflammation

It was not feasible to evaluate all biomarkers involved in inflammation to visualize the immunological aspect of shed pleural blood, thus we decided to analyze two essential pro- inflammatory cytokines (Il-6, TNFα) and C-reactive protein. In vivo studies have shown that infusion of recombinant TNFα have immunomodulatory effects and may result in systemic inflammatory response syndrome (SIRS) (82).

Further, a large double blinded RCT, where a treatment group receiving Afelimomab (anti-

TNFα monoclonal antibody fragment), showed that reduced serum TNFα and Il-6 resulted in 36

more rapid improvement in organ failure score compared to placebo (58). Concerning Il-6, it can, simplified, be described as a “stress cytokine” with many important inflammatory response actions such as acute phase protein generation, leukocyte activation and cellular signaling modulation, but also inducing myocardial depression. It is released in response to tissue injury and greater tissue trauma results in greater Il-6 release. An association between higher levels of Il-6 in blood and organ dysfunction and mortality in polytraumatized patients has been observed (83).

Limitations of the prospective study

Inclusion

Sweden is a country with relatively low trauma burden compared to many other countries, especially low and middle-income countries (84). According to the internal statistics of the emergency department at Sahlgrenska university hospital for 2020, 693 “level 1”, and 510

“level 2” trauma alerts had been issued when this study was initiated (1 Jan. – 1 Oct.), an average of ~2 “level 1” trauma alerts per day.

Based on statistics from previous years, normally ~2-3 patients with the requested injury pattern were admitted to SU every month, thus our goal was to include 8 patients during the study period. The intention was to make a prospective descriptive pilot study of shed pleural blood from patients with various injury severity and duration in pleura before drainage. Since the required injury pattern is comparatively rare and the time frame for collecting HTB for analysis was somewhat narrow, the basis for this study did not reach the set target regarding included patients. Some patients were hemodynamically unstable and in a poor condition upon arrival and, of course, collecting study material from an inserted chest tube was not prioritized when a life is at stake. A few patients with suspected hemothorax deceased before a thoracostomy tube could be inserted. Further, only the emergency department and trauma care unit were participating in the study, and thus patients with major trauma, and in need of

immediate surgical intervention or intensive care, were not included if a chest tube was not inserted in the trauma room. Ideal candidates for inclusion (stable patient with acute hemothorax >400 ml) were rare due to the, often, complex injuries of requested patients.

Because of these circumstances, samples were collected from only one trauma patient with acute traumatic hemothorax. It is thus impossible to exclude the impact of coincidental deviations with the sample size of just one patient.

Since we could not influence admission of trauma patients, blood was collected perioperatively from patients with expected bleeding into the thoracic cavity during elective surgical interventions. Blood samples drawn from the collection bag of the suction device was initially analyzed, but the laboratory results displayed hemolysis and dilution. We proceeded to analyze blood drawn straight from the pleural cavity with a syringe, but the collected amount of blood provided from a patient undergoing a thoracoabdominal esophageal resection was too small to analyze. Thoracic intensive care unit wished to keep unnecessary visits to a minimum during the covid pandemic and rejected participation.

In a last attempt we attended an open chest - abdominal aortic aneurysm repair surgery, but once again the sample demonstrated considerable hemolysis.

In the end, we were forced to settle for the limited data provided.

Table 2 - Sampled, but excluded patients

# Diagnosis Reason for exclusion

1 Trauma, hemothorax <100 ml drained 2 Trauma, hemopneumothorax <100 ml drained 3 Trauma, hemothorax <25% hematocrit (hydrothorax)

4 Trauma, hemothorax <25% hematocrit (hydrothorax) 5 Trauma, hemothorax Laboratory error

6 Abdominal surgery Hemolysis 7 Abdominal surgery Sample amount too small to analyze 8 Vascular surgery Hemolysis

Table demonstrating the reason for exclusion in 8 of the 9 patients from whom blood were collected.

We wanted to include as many admitted patients as possible during the very limited study period. Thus, to get more material we narrowed down the blood required to 100 ml, even though there may be a discrepancy in the blood properties between minor and major pleural hemorrhage. The drained volume of blood from the included patient was 300 ml.

Methodology

In the chaotic setting of the trauma room with a, sometimes, unstable patient, there is no time for delays. To simplify for the staff, we filled one blood bag with 111 ml of water and used as a template to mark the water level on all prepared “autotransfusion kits”. This solution is suboptimal. To visually appraise when the line is reached in a 400 ml bags is not fully accurate and is deeply affected by human factor, thus the drained amount may vary from patient to patient and therefore also CPD to blood proportions. Optimally, a scale would be used to get more precise ratios, however this was not practically feasible.

Cl, Ca, HCT, TNFα, Il-6 and fibrinogen were only compared to reference values since these are not routine samples analyzed in trauma patients. It must thus be taken into consideration that these parameters may be influenced by eventual disturbance in electrolyte balance/hemostasis/inflammation already present upon admission (e.g., the included patient had a two-week history of cough and fever when the trauma occurred). HCT could by reduced due to dilution from crystalloid/colloid administration. Nevertheless, our aim was to evaluate the blood that would have been re-transfused regardless of preexisting deviations and iatrogenic influence.

In an acute trauma situation, the blood would not have been analyzed before transfusion and physicians must buy “a pig in a poke” as transfusion suitability may only be assessed visually, e.g., with respect to color, visual contamination, formed blood clots etc.

Conclusion

The aim of this study was to evaluate the usefulness of direct, whole blood, autotransfusion with hemothorax blood in trauma at SU, to summarize previous research in the field of direct autotransfusion in trauma and to assess HTB properties.

In summary, autotransfusion with HTB in a trauma setting is already a tested, working and well used methodology at some trauma centers throughout the world. However, it is not a presently adopted alternative in Swedish hospitals. Previous research indicate that the method appears to be safe, economic and with lower incidence of post-transfusion complications than allogenic blood transfusion when correctly executed on proper indications.

The register study of possible candidates that could have been treated with the proposed technique identified 24 patients over a 33 month period, making the applicability rather low during normal conditions.

Based on current state of knowledge, we cannot advocate autologous transfusion with shed pleural blood in acute trauma situations to be implemented in everyday care at Swedish hospitals. We can only speculate that autotransfusion with HTB could be a possible option in an emergency with shortage of donated blood. Autotransfusion comes with several benefits and during the review of previous research, we found no reason not to further investigate the possibilities of introducing autologous transfusion of HTB in trauma at Swedish centers. The three primary question marks concern inflammation, contamination, and coagulation.

Transfused blood with high levels of proinflammatory cytokines could possibly disturb the balance in the inflammatory system during massive transfusion, although no excess morbidity has been noted in clinical studies. Concerning contamination, prophylactic, broad spectrum antibiotic treatment diminished additional risk in transfusion of contaminated blood in an animal study (51). However, we found no human studies on direct autotransfusion. It is thus

hard to motivate autotransfusion of shed pleural blood with possible bacterial contamination, e.g., in case of suspected diaphragmic/intestinal injury, when donated blood is available.

The most extensive study we found, a multicenter retrospective study on 272 patients, concluded that whole blood autotransfusion with HTB was safe without excessive risk of complications, as compared to ABT. The authors also found that the HTB group was transfused PCs to a lesser extent – indicating that this blood, in fact, had some hemostatic capacity, in contradiction to results of analyzed longstanding hemothorax. (46)

Finally, no previous research has investigated the timing of autotransfusion and compared hemostatic capacity in “early” drained pleural blood with “long standing” hemothorax.

We thus propose future research to clarify this relationship and facilitate to better appraise eventual dosage of concomitant FFP / PCs replacement and the need of anticoagulant in the autotransfusion system.

Acknowledgements

I would like to thank everybody listed below for the kind guidance, valuable input, or for the effort they put into this project in other ways. Prof. Ken Boffard, WITS RN Patric Antonsson, trauma-coordinator, SU Assoc. Prof. Camilla Hesse, biomedicine, GU/SU Assoc. Prof. Agneta Wikman, transfusion medicine, KS Assoc. Prof. Eva-Corina Caragounis, SU Medical administrator Nora Arifi-Nilsson, SU CNA Mathias Birgersson, SU Emergency department and trauma care unit staff at Sahlgrenska University Hospital. Further, I wish to thank Ragnar Ang for the commitment to supervise this project, despite lack of time, as well as Christoffer Örtenwall and David Flanking for the eminent company during this semester. I would also like to thank Cecilia Engström for the very valuable input and support during the writing of this report.

Finally, I would like to thank my better half, Viktoria Pettersson, and my beloved mother and father, Åsa & Per Örtenwall for their never-ending support – not in particular through this project, but throughout life.

Thank you.

Populärvetenskaplig sammanfattning

Återföra blod från lungsäcken till blodomloppet vid traumaorsakad blödning?

av Henrik Örtenwall Trauma är den vanligaste dödsorsaken i Sverige i åldersgruppen 15–40 år. Stor blödning medför ett livshotande tillstånd. Den livräddande åtgärden är att brådskande stoppa pågående blödning och återställa blodvolymen. På svenska sjukhus används 0 negativt blod (”akutblod” – kompatibelt med samtliga blodgrupper) i akutskedet för att upprätthålla cirkulation vid kraftig blödning till dess att blodgruppsmatchat blod finns att tillgå. Blod går ej att framställa syntetiskt och blodbankslager är avhängt av frivilliga donationer, således finns risk för blodbrist vid större trauman med flertalet skadade. Ett sätt att försöka minska behovet av donerat blod är att återföra patientens eget blod tillbaka till blodomloppet, en metod som kallas autotransfusion. Autotransfusion vid trauma används redan på traumacenter med högt patientflöde och sämre tillgång av donerat blod från blodbanker, till exempel i Sydafrika, men är ännu en obeprövad teknik på svenska sjukhus. Fördelarna som framhävs, bortsett från det minskade behovet av donerat blod, är associerade med att endast kroppseget material återförs till patienten. Således riskerar patienten inte att tillföras några nya blodburna sjukdomar, risken för immunreaktioner minimeras och man kan möjligen komma runt problemet med patientgrupper som vägrar bloddonation, till exempel av religiösa skäl. Studier har dessutom visat att både komplikationsrisken samt kostnaden per blodenhet är lägre jämfört med donerat blod, då ingen förvaring eller testning är nödvändig. Lungsäcken är ett område mellan lunga och bröstkorgsvägg. Vid kraftigt, alternativt penetrerande, våld mot bröstkorgen kan blödning in i detta tomrum uppstå, en så kallad ”hemothorax”. Vardera lungsäcken kan rymma över hälften av en patients totala blodvolym. Den akuta behandlingen innefattar att tömma ut blodet via en slang, ett thoraxdrän, och på så sätt åter ge lungorna rum att expandera för att förbättra andningen. Det är dock inte bara andningen som påverkas utan den stora mängden förlorat blod påverkar även cirkulationen. En föreslagen, men i Sverige ännu obeprövad, metod är därför att tömma detta blod ner i en påse förberedd med koagulationshämmande medel och därefter, via ett filter, ge det direkt åter till patientens blodomlopp. Syftet med vår studie var att genom en registerstudie undersöka hur många patienter, som inkommit till Sahlgrenska sjukhuset mellan 1 jan 2018 – 1 okt 2020, vilka varit kandidater för att behandlas med föreslagna metod. En sökning genomfördes därför i journalsystems databas för att sortera fram alla patienter som vårdats på sjukhuset med hemothorax under perioden. Därefter granskades samtliga journaler och endast de patienter med akut traumaorsakad hemothorax där drän satts inom ett dygn från traumat, mer än 400 ml blod omedelbart tömts och patienten sedermera krävt blodtransfusion inkluderades. Slutsatsen blev att totalt endast 24 patienter, under de 33 månader vi studerat, hade en skadebild som lämpat sig för autotransfusion med blod från lungsäcken. Metoden borde därför främst implementeras som en metod att ta tillvara allt tillgängligt blod och motverka blodbrist vid eventuell framtida masskadesituation.

Appendix

Appendix 1. Included patient variables

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