The new TCCC recommend transfusion of fresh whole blood (FWB). This mean that Saline solution is not recommendable partly due to the increased risk of death by using it. FWB transfusion also comes with a couple of risks. First, the risk related to a transfusion reaction and second, the risk for transfusion transmitted diseases (most scearing Hepatitis and HIV). Having mentioned these risks, these risks are considered less severe than the risk of death.
The best way to administer FWB is to use Type O blood. In that way we do not have the risk of matching donor and recipient wrongly due to blood type. This means that a military unit need to find universal Type O donors before going into battle. These Type O soldiers need to be checked for diseases and identified by fellow soldiers and tactical paramedics. In this way it is possible to find them and use them as direct transfusion donors within 15 minutes after the need of blood. When the need is there the tactical paramedic just call for blood and the donor come directly to the patient. The transfusion can start immediately.
The question is what happens when we don’t have the possibility for FWB transfusion. We know that a loss of blood reduces our capacity to transport oxygen to the cells; mainly due to the loss of red blood cells. The blood has a relative safety margin of 9 xs; meaning that the blood has a relative estimated capacity to survive with 9 times less oxygen carrying liquid. It is possible to use saline solution (crystalloid) to restore blood volume, but saline solution will not do anything with the oxygen properties in the lost blood. It might be used saline solution in mild blood loss to secure the volume, but not to secure the oxygen. Another aspect with saline solution is the ability to create coagulopathy (Bleedings). Normally it is field recommended to use one saline unit per FHB unit (The perfect ration is still unknown). This is the main reasons why we want FHB transfusion; to prevent coagulopathy. We know that to mush saline solution will create an increase the risk of death.
Saline solution is normally today used to clean wounds, IV therapy to rehydrate patients and to provide salts. It is also common to accept the dangers of saline solution due to its low osmolality. Normally crystalloid solutions are used to increase intravascular volume. Most commonly used are isotonic like 0.9% saline and Ringer’s lactate (RL); these liquids are equal effective. Here we need to notice that only 10% of isotonic fluids remain in the intravascular space. We also have another type of fluid called hypotonic fluids like 0.45% saline. This type of liquids basically does not stay in the intracellular space. If a person have a hypovolemic shock it is preferred to use RL of two reasons: less chance for acidosis and does not cause hyperchloremia. If the person has an acute brain injury it is preferred to use 0.9% saline. Hypertonic saline will not change any outcome of the resuscitation. Then we have the Colloid solutions that help to increase the blood volume when the patient has a massive haemorrhage. Research has shown that the effect of these colloid solutions is not better that crystalloid solutions (saline), and if a traumatic brain injury colloid solutions might create more damages in the patient. Coagulopathy might occur of given more than 1,5 L of colloid solution. If a blood transfusion is needed it is normal to give 1-2 unites of Type O Rhesus negative; O Rh – can be given to all. The best is to heat up the blood to 37°C before the transfusion. It exist blood substitutes that might carry oxygen; Hb- based fluids (Can be stored over a year) and Perfluorocarbons. Still this product has no proven effect on survival, can give hypotension and is not for commercially use; but this is a promising product. If the patient suffers from a non-haemorrhagic hypovolemic condition it is normal to give an isotonic crystalloid solution; colloid solutions are normally not used. Research does not find a major difference on the different IV liquids and the survival rate; meaning that selection of solution is not that important as we think.
To sum up and conclude in the IV problem; normally we do not have FWB and we need to give the patient something. We need to just give a little liquid to avoid the three aspects hypothermia (cold liquid in the blood vessel, blood loss and temperature loss; blood coagulates at 37oC), acidosis (bad tissue perfusion, over use of saline solution and lowering of pH) and coagulopathy (increased bleeding). Remember that more than 2 L of Saline solution IV gives coagulopathy in 40% of the cases, 50% with 3L and 70% with 4 L. Do not forget that 33% of ALL trauma patients get coagulopathy; IV or not. The solution to this problem created of a lack of FWB seems to be Permissive hypotension. This is to use a defence mechanism in the body to manage better a hypovolemic state. Damage Controlled Resuscitation (DCR) normally builds around delaying the initiation of fluid resuscitation. The focus lies on the blood pressure, and the blood pressure (BP) decides the point of IV initiation. The BP should be about 90/50 mmHg; this BP decreases the chance for coagulopathy, let the blood coagulate in peace and reduce the inflammatory cascade. In short, the survival rate increases with a BP on 90/50. Note that a permissive hypotension (BP: 90/50) for more than 2 hours might danger vital organs. At the same time note that less IV fluid increases the postoperative survival rate. When you have a hypovolemic patient check the BP and do not give IV if it is above 90/50. The most important focus is to stop further bleeding; use tourniquet, Celox gauze and pressure bandages. Monitor frequently the blood pressure, and if the BP goes down under 90/50 give 150 ml IV Saline solution. Research has not shown any great difference between different IV liquids in clinical use, but theoretical discussions show exaggerated differences. If no time to monitor the patient closely; give a 500 ml bag and revise after every bag. BP 90/50 is the standard measurement to remember, but a more exact measurement is a Mean Arterial Pressure (MAP) on 50 mmHg. A MAP on 50 mmHg is considered as the minimum blood flow to the vital organs. DCR normally operates with 80 mmHg, but can go down to 50 mmHg. The mathematical formula for MAP is as follow: multiply the diastolic pressure with 2 and add the systolic pressure. Then you divide the sum with 3. The number you get is the MAP. If you are stressed perhaps it is better with 90/50, but MAP is a better measurement. A BP of 120/ 80 gives a MAP of 93, BP 90/50 gives MAP of 77, and BP 80/50 gives MAP of 70. Another way to administrate the IV if you do not have a way to measure the BP is with the radial pulse of the patient. When the redial pulse becomes non-palpable you give 150 ml saline solution (0.9% NaCl); also give 150 ml saline solution if the patient get an altered consciousness or a dramatic change in blood pressure. Some other important clues is the maximum amount of saline solution (0,9% NaCl) of 20 mL/ kg. Something that is for a 100 kg person 2 L and for a 60 kg person 1,2 L. Remember to stop IV when the radial pulse returns and when the bleeding stops. It is normal to give a moderate IV during the bleeding if you do not have a way to monitor the patient well.
One unit of crystalloid with a 16 G needle takes an estimated 10- 15 minutes. If in desperate need some paramedics use pressure on the solution bag to increase the speed; a bag then normally takes 5 minutes. Just to have mentioned it the normal speed is 500 mL/ h. Patients in shock tolerates very well maximum rate of infusion. Remember MAP around 80 and BP 90/50 as the DCR golden rule when reading this.
Finally, we need to remember that we got three important preventable causes of death in war. Massive haemorrhage, tension pneumothorax and airway obstruction; bleeding, air in the chest, and problems of breathing. In all TCCC courses it is a strong focus on exactly these elements and to drill these abilities under stressful conditions. In war adrenaline fills the air and the brain pounds. The tactical paramedic need to stay calm and focused. That is why these techniques need to be exercised and repeated a million times under different conditions. Remember that 40% of the times a paramedic enters a scene he will not do what he is supposed to do. Situations often block the mind and for the patient – this is deadly. Training in real life like situations is very important.