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Shock & Post Injury Hypothermia

This is the beginning of a series of articles about medical training. I would like to start with a look at Med Kits. Everywhere you look someone is selling them.

Med Kits come in many forms and have many names: Blow-Out Kit, Individual First Aid Kit (IFAK), Individual Patrol Officer Kit (IPOK), Combat Life Saver Kit (CLS) and the list goes on. In reviewing what’s on the market (Kit Wise) for purchase, I noticed some things that are lacking and some things that are not needed unless the provider has advanced training.

So what do I think is missing?

First and foremost the Emergency Blanket - the ones that are Silver in color - you need at least one. They are small, light-weight, have more than one use (up to 50 according to this web site:, and cost less than $2 each.

No matter what type of kit you purchase they all have one thing in common: they have something in them to stop bleeding. What is bleeding? Bleeding is the name commonly used to describe blood loss. It can refer to blood loss inside the body (internal bleeding) or blood loss outside of the body (external bleeding).

Blood loss can occur in almost any area of the body. Typically, internal bleeding occurs when blood leaks out through damage to a blood vessel or organ. External bleeding occurs either when blood exits through a break in the skin, or when blood exits through a natural opening in the body such as the mouth, vagina, or rectum. Losing about 1/5 or more of the normal amount of blood in your body causes shock. (The average human adult body has 5 to 6 liters of blood)

Where blood loss is concerned, we’d be remiss if we failed to talk about Shock. Medically, shock is defined as a condition where the tissues in the body don't receive enough oxygen and nutrients to allow the cells to function. This ultimately leads to cellular death, progressing to organ failure, and finally, if untreated, whole body failure and death.  Shock is a life-threatening medical condition as a result of insufficient blood flow throughout the body. Shock often accompanies severe injury or illness. It requires immediate treatment as symptoms can worsen rapidly.

There are many types of shock but we’re going to focus on Hypovolemic shock which is caused by severe blood and fluid loss, such as from traumatic bodily injury, which makes the heart unable to pump enough blood to the body, or severe anemia where there is not enough blood to carry oxygen through the body. To treat this type of Shock we need to:

First things first: we must always stop the bleeding first. I have a very good friend, whom I have worked with for years. He was a special operations medic and now teaches for the State Department (OPMED). He would always say, “Every red blood cell that leaves the body is one less the body has to breathe.” I am glad to see, in the civilian world, that the use of tourniquets and haemostatic agents are no longer frowned upon. Whether it is capillary, venous or arterial bleeding we must stop it first.

Another Medic friend of mine loves to say, “All bleeding stops eventually!” Remember we only have 5 to 6 liters of total blood volume in our body.

When I first went to Medic school a good instructor told me, “Air goes in and out and blood goes round and round if you remember that you are good to go!” At first I thought he was crazy but now I understand.

We also need to understand what happens to the body in Shock. The body acts to defend itself from hypovolemia by way of a series of reflex mechanisms involving the cardiovascular and neurohormonal systems. Shock is a compensatory response. The initial loss of volume leads to a reduction in venous return and consequent reduction in end diastolic volume. Cardiac output is determined by heart rate times stroke volume. Stroke volume relates to end diastolic volume on the Starling curve. (Google Starling curve for further on that)

When the body shunts blood from the extremities, by the process known as vasoconstriction, it moves blood to the core of the body. It does this so that blood is preferably shunted to essential organs such as the brain, the heart and the kidneys.

In a patient with approximately 20% of lost blood volume the clinical signs of shock are often subtle: blood pressure may be normal; there is tachycardia, cold and clammy peripheries, decreased capillary refill and a widened core to peripheral temperature gradient. This state is known as “compensated shock.”

When 20 – 40 % of circulating volume has been lost the blood pressure begins to fall, there is profound peripheral vasoconstriction and tachycardia. When greater than 40% of circulating volume has been lost, blood pressure may become unrecordable and there are signs of end organ failure: oliguria and confusion. The urinary output is probably the most reliable way of estimating circulating volume.

Today’s civilian EMS providers follow the pneumonic when checking a patient:

ABC = Airway, Breathing, Circulation

CAB = Circulation, Airway, Breathing

The Tactical or Military pneumonic:

M= Massive Bleeding

A= Airway

R= Respiration (Rate & Quality)

C= Circulation (Pulse)

H= Head Injury & HYPOTHERMIA

Don’t forget to give a MIST report to the hospital or treating MD:

M – Mechanism of injury

 I – Injury(s)

- Signs and Symptoms (+LOC & Peripheral Pulse)

T – Treatments.

So let’s talk about Hypothermia and Patient temperature. Although not indicative

of either the presence or absence of shock,  they may help define the etiology and can have significant prognostic value. The presence of hypothermia (core temperature below < 96.8° F or 36.0° C) is of significant importance in the definition and treatment of shock as it suggests severe physiologic derangement and has a significant impact on patient survival.

Hypothermia places the patient at risk for cardiac dysrhythmias, acute renal failure, and refractory coagulopathy. When hypothermia is not rapidly corrected, mortality is extremely high. What do I mean by extremely high? Secondary hypothermia in trauma patient with a body core temperature below 90 degrees F results in patients with a 100% mortality rate.  

So you can do everything else right and if the body core temperature drops blow 90 degrees F they are still dead.  Well how can we fix that? Remember that Emergency Blanket - the ones that are Silver in color? This ultra-compact product of space-age technology folds to the size of a small sandwich for easy packing, yet opens to a 52 x 82½" blanket that retains up to 80% of your radiated body heat. It's also lightweight (less than 2 oz).

So why do we have a100% mortality rate when the body core temp drops below 90 F?  Coagulopathy: what is that? Coagulopathy is a condition in which the blood’s ability to clot (coagulate) is impaired. This condition can cause prolonged or excessive bleeding, which may occur spontaneously or following an injury; blood will start to ooze out of every orifice of the body. And as I said - all bleeding stops eventually. Coagulopathy may cause uncontrolled internal or external bleeding.

What else can we do to stop Hypothermia in our patient?

  1. Stop the bleeding!
  2. Make the patient warm; wrap them completely in the Emergency Blanket!
  3. Get them off the ground especially in the cold. The heat from your body is pulled out by the process of conduction. Conduction is the transfer of heat from one molecule to another through a substance. 
  4. If you have it, you can give the Patient O2 at 15L per minute on a non-re-breather mask. Unless they have COPD, in which case I would put them on a nasal cannula at 4 L per minute. (That is a story for another article.)
  5. Note that elevating the legs has shown to be of little to no help.(This is due to the body shunting)
  6. If the systolic BP is 90 or above I would not give fluids. That is not to say I would not start a line and then use a saline lock. With a BP of 90 systolic introducing crystalloid or colloid solutions can lower the body core temp if they are not warmed first. And most importantly IV fluids do not carry O2 like blood due to the total lack of hemoglobin.

Knowing all that, is your medical kit, blow-out kit, IFAK, complete? 

Not unless you have at least (1) emergency blanket in your kit. We have literally thousand of kits and companies that make kits to choose from. Get a kit that fits your medical training and certification.

Most importantly get some medical training. A great start is a Red Cross or “ASHI” First Aid & CPR course. Start with a good foundation of the basics and work up from that!

Stay Safe! And remember air goes in and out and blood goes round and round if you remember that you are good to go!