EDITOR'S NOTE: Thanks to our guest blogger this week, Dean Meenach, MSN, RN, CNL, CEN, CCRN, CPEN, EMT-P. **
The effects of shock due to major blood loss rapidly become irreversible, so quick identification and intervention are critical.
Shock is not a disease, but a clinical manifestation of the body’s inability to perfuse its tissues adequately. [1] Shock is considered a systemic response to an illness or injury resulting in inadequate tissue perfusion and decreased oxygen to the cells.
Hypovolemic shock is the loss of volume, which can include:
- Loss of blood, internal or external bleeding/hemorrhage.
- Loss of water, vomiting, diarrhea, perspiration.
- Movement of cellular fluid from within cells to the space around cells.
The effects of shock are initially reversible, but rapidly become irreversible. For prehospital professionals to improve shock outcomes, these interventions must begin early in the prehospital setting. [2,3] Here are 10 things you need to know to help you identify hypovolemic shock early and manage it effectively to save lives.
1. TWO MAJOR TYPES OF HYPOVOLEMIC SHOCK
Hypovolemic shock is caused by a decrease in the amount of circulating volume [absolute hypovolemia]. In trauma patients, one type of hypovolemic shock, this is usually caused by hemorrhage. Volume loss in non-trauma patients, the other type of hypovolemic shock, it can be caused by hemorrhage, vomiting, diarrhea, excessive perspiration, fever, medication induced diuresis, etc. [1,10,18,19]
2. SCOPE OF THE PROBLEM
Available studies suggest that 2% of EMS calls present with traumatic or nontraumatic hypotension and 1-2% with hypovolemic shock.
Hypovolemic is the second leading type of shock experienced. [6] Hemorrhage is the second leading cause of death in trauma patients, making hemorrhagic shock the most common cause of preventable trauma death within 6 hours of admission. [7,8,9] According to the literature, 1.9 million people die per year worldwide due to hemorrhagic shock. [6,10] It is no surprise that trauma is the most frequent condition leading to hemorrhagic shock. [10,11] Finally, patients with trauma-related hemorrhagic shock have better outcomes when transported to specialty trauma centers. [12,44,47]
3. THREE MAJOR STAGES OF SHOCK
In the early stages of shock, the body is unable to meet the demand for oxygen and cellular nutrients. To maintain perfusion to the organs, the body reacts by activating various compensatory mechanisms that result in shunting perfusion away from other organs.
If the shock state is unrecognized, prolonged or untreated, it will progress to a terminal stage. The pathophysiologic changes that occur during shock can be divided into three stages: compensated, uncompensated, and irreversible. [1,13]
- Stage I [compensated]: The sympathetic nervous system is selective, shunting blood to the heart, brain and lungs, which decreases perfusion to other organs. During the compensated stage, there is a narrow window of opportunity to rapidly intervene and restore perfusion. [13]
- Stage II [decompensated or progressive]: Decompensated or progressive shock occurs when compensatory mechanisms begin to fail and are unable to restore perfusion. [1,14] This results in hypotension, reduced organ perfusion, impaired oxygen delivery, anaerobic metabolism and lactic acid production. However, shock may still be reversible at this stage with immediate intervention. [13,14,15,16,21]
- Stage III [irreversible]: Irreversible shock occurs when tissues and cells become ischemic and necrotic. This results in hypotension and possible multiple organ dysfunction. [10,17] Despite aggressive resuscitation, interventions may only have minimal results in reducing morbidity and mortality.
4. UNDERSTAND THE TRAUMA TRIAD OF DEATH
Resuscitation-associated coagulopathy in hemorrhagic shock has been recognized as the major cause of the trauma triad of death. [15] These three lethal complications include:
Resuscitation-associated coagulopathy in hemorrhagic shock has been recognized as the major cause of the trauma triad of death. At present, this can only be treated with blood product replacement.[image/EMS1]- Hypothermia: Hypothermia results in an increase in clot breakdown and bleeding. [14] Prehospital IV fluid warmers, peripheral warming devices and blankets are typically used to reduce this type of hypothermia.
- Acidosis: Acidosis decreases production of coagulation factors by as much as 40% due to reduced pH, elevated lactic acid production and increasing base deficit. [14,21] EMS agencies can use point-of-care blood gas analyzers to identify acidosis and sodium bicarbonate to treat the metabolic acidosis.
- Coagulopathy: Blood loss results in a depletion of clotting factors that may be present in up to 25-35% of trauma patients that arrive to the ED. [14] At present, this can only be treated with blood product replacement. This has led to the push by some EMS agencies that serve remote areas or have prolonged transport times to consider carrying blood products such as packed red blood cells, fresh frozen plasma and other components. [48] Just as with IV fluids, all blood products should be administered through a warming infuser.
5. THE VARYING SIGNS AND SYMPTOMS OF SHOCK
Vital signs are important indicators of the patient's physiologic status.
- Temperature: Fever may direct a further search for signs of infection, but a temperature less than 95 degrees may indicate hypothermia in a shock victim. Hypothermia contributes to poor perfusion.
- Heart rate: Due to compensatory mechanisms, the heart rate is typically elevated in hypotension. In hypovolemic shock, the heart rate will likely be elevated.
- Blood pressure: Hypotension defined as MAP