Let's recap what we've learned so far about hemorrhage, other than it's a mouthful to say and a hard word to spell correctly. There are two types of hemorrhage, internal and external. External hemorrhage is obvious to the EMT, and can be controlled with direct pressure and/or a tourniquet. Internal hemorrhage is less obvious, and cannot be controlled easily by the EMT. Arterial bleeding leads to faster blood loss than venous and capillary, but any or all may be present, and any or all may lead to shock and death. Sick trauma patients require rapid assessment, ongoing treatment, and immediate transport to a trauma capable facility. Surgery and blood replacement is often the only definitive treatment for these patients. In this video, we will delve into more physiology behind blood loss. This will help you understand how and why trauma patients become sick and die if left untreated, or if their injuries are beyond repair. We remember that shock is a state of emergency within the body and defined as inadequate profusion or hypoperfusion to organs and tissues. Hemorrhagic shock results from large volume of blood loss that exceeds the body's ability to correct itself without external intervention. When an injury occurs, the body sends out chemical and electrical signals indicating distress. If the body is losing blood, the adrenal glands release our flight and fight, chemicals, epinephrine or adrenaline, and norepinephrine. These chemicals act to constrict blood vessels, reducing the volume of blood loss and drive up heart rate and blood pressure and respiratory rate. This helps the body prepare itself for worsening injury. This is called compensation. Remember, in compensated shock, an ongoing illness or injury is occurring but the body is taking steps to maintain homeostasis. Therefore, vital signs may be normal or only slightly abnormal. Mental status should be normal. As more peripheral vasoconstriction occurs, skin appears pale, cool, and clammy. Urine output will decrease and distal pulses become weak. You may assess blood pressure to be elevated due to the adrenaline causing vasoconstriction. Look for a high diastolic number to indicate this phenomenon. As hemorrhage continues and blood loss overtakes compensatory measures, perfusion to the brain and heart is lost, and those organs become ischemic or lacking oxygen. CO2 or carbon dioxide builds up in the body causing changes in acid-base balance. Mental status will change, the patient will be less responsive, altered, or unresponsive. Skin signs will look dusky, the sweating may even stop. The patient's heart rate may be severely tachycardic or now very slow and bradycardic. Blood pressure will start to fall, respirations will slow, and in this phase the compensation has ended. The patient is headed toward cardiac arrest. As additional organs fail from ischemia, death is certain. It is important to note that a trauma patient found in cardiac arrest by EMTs at the scene have a very low chance of survival. This is especially true for blunt trauma arrest patients, as likely massive internal hemorrhage has already overcome the body's ability to compensate, and are too severe for surgery to correct. Surgery itself may be too taxing on a body's ability to survive. Some penetrating trauma arrest patients may benefit from advanced rapid interventions including chest decompression, thoracotomy, and blood infusions. Consult your local protocols and consider the availability of advanced resources when deciding whether to transport traumatic arrest victims or not. Realize, too, that typical interventions for medical arrest patients may be futile in trauma arrest patients due to the different physiology of the cardiac arrest. To reiterate, the most important intervention by EMTs in hemorrhagic shock is quick determination that it is happening. This is followed by controlling external hemorrhage, identification of potential internal hemorrhage, brief scene time, rapid transport with early notification to a trauma capable facility. Few advanced interventions are actually beneficial in the pre-hospital environment. As mentioned previously, some include chest decompression, endotracheal intubation, and blood product or clotting factor administration. Interestingly, pre-hospital IV fluids given in large quantities to a hemorrhagic shock patient have been proven to be harmful. There are different classes of hemorrhage and this is the way to classify shock. The classification depends on the amount of blood lost, the heart rate, whether or not there is vasoconstriction, their ventilatory rate, their systolic blood pressure, their pulse pressure, and how their skin appears. There are four different classes of hemorrhagic shock, with class four being the most severe. Please see the additional readings for the table that helps you determine which class of shock your patient may be in.
