Shock is a life-threatening condition of circulatory failure that is defined as a state of cellular and tissue hypoxia resulting from reduced oxygen delivery, increased oxygen consumption, or inadequate oxygen use. Four types of shock are recognized:
Cardiogenic shock, resulting from: myocardial infarction; atrial or ventricular dysrhythmias; and valvular or ventricular septal rupture.
Hypovolemic shock, due largely to hemorrhagic and nonhemorrhagic fluid losses.
Obstructive shock, due to: pulmonary embolism; pulmonary hypertension; tension pneumothorax; constrictive pericarditis; and restrictive cardiomyopathy.
These should not, however, be considered exclusive. Many patients with circulatory failure have more than one form of shock. 'Undifferentiated shock' refers to a situation where shock is recognized, but the cause is unclear.
Paramedics and EMRs/FRs should suspect shock when confronted with hypotension, altered mental status, tachypnea, cool and clammy skin, oliguria, and metabolic acidosis (usually from hyperlactatemia). Most of these clinical features are not specific or sensitive for the diagnosis of shock and should be used primarily to narrow the differential diagnosis so that empiric therapies can be delivered in a timely fashion.
Shock differentiation is a hallmark of CCP care. The first thing when dealing with a patient in shock is to differentiate the shock state. Each shock state is specific to the presenting disease or injury pattern. As such each has a specific treatment. The overarching goal is to maintain tissue homeostasis. One of the tools used for differentiation is the use of ultrasound and the RUSH protocol. However this gives a singular data point and needs to be corroborated with history, clinical presentation, and lab data.
Is loss of fluid
Replace fluid and electrolytes
Stop further fluid loss
Loss of blood
Replace blood with a balanced blood product administration.
Stop further blood loss.
Bradyarrhythmias are treated as per ACLS protocols
Tachyarrhythmias are treated as per ACLS protocols
This is a failure of the muscle to contract properly and eject blood effectively. The most common cause is a STEMI. Regardless of type treat as per ACLS protocols. Determination of Killip class may be helpful.
Important to identify right versus left and HFrEF and HFpEF (Heart failure with reduced ejection fraction, Heart failure with preserved ejection fraction)
This is a failure of the mechanics of the heart. The most common is valvular issues such as regurgitation. Other examples are VSD, PFO, or septal rupture.
Failure to fill
Abdominal compartment syndrome, pericardial tamponade, tension pneumothorax, and excessive PEEP are examples that lead to a reduction in blood returning to the ventricle.
Treatment consists of removal of the offending pressure.
Failure to eject
Pulmonary embolism, aortic stenosis, or iatrogenic levels of vasopressor support are examples that restrict the ability of forward blood flow.
Remove the offending pressure and support preload, afterload, or contractility.
Characterized by the loss of vascular resistance
Differentiation can start immediately with a pulse pressure and skin temperature.
Further delineation can be identified with heart rate (bradycardia) as in the case of neurogenic.