What is Shock?

In this lesson, we'll go over shock in general, four of the most common types of shock in pediatric patients, and some information on treating shock.

Let's first put shock into the proper perspective – when a person dies, it's almost always due to some form of shock, regardless of what caused the shock. The definition of shock (inadequate tissue perfusion) means that the body is unable to circulate blood with adequate oxygenation into the vital organs and the rest of the body.

Shock can occur due to several different things, like:

• Loss of blood
• Sepsis
• Impaired heart function
• Anaphylaxis

While there are many different subcategories and causes of shock, the types we'll be focusing on here are:

1. Hypovolemic shock
2. Distributive shock
3. Cardiogenic shock
4. Obstructive shock

Hypovolemic Shock

Hypovolemic shock is characterized by low cardiac output and is caused by incidences like severe bleeding and blood loss.

In patients with hypovolemic shock, initially their systolic blood pressure may appear normal but there will be a narrow pulse pressure. Peripheral pulses will be weak or absent and the patient's level of consciousness will decrease as the shock progresses.

The body will continue to shunt blood flow to the extremities in order to increase blood flow to the vital organs, right up until the latter stages of hypovolemic shock.

Distributive Shock

While a patient is in distributive shock (like sepsis shock or neurogenic shock), systemic vascular resistance is reduced, which leads to excessive vascular space. Blood flow is severely reduced to vital organs, which results in poor distribution of oxygen.

Extremities can also be warm due to the widening of the blood vessels and greater blood flow to the skin. The signs and symptoms of distributive shock can seem contradictory and can lead to confusion when diagnosing it.

Cardiogenic Shock

Cardiogenic shock is a failure of the heart to pump correctly and is distinguished from other types of shock by a marked increase in respiratory effort.

One key to treating cardiogenic shock is to increase cardiac output. This is typically done with medications, which helps improve myocardial function.

Unlike hypovolemic and distributive shock, fluid replacement must be done slowly over time. Rapid fluid replacement will reduce cardiac output and oxygenation and can increase the risk for pulmonary edema.

Obstructive Shock

Obstructive shock occurs when a mechanical or physical obstruction limits blood flow. Examples of what can cause this form of shock are:

• Cardiac tamponade
• Tension pneumothorax
• Pulmonary embolism

An example of this would be how a blunt force trauma to the chest would indicate a high risk for tension pneumothorax or a cardiac tamponade situation. In contrast, external bleeding would be more indicative of hypovolemic shock.

Immediate recognition and correction of the underlying cause of obstructive shock is extremely important for the patient's survival.

Shock in Pediatric Patients

With infants and children, all types of shock can quickly lead to the ultimate failure of the body – cardiac arrest. Especially if it isn't treated early.

The progression to cardiac arrest is particularly fast in infants and children that have gone from a state of compensated shock – when their heart is racing, and respiratory rate is high. Then suddenly, the body exhausts.

At this point, they go into late stage decompensated shock, which is a difficult syndrome to get the patient out of. Which is why early recognition and treatment of shock are critical to saving a child's life.

Shock Treatments

First line of treatment in pediatric shock is to maintain an open airway and deliver high-flow supplemental oxygen.

After the airway is open and oxygen is in place, the next priority is vascular access. If the child is in hypotensive shock, vascular access for fluid replacement is critical.

Once the IV or IO is in place, a bolus of an isotonic crystalloid, such as normal saline, should be administered at 20ml/kg over 5 to 10 minutes. A bolus of 20ml/kg may be repeated if necessary.

Because hypoglycemia is common in critically ill children and infants, blood glucose levels need to be checked early in your course of treatment. If low glucose levels aren't identified early and treated, brain injuries can occur.

Hyperglycemia can also be present and contribute to the shock symptoms. Which is why it's important to remember to look for the H's and T's and treat the underlying causes of shock.

If the child or infant remains hypotensive after the bolus of fluid is administered, you can consider administering epinephrine with IV or IO access at .1 – 1mcg/kg per minute.

You can also consider administering dopamine via IV or IO access at 10 – 20mcg/kg per minute.

And finally, norepinephrine via IV or IO access at .1 – 2mcg/kg per minute.

Serial and frequent vitals are so important up until, and after, the child or infant has been stabilized and passed to the next level of care.