Hypovolemic shock: Clinical sciences

Chapters:

Watch video only

Introduction0:00–0:46

Hypovolemic shock is a life-threatening condition associated with decreased intravascular volume, which in turn leads to decreased venous return to the heart, decreased cardiac output, and eventually shock.
Now, hypovolemic shock can be defined as hemorrhagic or non-hemorrhagic. Hemorrhagic shock is associated with blood loss, which can be seen in traumatic conditions, such as a ruptured spleen; or non-traumatic conditions, like variceal bleeding.
On the other hand, non-hemorrhagic shock is associated with fluid loss, most commonly from dehydration, like after prolonged vomiting or diarrhea, as well as severe widespread burns.
Now, patients presenting with signs and symptoms of hypovolemic shock will generally present as unstable. Start by immediately performing an ABCDE assessment, then begin acute management.

Acute Management0:46–1:21

Stabilize their airway, breathing, and circulation. This means that you might need to intubate the patient.
Next, obtain IV access with 2 large bore IVs and start IV fluids. Finally, put your patient on continuous vital sign monitoring, such as pulse oximetry, blood pressure, and heart rate.Once you’ve stabilized the patient, obtain a focused history and physical examination.

History and Physical1:21–2:10

History often reveals the underlying cause or source of fluid or blood loss, as well as symptoms of organ hypoperfusion.
For example, hypoperfusion of the brain can result in lethargy and confusion, while kidney hypoperfusion can lead to oliguria.
Additionally, individuals might report postural dizziness. On the other hand, a physical exam primarily reveals signs of shock, such as hypotension, and tachycardia, as well as weak peripheral pulses and low jugular venous pressure.
Additionally, patients can present with pale, clammy skin; decreased skin turgor; dry mucous membranes; and cold extremities.If you suspect hypovolemic shock, the next step is to order labs, which can also help you determine the type of shock.

Labs2:10–2:26

These include CBC, lactate, and CMP, as well as PT, PTT, and INR. Okay, now let’s look at how H&P findings plus lab values can help you determine the type of shock, starting with non-hemorrhagic shock.

Non-hemorrhagic shock2:26–4:37

These individuals typically have a history of prolonged vomiting and diarrhea, or widespread burns. All these conditions can lead to fluid loss.
Additionally, CBC usually reveals a high hemoglobin level, since fluid loss can result in hemoconcentration. Next, lactate will be elevated because hypoperfused organs are forced to switch to anaerobic metabolism, producing lactate as a byproduct.
On the other hand, CMP might reveal elevated BUN, creatinine, and transaminases due to renal and hepatic hypoperfusion. Finally, PT, PTT, and INR are usually normal.At this point, you’ve determined that your patient has non-hemorrhagic shock, so the next step is to assess each of your patient’s organ systems for the cause of fluid loss.
In patients who describe excessive diarrhea or vomiting, think of gastrointestinal fluid losses due to inflammatory bowel disease or underlying gastrointestinal infection, like cholera or giardiasis.
On the other hand, if your patient presents with severe blistering or eschar formation, consider burn injury and fluid loss through the skin.
Next, a history of diuretic use or polyuria should make you suspect underlying renal fluid losses, such as diuretic-induced dehydration or salt-wasting nephropathy.
Finally, if there’s severe abdominal pain or ascites, consider intravascular volume depletion due to third-spacing, where fluid leaks out of the vascular circulation into the interstitial space between cells, which is common in pancreatitis due to inflammation and in cirrhosis due to low albumin levels.Now, treat the underlying cause accordingly once you identify it, but don’t forget to replace lost volume with crystalloid fluids to stabilize the patient’s hemodynamics.
Alright, now let’s switch our focus to hemorrhagic shock. These individuals can present with a history of trauma or bleeding and their CBC typically reveals a low hemoglobin level since there's a recent or active blood loss.

Hemorrhagic shock - External source4:37–5:44

Similar to non-hemorrhagic shock, lactate could be elevated and CMP can reveal high BUN, creatinine, and transaminases. Finally, in contrast to non-hemorrhagic shock, PT, PTT, and INR might be elevated in people with a bleeding disorder or coagulopathy.At this point, you've determined that your patient has hemorrhagic shock, so the next step is to assess the source of bleeding.
In individuals that present with obvious external bleeding or signs of trauma, call the surgical team for a consultation and restore the lost blood volume with a transfusion of blood products, such as red blood cells and platelets.
Also, keep in mind that individuals with coagulopathy might require fresh frozen plasma, or FFP for short.On the other hand, for patients with internal bleeding, where there is no obvious external or traumatic cause of bleeding, your next step is finding the type or source of blood loss.
Internal bleeding can be overt or concealed. Overt bleeding means there are visible signs of bleeding.

Hemorrhagic shock - Internal source - Overt5:44–7:04

For example, one common source is the GI tract where signs of overt bleeding include hematemesis, melena, or hematochezia.
In this case, order an esophagogastroduodenoscopy or EGD, or colonoscopy to visualize the upper and lower parts of the gastrointestinal tract.
Common causes of upper gastrointestinal bleeding include esophageal varices and peptic ulcerations; while common causes of lower gastrointestinal bleeding include diverticulitis and colorectal cancer.
If you suspect GI bleeding, you will need to consult the surgical or interventional radiology team for further evaluation and definitive treatment with endoscopy or arterial embolization.
Meanwhile, start transfusion of blood products to restore the circulating blood volume and stabilize the patient’s hemodynamics.
Finally, if needed, use fresh frozen plasma to correct coagulopathy if present.Now, let’s go back and take a look at individuals that have no visible signs of bleeding.
In this case, you should suspect concealed bleeding, which refers to internal bleeding without outward signs. A good place to start is with imaging studies, such as an abdominal ultrasound or CT, which can help you visualize potential sources, such as an arterial rupture or hematoma.

Hemorrhagic shock - Internal source - Concealed7:04–8:05

If you identify any type of concealed bleeding, immediately consult your surgical team.Now here’s a high-yield fact to keep in mind.
If you suspect hypovolemic shock in a biologically female individual of child-bearing potential, be sure to check for the presence of beta HCG in the urine or serum.
There are several potential causes of hemorrhage during all stages of pregnancy, and the most important ones include ruptured ectopic pregnancy and placental abruption.
In this case, use ultrasound to confirm the diagnosis and immediately call the surgical team! Alright, as a quick recap… Hypovolemic shock is a life-threatening condition that needs to be diagnosed quickly.
First, you should perform an ABCDE assessment and stabilize the patient’s airway, breathing, and circulation. Next, obtain a focused history and physical examination, and labs to determine the type.

Review8:05–9:23

Non-hemorrhagic shock is associated with fluid loss and high hemoglobin, and requires a thorough assessment of organ systems for the underlying cause.
Once you identify the cause, treat it accordingly and administer IV crystalloid fluids to stabilize the hemodynamics. On the other hand, hemorrhagic shock is associated with blood loss and low hemoglobin levels, so your next step is to assess the patient for signs of bleeding or trauma.
If the patient presents with an external source, call the surgical team for consultation, transfuse blood products and fresh frozen plasma, if needed.
On the other hand, if the patient presents with no external source, it might be internal, so determine the type of bleeding, whether overt or concealed.
If the bleeding is overt, order EGD or colonoscopy to visualize the GI tract and determine the cause, you might need to call the surgical or interventional radiology team for further evaluation and definitive treatment.
Also, don’t forget to transfuse blood products when needed. On the flip side, if the bleeding is concealed, immediately order abdominal imaging to determine the source of bleeding, and call the surgical team for consultation!