Hypovolemic Shock
What are the complications of hypovolemic shock? All the information about the causes, symptoms, and prognosis of the disease.
Symptoms and Causes
Hypovolemic shock is a critical condition that results from a sudden and severe reduction in circulating blood volume, which can be caused by bleeding (either internal or external) or the loss of other body fluids. The reduced blood volume makes the heart unable to pump enough blood to the rest of the body, causing organs and tissues to lack the oxygen and nutrients they need. This can result in cell damage, organ dysfunction, and ultimately death.
Depending on the cause of the blood volume loss, there are two types of shock:
- Hemorrhagic hypovolemic shock: caused by severe bleeding (external or internal).
- Non-hemorrhagic hypovolemic shock: caused by the loss of body fluids (dehydration due to renal, digestive, or skin losses—such as in severe burns).
According to the evolution of the shock, there are four stages:
- Stage I or compensated shock: initially, the body's compensatory mechanisms try to preserve vital function.
- Stage II or early decompensated shock: as blood or fluid loss progresses, compensatory mechanisms lose capacity, and blood flow to organs decreases.
- Stage III or late decompensated shock: symptoms progressively worsen.
- Stage IV or irreversible shock: the situation is critical. Multiple organ failure and cell death occur.
Hypovolemic shock is one of the most common types of shock and one of the leading causes of mortality in trauma and surgical procedures.
Symptoms
The symptoms of hypovolemic shock worsen and become more severe as blood and fluid loss increases:
- Paleness
- Anxiety
- Cold sweating
- Dry mucous membranes
- Rapid and weak heart rate
- Accelerated and shallow breathing
- Low blood pressure
- Hypothermia
- Generalized weakness, dizziness
- Confusion
- Decreased urine production
- Loss of consciousness
If the cause of shock is internal bleeding, additional symptoms may include nosebleeds or bleeding from the mouth, abdominal discomfort or pain, chest pain, and the presence of blood in stools or urine.
Causes
Hypovolemic shock occurs when the body loses more than 15% of its blood volume suddenly, which can result from:
- Severe bleeding from a major trauma or an underlying condition.
- Excessive loss of body fluids (plasma, water, and electrolytes) caused by severe burns, vomiting, diarrhea, renal loss, or excessive sweating, among other factors. In these cases, the body replaces the lost fluid from the blood, reducing its circulating volume.
- Less commonly, insufficient fluid intake can also cause it.
Risk Factors
The risk of experiencing hypovolemic shock increases in the following situations:
- Trauma, accidents, or severe burns
- Deep wounds or cuts
- Surgical procedures
- Childbirth and postpartum
- Coagulation disorders
- Use of anticoagulant medications
- Gastrointestinal disorders
- Dehydration
- Underlying conditions such as heart failure, kidney failure, or diabetes
- Age: elderly individuals are at higher risk of not surviving shock
Complications
The prognosis of hypovolemic shock primarily depends on the amount of blood or body fluids lost and how quickly treatment is initiated. If left untreated, it can lead to:
- Permanent damage to vital organs such as the kidneys or brain
- Heart attack
- Gangrene in the extremities
- In irreversible cases, death
Prevention
Staying hydrated is essential to avoid hypovolemic shock, especially in hot conditions or during intense activity. Additionally, it is necessary to follow safety measures to reduce the risk of injuries and accidents, as well as provide first aid in cases of external bleeding or burns.
Which doctor treats hypovolemic shock?
Hypovolemic shock is evaluated and treated in the intensive care unit along with various specialists who will address the underlying cause.
Diagnosis
Early diagnosis is key to a positive outcome. To confirm hypovolemic shock, various tests are performed:
- Physical examination to measure temperature, blood pressure, and heart and respiratory rates
- Blood count and biochemical analysis: to determine blood cell volume, plasma and electrolyte levels, kidney function, coagulation, or lactate levels (elevated levels indicate insufficient oxygen supply to organs)
- Bladder catheter to measure urine output and kidney function
- Diagnostic imaging tests such as ultrasound, CT scan, or MRI to look for internal bleeding or organ damage
Treatment
Hypovolemic shock requires immediate medical attention. However, first aid may be necessary before hospital care is available:
- Keep the patient warm to prevent hypothermia
- Lay the patient down and elevate their legs by about 30 centimeters to facilitate blood flow (if there is a risk of head, neck, spine, or leg injuries, do not move the patient unless they are in immediate danger)
- For external bleeding, apply pressure with a clean cloth to control the bleeding
- Do not administer fluids orally
Hospital treatment focuses on replenishing blood and fluids and supporting affected organs:
- Intravenous saline solutions to replenish fluids; this should be a priority to ensure adequate blood pressure and organ perfusion
- Blood transfusion (blood products); if the patient is receiving anticoagulant treatment (e.g., Sintrom or similar), its effects should be reversed whenever possible. Red blood cells, plasma, or platelets will be administered as needed
- Medications to increase blood pressure and the amount of blood pumped, such as epinephrine or norepinephrine
- Surgery to repair injuries and control bleeding
- Supportive measures to maintain vital signs: administration of oxygen and monitoring to measure heart rate, blood pressure, oxygen saturation, and urine output
