Hypovolemic Shock – A Run Through

Introduction

Hypovolemic shock is a severe condition that requires immediate attention. When a large amount of fluid or blood loss occurs, it makes it challenging for the heart to pump blood to the organs. This can cause organ failure and can be dangerous. Experts state it usually occurs in more than 15 to 20 percent of fluid loss. It can be brought on by substantial fluid loss, due to diarrhea, throwing up, or sweating.

What Is Hypovolemic Shock?

Hypovolemic shock is a dangerous condition where the heart cannot pump sufficient blood to the organs. As a result, the body does not get the sufficient amount of oxygen required. The heart cannot pump blood unless there is a minimal blood volume in the body. It is a medical emergency that is difficult to diagnose and treat. Early diagnosis and appropriate management of the condition is essential.

What Are the Causes of Hypovolemic Shock?

There can be chances of hypovolemic shock when there is a blood loss of one-fifth or more. Blood loss can be due to various reasons that can be including:

• Bleeding due to wounds.

• Bleeding from injuries.

• Internal bleeding (primarily due to gastrointestinal bleeding).

The amount of circulating blood can reduce due to conditions like:

• Major burns.

• Diarrhea.

• Excessive sweating.

• Vomiting.

Hypovolemic shock can also be due to non-hemorrhagic fluid loss. The cause of non-hemorrhagic fluid loss can include:

• Gastrointestinal Losses: The gastrointestinal tract usually secretes three to six liters daily. About 100 to 200 ml of the fluid would be lost in the stool. However, the body reabsorbs the rest. There can be fluid loss in case of intractable vomiting, diarrhea, bowel obstruction, or external drainage via stoma or fistulas.

• Renal Losses: The kidney excretes sodium and water proportional to its intake. Diuretic therapy and osmotic diuresis due to hyperglycemia can cause more renal sodium and fluid loss. Moreover, several tubular and interstitial diseases can also cause increased fluid loss.

• Skin Losses: In sweltering conditions, fluid loss can also occur from sweating. If this fluid is not replaced, it can cause hypovolemic shock.

• Sequestration From Third-Space: When there occurs loss of interstitial fluid, it can cause sequestration. This can be seen in intestinal obstruction, pancreatitis, burn, and obstruction of a primary venous system. It is also seen in severe inflammatory processes.

What Are the Symptoms of Hypovolemic Shock?

The symptoms worsen as the fluid or blood loss increases. The symptoms can include:

• Breathing faster than normal.

• Feeling anxious or confused.

• The skin becomes cold and clammy.

• Decreased or no urine output.

• Weakness in the body.

• Skin pallor (the skin becomes pale).

• Lack of proper response.

• Fainting.

• Low body temperature.

• Low blood pressure.

What Are the Stages of Hypovolemic Shock?

Hypovolemic shock is classified into four stages depending on the amount of blood loss. They are:

1. Stage 1: When 15 percent of the blood in the body is lost, it is considered stage 1. This can be about 25 ounces of blood. Blood pressure and heart rate will still be normal at this stage.

2. Stage 2: When 15 to 30 percent of blood is lost, it is categorized as stage 2. This can be about 51 ounces of blood. At this stage, the heart rate increase. The rate of breathing also increases. There can be an elevation in the diastolic blood pressure.

3. Stage 3: At this stage, about 30 to 40 percent of blood is lost. This can be about 60 ounces of blood. At this stage, blood pressure drops very low. The heart rate and breathing rate increase. There will be no or minimal urinary output at this stage. The patient's mental status will begin to change, they might become anxious or confused.

4. Stage 4: When more than 40 percent of blood is lost, it is considered stage 4. More than 69 ounces of blood is lost in this stage. Low blood pressure and high heart rates are seen in this stage. The fingertips and lips begin to show bluish discoloration.

How Is Hypovolemic Shock Diagnosed?

A clear history and a physical examination will help diagnose hypovolemic shock. A history of recent trauma, excessive bleeding, or surgery will be evident in hemorrhagic shock. For non-hemorrhagic hypovolemic shock, a thorough physical examination should be done to check for any gastrointestinal causes for fluid loss, renal causes for fluid loss, open wounds, skin, or any other cause of fluid loss. The patient will have low blood pressure, body temperature, and a weak and rapid pulse. These observations can help in steering the diagnosis of this condition. Thirst, muscle cramps, and orthostatic hypotension may be the complaints presented by the patient. Other tests done to diagnose the condition can include

• Blood Tests: It includes kidney function tests and creatine kinase test, which gives details regarding heart muscle damage.

• Complete Blood Count (CBC): A complete blood count will help analyze the extent of blood loss.

• Imaging: CT scan (computed tomography), ultrasound, or X-ray These tests can give details of internal bleeding, if any.

• Echocardiogram: In this test, sound waves are used to examine the structure and function of the heart. This can also give details regarding the extent of heart damage, if any.

• Endoscopy: It helps to get details regarding any bleeding in the gastrointestinal tract.

• Swan-Ganz Right Heart Catheterization: It is also called pulmonary artery catheterization. It measures the heart's function, blood flow, and pressure within the heart.

How Is Hypovolemic Shock Treated?

The first requirement is to elevate the body fluids and blood. Hence intravenous fluids like normal saline will be given first. A blood transfusion will be done next. Balanced blood transfusions using 1:1:1 or 1:1:2 of plasma, platelets, and packed red blood cells help to get better hemostasis. Medications to elevate the blood pressure will be given. Monitoring the cardiac functions will give details on the response to the treatment.

What Are the Complications of Hypovolemic Shock?

The complications of hypovolemic shock can include:

• Severe dehydration.

• Damage to the internal organs like the kidney or the heart.

• Metabolic Acidosis: When the body's pH reduces to less than 7.35, it is termed metabolic acidosis.

• Hypoxia: The oxygen supply is not sufficient to the body tissues for normal body functions.

• Heart attack.

Conclusion

Recovery from the hypovolemic shock depends on the severity of the shock, the presence of comorbidities, and the patient's age. Mild shocks are relatively easier to recover from. As the severity increases, the risk of organ damage also increases. Hence recovery can also be challenging. Organ damage in very severe cases can be irreversible.