Hypovolemic shock: emergency diagnosis and treatment

2021-08-03 11:48 PM

Hypovolemic shock is shock caused by a sudden decrease in circulating volume that results in decreased tissue perfusion (cellular hypoxia), cell metabolism disorders.

Shock is a life-threatening condition of circulatory failure that results in inadequate oxygen delivery to meet the metabolic needs of cells and oxygen consumption requirements, creating cellular and tissue hypoxia. The effects of shock are initially reversible, but quickly become irreversible, leading to multiple organ failure (MOF) and death. When a patient is in undifferentiated shock, it is important that the clinician immediately initiate therapy while rapidly identifying the cause so that definitive treatment can be given to reverse shock and prevent MOF and death. 

Hypovolemic shock

Hypovolemic shock

Shock is defined as cellular and tissue hypoxia due to decreased oxygen supply, increased oxygen consumption, inadequate oxygen utilization, or a combination of these processes. This usually occurs in the presence of circulatory failure manifesting as hypotension (ie, hypoperfusion of tissues); however, it is important to recognize that a patient in shock may present with hypertension, normal or hypotensive. The initial shock is reversible but must be recognized and treated immediately to prevent progression to irreversible organ dysfunction. "Undifferentiated shock" refers to a situation where the shock is recognized but the cause is unclear.

Hypovolemic shock is shock caused by a sudden decrease in circulating volume that results in:

Decreased tissue perfusion (cellular hypoxia).

Cell metabolism disorders.

Prolonged cellular hypoxia leads to organ damage, if late, it causes refractory shock leading to death.

The cause is usually severe, easily identifiable bleeding. Sometimes the hypovolemic shock is due to plasma loss or to massive dehydration, of gastrointestinal, renal, or cutaneous origin.

The disease is aggravated if there is a combination of diseases: diabetes, cardiovascular disease, kidney disease...

It needs early detection and prompt treatment.

Definitive diagnosis of hypovolemic shock

Small pulse difficult to catch, low blood pressure (systolic blood pressure <90 mmHg)

Struggling, lethargic, confused.

Mucous skin cold, pale.

Rapid breathing, purple lips, and extremities.

Less urination, anuria.

Symptoms of blood loss if hemorrhagic shock.

Testing: usually slow.

+ Her blood (hematocrit increased, blood protein increased) if the shock is hypovolemic alone.

+ Decrease in red blood cells, hematocrit in case of hemorrhagic shock.

+ Electrolyte disturbances.

+ Disorders of acid-base balance: metabolic acidosis in case of diarrhea or prolonged shock, metabolic alkalosis in case of profuse vomiting.

Differential diagnosis of hypovolemic shock

Cardiac shock: Central venous pressure is often increased; cardiac output is decreased.

+ Septic shock: fever, infection, white blood cell increase...

+ Anaphylaxis also has a decrease in circulating volume. Diagnosis is difficult if the shock is delayed.

Level diagnosis in hemorrhagic shock

Board. Degree of blood loss

Diagnose the cause

Blood loss shock

Trauma (external bleeding, internal bleeding): broken liver, spleen, kidney, broken pelvis, pleural bleeding, vascular wound...

Non-traumatic: upper gastrointestinal bleeding, lower gastrointestinal bleeding, ruptured ectopic pregnancy, ruptured abdominal aorta, ruptured liver tumor...

In some special cases, it is necessary to have combined diagnostic measures such as:

+ Laparotomy: determine the amount of blood loss in the peritoneal cavity.

+ Abdominal ultrasound: to explore retroperitoneal hematomas.

+ Insert gastric tube, anal catheter, monitor the amount of black stool, monitor bleeding in the esophagus, stomach, duodenum, rectum.

The hypovolemic shock alone, without blood loss

Gastrointestinal causes: vomiting, diarrhea without rehydration, intestinal obstruction...

Endocrine causes: diabetes insipidus, osmotic polyuria.

Causes of heatstroke, heatstroke, extensive burns, Lyell's syndrome -> shock due to loss of a large amount of plasma.

Loss of fluid into the third compartment: acute pancreatitis, peritonitis, intestinal obstruction.

Treatment of hypovolemic shock

Treatment has two purposes: resuscitation and treatment of the cause

The four basic steps in treatment include:

Immediately assess basic life functions.

Quickly identify the cause.

Do basic tests, immediately determine blood type if blood loss shock.

Immediate replacement infusion.

Recovery

Basic first aid movements

Place the patient in the low-lying position but pay attention to the risk of aspiration into the lungs.

Breathe O 2 noses 2 - 6l/min.

Intubate if there is a risk of regurgitation into the lungs or if there is a respiratory failure or impaired consciousness.

Place 2 sturdy and large enough intravenous lines. Place a central venous catheter, measure central venous pressure (CVP) if heart failure is present.

Keep the patient warm.

Place a bladder catheter to monitor urine output.

Take blood for the basic test, do an electrocardiogram.

Volume recovery and shock resistance

The first priority in emergency care is to replace fluid loss and restore hemodynamic status.

Infusion: 0.9% sodium chloride or Ringer lactate, rapidly infusion to achieve 500ml in 15 minutes.

When systolic blood pressure is up to 70-80 mmHg reduce the infusion rate, in most patients 1-2 L of isotonic saline will correct the volume loss.

Administer colloidal solution when isotonic saline has been infused up to a total dose of 50 ml/kg and the patient is still in shock.

The amount and rate of infusion depends on the degree of shock and the patient's cardiovascular status

Purpose: the patient is out of shock (warm skin, systolic blood pressure > 90, urine > 50ml/hour, no stimulation).

Closely monitor pulse, blood pressure, auscultation, CVP, electrocardiogram (if any), especially patients with cardiovascular disease.

Blood transfusion: for hemorrhagic shock, give blood immediately. In case of emergency or rare blood type, immediately transfuse type o blood while waiting for the blood of the same group.

Treat the cause

Treatment of bleeding is basic, such as hemostasis of the wound, injection of sclerotherapy in esophageal varices, gastrectomy, Blakemore catheterization with terlipressin vasopressin infusion, splenectomy, hysterectomy...

Prevention of hypovolemic shock

Preventing shock from happening is easier than treating shock.

Quickly solve the causes that easily lead to hemorrhagic shock: bleeding due to trauma...