Hypovolemic ShockHypovolemic ShockNULL

Hypovolemic Shock

Hypovolemic Shock

Shock is a life-threatening condition characterized by inadequate tissue perfusion, which means that the cells and organs do not get enough oxygen and nutrients to function properly.  Shock can get worse very rapidly and requires immediate treatment. If this condition is untreated, cell death and organ failure occurs. As many 1 in 5 people who suffer shock will die from it.

Depending upon underlying etiology, shock is commonly divided into three broad categories:

  1. Hypovolemic Shock (Blood Volume)
  2. Cardiogenic Shock (The Heart)
  • Vasogenic Shock/ Distributive Shock (Vascular Tone): Further 3 types:
  1. Anaphylactic Shock
  2. Septic Shock
  3. Neurogenic Shock

Hypovolemic shock is the most common type of shock which develops when the intravascular volume decreases to the point that it is not sufficient to maintain organ and tissue perfusion required to meet body’s metabolic needs.

Causes: It may occur due to actual blood/fluid loss (such as in case of  haemorrhage, vomiting or diarrhea) or fluid shift from intravascular compartment to interstitial space (as in case of burns).

  1. Haemorrhage: It can be external or internal. Shock develops depending upon amount of blood loss and length of time over which blood loss occurs.

Clinial manifestations begin to appear with a blood volume deficit of 20% (1/5th) i.e. about 1000 ml in an adult with normal circulating volume. Although smaller amounts of blood loss can cause shock in clients who are less able to compensate rapidly e.g. older people with decreased vascular tone and impaired cardiac function.

  1. Burns: common with large partial thickness and full thickness burns. It is caused primarily by shift of plasma from vascular space into interstitial space. Decreased circulating blood volume leads to decreased cardiac output and hypoperfusion.
  • Other causes resulting in fluid shifts similar to those in burns include:
  • Nephrotic syndrome
  • Severe Crush Injuries
  • Starvation
  • Surgery
  • Cirrhosis of Liver, Pancreatitis and Bowel Obstruction
  1. Dehydration:
  • Rigorous exercise, profuse sweating, hot environment
  • Prolonged vomiting/ diarrhea
  • Excessive urine output

Pathophysiology:

Fluid loss/ fluid shift

Decreased circulatory blood volume

Decreased preload

Decreased cardiac output

Decreased tissue perfusion

Cell death/ organ failure

Stages:

  • Non progressive/ Compensatory stage
  • Progressive/ Decompensatory stage
  • Irreversible stage

Clinical Manifestations: Shock affects every system in the body. Subjective complaints are usually nonspecific and may not help clinician to diagnose and treat client. The client may report feeling sick, weak, cold, hot, nauseated, dizzy, confusedthirsty, or short of breath.

Objective findings:

  • BP, cardiac output, and urine output are usually decreased.
  • Rapid, shallow breathing
  • Dyspnoea, altered sensorium, and diaphoresis may be present.
  • Cyanosis
  • Flat neck veins
  • Rapid, thready pulse, slow capillary refill
  • Decreased level of consciousness, irritability, weakness
  • Dilated pupils
  • Thirst, dry mucous membranes
  • Cold clammy skin
  • Metabolic Acidosis
  • Vomiting
  • Decreased bowel sounds
  • Hypothermia

Assessment:

  • Physical Examination (Observe for clinical manifestations)
  • ECG
  • Pulse Oximetry
  • ABG analysis
  • CVP monitoring
  • Swan Ganz catheterization

Management: Three goals exist in the emergency department treatment of the patient with hypovolemic shock as follows:

  1. Maximize oxygen delivery – completed by ensuring adequacy of ventilation, increasing oxygen saturation of the blood, and restoring blood flow,
  2. Control further blood loss, and
  • Fluid resuscitation.

* These can be achieved by:

  • High-flow supplemental oxygen should be administered to all patients, and ventilatory support should be given, if needed.
  • Two large-bore IV lines should be started.
  • Placement of an arterial line should be considered for patients with severe hemorrhage. For these patients, the arterial line will provide continuous blood pressure monitoring and also ease arterial blood gas testing.
  • Once IV access is obtained, initial fluid resuscitation is performed with an isotonic crystalloid, such as lactated Ringer solution or normal saline.
  • 3% hypertonic saline solution (HSS) has been found to be safe and effective in the resuscitation of patients with hypovolemic shock.
  • The position of the patient can be used to improve circulation e.g. raising the hypotensive patient’s legs while fluid is being given.
  • Control of internal hemorrhage depends on the source of bleeding and often requires surgical intervention. In the patient with trauma, external bleeding should be controlled with direct pressure; internal bleeding requires surgical intervention. Long-bone fractures should be treated with traction to decrease blood loss.
  • In the patient with GI bleeding, intravenous vasopressin has been used. Vasopressin commonly is associated with adverse reactions, such as hypertension, arrhythmias, gangrene, and myocardial or splanchnic ischemia. Therefore, it should be considered secondary to more definitive measures.
  • Virtually all causes of acute gynecological bleeding that cause hypovolemia (eg, ectopic pregnancy, placenta previa, abruptio placenta, ruptured cyst, miscarriage) require surgical intervention.

 

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