Hypovolemic shock

Hypovolemic shock . Also known as hemorrhagic shock, it is a syndrome of multifactorial etiology but which has in common the reduction of blood volume. It is triggered by an inadequate systemic acute perfusion due to an imbalance between oxygen demand and supply to tissues due to inadequate supply or misuse on a cellular scale , leading to tissue hypoxia and dysfunction of vital organs determined by a reduction in circulating blood volume. This renders the heart unable to pump enough blood to the body.


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  • 1 Pathophysiology
  • 2 Classification
  • 3 Complications
  • 4 Symptoms it produces
  • 5 First aid
  • 6 Physical exam
  • 7 Complementary exams
  • 8 General measures
  • 9 Specific measures
  • 10 Steps to follow while medical help arrives
  • 11 Source


The initial primary injury is loss of circulating effective volume. It is a cyclical process that, once triggered, generates a sequence of phenomena, each of which unfavorably affects the next. The deterioration of blood flow to vital organs and tissues causes insufficient supply or inadequate distribution of oxygen, responsible for the serious alterations that this state of microcirculatory failure generates.


  • For hemorrhages
  1. Internal: Traumatic, broken vessels or solid viscera, complications of pregnancy (Ectopic), coagulation disorders.
  2. External: Pulmonary, gastrointestinal (ulcers, varicose veins), trauma, renal (infections, tumors)
  • By fluid depletion
  1. External losses: Vomiting, diarrhea , cutaneous burns, polyuria (diuretics, Diabetes)
  2. Internal losses: Pancreatitis, intestinal occlusion, ascites, generalized edema from burns, dehydration .


  • Kidney damage
  • Brain damage
  • Gangrene of arms or legs, sometimes leading to amputation
  • Heart attack

Symptoms it produces

  • Trauma or burns

Damage Scheme

  • Abdominal pain
  • Diarrhea
  • Vomiting
  • Amenorrhea
  • Bleeding
  • Thirst
  • Pain at injury site
  • Anxiety or agitation
  • Cold, clammy skin
  • Confusion
  • Decreased or absent urinary output
  • General weakness
  • Pale-colored skin (paleness)
  • Fast breathing
  • Sweating, clammy skin
  • Loss of consciousness

First aid

  • Loosen clothing or objects that press on your neck, chest, or waist.
  • Anti-shock position, lying on your back with your legs raised no more than 45º.
  • Avoid heat loss.
  • Insist on the control of bleeding.
  • Transfer to a health center, monitoring vital signs.

Physical exam

  • Low blood pressure (main sign). Decrease in systolic blood pressure below 90 mmHg or reduction by 30 mmHg of previous blood pressure levels in hypertensive patients
  • Profuse sweat
  • Cold, clammy skin
  • Mucous skin pallor
  • Visible external bleeding
  • It is related to the amount of volume loss
  • Weak and filiform radial pulse. The absence of peripheral pulses indicates greater severity. The presence of bradycardia suggests significant hemodynamic deterioration and the possibility of cardiac arrest
  • Superficial polynea
  • Oliguria or oligoanuria: It is one of the early signs that suggest inadequate renal perfusion
  • Peritoneal reaction in processes of intra-abdominal origin
  • Distal cyanosis
  • Poor capillary refill
  • Lightness (peripheral vasoconstriction)
  • Trauma, injury and / or fracture areas
  • Mental confusion

Complementary exams

  • Blood count: Normal hemoglobin at the beginning, decreases if bleeding
  • Hematocrit: Normal or decreased in acute bleeding
  • Blood group and factor
  • Glycemia
  • Creatinine
  • Abdominal UTS: If intra-abdominal cause of shock is suspected, blood or fluid may appear
  • Chest x-ray if hemothorax is suspected
  • Ionogram if possibilities
  • Gasometry

General measures

  • Horizontal rest or Trendelemburg of 10º
  • Leaky airway. If necessary, intubation of the patient
  • Improve the patient’s oxygenation. For this you need:
  1. Measurement of Hb saturation by pulse oximetry if available
  2. Oxygen therapy at 3-5 L per minute per mask with a reservoir or nasal catheter if the measured saturation decreases (remember that shock patients have increased oxygen demands)
  • Monitor:
  1. Blood pressure
  2. Heart rate (presence, frequency and quality)
  3. Breathing frequency
  4. Temperature
  5. Neurological state
  6. Pass bladder catheter to measure urine output if necessary
  • Inspection of the skin and search for external wounds with signs of bleeding and control of these. If there is an open fracture zone, immobilize the site and try to contain bleeding
  • Adequate intravenous access. Use 1 or 2 short and thick peripheral routes since the picture is recognized. Use trocars. According to the magnitude of the picture, perform a deep venous approach
  • Bladder catheterization and measuring hourly urine output
  • Levine probe open to bottle
  • Measure Central Venous Pressure (PVC) and take into account that:
  • Low indicates need for volume delivery (normal value: 8-12 cm H2O)
  • PVC that persists low or in decrease suggests persistence of blood loss and requires careful observation of the patient and also increases volume administration
  • Lower the temperature with antipyretics if the patient has fever (present in hypertonic dehydration)

Specific measures

  • If the patient does not improve oxygenation with oxygen therapy and has respiratory distress or respiratory depression, intubate for mechanical ventilation. Please note: Glasgow Coma Scale less than 8 points, signs of acute respiratory failure (PaO2 <60, PaO2 / FiO2 ratio <200 and / or PCO2 retention) or signs of muscle fatigue
  • Correction of alterations of the basic acid balance, especially of metabolic acidosis. If metabolic acidosis with pH less than 7.20 use sodium bicarbonate: 0.3 meq x kg x EB of the blood gas. Pass half of the calculated dose and repeat blood gas to assess the need to administer the rest of the calculated • Use of antishock pants, if available, taking into account:
  1. If there is shock and trauma to the chest, the use of this can aggravate bleeding and increase the possibility of death.
  2. It is very useful in patients with unstable pelvic fractures where it can stabilize the fracture and inhibit peritoneal hemorrhage.
  3. Blood volume replacement:

Steps to follow while medical help arrives

  • Keep the person warm and comfortable to avoid hypothermia.


  • Have the person lie down horizontally and raise their feet about 12 inches (30 cm) to increase circulation. However, if your head, neck, back, or leg injury is present, do not change your position unless you are in immediate danger.
  • Do not give liquids by mouth.
  • If the person has an allergic reaction, treat the reaction if you know how to do it.
  • If the person needs to be moved, try to keep the person lying down, head down, and feet elevated. Stabilize the head and neck before moving a person with suspected spinal injury.


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