Shock can be classified into 3 different types: Hypovolaemic Shock, Cardiogenic Shock, and Septic Shock. Whilst the management of shock varies based on the type of shock it is, the resulting effect of all 3 types of shock is the same – decreased tissue perfusion.
Features of a Hypovolaemic Shock
Hypovolaemic shock is the most commonly occurring type of shock, which is also easily reversible if treated in a timely manner. Features of a hypovolaemic shock include:
- loss of circulating or intravascular volume
- impaired tissue perfusion
- inadequate delivery of oxygen and nutrients
- may be caused by relative and absolute hypovolaemia, or loss of blood or other fluids
Absolute Hypovolaemia
The phrase Absolute Hypovolaemia refers to external loss of fluids from the body. Fluid loss may be that of whole blood (through trauma or major surgery), loss of plasma (through burns) and loss of other fluids such as massive diuresis (through skin loss), severe vomiting, diarrhoea, and dehydration (through diabetes insipidus – a rare condition unrelated to type 1 or 2 diabetes which causes diuresis and polydipsia, diabetic ketoacidosis, and HONK – hyperglycaemic hyperosmolar non-ketotic coma – coma resulting from very high blood glucose levels in a patient with normal ketone levels; very high blood glucose levels combined with high ketone levels may be due to ketoacidosis).
Internal Haemorrhage
Internal Haemorrhage may be caused by:
- fractures
- GI bleeding
- organ rupture (eg. spleen, liver, and kidneys)
- pregnancy complications (eg. ectopic pregnancy or post-partum haemorrhage)
Fluid Loss – from intravascular space to extravascular space – may be caused by:
- burns
- pleural effusion
- peritonitis – inflammation of the peritoneum
- pancreatitis – inflammation of the pancreas
- ascites – a condition in which fluid collects in spaces within the abdomen
Pathophysiology of Hypovolaemic Shock
- relative or absolute hypovolaemia
- decreased circulating volume
- decreased venous return (decreased preload)
- decreased stroke volume
- decreased cardiac output
- decreased cellular oxygen supply
- impaired tissue perfusion
- impaired cellular metabolism
Signs & Symptoms
- impaired consciousness
- pale, cool, clammy extremities
- prolonged capillary refill time
- increased heart rate
- increased respiratory rate
- hypotension (SBP <90mmHg & reduced pulse pressure SBP-DBP)
- reduced urine output
- metabolic acidosis
- signs of bleeding (decreased Haematocrit & Haemoglobin)
Management
- Identify & Treat the Underlying Cause
- Restore Intravascular Volume & Blood Pressure
- Redistribute Fluids to Ensure Perfusion
- Prevent Shock Progression
- Avoid onset of Cardiogenic Shock
- stop the bleeding by applying pressure to injured site and prepare patient for surgery
- administer antiemetics for severe vomiting, antidiarrhoeal agents to treat diarrhoea, insulin for dehydration caused by diabetes, and desmopressin for diabetes insipidus
- establish good venous access through large peripheral lines and central venous catheters
- insert a urinary catheter to monitor renal perfusion and fluid balance
- monitor haemodynamic parameters and the patient’s condition, and titrate fluid administration according to patient’s needs
- crystalloids are electrolyte solutions such as Isotonic (eg. normal saline or RLactate), Hypertonic (eg. 10% Dextrose) or Hypotonic (eg. 0.45% NaCl – Sodium Chloride); these address both fluid and electrolyte loss
- colloids include blood and its products such as Fresh Frozen Plasma (FFP), as well as synthetic plasma expanders such as Gelafundin (a colloidal plasma volume substitute in an isotonic balanced whole electrolyte solution that can be used for prophylaxis and therapy of hypovolaemia and shock); ADVANTAGES: colloids remain in the intravascular space, restoring fluids faster and with less volume, while blood restores Hgb; DISADVANTAGES: colloids are expensive, may cause reactions, and may also leak out of damaged capillaries, causing additional problems including cardiac failure and peripheral oedema
- based on the patient’s blood group and cross match, administer infusions of packed red blood cells to increase circulatory volume and oxygen carrying capacity; fresh frozen plasma, platelets, and cryo precipitate (the insoluble portion, or precipitate, that remains when the liquid portion of the plasma drains away) may also be indicated – blood products are commonly administered through a blood warmer so as to prevent or manage hypothermia
- during surgical procedures such as cardiothoracic surgery, chest and abdominal trauma, and orthopaedic surgery, the patient can receive own blood through the intra-operative blood salvage machine, which collects lost blood through a filtered tube and readministers it within 4 hours; this reduces the risk of reactions and infections, however, it does carry an increased risk of haemolysis and microemboli formation during the collection and administration period
- pay attention to any arising complications of fluid administration eg. allergic reactions and infection, electrolyte imbalance, dilution of haemoglobin and clotting factors, and pulmonary oedema (higher risk in older adults, and patients with chronic heart failure or renal failure); monitor patient’s urine output and fluid balance, haemodynamic monitoring, fluid responsiveness, and lung sounds
- haemorrhagic stroke drug therapy may include inotropes and vasopressors (typically adrenaline or noradrenaline and dobutamine) to increase cardiac output and blood pressure for better perfusion; these however increase oxygen demands; ensure secure airway and administer oxygen if needed to treat hypoxia; antifibrinolytics such as tranexamic acid may be required to prevent the breakdown of fibrin, which is the main protein in a blood clot
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Claire is keen about public education on health-related subjects as well as holistic patient-centered care. She is also passionate about spreading awareness on the negative effects that domestic abuse leaves on its victims’ mental, emotional, social and physical wellbeing.
Claire aspires to continue studying following completion of her Nursing Degree, because she truly believes in lifelong education.
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