Shock Flashcards
How is shock defined?
-Clinical syndrome caused by inadequate tissue perfusion and oxygenation leading to abnormal metabolic function
When does hypovolaemic shock occur?
-When the volume of the circulatory system is too depleted to allow adequate circulation to the tissues of the body
How does hypovolaemic shock present?
-Patient feels cold, unwell, faint, breathless
-Postural hypotension may be present
-Gut ischaemia –> N+V
-Pale and sweaty appearance
-Tachypnoea
-Prolonged CRT
-Tachycardia and BP drop (NB young people may not have as significant a drop)
What are the stages of hypovolaemic shock?
-Class 1 = 10-15% blood loss, physiological compensation means no clinical changes
-Class 2 = 15-30% blood loss, postural hypotension, vasoconstriction and reduction in urine output to 20-30ml/hour
-Class 3 = 30-40% blood loss, hypotension, HR >120, tachypnoea, urine output <20ml / hour, confusion
-Class 4 = 40% blood loss, marked hypotension, tachycardia and tachypnoea, no urine output and patient is comatose
How would you investigate a patient with hypovolaemic shock?
-Hb, U+Es, LFTs and G&S and crossmatch if haemorrhage or burns
-Coagulation screen
-Blood gases (raised lactate = tissue hypoxia)
-Monitor urine output –> catheter
-USS to differentiate between hypovolaemic and cardiogenic
How would you manage a patient with hypovolaemic shock?
-High-flow oxygen
-Early venous access
-Fluid resuscitation (crystalloid eg Harmtann’s, saline)
-Cross match blood
-Central venous pressure line measures volume balance more sensitively than BP/pulse
-IV analgesia for pain (pain increases metabolic rate so aggravates tissue ischaemia)
What causes cardiogenic shock?
-Failure in pumping action of the heart leading to decreased cardiac output and reduced end-organ perfusion
-Most commonly occurs as a consequence of MIs, particularly affecting the anterior wall of the heart
-PE, tension pneumothorax and tamponade can also cause it
How is cardiogenic shock defined?
-Sustained hypotension (systolic <90 for >30mins)
AND
-Tissue hypoperfusion (cold peripheries, oliguria)
How does cardiogenic shock present?
-Skin, brain, heart and kidneys are usually the most severely affected organs
-Often presents with specific MI symptoms as the. main cause is ischaemic heart disease (other causes include trauma)
How should you manage a patient with cardiogenic shock?
-A-E approach
-TTE used to determine evidence of pericardial fluid or direct myocardial injury (trauma)
What is the mechanism of anaphylactic shock?
-Allergen reacts with IgE abs triggering rapid release of histamine and synthesis of newly formed mediators
-Causes capillary leakage, mucosal oedema –> shock and asphyxia
What upper and lower airway symptoms does anaphylactic shock cause?
Upper:
-Swelling of lips, tongue, oropharynx, epiglottis
-Laryngeal oedema
Lower:
-Bronchospasm
-Wheeze
-Dyspnoea
-Chest tightness
How do you manage anaphylactic shock?
A - if compromised, manage appropriately (LMA, NGA), give IM adrenaline ASAP
B - administer 15L via NRBM, give bronchodilator if further deterioration
C - give 0.9% saline 500ml/1L if hypotensive, raise legs
Give chlorphenamine followed by hydrocortisone IM or slow IV
How are sepsis and septic shock defined?
-Sepsis = an infection triggering Systemic Inflammatory Response Syndrome
-Septic shock = sepsis with organ failure and dangerously low BP, altering metabolism - toxins damage blood vessels, causing them to leak fluid into surrounding tissues
Which surgical patients are most at risk of developing septic shock?
-Those with anastomotic leaks, abscesses and extensive superficial infections eg necrotising fasciitis
