14.1 Shock, Crush Syndorme, Burns, Bites & Stings Flashcards
Define shock
- state whereby the cardiovascular system does not meet the metabolic demands of the tissue
- imbalance between oxygen delivery and consumption
- various types of shock, and can even occur in combination.
- common clinical finding: hypotension (Low Blood pressure)
Blood pressure (BP) is a function of the cardiac output (CO) and the peripheral vascular resistance (PVR). Cardiac output in turn is a function of Heart rate (HR) and stroke volume(SV). In other words how much blood and how fast it is pumping it
How do you calculate BP?
BP = CO x PVR
BP = (HR x SV) x PVR
- blood pressure will therefore be decreased if either the cardiac output is affected (Hypovolaemic shock, cardiogenic, obstructive) or if the peripheral vascular resistance drops (Distributive)
List and describe the 4 types of shock
Hypovolaemic
- loss of fluid (blood or water)
- most common
Cardiogenic
- cardiac muscle have been injured
Obstructive
- Cardiac muscle functions normally, but blood flow is impeded by pathology outside of the heart
- Causes incl: Tension Pneumothorax, Cardiac tamponade and Pulmonary embolism
Distributive
- peripheral circulation, blood vessels are vasodilated - decreased peripheral vascular resistance - impairs perfusion of tissue - anaerobic metabolism due to inadequate oxygen delivery
- Causes incl: Septic shock, Anaphylactic shock and Neurogenic shock
Triad of death
Sequence of cascading events can worsen outcomes
Triad:
- Metabolic acidosis
- Hypothermia
- Coagulopathy
Crush Syndrome Define
- Crush syndrome = significant trauma to muscle resulting in Rhabdomyolysis.
- This results in intracellular components being released into the circulation.
- “Crush injury” becomes a “Crush Syndrome” when this rhabdomyolysis leads to organ failure.
- Multi organ dysfunction is possible, but the most commonly affected organ is the renal system.
Crush syndrome
Pathogenesis
- reperfusion injury that appears after release of crushing pressure
- mechanism: release of breakdown products into blood
Products of rhabdomyolysis:
- myoglobin (nephrotoxic metabolism on kidneys)
- potassium
- phosphorus
- thromboplastin
- creatine
- creatine kinase
Systemic effects
- when crushing pressure is suddenly released without proper prep of pt
- causing reperfusion syndrome
- caused by traumatic rhabdomyolysis
Crush syndrome
Aetiology
- trauma
- exercise induced
- muscle ishaemia
- toxins
- prolonged immobilisation
- idiopathic paroxysmal myoglobin
- drugs
- infections
- connective tissue disorders
- viral
- electrolyte derangement & endocrine
- genetic disorders
- temp extremes
Classification of snake venom
- hemotoxic venom (RBCs; monovalent anti serum)
- myotoxic venom (Muscles)
- neurotoxic venom (nervous system; polyvalent; no anti serum)
- cytotoxic venom (living cells; polyvalent; no anti serum; lymph nodes)
- haemorrhagic envenoming (multiple organs)
Slide 10 +11
Classification of spider bites
Neurotoxic
- black and brown widow
- symp 1 hr after bite
Cytotoxic
- violin spider / sac spider
Rest on slide 13
Scorpion stings
Pedipalps vs Stingers
- Chill if the pedipalp{second pair of appenditures} is thicker than the stinger{tail}
- Venom acts on Sodium, potassium, Calcium and Chloride channels
- Causes excessive parasympathetic and sympathetic overstimulation with over activity of skeletal muscles
- Death caused by inability to swallow and ineffectual breathing
- P. transvalicus- 0.3 % mortality
- P. granulatus 3% mortality
- Greek for “to stretch”
- Caused by neurotoxin: tetanospasmin from Clostridium Tetani (gram +)
Distinguish between venomous scorpions
Highly venous
- thick tail
- thin pincers
- intense pain at site
- life threatening
Mildly venomous
- medium tail
- medium pincers
- wasp sting like symp
- localised pain
Weakly venomous
- thin tail
- thick pincers
- pin prick like symp
- itching
Burns: electrical burns
- Direct contact (low and high voltage)
- Indirect contact (through material that is an conductor)
- Electric arcs
- Flame
- Flash
- High energy current travels through body due to contact with electrical source
Injuries occur due to:
- flow of current through body
- arch flash
- clothing that catches fire
- arch flash or flow current: body produces electricity to thermal heat
- outward appearance of electric burn does not = to inward tissue and organ damage
Electrocution = refers only to person that have been killed as result of exposure to electricity
Full thickness burns
• destroy all layers of dermis
• injure underlying subcutaneous tissue
• Burn esher intact
• Anaesthetic / hyper aesthetic
• Waxy white, leather grey, black
• Dry skin, does not blanch with pressure
• hairs easily pulled from hair follicles
Two most common methods to assess total body area
1. Lunn brower chart
• recommend for children
• Superficial burns not included
• Most accurate for adults and children
• In %
2. Rule of 9’s
• patchy
• Used for health assessment
• Head: 9%
• Each arm: 9%
• Each leg: 18%
• Ant & post front: each 18%
Inhalation injury
- Injury to the airway from smoke, heat, vapors
- Can affect airways and cause systemic toxicity
- Based upon the primary localization of the insult, inhalation injury is classified into: upper airway injury; tracheobronchial injury; parenchymal injury
- Systemic toxicity: carbon monoxide toxicity; hydrogen cyanide toxicity
