Burns and Shock

Question 1

What is distributive shock

Answer 1

-Damaged tissue releases permeability factors→ neutrophils release more permeability factors and cytokines
- If large body surface area affected (i.e. 15-20% TBSA burns) → more permeability factors → can diffuse into bloodstream to become systemic
Even areas unaffected by the burn injury have leaky capillaries
-Protein leaks into the interstitial space reducing colloid osmotic pressure → less reabsorption of fluid at venous end
-Volume is not lost, just redistributed within interstitium around body → causes blood volume and then BP to fall leading to shock
Blood becomes hypercoagulable as RBC count is still the same in lower blood volume

Question 2

What is hypovolaemic shock

Answer 2

• Fluid is lost from exposed tissues and skin via evaporation
• Normally skin is a barrier to help retain fluid
• Loss of fluid can cause hypovolaemia
• Can add to problem of distributive shock in burns injuries

Question 3

What is cardiogenic shock

Answer 3

• Massive drop in blood volume → reduced venous return → reduced preload → reduced heart contractility
• Cytokines released as part of inflammatory response can also get into the blood and become systemic → some cytokines e.g. TNF-alpha, reduce cardiac contractility
• Cardiac stress leads to cardiogenic shock

Question 4

What are the examination and observations/trend results for:

• Trauma/bleeding
• Dehydration/poor intake
• Vomiting and diarrhoea
• Sepsis

Answer 4

EXAMINATION | OBS & TRENDS |

Signs of fluid loss
SBP < 100mmHg

Cool peripheries
HR > 90bpm

CRT > 2 secs
RR >20 breaths per min

45 degree leg raise +ve
NEWS = 5 or more

Question 5

What are examples of volume loss and volume shift?

Answer 5

• Volume loss
  
  • trauma/bleeding
  • dehydration/poor intake
  • vomiting and diarrhoea
• Volume shift
  
  • sepsis
  • anaphylaxis
  • neurogenic

Question 6

What is the Parkland Formula

Answer 6

2 - 4 ml x actual body weight (kg) x %TBSA burned

Used to work out fluid requirements in burn patients.

Question 7

What type of burn is the Parkland Formula not used for

Answer 7

Doesn’t include epidermal (first degree) burns

Question 8

How is the fluid given to the patient after calculated with the Parkland Formula

Answer 8

• From the time the burn was sustained, give 1/2 of fluid requirement in first 8 hours
• Give other 1/2 in subsequent 16 hours
• This is fluid given in addition to maintenance fluid

Question 9

Why is it important to not give too much fluid

Answer 9

• Leaky capillaries means lots of fluid can still get into interstitium leading to excess oedema in tissues
• Increased risk of compartment syndrome → where oedema compresses vessels in muscle compartments, leading to ischaemia within that compartment
• Ultimately it is important to always use end points for patients to tailor their fluid treatment.

Question 10

What is the rule of nines for TBSA for burns

Answer 10

Pretty much everything is 9%
Each leg is 18%, with front being 9% and back being 9%
Each arm is 9%, with front being 4.5% and back being 4.5%
Front of abdomen is 9%
Front of chest is 9%
Upper back is 9%
Lower back is 9%
Genitals is 1%

Question 11

How do the resus fluids differ from each other

Answer 11

Different types of fluid distribute differently across intravascular, interstitial and intracellular fluid.

Question 12

How does Dextrose distribute across the body’s tissues?

Answer 12

Assuming the glucose transporter is passive, glucose is distributed across all fluid compartments until equilibrium is reached

• It aligns with the 1/3 and 2/3 split of fluid across interstitial fluid and intravascular fluid
• This means dextrose is not very good for dehydration as it doesn’t really bulk up blood volume

Question 13

How does Saline distributed across the body’s tissues?

Answer 13

• Cells have lots of sodium transporters to prevent cell swelling and lysis and cellular dysfunction
• Cells actively pump sodium out if there’s excess
• This means very little of sodium gets into cells and sodium is pumped out with fluid following via osmosis.
• Saline gets split with 3/4 in intersitital fluid and 1/4 intravascularly.

Question 14

How is Ringers Lactate distributed across body tissues

Answer 14

Increase in intracellular volume
- as it contains Ca and K
so osmolarity is lower than in cells
so a bit of fluid will enter cells

Lactate helps to correct acidosis as it can be used to make bicarbonate

Question 15

How does saline and Hartmann’s compare in terms of
- Intracellular volume
- Extracellular volume
- Acidosis
- Coagulation
- Fluid balance

Answer 15

Intracellular:
Saline- no increase
Hartmann’s- mild increase

Extracellular- both increase

Saline- Hyperchloremic Metabolic Acidosis
Hartmann’s- lactate corrects acidosis

Saline- associated with HYPOcoagulopathy
Hartmann’s- clumping of RBC if infused alongside blood products

Saline- Unbalanced fluid (high CL-)
Hartmann’s- Balanced fluid (Ca, Cl, K)

Question 16

What does an epidermal burn mean

Answer 16

Epidermal → only involves the epidermis

Question 17

What is a superficial partial burn and does this require surgery

Answer 17

Superficial partial thickness burn:
Upper dermis damaged but the vascular plexus and most adnexal structures remain intact
- does not often require surgery

Question 18

What is a deep partial burn and does this require surgery

Answer 18

Deep partial thickness burn:
Extends into deep dermis affecting vascular plexus but not all of dermis is destroyed. Only deep adnexal structures are intact
- often require surgery to replace skin or remove dead skin

Question 19

What is a Full thickness burn and does this require surgery

Answer 19

Full thickness burn → has extended through entire thickness of dermis and no dermal tissue remains

Question 20

What is a Fourth degree burn and does this require

Answer 20

Fourth degree → extends to bone, skin is waxy and completely damaged, loses sensation

Question 21

After resus, what other aspects of care need to be considered

Answer 21

1. Admission to a specialist burns centre?
   
   • Burns require MDT management
   • Need to think of size, depth and location of burn
     
     • > 10% TBSA could be enough for burn centres to admit patients as higher percentage suggests more cardiovascular involvement
     • Full or deep thickness burns require surgical intervention
     • Burns on the face, groin or hands and circumferential burns which could limit function need specialist treatment
2. Ongoing fluid resuscitation
3. Supportive care
4. Tetanus immunisation → patients with burns at high risk due to large exposed wound
5. Surgery → required for deeper burns e.g. skin grafts, fasciotomy
6. VTE prophylaxis → due to immobility
7. Pain and anxiety → managed with analgesic, anaesthetics, psychological support

Question 22

What are some psychological impacts of major burns ?

Answer 22

• Flashbacks → vividly remembering a past time or incident
• Dissociation → mental process of disconnecting from one’s thoughts, feelings, memories and sense of identity
• Avoidance → maladaptive form of coping in which a person changes their behaviours to avoid thinking about, feeling or doing difficult things
• Insomnia → sleep disorder where trouble falling and/or staying asleep
• Hyperarousal → increased responsiveness to simuli with various physiological and psychological symptoms
• Hypoarousal → decreased responsiveness

Question 23

What are some examples of psychological support that can be offered

Answer 23

Some support that could be offered includes CBT, psychoanalytic therapy, support networks, pharmacological treatments of insomnia etc.

Question 24

How does Saline cause Acidosis

Answer 24

• Saline can start to dilute blood bicarbonate significantly which normally buffers blood so have to be careful of acidosis in patients with too much saline intake

Question 25

What is the most common mechanism of injury requiring admissions and most common cause of major burns

Answer 25

- most common mechanism of injury requiring admissions = scalds - most common cause of major burns = flame injuries

Question 25

What is the Baux score

Answer 25

main scoring system used to predict mortality and length of hospitalisation in adult burns injury

Question 25

What are the risk factors for burns

Answer 25

- worldwide risk factors for burn injury: - low socioeconomic status - overcrowding - cooking with kerosene - generalised poor health - poor safety practices - injuries more common in patients w/pre-existing psychiatric diagnoses, substance use problems and extremes of age - children = accidental and non-accidental - older and frail individuals with pre-existing medical conditions can present as collapse

Question 26

What is the first aid process for a burn

Answer 26

burn should be managed under cool or tepid running water for 20 min even up to 4hrs after injury sustained Stop burning process, cool burn and cover in non-adherent dressing e.g. clingfilm rest of patient must be warmed to prevent hypothermia

Question 27

What are the layers of the skin

Answer 27

5 layers of epidermis 2 layers of dermis subcutaneous fat connective tissue muscle

Question 28

What are the functions of the epidermis

Answer 28

immune function barrier to entry sensation and pain prevent fluid loss social and psychological

Question 29

What are the functions of the dermis

Answer 29

Regulation of temperature - sweating - dermal vascular plexus - piloerection skin durability and flexibility

Question 30

What is a first degree burn and how easily treated is it

Answer 30

First degree → epidermal/superficial partial thickness - has good blood supply + sufficient regenerating epidermal cells - with proper Rx can heath w/o scarring in 1-2 weeks

Question 31

What are second and third degree burns and how easily treated are they

Answer 31

Second degree → deep partial thickness Third degree → full thickness - deep partial thickness and full thickness have lost dermal vascular plexus and cells to heal - generally Rx inc. excision and skin grafting

Question 32

What is a fourth degree burn

Answer 32

burn that affects tissue deeper than dermis, fat and muscle - muscle injury can lead to compartment syndrome and rhabdomyolysis

Question 33

What factors affect the amount of tissue damage caused from a burn

Answer 33

Can be burn related or patient related: - burn related factors inc. aetiology, temp, duration of exposure e.g. wet heat causes greater damage than dry heat - patient related factors inc. skin thickness, age, if first aid was given

Question 34

What are the three zones of tissue injury for local effects

Answer 34

zone of coagulation = dead tissue as result of direct injury zone of stasis = hypoperfusion due to vasoconstriction in response to injury, vulnerable to ischaemia, infection and necrosis zone of hyperaemia = dead tissue prompts release of inflammatory mediators, act locally to cause vasodilation leading to increased vascular permeability and oedema

Question 35

What is the first aid process for a chemical burn

Answer 35

Same as for the other burns, with an added step: patient should be removed from exposure and all contaminated clothing removed, irrigate with running water or sterile fluids - acid 45 mins, alkali 1 hr irrigation

Question 36

When would you suspect hydrogen cyanide poisoning

Answer 36

If inhalation injury, cardiovascular instability and increasing blood lactate levels not responding to treatment - specific antidote - hydroxycobalamin - should be given

Question 37

How many cannulas are necessary for IV fluid resus

Answer 37

2 large bore cannulas are necessary

Question 38

Why do you need to look for the cause of reduced GCS in burns

Answer 38

- reduced GCS at presentation in major burns not caused by burn itself - must search for cause and appropriate management, could be - poisoning by inhaled toxins e.g. CO, hydrogen cyanide - overdose - trauma inc. head injury - medical comorbidities leading to collapse

Question 39

What is an Escharotomy

Answer 39

Escharotomies are surgical incisions through non-compliant full thickness burn, which restricts ventilation on chest and abdomen or causes sig. reduced perfusion in circumferential burns to limbs

Question 40

What is needed for an escharotomy

Answer 40

Escharotomies to produce decompression should be performed as soon as needed for ventilation or perfusion - incision longitudinal from unburned skin to unburned skin if possible, deep enough to reach subcutaneous fat and release eschar - need anaesthesia, diathermy to keep blood loss minimal, and prophylactic antibiotics

Question 41

When are fasciotomies most indicated

Answer 41

Involves cutting through subcut tissues and fascial layers around muscle compartments most commonly indicated in high-voltage electrical burns where tissue necrosis of muscle causes compartment syndrome.

Question 42

How do you examine corneal damage from a burn

Answer 42

examined with fluorescein stain

Question 43

How do you asses rhabdomyolysis

Answer 43

Electrical burns Measure CK level

Question 44

What are the benefits of early wound excision

Answer 44

shown to decrease blood loss, burn wound sepsis and length of stay

Question 45

What is the next step in surgical management after the skin has been excised

Answer 45

once burned tissue is excised, wound closure must be achieved to decrease fluid loss, prevent further wound desiccation and infection and reduce hypermetabolism - temp covering with allograft (skin from organ donors) or synthetic skin subsitutes - permanent with autologous split skin grafts = gold standard for burn wounds

Question 46

What is a hypermetabolic response

Answer 46

Hyperdynamic circulatory, physiological, catabolic and immune system responses

Question 47

How does acute hypermetabolic response occur

Answer 47

marked and sustained increase in catecholamines, glucocorticoid, glucagons and dopamine secretion initiate cascade

Question 48

What are some some examples for what occurs in hypermetabolic response

Answer 48

- massive protein and lipid catabolism - total body protein loss - muscle wasting - peripheral insulin resistance - increased energy expenditure - increased body temp - increased infection risks - stimulated synthesis of acute phase proteins in liver and intestinal mucosa