Chapter 63 - Thermal Burns

Question 1

What is the pathophysiology of thermal burns injuries?

Answer 1

Temp below 44C are generally tolerated for long periods of time without injury

Burn progression is a result of both necrosis and apoptosis of damaged cells

Young and old have thinner skin and fewer sweat glands/hair follicles - hence more susceptible to injury

Most commonly from residental fires

5-35% of patients hospitalized with burns will have inhalational injury

Question 2

What are the three concentric zones of a burn and their pathophysiology?

Answer 2

1) irreversible coagulation and necrosis - formed immediately
2) Ischemia with impaired circulation (tissue is at risk of subsequent necrosis) \
3) transient hyperemia

Question 3

List 6 indications for intubation in the burn patient?

Answer 3

1) Upper airway obstruction
2) Inability to handle secretions
3) hypoxemia despite 100% O2
4) patient obtundation
5) muscle fatigue suggested by high or low respiratory rate
6) hypoventilation (Pco2 >50mmHg and pH <7.2)

Question 4

What are the pulmonary complications of a thermal injury?

Answer 4

• Direct thermal injury rarely happens below the vocal cords but the smoke byproducts (chemical injury) lead to V/Q mismatch and pulmonary edema
• shedding necrosis of the mucosa leading to a cascade of dysfunction in all parts f the pulmonary system leading to |ARDS
• consider intubating early in patients who may look well but at risk of developing complications of airway burns (i.e patients with oropharyngeal swelling and a hoarse voice)

Question 5

How do you fluid resuscitate a burn patient?

Answer 5

1) parkland formula:
4cc/kg/%TBSA (excluding 1st degree)
use Ringer’s lactate
give 1/2 of the fluid in first 8 hours, remainder in teh next 16 hours

-titrate to urine output of 0.5-1.0 cc/kg/hr

Question 6

What is different about fluid resuscitation in pediatrics?

Answer 6

-Urine output target is 1.0cc/kg/hr
-infants should receive 5% glucose in their maintenance fluid as they lack carbohydrate reserves
-

Question 7

describe the depth classification for burn injuries?

Answer 7

1) first degree: 
Appearance: pink or red
Surface: dry 
sensation: painful 
Time to healing: days

2) superficial second degree
Appearance: pink , clear blisters
Surface: moist 
sensation: painful 
Time to healing: 14-21days

3) deep second degree
Appearance: pink , hemorrhagic blisters, red
Surface: moist
sensation: painful
Time to healing: weeks or may progress to 3rd degree and require graft

4) third degree
Appearance: white, brown
Surface: dry, leathery 
sensation: insensate 
Time to healing: requires excision 

5) fourth degree
Appearance: brown, charred
Surface: dry
sensation: insensate 
Time to healing: requires excision

Question 8

List indicators for upper airway and lower airway burns:

Answer 8

1) upper airway (supra-glottic)
- soot in and around nose/mouth
- charring
- mucosal inflammation or necrosis
- edema

2) lower airway (subglottic)
- wheezing
- crepitations
- hypoxemia
- abnormalities on CXR
- V/Q mismatch, decreased lung compliance, microatelectasis >ARDS

Question 9

What is the Rule of 9’s?

Answer 9

Head front and back - 9%
upper limb - 9% each arm (front and back)
Trunk -36% total; 18 front and 18 back
lower limb - 18 % each leg (front and back)
-perineal: 1%

Question 10

What’s the modified rue of 9’s in pediatrics

Answer 10

A lund-browder chart

children have larger heads, smaller thighs, and smaller lower legs

Question 11

What are the criteria for transfer to a burn unit?

Answer 11

• Large burns (>20% TBSA in adults, >10% in children or elderly)
• Deep burns (>5%full thickness)
• high voltage burns
• burns over sensitive areas (i.e. face, ears, joints, hands, feet, perineum)
• escharotomy required

Question 12

Describe basic burn dressing management:

Answer 12

1) ABCs
2) Analgesia, analgesia, analgesia
3) Prevent hypothermia
4) assume burns are contaminated - clean and debride gently
5) tetanus toxoid booster if eligible (>5 years since last)
6) Leave blisters intact, debride ruptured blisters
7) Dressing for patial-thickness burns
8) clearly infected, purulent wounds should be managed in an open manner (topical antimicrobials, non-adherent dressing, daily dressing exchange)

Question 13

What are the indications for an escharotomy?

Answer 13

1) circumferential chest or neck burns with:
- increased airway pressure
- hypoxemia
- difficulty with ventilation

2) Circumferential extremity burn with:
- decreased doppler signal distally
- pulse oximetry of less than 90% distally in the limb
- pain, loss of sensation, delayed cap refill (early signs)

Question 14

What are the investigations and management for burn patients?

Answer 14

1)CBC
2)lactate - predicts mortality with cyanide poisoning
3)VBG - tells you the level of acidosis (pH), metabolic, anion-gap
4)carboxyhemoglobin - level of CO poisoning
cyanide level
5) NPO
6) fluids (parkland formula) vs. just bolus if not severe
7) tetanus shots for burns
8) CXR - risk of pneumonitis/ARDS after fluid resuscitation
9) bronchodilators if wheezing patient