Burns
Introduction
A burn is damage to the skin (or also to a mucosa) caused by the effect of an energy source. Apart from the skin, burns can also affect mucous membranes, such as the ocular, oral, respiratory, and genital mucosa. The skin consists of two layers, the epidermis, and dermis. Deep to the skin is the subcutaneous fat and then a fascial membranous layer before the deeper tissues, such as muscle. Heat (and other mechanisms of injury) can cause protein denaturation, leading to plasma membrane damage and cell necrosis. Depending on the source of energy that has resulted in skin damage, burns are classified into the following types:
Thermal burns (due to a heat
source, such as a warm liquid, steam, fire, contact with a warm metal surface,
etc). The thermal burns are the most common ones).
Electrical burns: these are
caused by the effect of electric current. A characteristic of electrical burns
is the so-called “iceberg effect’’. This term refers to the fact, that in severe
electrical burns, the damage is not limited to the skin lesion that is visible.
There is often severe damage to the underlying tissues (e.g. muscles). In
addition, a risk of concomitant complications of an electric shock (e.g.
cardiac arrhythmias) is also present.
Chemical burns due to the
effect of a chemical agent (acid or alkali). Patients with chemical burns also
have a risk of inhalation injury.
Burns due to the effect of radiation (sun-burns, radiation treatment of
cancer etc.)
Cold (Damage to the skin similar to a burn can also be caused by the
effects of cold)
Major factors that determine the severity of the patient’s condition are:
•The depth of the burns
•The total percentage of the body surface area affected. (If this percentage is about 15-20% or more,
the case is considered as a severe burn injury, because these patients have an
increased risk to develop complications).
Generally, a major burn is any burn with >20% of total body surface area (>10% in
children) of partial or full-thickness burns, i.e. second or third-degree burns
(see below). Superficial burns are not included in this calculation of the percentage
of total body surface area burned. Major burns can result in profound
inflammatory responses and large fluid shifts, therefore aggressive fluid
resuscitation is often required to prevent the development of circulatory shock.
•The patient’s age: Children, as well as elderly people, have a higher
risk of complications.
•Comorbidities (Diabetes, peripheral vascular disease, and heart failure
increase the risk of complications)
Patients with severe burns enter a state of ‘‘burn shock,’’ which is
characterized by profound capillary fluid leakage and widespread release of
inflammatory mediators leading to a state of shock with poor tissue perfusion.
Physical examination of the patient with burns
In a patient with major burns, his or her general condition (vital signs, airway and respiration, circulation, level of consciousness) should first be assessed, as in the case of a trauma patient. Hypothermia is a severe risk following burns injury, due to the extensive heat and fluid loss that can occur from the damaged skin, therefore assessment should take place in a warmed room.
Also, assess for the concomitant presence of trauma and obtain the patient's history (chronic disease, allergies, medications, and tetanus immunization status). Examine the patient for signs of inhalation injury, such as respiratory distress, wheezing, hoarseness, facial burns, carbonaceous sputum, soot in the mouth, or singed nasal hair. If evidence of airway compromise is present, with swelling of the neck, wheezing or respiratory distress, perform early endotracheal intubation.
The adequacy of the circulation should be assessed by noting the blood pressure, pulse rate, capillary refill time, and mental status. Intravenous fluids should be administered to patients with signs of decreased intravascular volume or extensive second or third-degree burns, according to the estimated requirements (see below). urinary output. The extent and depth of the burns are also assessed and wound care is performed. An assessment of the depth and the extent of burns follows. Burns often occur unevenly, thus a patient may have burns with various depths.
• First-degree (superficial)
burns: They affect only the epidermis. The skin is intact, erythematous (with red color), and very painful, with minimal to no edema and no blistering.
Treatment is with topical salves (ointments). Analgesics (NSAIDS or
paracetamol) occasionally may be required for pain management. These burns heal
spontaneously after 2-5 days without scarring.
• Second-degree
(partial-thickness) burns: The epidermis and part of the dermis are affected. These
burns are further classified into:
-Superficial partial-thickness
burns: The skin is cherry-red and moist with edema and blistering. The skin is
also very painful and two-point tactile discrimination is intact. When pressure is applied to the skin, it blanches easily with a virtually immediate
capillary refill. If blisters are present, they are usually thin and can be
addressed with mild debridement. These burns are treated with topical
antimicrobials and sterile dressing. Analgesics are prescribed for pain
management. Skin grafting is not required. They heal in about 7-21
days without scarring.
-Deep partial-thickness burns: Tissue
injury involves not only the epidermis and papillary dermis but also part of
the reticular dermis (which is the deep layer of the dermis). The skin appears red to pale pink in color, with
extensive blistering. It blanches poorly due to the destruction of blood vessels.
The sensation of pain is absent or significantly decreased in the burned area
(although it may be present in the periphery). Only the sensation of pressure
is intact in these burns. These burns are treated with topical antimicrobials
(antimicrobial ointments) and sterile dressing. Healing time is more prolonged,
about 21-35 days with no infection. If they are infected they can convert to
full-thickness skin damage, like a full-thickness burn. If a majority of the
dermis has been damaged, this type of burn can result in scarring. Scarring may
cause functional impairment especially if the injury is over a joint area.
• Third-degree (full-thickness)
burns: The epidermis and the whole thickness of the dermis are affected, and often also part of the subcutaneous tissue (hypodermis). Hair follicles and sweat glands have been destroyed. The skin is dry, charred (with a black
surface) or white, painless (as a result of the damaged nerves) and leathery.
There is very little or no pain, and hair can be pulled out easily. These burns
are covered with an antimicrobial ointment and are referred to a burn
specialist (plastic surgeon) for excision and skin grafting. Small areas may
heal from the edges after some weeks without grafting, but large areas will
need skin grafting.
• Fourth degree, deep full-thickness burns, extend past the layers of the skin and subcutaneous tissue with damage to deeper tissues, such as muscles, tendons, or even bone. Tissue destruction is prominent and obvious and the skin is usually black in color. Usually, there is a large surrounding zone of injury which contains varying depths of tissue damage. Treatment requires extensive debridement, tissue reconstruction (muscle flaps), and occasionally amputation.
 |
| Types of burns according to their depth (from left to right first degree, second degree, third degree) |
 |
| Superficial (first degree) burn |
 |
1,2: Partial thickness (second degree) burns 3,4: Full-thickness (third degree) burns |
The rule of nines
The Rule of Nines, also known
as the Wallace Rule of Nines, is a tool utilized to estimate the percentage of
the total body surface area burned. This tool is used only for second-degree
and third-degree burns (also referred to as partial thickness and full-thickness burns) and aids the physician to determine the severity of the
patient’s condition and to estimate intravenous fluid requirements.
According to this rule percentages
of the total body surface area (TBSA) are assigned to different body areas, as
follows:
The entire head: 9% (4.5% for
anterior and posterior aspect).
The entire trunk is estimated
at 36%. This can be further divided into the anterior surface of the trunk (18%)
and the back (18%). The anterior aspect of the trunk can further be divided
into the chest (9%) and the abdomen (9%).
The upper extremities are
estimated at 18% of the TBSA and thus 9% for each upper extremity. Each upper
extremity is divided into its anterior surface (4.5%) and posterior surface
(4.5%).
The lower extremities are
estimated at 36% of the TBSA. Thus, each lower extremity is estimated at 18%
TBSA and this can be divided into the anterior aspect (9%) and the posterior
aspect (9%) The groin and the genital area is estimated at 1%.
The size of the patient’s palm is estimated at 1% of TBSA.
Treatment of the patient with burns
In a patient with severe burns, his or her general condition (vital signs, airway, and respiration, circulation, level of consciousness) should first be assessed, as in the case of a trauma patient. Protection of the airway (if needed) and management of shock (if present or imminent) are the first actions.
In some severe cases, endotracheal intubation will be required to protect the airway and support
respiratory function. Endotracheal intubation (not LMAs) is indicated in the
following circumstances:
Comatose patient
Symptomatic inhalation injury
Deep facial burns
Burns extending over 40% of
the total body surface area (TBSA)
Fluid resuscitation is
required for patients with second or third-degree burns that involve ≥ 20% of
TBSA (total body surface area). Typically lactated Ringer (L-R) solution is
used. The required amount of intravenous fluids is usually calculated by the
Parkland Formula. Although this formula is helpful as an initial guide, i
Parkland Formula for Fluid
Resuscitation
Adults:
The total volume (in ml) of lactated
Ringer (L-R) solution administered over the first 24 hours =
4 mL × weight (kg) × % BSA burned (with second
or third degree burns)
Half of this volume is infused
over the first 8 hours and the other half over the subsequent 16 hours
Example: 80-kg adult with 30%
second- and third-degree burns:
4 mL × 80 kg × 30 = 9600 mL
over 24 h
BSA= body surface area.
In children :
The total volume (in ml) of L-R
administered over the first 24 hours =
3 mL × weight (kg) × % BSA
burned (with second or third degree burns) plus maintenance fluids
Half of this fluid volume will
be administered over the first 8 hours and the other half over the subsequent
16 hours
Ongoing fluid administration after the initial
24 hours is guided by the vital signs, peripheral perfusion, and adequate urine
output. Urine
output is an especially useful guide.
A urinary catheter should be placed in patients with:
:•Extensive second or third degree burns (> 20% TBSA). This is required during the first 48 hours to guide fluid administration.
•Genital burns.
Wound care- prevention of infection
Burns create an open wound
where bacteria can easily colonize and this may lead to cellulitis (topical
bacterial infection) or sepsis. Thus, wound care is required to prevent
infection and facilitate healing. Wound care should be performed immediately
after completing the primary and secondary assessment and the treatment of any
life- or limb-threatening conditions. Before wound treatment, an analgesic agent should be
administered (Severe pain is usually
managed with opioids such as IV fentanyl or morphine).
Wash the area with water and
skin disinfectants or antibacterial soap. Clean away any materials present on
the wound and debride large ruptured blisters and apply antibacterial ointment and
nonadherent gauze. The gauze, secured with tape, should be loose enough to
allow for subsequent swelling of the wound.
Tetanus immunization is administered
in any patient with burns deeper than superficial.
If the patient develops a high fever, the infection should be managed promptly. Then obtain cultures and administer broad-spectrum antibiotics until a specific causative organism is identified in the cultures.
Complications of Burns
Local complications
Local complications include local infection, eschars, contractures (impairing the function of joints) and scarring. An eschar is stiff and hard dead tissue which may be present in deep burns. A circumferential eschar, which completely encircles a limb, or occasionally the neck or torso may cause local constriction. A constricting eschar may cause severe ischemia of limbs and digits. In the limbs, this can present with pallor, pain, paresthesia (tingling or numbness), paresis, decreased temperature (the affected limb will be cold), and absent pulse (a late sign). Moreover, oxygen saturation will be decreased (usually less than 95%) and Doppler signals will be decreased or absent in the affected limb. A constricting eschar around the neck or thorax can compromise ventilation.
In case of a constricting eschar a surgeon must perform escharotomy, a surgical procedure that creates an incision of the eschar down to the level of the subcutaneous fat.
Systemic complications
The most common systemic complications are hypovolemia and infection.
■Fluid loss can result from deep burns involving a large part of the body surface and in severe cases it can lead to severe hypovolemia (reduced circulatory volume) and shock. Fluid loss results from the damage to the normal epidermal barrier which allows external fluid loss and from extravasation of fluid into the interstitium of edematous damaged tissues. Electrolyte disorders (e.g. hypokalemia, hypomagnesemia), hypoalbuminemia (due to protein loss into the extravascular space through damaged capillaries and also due to hemodilution resulting from the administration of IV fluids)), or metabolic acidosis (due to circulatory shock) may also occur.
■Infection, localized initially, may become systemic and lead to sepsis. In the first few days, the most common pathogens are streptococci and staphylococci, whereas gram-negative bacteria are common after 5 to 7 days.
■Rhabdomyolysis can occur in cases of electrical or deep thermal burns causing damage to muscular tissue. It may also result from muscle ischemia due to constricting eschars. Rhabdomyolysis results in myoglobinuria, which in turn may lead to acute tubular necrosis and acute renal failure
■Hypothermia may also occur in patients with extensive burns.
■Paralytic ileus is common in patients with extensive burns.
GO BACK TO THE TABLE OF CONTENTS
LINK: Emergency medicine book-Table of contents
Bibliography
Lang TC, Zhao R, Kim A, et al..
A Critical Update of the Assessment and Acute Management of Patients with
Severe Burns. Adv Wound Care 2019;8(12):607-633. doi: 10.1089/wound.2019.0963
Moore RA, Waheed A, Burns B.
Rule of Nines. [Updated 2021 Jul 9]. In: StatPearls [Internet]. Treasure Island
(FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513287/
Burns assessment .
Teachmesurgery.com LINK https://teachmesurgery.com/plastic-surgery/burns/burns-assessment/
Strauss S, Gillespie GL. Initial
assessment and management of burn patients. AmericanNurseToday.com
LINK https://www.myamericannurse.com/initial-assessment-mgmt-burn-patients/
Cancio LC. Initial assessment
and fluid resuscitation of burn patients. Surg Clin North Am. 2014;94(4):741-754.
No comments:
Post a Comment