Burns and Smoke Inhalation

  • Author: Listy Thomas, MD FACEP, Emergency Medicine / Internal Medicine, Assistant Director, Clinical Arts and Sciences Course, Associate Professor, Department of Medical Sciences, The Frank H. Netter MD School of Medicine at Quinnipiac University
  • Editor: Nicholas E. Kman, MD, FACEP, Director, LSI Part 3/Med 4 Academic Program, Associate Professor of Emergency Medicine, The Ohio State University Medical Center 
  • Last Updated: 2016

Introduction

Burns are a major cause of injury worldwide. In the US, about 500,000 patients are treated for burns annually. Burns affect all ages and correct management is crucial in the prevention of morbidity and mortality.

Objectives

  • Summarize the mechanisms of injury in burns
  • Recognize the different types of burns and their characteristics
  • Describe the basic management protocols of the different types of burns
  • Assess and treat a patient for inhalational injuries

Flames cause the majority of thermal burns. Other types of burns are scalds (which are the second most common), chemical, electrical, and radiation. 90% of burns are preventable by employing proper fire prevention techniques.

  • Zone of coagulation – irreversibly damaged at the time of injury; thrombosed blood vessels so no blood flow. 
  • Zone of stasis – area immediately surrounding the necrotic zone of coagulation and has decreased tissue perfusion, may become necrotic also or survive. This is the area you are trying to save.  
  • Zone of hyperemia – area of inflammatory vasodilatation surrounding the burn wound, with increased blood flow, so it will recover spontaneously. Not at risk for necrosis.  

Initial Actions and Primary Survey

Priority: Assess and manage the patient’s ABCDE’s and stop the burning process (for example, remove all clothing, jewelry, injurious material, and decontaminate the patient if necessary).

  • Airway: Early prophylactic intubation is advised for severe airway burns or smoke inhalation. Airway edema can occur 12 to 24 hours later.
  • Breathing: 100% Oxygen therapy for inhalational injuries; mechanical ventilation as needed.
  • Circulation: Placement of 2 large bore peripheral lines in unburned areas of skin. IV fluid resuscitation based on Parkland formula (Ringer’s lactate at 2 to 4 ml/kg per % TBSA per 24 hours with half the calculated fluid given in the first 8 hours is an effective modality in severe burns).
  • Disability: Assess mental status and GCS.
  • Exposure: Carefully expose the entire body to assess all areas of burn, remove all clothing and jewelry. Avoid hypothermia in the process. Decontaminate as needed for chemical injuries.

Presentation

Ascertain from the patient the mechanism of injury and areas affected, the circumstance surrounding the event, the material causing the injury (i.e. fire, smoke, steam/scald, electrical, chemical, etc.), time and length of time of exposure, associated symptoms, prehospital care, and presence of comorbid conditions and substance use.

Burns can cause injury to more than just the skin. Be mindful of ocular, pulmonary, and cardiac injuries from burns, but also delayed injuries to the musculoskeletal system, nervous system and kidneys.

  • Minor burns are partial thickness, isolated, do not cross major joints, are not circumferential, and do not involve the hands, face, feet, or perineum.
  • Major burns, by convention, are the ones that would require referral to a burn center.

Burn Center Referral Criteria (ABA)

Burn injuries that should be referred to a burn center include:

  1. Partial thickness burns greater than 10% total body surface area (TBSA).
  2. Burns that involve the face, hands, feet, genitalia, perineum, or major joints.
  3. Third degree burns in any age group.
  4. Electrical burns, including lightning injury.
  5. Chemical burns.
  6. Inhalation injury.
  7. Burn injury in patients with preexisting medical disorders that could complicate management, prolong recovery, or affect mortality.
  8. Any patient with burns and concomitant trauma (such as fractures) in which the burn injury poses the greatest risk of morbidity or mortality. In such cases, if the trauma poses the greater immediate risk, the patient may be initially stabilized in a trauma center before being transferred to a burn unit. Physician judgment will be necessary in such situations and should be in concert with the regional medical control plan and triage protocols.
  9. Burned children in hospitals without qualified personnel or equipment for the care of children.
  10.  Burn injury in patients who will require special social, emotional, or rehabilitative intervention.

Depths of Thermal Burn

Based on image from Sabiston
Depths of Thermal Burns

First-degree burns are confined to the epidermis. These burns are partial thickness and appear superficial, red, and sometimes painful. Heal in one week generally with no scar.

First degree burn (sunburn)

First Degree Burn (source: Wikimedia-First-degree burn.jpg)

https://commons.m.wikimedia.org/wiki/File:First-degree_burn.jpg
First Degree Burn

Second-degree burns extend into the dermis and can be superficial or deep partial thickness. Skin may be red, blistered, swollen. They are generally very painful. Superficial burns can heal in 2-3 weeks with no scarring. Healing can occur in 4-6 weeks for deep burns, with scarring.

 

Second degree burn with blister formation

 
2nd Degree Partial Thickness Burn
 

Second Degree (Superficial Partial-Thickness Burn) to Shoulder (Wikimedia-second-degree burn on shoulder.jpg)

Third-degree burns are full thickness through the epidermis and dermis, and thus require skin grafting to heal appropriately. Skin appears whitish, charred or translucent, no pin prick sensation in burned area.

Third degree full thickness burn

Fourth-degree burns involve injury to underlying tissue structures such as muscle, tendons, and bone. These require extensive reconstructive surgical repair/ skin grafting.

Electrical injuries are associated with burns as well. Burns occur with high voltage electrical injuries (> 1000V) and the extent of the injuries may not be clearly evident on the initial skin assessment. When an electrical burn is suspected, it is important to consider the type of current causing the insult as well as the flow of current through the body. AC current is used in standard households, but can result in tetany and ventricular fibrillation due to the cyclical alternating current. DC current is supplied in batteries and lightning. Both are associated with cardiac dysrhythmias and both can cause associated blunt force trauma by hurling the patient.

Differential diagnoses include: photosensitive drug reaction, cellulitis, Stevens Johnson syndrome/TEN.

Diagnostic Testing

Percentage Total Body Surface Area (TBSA) (is it possible to insert a calculator on the site for this??)

The “rule of nines” for estimating second-degree and third-degree burns.

https://commons.m.wikimedia.org/wiki/File:513_Degree_of_burns.jpg
Rule of Nines chart: https://commons.m.wikimedia.org/wiki/File:513_Degree_of_burns.jpg

Because infants have significantly larger heads and smaller legs than do adults, different rules must be used in evaluating these patients. A simple, practical rule is that the palm of the patient’s hand, with fingers, equals 1% of the total body area.

 

Labs: CBC, electrolytes, glucose, renal function, coags, type and cross, lactic acid and carboxyhemoglobin (if fire), alcohol level and toxicology screen. EKG, CXR.

In Electrical Burns: Lack of findings on the overlying skin does not eliminate the possibility of severe deep injury to muscle and fascia. If the patient has myoglobinuria, fluids should be increased to achieve a urinary output of 100 mL/hour. If metabolic acidosis exists, it is important to maintain adequate perfusion, and the patient may need sodium bicarbonate intravenously.

Treatment:

Accurate estimation of the burn size is crucial in early management decisions. More than 15% BSA burns require aggressive IV hydration. Be cautious of overly aggressive hydration in patients with inhalational injuries (see below), as these patients are at risk for ARDS.

Parkland’s formula: Ringer’s lactate at 2 to 4 ml/kg per % TBSA per 24 hours with half the calculated fluid given in the first 8 hours is an effective modality in severe burns. In general, infusion rates should be titrated to maintain urine output at 0.5–1.0 mL/kg/h for adults and 1.0 mL/kg/h for children under 10 kg.

http://www.mdcalc.com/parkland-formula-for-burns/

 

Labs: CBC, electrolytes, glucose, renal function, coags, type and cross, lactic acid and carboxyhemoglobin (if fire), alcohol level and toxicology screen. EKG, CXR.

Escharatomy is required for circumferential burns, especially of the thorax.

 

Escharotomy of the chest (http://lifeinthefastlane.com/trauma-tribulation-005/)

All burns should be treated with cooling of the skin (do not ice burns as this can extend the zone of coagulation), tetanus vaccination and pain control. Minor burns require cleansing of the skin, possible debridement, and sterile dressings. Topical antimicrobial ointments that have efficacy against Gram-negative organisms such as silver sulfadiazine should be applied. Oral antibiotics are usually not necessary for initial burn presentations. Patients should be advised follow up for wound reevaluation in 2-3 days.

Major burns should be referred to a regional burn center. Electrical burns from high voltage require at least 24 hours of cardiac monitoring, as well as evaluation for rhabdomyolysis and myoglobinuria. Patients who have electrical, chemical, or inhalation burns also merit burn center referral.

 

Burn Zones and Resuscitation (diagram c/o Dr. Ann Dietrich)

Protection of health care personnel and early decontamination is paramount in treating patients who have chemical injuries.

Pearls and Pitfalls

Prevention is key! Functional smoke detectors, splash guards on stovetops, safety devices around fireplaces, practicing fire escape plans for the family, and lowering the maximum temperature of the hot water heater are all practical ways to practice burn prevention at home.

Consider abuse. Suspect child abuses in delay of care presentations or discrepancies in history and physical. Most common areas of burns are in the buttock and perineum especially in toilet training children who are exposed to scalding immersion. Cigarette burns are also common in every age group.

Infection control is a priority for burn patients, as sepsis is the major leading cause of mortality. High-risk patients include the elderly over 50 years of age and young children less than 10 years of age. Patients with comorbid conditions such as diabetes, heart disease, chronic lung diseases and renal disease are always associated with increased risk of complications as well. The risk of death from a major burn is associated with the presence of inhalational injuries, female sex, older age and larger burn size.

Smoke inhalation:

A major cause of mortality from burns comes from smoke inhalational injuries.

Consider airway injury in any patient exposed to a fire in a confined location as well as in the intoxicated patient and any patient with neck and facial burns. Upper airways tend to be more affected than lower airways. Symptoms include shortness of breath, sore throat. Exam findings include stridor, drooling, change in voice, wheezing, singed nasal hairs, burned facial hairs, soot in the nares, and soot in sputum are all indications of thermal injury to the airway.

Combustion of noxious chemicals can also be a risk factor for smoke inhalation. Acrolein, Hydrochloric acid, toluene, and nitrogen dioxide are common examples.

Airway edema is confirmed by direct laryngoscopy or fiberoptic bronchoscopy. Patients with smoke inhalation injury require hospitalization for observation for 24 hours due to the delayed nature of airway edema.

The most common complication of smoke inhalation is carbon monoxide poisoning . The classic clinical finding of cherry-red skin color is not a frequent or reliable finding in patients with carbon monoxide poisoning. Carbon monoxide is a tissue asphyxiant through its stronger affinity to hemoglobin compared to oxygen. Carboxyhemoglobin shifts the oxy-hemoglobin dissociation curve to the left, making it more difficult for hemoglobin to release bound oxygen to the tissues, resulting in tissue hypoxia and mitochondrial dysfunction. The half-life of carboxyhemoglobin is about 4–5 hours; administration of 100% oxygen reduces it to one hour. Hyperbaric oxygen will reduce the half-life of carboxyhemoglobin to 20 minutes.

Smokers usually have baseline carboxyhemoglobin levels of 4–6%. Levels above 10% signify significant exposure but patients may be asymptomatic when carboxyhemoglobin levels are below 10–15%. Hyperbaric oxygenation may be useful in the severely poisoned patient who fails to respond to therapy with 100% oxygen. Patients with carboxyhemoglobin levels greater than 25% may require hyperbaric management. Other indications for hyperbaric oxygen therapy in the setting of carbon monoxide toxicity have been described in patients with neurologic symptoms, seizures, pregnancy, or depressed consciousness.

Check ABG but remember that patients with carbon monoxide poisoning may have normal PaO2 and normal SaO2 (oxygen saturation) so remember to check the carboxyhemoglobin levels. SubstractSubtract the percent of carboxyhemoglobin from the measured saturation obtained from the pulse oximeter to obtain the actual saturation of oxygen.

Also check cyanide levels (especially if high lactic acidosis).

Give bronchodilators to relieve bronchospasm.

References

  1. Saks, Mark. “Burns and Smoke Inhalation.” CDEMCurriculum. 2008.  https://cdemcurriculum.com/burns-and-smoke-inhalation/
  2. Advanced Trauma Life Support (ATLS) 9E. American College of Surgeons, 2013.
  3. American Burn Association Excerpted from Guidelines for the Operation of Burn Centers (pp. 79-86), Resources for Optimal Care of the Injured Patient 2006, Committee on Trauma, American College of Surgeons
  4. Drigalla D, Gemmill J. Chapter 45. Burns & Smoke Inhalation. In: Stone C, Humphries RL. eds. CURRENT Diagnosis & Treatment Emergency Medicine, 7e. New York, NY: McGraw-Hill; 2011.
  5. Hettiaratchy, S.; Dziewulski, P. “ABC of burns: pathophysiology and types of burns.” BMJ: British Medical Journal, v. 328 issue 7453, 2004, p. 1427-9.
  6. Jesche M, Williams, F, et al. Chapter 21. Burns. In: Townsend, C et al. Sabiston Textbook of Surgery. Elsevier; 2012.
  7. Schwartz L.R., Balakrishnan C. Chapter 210. Thermal Burns. In Tintinalli J.E., Stapczynski J, Ma O, Cline D.M., Cydulka R.K., Meckler G.D., T (Eds), Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7e. New York, NY: McGraw-Hill; 2011.
  8. First Degree Burn, Wikimedia Commons: https://commons.m.wikimedia.org/wiki/File:First-degree_burn.jpg