Smoke Inhalation—Part 2

   Smoke inhalation is a caustic event that can be lethal. In the United States, there are between 5,000 and 10,000 deaths from smoke inhalation each year. In the May issue we reviewed assessing the scene and your patient. This month we review patient management.

Management

   Treatment should always start with securing the patient's airway, breathing and circulation, as well as management of any life-threatening injuries. Administer supplemental oxygen in cases of smoke inhalation. Depending on the source consulted, humidified oxygen may be used. Oxygen administration is important when trying to reverse or prevent hypoxia, as well as assisting with displacement of carbon monoxide from hemoglobin. The half-life (which can be broadly defined as the amount of time it takes for half of the active elements to be either broken down or eliminated from the body) of carbon monoxide at room temperature is approximately 3 to 4 hours; 100% oxygen reduces the half-life to a range of 30-90 minutes. Hyperbaric oxygen can reduce the half-life of CO to 15-30 minutes.1-3

   Aggressive airway management may be required in cases of smoke inhalation. Heat exchange in the upper airway is normally efficient. Because of this, distal airway involvement may be spared, while the upper airway remains at increased risk for injury and edema. Airway injury is possible due to the direct effects of the products of combustion on the mucosa and alveoli. This can present a challenge in the field, as airway edema can develop quickly despite seemingly benign initial presentations.4-6

Airway & Breathing

   The following factors should be assessed in any patient who has been the victim of smoke inhalation: Is the patient's airway patent or at risk for becoming occluded? Is the patient able to speak in complete sentences, or is he speaking in partial sentences while using accessory muscles to breathe? Are there signs of potential smoke inhalation, such as soot in the nares and oropharynx?4-6

   Different techniques can be used to address the patient's airway. The head-tilt chin-lift is often used in atraumatic situations. A traumatic situation may require a chin-thrust or modified jaw-thrust. If the airway is closed or is at risk for closing, and depending on the patient's condition, consider using a variety of airway management techniques. Oropharyngeal or nasopharyngeal airways are useful to assist in preventing the tongue from occluding the patient's airway.4-9

   Advanced airway management may be needed in patients who show signs of possible respiratory tract injury, such as singed nasal hairs, facial burns, oral burns, sooty sputum, and/or respiratory difficulty with stridor or wheezes. There is extensive information available in the scientific literature regarding optimal airways in the field. Providers are encouraged to become familiar with the various techniques available. Examples include the use of rapid sequence intubation, blind nasotracheal intubation and surgical airways.4-6, 7

   Your decision to provide airway intervention must take numerous factors into consideration. The patient's overall condition, provider's experience level, provider's comfort level, location of the closest emergency department, local protocols and medical direction guidance are only a few of the variables that need to be considered. Each situation will be unique, and you should consult with your local protocols regarding the use of any advanced airway techniques.4-6, 7

Intravenous Fluids

   Establish IV access as soon as possible. The type of fluid and rate of administration will vary with each scenario and should be partially guided by the patient's overall condition. While aggressive fluid administration may not be required initially, intravenous access may prove to be invaluable, especially if the patient is to receive intravenous medications. Continued burn damage and edema may make intravenous access more challenging later in the patient's course, so, when possible, consider establishing an intravenous line early, even if it will be at a “keep-open” rate initially.4, 5 If burns are present, you may need to consider using a greater rate of fluid administration. For example, intravenous fluid administration is recommended for adults with total body surface area (TBSA) burns of 18% or more and for pediatric patients with TBSA burns of 12% or more. The goal of fluid resuscitation is to allow for the perfusion of vital organs without overhydrating the patient. Crystalloid solutions, such as normal saline or lactated Ringer's, are frequently used and very appropriate in the prehospital setting for initial fluid resuscitation. Fluid selection and flow rates will vary depending on a variety of factors, including the age of the patient, the BSA involved and local protocols.8, 10

Medications

   There are antidotes for some chemical exposures that may be available to EMS providers. Prehospital initiation of antidotes will vary depending on the situation, availability, local protocols and medical direction. 8-9, 11-15

   A cyanide antidote kit may involve two steps in which the cyanide is unbound and then excreted from the body. If a cyanide antidote kit is given, you will need to closely monitor the patient's vital signs, particularly blood pressure, as changes may occur following administration. Administration of medications will be guided by factors such as the patient's medical history, physical assessment findings, local protocols and the treatment already provided (if any).8-9, 11-15

Immobilization

   Depending on the nature of the incident, such as a building explosion, a variety of blunt or penetrating traumatic injuries may be present in addition to smoke inhalation. In these cases, spinal immobilization may be indicated. Remember that life-threatening injuries should be managed as they are identified.4-6

Body Temperature

   You are encouraged to maintain the patient's body temperature within a normal range, and, when possible, prevent him from cooling to the point of shivering. When clothing is removed and IV fluids are administered, hypothermia can be induced. Prewarmed blankets and fluids may assist in avoiding this.4 Research is currently being conducted to explore the potential benefit of hypothermia in certain cases; however, intentionally inducing hypothermia in the prehospital setting in patients who have not suffered cardiac arrest is not standard practice at this time and should be avoided.

Restraints

   The use of physical or chemical restraints may be indicated. Restraints may be used to help minimize patient movement or to protect the patient from additional injury. If restraints are used, clearly document the methods of restraint selected and the reason restraint was necessary. Frequent reassessment of the patient's overall status is critical.4-6

Hospital Notification and Destination

   Notify the receiving hospital as soon as possible. Early notification can play an important role in ensuring the appropriate resources are available when the patient arrives. Follow protocols and guidelines when determining hospital destination.

   Depending on the resources available at local hospitals, the patient suspected of experiencing smoke inhalation (i.e., carbon monoxide poisoning) may benefit from a hospital that offers hyperbaric oxygen therapy. Hyperbaric oxygen therapy has been described as breathing 100% oxygen while under increased atmospheric pressure. When this occurs, hemoglobin is saturated and the blood can be hyperoxygenated to dissolve the oxygen within the plasma. Through the use of hyperbaric therapy, oxygen displaces carbon monoxide from hemoglobin, reducing additional hypoxia and promoting end-tissue perfusion and oxygenation.4, 15

Conclusion

   In the prehospital setting, the patient suffering from smoke inhalation can present with subtle signs and symptoms. It is essential for providers to be able to thoroughly assess and suspect the potential for smoke inhalation. Failing to recognize or treat a patient for smoke inhalation can have significant consequences and lead to less-than-desirable outcomes. The provider who has a solid understanding of smoke inhalation pathology and is able to form an appropriate treatment plan is more likely to be successful providing optimal patient care while reducing smoke inhalation-related morbidity.

REFERENCES

   1. Shochat GN, Lucchesi M. Carbon Monoxide Toxicity in Emergency Medicine. http://emedicine.medscape.com.

   2. Whatis.com. Half-life. http://whatis.techtarget.com.

   3. Lafferty KA, Goett HJ. Smoke Inhalation: Treatment & Medication. http://emedicine.medscape.com.

   4. Chapleau W, Burba A, Pons P, Page D. The Paramedic. Boston: McGraw-Hill, 2008.

   5. Hubble M, Hubble J. Principles of Advanced Trauma Care. Albany: Delmar Thompson Learning, 2002.

   6. Dries DJ, Perry JF. Initial Evaluation of the Trauma Patient. http://emedicine.medscape.com.

   7. Stiell IG, Spaite DW, et al. Advanced life support for out-of-hospital respiratory distress, NEJM 356: 2,156-64, 2007.

   8. Goodis J. Thermal Burns in Emergency Medicine: Treatment & Medication. http://emedicine.medscape.com.

   9. Leybell I, Borron SW. Toxicity, Cyanide: Treatment & Medication. http://emedicine.medscape.com.

   10. U.S. Department of Health & Human Services. Radiation Emergency Medical Management. Burn Triage and Treatment: Thermal Injuries. www.remm.nlm.gov/burns.htm.

   11. Martin CO. Chemical Terrorism Update: Cyanide Toxins. www.emedmag.com.

   12. Shepherd G, Velez L. Role of hydroxocobalamin in acute cyanide poisoning. Ann Pharmaco 42(5): 661-9, 2008.

   13. Fortin JL, Giocanti JP, et al. Prehospital administration of hydroxocobalamin for smoke inhalation-associated cyanide poisoning: 8 years of experience in the Paris Fire Brigade. Clin Toxicol (Phila) 44 Suppl 1: 37-44, 2006.

   14. Guidotti T. Acute cyanide poisoning in prehospital care: New challenges, new tools for intervention. Prehosp Dis Med 21(2): s40-s48, 2006.

   15. Latham E, Hare MA, Neumeister M. Hyperbaric Oxygen Therapy. http://emedicine.medscape.com.

Paul Murphy, MSHA, MA, is a regional sales manager with InTouch Health, with administrative and clinical experience in healthcare organizations.

Chris Colwell, MD, is medical director for Denver Paramedics and the Denver Fire Department and an attending physician in the emergency department at Denver Health (CO) Medical Center.

Gilbert Pineda, MD, FACEP, is medical director for the Aurora Fire Department and Rural/Metro Ambulance, Aurora, CO, and an attending physician in the emergency department at The Medical Center of Aurora, Aurora, CO, and Denver Health (CO) Medical Center.

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