Smoke inhalation

OVERVIEW

  • Smoke is a complicated heterogeneous mixture of potentially toxic gases, chemical fumes, asphyxiants and particulate debris
  • Smoke inhalation is commonly seen in patients with burns as a result of fire
  • it is associated with high morbidity and mortality
  • Consider concomitant carbon monoxide and/or cyanide poisoning (cyanide is produced by the combustion of plastics, wools and various polymers)

MECHANISM

  • thermal injury to the airway and respiratory tract from steam and heated products of combustion
  • chemical injury to the upper and lower respiratory tract due to irritant gases produced by thermal degradation and combustion e.g. nitrogen oxides, phosgene, HCl, etc
  • systemic effects from lung-mediated absorption of toxic agents
  • asphyxia due to oxygen consumption by fire and the production of asphyxiants such as carbon dioxide

ASSESSMENT

  • suspect more severe smoke inhalation effects if exposed to fire in a confined space
  • assess for airway injury and respiratory compromise
    — features of airway burns
    — upper airways: singed nasal airs, facial burns, soot in nose and pharynx, stridor, hoarseness
    — lower airways: wheeze, dyspnea, APO, ARDS
  • suspect significant systemic toxicity if severity of presentation is out of keeping with degree of burns (e.g. coma, seizures, shock)
    — CO and/or CN, metHb

Investigations

  • lactate (>10 mM is sensitive and specific for CN toxicity in the absence of severe burns)
  • COHb
  • methemoglobin
  • CN levels (only useful for retrospective diagnosis)
  • CXR
  • spirometry/ PEFR
  • other investigations appropriate to mechanism (e.g. associated trauma)

SpO2 is unreliable in the presence of metHb or CO poisoning

MANAGEMENT

Resuscitation

  • ensure secure airway, early intubation is often appropriate if evidence of airway burns
  • provide high flow oxygen (ideally FiO2 1.0 for carbon monoxide poisoning
  • treat bronchospasm (e.g. salbutamol, iprotropium)
  • treat ARDS/ non-cardiogenic pulmonary edema

Specific therapy

  • treat coexistent burns
  • treat suspected cyanide toxicity
    —sodium thiosulfate and hydroxocobalamin are preferred for suspected severe toxicity
  • treat treat methemoglobinemia with methylene blue
  • treat carbon monoxide therapy
    — high flow O2 (ideally FiO2 1.0) until asymptomatic, 24 hours if pregnant
    — the role of hyperbaric oxygen is controversial

Supportive care and monitoring

Disposition

  • if no other injuries and asymptomatic at 6 hours then smoke inhalation patients can be discharge home with GP follow up
  • patients with any respiratory symptoms should be admitted for observation, as delayed pneumonitis/ APO/ ARDS may occur
  • pateints with severe effects need ICU admission

References and Links

LITFL

FOAM and web resources


CCC 700 6

Critical Care

Compendium

Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also the Innovation Lead for the Australian Centre for Health Innovation at Alfred Health and Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of two amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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