History: burned in an enclosed space but inhalation injury can occur outside, sore throat, throat tightness, difficulty breathing
Exam: face and/or neck burns, hoarse, tachypnea but may be ABSENT, coughing carbon debris, oropharyngeal edema, singed hair (facial, nares or scalp), stridor
There are two primary mechanisms of inhalation injury:
1. Carbon monoxide (CO) poisoning
• The Problem: CO binds to hemoglobin with a much greater affinity than oxygen
• SIGNS: Cherry red skin, anxious, confused
Measure the carboxyhemoglobin level (CHg)
CHg Level Sx’s
< 20 Headache, blurred vision
> 20 GI: nausea, vomiting
> 50 Seizure, death
2. Injury to the orophanyx and lungs
• Etiology: smoke, chemicals, heat
• Causes direct irritation to the tissues
PATHOPHYSIOLOGY of the injury: Most of the pathology is due to increased vascular permeability secondary to local inflammatory mediators. This results in fluid shifts and edema in the oropharnyx and in the lung. Direct chemical damage may occur to the epithelial cells lining the tracheobronchial tree.
How do you make the diagnosis?
Obtain a carboxyhemoglobin level
Not very helpful: O2 sat,
V/Q scan (historic importance) usually not readily available
What do you see at bronchoscopy?
(early) the mucosa appears edematous, erythematous, there is carbonaceous debris, the mucosa may just be pale
(at 48h) you may seeulceration, blood, blood clots, mucosal slough, thick secretions
What is the therapy for carbon monoxide poisoning?
Therapy is 100% O2 (this rapidly decreases the ½ life of carboxyhemoglobin rapidly).
Secure a patent airway. This is best done early, EDEMA/OBSTRUCTION MAY MAKE IT IMPOSSIBLE LATER!
• Consider use of a Volumetric Diffusive Respirator ventilator if available. This unfortunately is only available in some specialized burn centers. It is very effective at oxygenating and ventilating patients that otherwise may not be maintained on a volume-controlled ventilator
• Nebulized albuterol and heparin
• IPV (Intrapulmonary Percussive Ventilation) every 6 hours
• Mucomyst or pulmozyme if secretions become thick
• No prophylactic antibiotics
10 scenarios to avoid with inhalation injury patients:
10 Anatomically difficult airway (get help)
9 Poor lighting
8 Uncontrolled setting i.e. on the ward
7 Tracheostomy or cricothyroidotomy not tray available (operator unprepared)
6 Anesthesia not available as backup
5 Hypoxic patient (hypoxic patients become agitated and combative)
4 You’re alone
3 Your assistant is inexperienced
2 You’re inexperienced
#1 Enroute by ground or flight (this is invariably disasterous)
PEARL: The safest time to intubate a patient with an inhalation injury is before he or she starts having respiratory distress. SECURE THE ENDOTRACHEAL TUBE WITH UMBILICAL TIES RATHER THAN TAPE WHICH WILL SLIDE OFF WHEN THE PATIENT BECOMES EDEMATOUS Although intubation is not a “benign” procedure, it may be the safest when nursing staff and monitoring is limited, nurse to patient ratio is low, in a MASCAL setting and during transport. So-called “crash intubations” require considerable skill to gain control of the airway. Attempts at surgical control of a loss airway are may result anoxic brain injury.