Respiratory problems in burns

Abstract

Summary Inhalation injury occurs in one-third of all burns admissions, with an overall mortality of 50%. Carbon monoxide poisoning, thermal obstructive injury confined to the supraglottic airway, and chemical tracheobronchitis from inhalation of toxic products of combustion may occur. Early severe pulmonary oedema is rare. The best early clues to inhalation injury are a history of burn in an enclosed space or loss of consciousness, cough with carbonaceous sputum or wheeze and deep central facial burn. Initial CXR films are usually normal, as may be the arterial blood gases. Only the test of time and failure to develop either respiratory symptoms and signs or abnormal investigations can contradict the diagnosis. Extensive skin burns do not result in increased alveolar-capillary permeability in the lung, but fluid resuscitation of burns aggravate airway but not lung oedema. Inhalation injury significantly increases the volume of resuscitation fluid required. Great care must be taken to err on the side of overtreatment by intubation (nasotracheal) when there is the slightest indication in major burn injury, unless direct airway inspection suggests otherwise. Respiratory failure is best managed by CPAP and IMV and respiratory toilet of mucosal slough which may obstruct airways. Steroids are of no value and antibiotic use should be therapeutic, not prophylactic. Respiratory complications occurring after 48 h are most commonly infection-related. Secondary bacterial infection, most commonly with Staphylococcus aureus, becomes apparent from days 3–7 postburn. Pneumonia accounts for one-third of all deaths in hospital and occurs in as many as 70% of victims with both inhalation and cutaneous burn injury. Aerobic gram-negative rods are common pathogens. The lung exhibits increased sensitivity to endotoxin after burn injury and large increases in EVLW are usually due to sepsis, often extrapulmonary. Most survivors of inhalation injury recover normal lung function, but severe small airways obstruction has been reported.