Lung Damaging (Pulmonary) Agents

Objectives

To guide the management of patients presenting to medical facilities with suspected pulmonary agent intoxication. 
To understand the common Chemical Agents and Toxic Industrial Chemicals that can cause lung damage.

Scope

This guideline describes the management of suspected pulmonary agent and inhaled toxic industrial chemical (TIC) exposure.

Owing to its idiosyncrasies, there is a separate guideline for suspected phosgene inhalation.

There are separate guidelines for the management of acute lung injury (ALI)/ acute respiratory distress syndrome (ARDS) which must be applied in severe cases of ALI secondary to pulmonary agent or TIC inhalation. 

Audience

This guideline is intended for the use of registered healthcare professionals fulfilling a general role in a forward medical locations or in an Emergency Department on deployed operations.

Initial Assessment & Management

Pulmonary Agents and Toxic Industrial Chemicals 
There are a multitude of pulmonary agents and TICs with considerable overlap. Very few of these have specific antidotes and treatment is generally supportive. Specific agents include chlorine, oxides of sulphur and ammonia, together with hydrogen fluoride produced by the decomposition of fluorinated fire-suppression systems following ballistic rupture or thermal breakdown. Most are non-persistent at temperate temperatures, have characteristic odours, and are denser than air, tending to accumulate in sheltered, low-lying areas. PPE and decontamination may be required in colder climates. 

Oxygen supplementation may be required to maintain oxygen saturation above 94%. Patients who are asymptomatic 4h post exposure can be considered for discharge. Bronchospasm can be treated conventionally with bronchodilators. 

Management of Suspected Hydrofluoric Acid Inhalation: 
 
Hydrogen fluoride (HF), or hydrofluoric acid can form during the decomposition of fluorinated fire-suppression systems following ballistic rupture or thermal breakdown.

Nebulised calcium chloride every 4h has been shown to be of survival benefit in affected patients. 
Profound hypocalcaemia accompanies HF exposure and should be aggressively corrected with IV calcium chloride. 
12 lead ECG for QTc and QRS duration should be performed. 
Keep K+, Mg2+ and Ca2+ in the high normal range. 

Advanced Assessment & Management

Measures to improve oxygenation include continuous positive airway pressure (CPAP) and can be escalated to invasive ventilation using established ARDS Net strategies.

Patients with stridor or other concerning upper airway signs warrant careful assessment and consideration prior to tracheal intubation. Emergency tracheal intubation prior to airway obstruction is preferred. Inhaled or intravenous steroids are unlikely to be of benefit.

Hypoxaemia refractory to the above measures is an indication for referral for extracorporeal membrane oxygenation (ECMO) where available. 

Prolonged Casualty Care

Oxygen supplementation to maintain adequate oxygen saturation may be required.

CPAP, if available can be of benefit in this situation and when applied early can reduce the overall oxygen requirement and need for ventilatory support.

Paediatric Considerations

As per adult and drug dosing iaw page per age