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Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Inhalational Agents as Inhalational Agents as Terrorist WeaponsTerrorist Weapons
Thomas R. Burklow, MDThomas R. Burklow, MD
LTC, MCLTC, MC
Division of Pediatric CardiologyDivision of Pediatric Cardiology
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Historical notesHistorical notes First “chemical agent” 423 B.C., Sparta: Burning
mixture of pitch, naphtha, and sulfursulfur dioxide
1915, Ypres, Belgium: Germans release 150 tons of chlorine
1917, Verdun: Germans use phosgene in artillery shells
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
AgentsAgents
Phosgene (CG) Chlorine (CL) Diphosgene (DP) Chloropicrin (PS)
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
ToxicokineticsToxicokinetics
Absorbed almost exclusively by inhalation Penetrates readily to alveolar Not systemically absorbed
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Toxicity: LCtToxicity: LCt5050 Toxicity:Lethal concentration-time product (i.e. dose) to
kill 50% of a group Ct50: agent concentration (mg/m3) multiplied by time
(minutes) The lower the LCt50, less of the agent is required, and thus
more potent is the agent Does not take into account physiological factors
Case example exposure to 50 mg/m3 for 10 minutes is the equivalent
exposure dose of 100 mg/m3 for 5 minutes
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
ToxicityToxicity
Phosgene Odor threshold (“new mown hay”), 1.5 mg/ m3
Irritation threshold, 4 mg/ m3
3200 mg-min/m2
Chlorine Odor of “swimming pool water” 6000 mg-min/m2
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Clinical effectsClinical effects
Exposure clinical latent period (up to 24 hrs) pulmonary edema
Creates defects in the alveolar-capillary barrier, but the exact mechanism is unknown
Early symptoms may result from irritation of mucosal membranes (conjunctivitis and irritation of larynx) by phosgene or chlorine.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Most prominent clinical symptom: Most prominent clinical symptom: DyspneaDyspnea
Initially unaccompanied by objective signs of pulmonary damage
Hypoxemia, tachypnea, decreased pulmonary compliance Cyanosis may become clinically evident Profound pulmonary edema (pulmonary sequestration of
plasma-derived fluid accumulates up to 1 liter/hr)
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
TREATMENTTREATMENT
Medical Management of Chemical Casualties Handbook, 3rd Ed, 1998
Chlorine http://www.emedicine.com/emerg/topic851.htm
Phosgene http://www.emedicine.com/emerg/topic905.htm
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
General principles of inhalation General principles of inhalation agent managementagent management
Decontamination Vapor: fresh air, supplemental oxygen Liquid: copious water irrigation
Management Termination of exposure ABCs of resuscitation Rest and observation Oxygen with or without positive airway pressure Monitor for delayed pulmonary edema
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Phosgene: Prehospital CarePhosgene: Prehospital Care
Full personal protective equipment for toxic vapor exposures, including Level A suits and self-contained breathing apparatus.
Not expected to pose a significant risk of contamination.
ABC’s Inhalational bronchodilator treatment
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Phosgene: Emergency Phosgene: Emergency Department CareDepartment Care
Appropriate ED care also depends on careful attention to the ABCs.
Ongoing reassessment is a key. Toxic effects may not be apparent in the first few hours.
Noncardiogenic pulmonary edema may develop 4-6 hours after exposure.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Pulmonary edemaPulmonary edema
Positive end-expiratory pressure via positive airway pressure mask or, in more severe cases, endotracheal intubation with positive pressure ventilation.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Phosgene inhalation caveatsPhosgene inhalation caveats No specific antidote Diuretics
Limited role Reduces fluid loss into the lungs via the damaged alveolar-
capillary membrane May cause hypotension in hypovolemic patients receiving
positive pressure ventilation. Steroids
Not effective Bronchodilator therapy
Benefits patients with hyperactive airways
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
ChlorineChlorine
Poisoning is common in the US. Common inhalational irritant One third of the morbidity cases following acute
irritant exposure involving both adults and children.
Toxic effects after inhalation exposure usually are mild to moderate, and death is uncommon. Large amounts of chlorine are produced in the industrial sector
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Chlorine: Prehospital CareChlorine: Prehospital Care
Remove victims from the toxic environment. Chlorine gas exposure represents a low risk for
cross-contamination Decontamination at the scene if eye or skin
involvement is found. Copious amounts of water may be used. Remove the patient's clothing if it has been contaminated with liquid chlorine.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Chlorine: Emergency Chlorine: Emergency Department CareDepartment Care
ABC’s Monitor for laryngospasm Irrigate the eyes and skin; wash skin with a mild
soap and water. Use a pH reagent strip for assess any eye injury.
Continue irrigation of the eye until the pH returns to near 7.
Evaluate the cornea with fluorescein staining under a slit lamp.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Chlorine poisoning: Chlorine poisoning: BronchospasmBronchospasm
Beta agonists such as albuterol. Ipratropium may be added to the treatment.
May require terbutaline or aminophylline. Nebulized lidocaine (4% topical solution)
may provide analgesia and reduce coughing.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Sodium bicarbonateSodium bicarbonate
In the past, several authors advocated nebulized sodium bicarbonate. Most recommendations are based on anecdotal experience, and little supporting clinical data are available.
The mechanism of action is believed to be the neutralization of hydrochloric acid formed in the airways. Theoretically, an exothermic reaction may occur.
Animal studies suggest nebulized sodium bicarbonate may cause chemical pneumonitis.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Other therapiesOther therapies
Corticosteroids: Inhaled and parenteral steroids have been used with many patients exposed to chlorine gas, but no strong clinical evidence supports their use.
Fluid management Diuretics
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Differential DiagnosisDifferential Diagnosis Riot control agents
More intense irritation than phosgene or chlorine. Not accompanied by odor of phosgene
Nerve agents Production of profuse secretions Lack of cholinergic effects: profuse secretions; miosis, Effects not delayed
Vesicants Predominately affects central rather than peripheral airways Dyspnea accompanied by airway necrosis and obstruction Pulmonary parenchymal damage usually manifests as hemorrhage
rather than edema
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Inhalational agents as Inhalational agents as terrorist weaponsterrorist weapons
“Weapon of opportunity” Actually terrorist potential uncertain 1995, the FBI uncovered a terrorist effort
to release a chlorine gas bomb in the Disneyland theme park in California
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Inhalational agents as Inhalational agents as terrorist weaponsterrorist weapons
Not stockpiled by the US military
US produces over a billion pounds a year for industrial use
Chlorine: 20.6 billion ton-miles shipped by rail, 1985-1995
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
The Washington Post The Washington Post November 12November 12thth 2001 2001
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Industrial injuriesIndustrial injuries Accidental industrial accidents Hamburg, Germany 1928: accidental factory release of
phosgene. The gas cloud spread over 10 km, killing and injuring hundreds of people
American Association of Poison Controls Centers' National Data Collection System 1988-1992, Chlorine Categorized outcome in 21,437 cases
• 40 resulted in a major effect• 2091 resulted in a moderate effect• 17,024 resulted in a minor effect• 2099 had no effect.
Thomas Burklow, MDThomas Burklow, MDDepartment of PediatricsDepartment of Pediatrics
Walter Reed Army Medical CenterWalter Reed Army Medical Center
Pediatric considerationPediatric consideration
Higher number of respirations per minute in children results in exposure to a relatively greater dosage.
The high vapor density of the gases places their highest concentration close to the ground in the lower breathing zone of children.
Having less fluid reserve increases the child's risk of rapid dehydration or frank shock with pulmonary edema