|
Acute Management Overview
- Agent: Phosgene - Phosgene is colorless, fuming liquid below 47°F (8.2°C) and a colorless, nonflammable gas above 47°F with a suffocating odor like new mown hay. The odor threshold for phosgene is significantly higher than current inhalation exposure limits. Thus, odor provides insufficient warning of hazardous concentrations.
- Responders should obtain assistance in identifying the chemical(s) from container shapes, placards, labels, shipping papers, and analytical tests. General information on these identification technicques is located in Emergency Response Guidebook.
- Identification Tools - CHEMM-IST, WISER, Phosgene Chemical Properties
- Devices - Chemical Agent Detector C2 Kit (liquid and vapor), M256A1 chemical agent detector kit (liquid and vapor), M18A3, M90 chemical agent detectors (vapor), Draeger CDS Kit (vapor and aerosol)
- A comprehensive source for the selection of chemical identification equipment is the Guide for the Selection of Chemical Detection Equipment for Emergency First Responders, Guide 100-06, January 2007, 3rd Edition published by the Department of Homeland Security to assist with this process.
- Persons exposed only to phosgene gas generally do not pose substantial risks of secondary contamination.
- Persons whose clothing or skin is contaminated with liquid phosgene (ambient temperature below 47°F) can secondarily contaminate response personnel through direct contact or off-gassing vapor.
- PPE required; Level B-C is generally adequate depending on the ambient temperature and distance from hot zone (bring in HAZMAT for Level As PRN). Use butyl rubber or other glove materials with adequate breakthrough characteristics. Be aware that use of protective equipment by the provider may cause fear in children, resulting in decreased compliance with further management efforts.
- Link to PPE, rescuer safety hospital management section
- Link to reference section for acute event PPE related safety information
- Immediate irritant effects such as conjunctivitis, rhinitis, pharyngitis, bronchitis, lacrimation, blepharospasm conjunctival hyperemia, and upper respiratory tract irritation may occur after exposure to concentrations of 3 to 5 ppm.
- Severe pulmonary toxicity may develop after exposure to higher concentrations or following exposures for longer periods of time.
- A phosgene casualty who develops respiratory distress within 4 hours of exposure has probably inhaled an LD50 and is at severe risk if not properly supported
- Signs and symptoms of toxicity may be delayed, although rare, for 24 to 72 hours and include choking, chest tightness, cough, severe dyspnea, production of foaming bloody sputum, and pulmonary edema. Non-respiratory symptoms include nausea and anxiety. Cardiac failure has occasionally occurred as a complication of severe pulmonary edema. Concentration-response guidelines include:
- Victims with inhalation doses of < 25 ppm/min and without clinical signs and symptoms require no immediate medical attention. Exposure to a cumulative dose of 50 ppm x minutes may cause pulmonary edema; a dose of 150 ppm x min will probably cause pulmonary edema and a dose of 300 ppm x min is likely to be fatal.
- Brief exposure to 500 ppm or greater may be rapidly fatal. Prolonged exposure to low concentrations (e.g. 3 ppm for 170 min) can also be fatal. Exposure to concentrations less than 3 ppm may not be immediately accompanied by irritant symptoms; delayed effects usually occur within 24 hrs of exposure.
- Victims with unknown phosgene exposure must be closely observed
- Liquid phosgene is a frostbite hazard and has caused corneal opacification.
- Victims with unknown phosgene exposure must be closely observed. Victims may be discharged if they are free of signs and symptoms and have clear chest x-ray films 8 hours after the end of phosgene exposure. However, if chest x-rays are not available observation of asymptomatic victims should be continued for 24 hours.
- Victims exposed only to phosgene gas that have no evidence of skin or eye irritation may be transferred immediately to the Support Zone as they do not pose substantial risks of secondary contamination to personnel outside the Hot Zone.
- Decontamination: unless previously decontaminated, all patients suspected of contact with phosgene liquid (ambient temperature below 47) and all victims with skin or eye irritation require decontamination as described below.
- Link to hospital management section
- Inhalation - Inhalation is the major route of phosgene exposure. Phosgene's effects as a respiratory irritant can be mild and delayed, which may result in a lack of immediate avoidance leading to exposure for prolonged periods. Phosgene is heavier than air and may cause asphyxiation due to oxygen displacement in poorly ventilated, low-lying, or enclosed spaces.
- Skin/Eye Contact - When phosgene gas contacts moist or wet skin, it may cause irritation and erythema. High airborne concentrations can also cause corneal inflammation and opacification. Direct contact with liquid phosgene under pressure can cause frostbite as well as severe irritation and corrosive effects.
- Ingestion - Ingestion of phosgene is unlikely because it is a gas at room temperature.
Clinical Signs and Symptoms
- Inhaling low concentrations may cause no signs or symptoms initially or cause symptoms that are secondary to mild irritation of the eyes and throat, some coughing, choking, feeling of tightness in the chest, nausea and occasional vomiting, headache, and lacrimation.
- Respiratory - after an asymptomatic period for 30 minutes to 48 hours, in those developing severe pulmonary damage a progressive pulmonary edema ensues with increasing work of breathing and subsequent hypoxia.
- Cardiovascular - circulatory collapse secondary to severe pulmonary edema.
- Dermal - phosgene can cause skin irritation and with sufficient concentration can cause, burning pain, inflammation, and blisters. Liquefied phosgene can cause frostbite injury.
- Ocular - high vapor concentration can cause tearing and blood in the eye. Contact with liquid phosgene may result in clouding of the cornea and delayed perforation.
- Link to Pediatric Vulnerabilities Hospital Management
- Link to Toxic Syndromes
- Link to Primary and Secondary Survey
- Since phosgene is a respiratory tract irritant, but has unique toxicological concerns due to the latency for onset of pulmonary edema, differentiating it from the typical presentation of symptoms from other common chemical irritants is an important consideration.
- Phosgene is distinguished by its smell in high concentrations and delayed onset of pulmonary edema.
- Chlorine has a characteristic odor even in low concentrations, immediate onset of respiratory distress, bronchospasm, eye, skin, and upper airway irritation.
- Riot agents cause an acute onset of burning sensation in the eyes and upper airway without progression of symptoms with ongoing exposures.
- Nerve agents induce watery secretions as well as respiratory distress, but have a host of other symptoms, such as miosis, seizures, rapidity of onset, that can distinguish them from pulmonary agents.
- The respiratory toxicity of vesicants (i.e. Mustard Gas) is usually delayed, but affects the central rather than the peripheral airway. Vesicant toxicity severe enough to cause dyspnea typically causes airway necrosis often with upper airway obstruction.
- Link to Chemical Hazards Emergency Medical Management Intelligent Syndromes Tool (CHEMM-IST)
Hot Zone
Show all sections
Establish hot zone - including hot zone triage, decontamination, re-triage locations.
If contaminated patients arrive at the Emergency Department, they must be decontaminated before being allowed to enter the facility. Decontamination can only take place inside the hospital if there is a decontamination facility with negative air pressure and floor drains to contain contamination.
Rescuers should be trained and appropriately attired before entering the Hot Zone. If the proper equipment is not available, or if rescuers have not been trained in its use, call for assistance in accordance with local Emergency Operational Guides (EOG). Sources of such assistance should be obtained from a local HAZMAT teams, mutual aid partners, the closest metropolitan strike system (MMRS) and the U. S. Soldier and Biological Chemical Command (SBCCOM)-Edgewood Research Development and Engineering Center. SBCCOM may be contacted (from 7:00 AM - 4:30 PM EST call 410-671-4411 and from 4:30PM - 7:00AM EST call 410-278-5201), ask for the Staff Duty Officer.
Hot Zone
- Agent: Phosgene - Phosgene is colorless, fuming liquid below 47°F (8.2°C) and a colorless, nonflammable gas above 47°F with a suffocating odor like new mown hay. The odor threshold for phosgene is significantly higher than current inhalation exposure limits. Thus, odor provides insufficient warning of hazardous concentrations.
- Responders should obtain assistance in identifying the chemical(s) from container shapes, placards, labels, shipping papers, and analytical tests. General information on these identification technicques is located in Emergency Response Guidebook.
- Identification Tools - CHEMM-IST, WISER, Phosgene Chemical Properties
- Devices - Chemical Agent Detector C2 Kit (liquid and vapor), M256A1 chemical agent detector kit (liquid and vapor), M18A3, M90 chemical agent detectors (vapor), Draeger CDS Kit (vapor and aerosol)
- A comprehensive source for the selection of chemical identification equipment is the Guide for the Selection of Chemical Detection Equipment for Emergency First Responders, Guide 100-06, January 2007, 3rd Edition published by the Department of Homeland Security to assist with this process.
Respiratory and Skin Protection: Positive-pressure-demand, self-contained breathing apparatus (SCBA) level A is recommended in response situations that involve exposure to potentially unsafe levels of phosgene liquid or vapor.
PPE required level B-C
Most likely B-C PPEs will be adequate. Levels As may be required if the hospital is close to the site of exposure and/or there is concern for vapor exposure (bring in HAZMAT for Level A PPEs).
Respiratory Protection: Positive-pressure, self-contained breathing apparatus (SCBA) is recommended in response situations that involve exposure to potentially unsafe levels of phosgene.
Skin Protection: Chemical-protective clothing is recommended because of the potential of inflammatory and corrosive effects.
- Level A - protective clothing is the highest level of protection. Level A includes a Self Contained Breathing Apparatus(SCBA) with a fully encapsulating vapor tight suit with gloves and booties attached to the suit (tanks last from 1/2 hour to 1 hour).
- Level B - requires the use of SCBA but has lesser skin protection. Level Bs are chemical resistant suits that are designed for splashes of liquids but not for gas or vapor hazards. A young soldier can last about 2 hours on a hot day with a external air hose.
- Level C is similar to B with the exception of the type of respiratory protection. The SCBA is replaced with an Air Purifying Respirator.
- Level D protective clothing is utilized when there are no respiratory hazard and no major skin hazard considerations. Level D for hospital personnel includes scrubs, safety glasses, shoe covers, and possibly a face shield.
Link to reference section for acute event PPE related safety information
Chemical casualty triage is based on walking feasibility, respiratory status, age, and additional conventional injuries. The triage officer must know the natural course of a given injury, the medical resources immediately available, the current and likely casualty flow, and the medical evacuation capabilities.
Mass Casualty Triage Standards
General Principles of Triage for Chemical Exposures
- Check triage tag/card for any previous treatment or triage.
- Survey for evidence of associated traumatic/blast injuries.
- Observe for sweating, labored breathing, coughing/vomiting, secretions.
- Severe casualty triaged as immediate if assisted breathing is required.
- Blast injuries or other trauma, where there is question whether there is chemical exposure, victims must be tagged as immediate in most cases. Blast victim's evidence delayed effects such as ARDS, etc.
- Mild/moderate casualty: self/buddy aid, triaged as delayed or minimal and release is based on strict follow up and instructions.
- If there are chemical exposure situations which may cause delayed but serious signs and symptoms, then over-triage is considered appropriate to the proper facilities that can observe and manage any delayed onset symptoms.
- Expectant categories in multi-casualty events are those victims who have experienced a cardiac arrest, respiratory arrest, or continued seizures immediately. Resources should not be expended on these casualties if there are large numbers of casualties requiring care and transport with minimal or scant resources available.
- In a given category prioritize a child, pregnant woman over a non-pregnant adult.
- Immediate irritant effects such as conjunctivitis, rhinitis, pharyngitis, bronchitis, lacrimation, blepharospasm conjunctival hyperemia, and upper respiratory tract irritation may occur after exposure to concentrations of 3 to 5 ppm.
- Severe pulmonary toxicity may develop after exposure to higher concentrations or following exposures for longer periods of time.
- A phosgene casualty who develops respiratory distress within 4 hours of exposure has probably inhaled an LD50 and is at severe risk if not properly supported
- Signs and symptoms of toxicity may be delayed, although rare, for 24 to 72 hours and include choking, chest tightness, cough, severe dyspnea, production of foaming bloody sputum, and pulmonary edema. Non-respiratory symptoms include nausea and anxiety. Cardiac failure has occasionally occurred as a complication of severe pulmonary edema. Concentration-response guidelines include:
- Victims with inhalation doses of < 25 ppm/min and without clinical signs and symptoms require no immediate medical attention. Exposure to a cumulative dose of 50 ppm x minutes may cause pulmonary edema; a dose of 150 ppm x min will probably cause pulmonary edema and a dose of 300 ppm x min is likely to be fatal.
- Brief exposure to 500 ppm or greater may be rapidly fatal. Prolonged exposure to low concentrations (e.g. 3 ppm for 170 min) can also be fatal. Exposure to concentrations less than 3 ppm may not be immediately accompanied by irritant symptoms; delayed effects usually occur within 24 hrs of exposure.
- Victims with unknown phosgene exposure must be closely observed
- Liquid phosgene is a frostbite hazard and has caused corneal opacification.
- Victims with unknown phosgene exposure must be closely observed. Victims may be discharged if they are free of signs and symptoms and have clear chest x-ray films 8 hours after the end of phosgene exposure. However, if chest x-rays are not available observation of asymptomatic victims should be continued for 24 hours.
ABC/ALS Reminders- Initial stabilization - Evaluate and support the airway, breathing, and circulation. Intubate the trachea in cases of respiratory compromise. As large as practical a tube should be inserted to avoid blockage by sloughed epithelium. Suctioning may be required for excessive bronchial secretions.
- Inhalation - Inhalation is the major route of phosgene exposure. Phosgene's effects as a respiratory irritant can be mild and delayed, which may result in a lack of immediate avoidance leading to exposure for prolonged periods. Phosgene is heavier than air and may cause asphyxiation due to oxygen displacement in poorly ventilated, low-lying, or enclosed spaces.
- Skin/Eye Contact - When phosgene gas contacts moist or wet skin, it may cause irritation and erythema. High airborne concentrations can also cause corneal inflammation and opacification. Direct contact with liquid phosgene under pressure can cause frostbite as well as severe irritation and corrosive effects.
- Ingestion - Ingestion of phosgene is unlikely because it is a gas at room temperature.
Clinical Signs and Symptoms
Respiratory
- Being only slightly soluble in water it is primarily absorbed by the lower airway. Inhaling low concentrations may cause no signs or symptoms initially or symptoms that are secondary to mild irritation of the airway. After an asymptomatic period for 30 minutes to 48 hours, in those developing severe pulmonary damage a progressive pulmonary edema ensues, which can produce up to 1 liter of fluid per hour.
Cardiovascular
- Circulatory collapse secondary to severe pulmonary edema. Destruction of RBCs in the pulmonary circulation can result in right sided heart failure.
Dermatologic
- Chlorine and Phosgene cause skin irritation and with sufficient concentration can cause, burning pain, inflammation, and blisters. Liquefied chlorine and phosgene can cause frostbite injury.
Ocular
- High vapor concentration can cause tearing and blood in the eye. Contact with liquid phosgene may result in clouding of the cornea and delayed perforation.
Hematological
- In severe cases of phosgene exposure hemolysis can occur with resultant plugging of pulmonary capillaries.
Hepatic
- Phosgene may be directly cytotoxic to the liver.
Renal
- Phosgene may also cause cytotoxicity to the kidneys with resultant loss of function.
Gastrointestinal
- Nausea and vomiting may occur following exposure to phosgene.
Potential Sequalae
- If the patient survives 48 hours recovery is likely. Persistent airway hyperactivity, pulmonary tissue destruction and scaring may lead to dilatation of the bronchi, lobar emphysema, and atelectasis. As with chlorine exposure RADS has been reported.
Link to Toxic Syndromes
Link to Primary and Secondary Survey
- Since phosgene is a respiratory tract irritant, but has unique toxicological concerns due to the latency for onset of pulmonary edema, differentiating it from the typical presentation of symptoms from other common chemical irritants is an important consideration.
- Phosgene is distinguished by its smell in high concentrations and delayed onset of pulmonary edema.
- Chlorine has a characteristic odor even in low concentrations, immediate onset of respiratory distress, bronchospasm, eye, skin, and upper airway irritation.
- Riot agents cause an acute onset of burning sensation in the eyes and upper airway without progression of symptoms with ongoing exposures.
- Nerve agents induce watery secretions as well as respiratory distress, but have a host of other symptoms, such as miosis, seizures, rapidity of onset, that can distinguish them from pulmonary agents.
- The respiratory toxicity of vesicants (i.e. Mustard Gas) is usually delayed, but affects the central rather than the peripheral airway. Vesicant toxicity severe enough to cause dyspnea typically causes airway necrosis often with upper airway obstruction.
- Link to Chemical Hazards Emergency Medical Management Intelligent Syndromes Tool (CHEMM-IST)
Pediatric/Obstetric/Geriatric Vulnerabilities
Children are more vulnerable to phosgene because:
- They are lower to the ground and are exposed to an increased concentration of phosgene.
- They have a higher respiratory rate and inhale a greater volume per minute.
- They have smaller diameter airways, anatomic subglottic narrowing, omega shaped epiglottic structure, relatively large tongue size, less rigid ribs and trachea which make them more vulnerable to phosgene induced pathology such as bronchospasm, copious secretions, and pulmonary edema.
- Their skin is thinner and has more moisture content therefore being more vulnerable to inflammatory/corrosive effects.
- Link to Primary and Secondary Survey
Treatment in the Hot Zone
Antidotes - there are no specific antidotes for phosgene.
Supportive
Intubate the trachea in cases of coma or respiratory compromise, or to facilitate removal of excessive pulmonary secretions. If not possible, perform cricothyroidotomy. Frequent suctioning of the airways will be necessary to remove mucous secretions.
Treat patients who have bronchospasm with aerosolized bronchodilators. The use of bronchial sensitizing agents in situations of multiple chemical exposures may pose additional risks. Consider the health of the myocardium before choosing which type of bronchodilator should be administered. Cardiac sensitizing agents may be appropriate; however, the use of cardiac sensitizing agents after exposure to certain chemicals may pose enhanced risk of cardiac arrhythmias (especially in the elderly). Phosgene poisoning is not known to pose additional risk during the use of bronchial or cardiac sensitizing agents.
Consider racemic epinephrine‡ aerosol for children who develop stridor. Dose 0.25-0.75 mL of 2.25 % racemic epinephrine solution in 2.5 cc water, repeat every 20 minutes as needed, cautioning for myocardial variability.
Patients who are comatose, hypotensive, or are having seizures or cardiac arrhythmias should be treated according to advanced life support (ALS) protocols.
Enforce rest - Even minimal physical exertion may shorten the clinical latent period and increase the severity of respiratory symptoms and signs in a lung-damaging agent casualty. Physical activity in a symptomatic patient may precipitate acute clinical deterioration and even death. Strict limitation of activity are strongly recommended for patients suspected of having inhaled phosgene.
‡ Not FDA approved for this indication/Off-label use
If victims can walk, lead them out of the Hot Zone to the Decontamination Zone. Victims who are unable to walk may be removed on backboards or gurneys; if these are not available, carefully carry or drag victims to safety. Should there be a large number of casualties, and if decontamination resources permit, separate decontamination corridors should be established for ambulatory and non-ambulatory victims.
Consider appropriate management of chemically contaminated children, such as measures to reduce separation anxiety if a child is separated from a parent or other adult.
Decontamination Zone
Show all sections
Victims exposed only to phosgene gas that have no evidence of skin or eye irritation may be transferred immediately to the Support Zone as they do not pose substantial risks of secondary contamination to personnel outside the Hot Zone. Victims whose clothing or skin is contaminated with liquid phosgene (ambient temperature below 47ºF) can secondarily contaminate response personnel through direct contact or off-gassing vapor and will require decontamination as described below.
Rapid decontamination is critical to prevent further absorption by the patient and to prevent exposure to others.
Decontamination Zone
Personnel should continue to wear the same level of protection as required in the Hot Zone.
Link to Hot Zone - Rescuer Protection.
If exposure levels are determined to be safe, decontamination may be conducted by personnel wearing a lower level of protection than that worn in the Hot Zone. However, do not attempt resuscitation without a barrier.
If the victim is symptomatic, immediately institute emergency life support measures. Treatment should be given simultaneously with decontamination procedures. Quickly ensure that the victim has a patent airway and is ventilating well. Assist ventilation with a bag-valve-mask device equipped with a canister or air filter if necessary. Maintain adequate circulation. Stabilize the cervical spine with a decontaminable collar and a backboard if trauma is suspected. Direct pressure should be applied to control heavy bleeding, if present.
Antidotes - there are no specific antidotes for phosgene.
Set up Considerations
- Use pictorial and written posted instructions for victims to self decon when able, use locale-appropriate multilingual signage
- Double bag contaminated clothing etc. (place hearing aids, valuables in small bag). Place bag in container by showers.
- Victims who are able may assist with their own decontamination.
- Children and the elderly are at increased risk for hypothermia - provide warm showers, blankets
- Privacy must be considered if possible.
- The decontamination system should be designed for use in children of all ages, by parentless children, the non-ambulatory child, the child with special needs, and also allow families to stay together.
- Use step-by-step child friendly instructions that explain to the children and parents what they need to do, why they are doing it and what to expect.
- Take into consideration that infants when wet are slippery and will need a way to get them through the decontamination process - i.e. plastic buckets, car seats, stretchers...
- Designate a holding area and provide staff to support and supervise the children
- Recommended age appropriate staffing ratios for untended children:
- 1 adult to 4 infants
- 1 adult to 10 preschool children
- 1 adult to 20 school-age children
Washing Instructions
- If there will be significant delay to decontamination have the victims rinse off with water exposed skin surfaces and disrobe (disposable clothing kits should be available).
- Remove all clothing (at least down to their undergarments) and place the clothing in a labeled durable 6-mil polyethylene bag (removal of clothing, at least to the undergarment level will reduce victim's contamination by 85 %).
- If clothes have been exposed to contamination, then care must be taken when undressing to avoid transferring chemical agents to the skin - i.e. any clothing that has to be pulled over your head should be cut off instead of being pulled over your head.
- If exposure to liquid agent is suspected, cut and remove all clothing and wash skin immediately with soap and water.
- If exposure to vapor only is certain, remove outer clothing and wash exposed skin with soap and water.
- Cover all open wounds with plastic wrap prior to performing head to toe decontamination (particular attention should be made to open wounds because phosgene is readily absorbed through abraded skin).
- Flush the exposed skin and hair with plain water for 2 to 3 minutes then wash twice with mild soap. Rinse thoroughly with water. Be careful not to break the patient/victim's skin during the decontamination process.
- Flush exposed or irritated eyes with plain water or saline for at least 15 minutes by tilting the head to the side, pulling eyelids apart with fingers, and pouring water slowly into eyes. Remove contact lenses if easily removable without additional trauma to the eye. If a corrosive material is suspected or if pain or injury is evident, continue irrigation while transferring the victim to the Support Zone.
- Scraping with a wooden stick, i.e. a tongue depressor or popsicle stick, can remove bulk agent
- Caution - many people shower as they do it at home rather than conducting a rapid decontamination of their bodies. Too aggressive scrubbing can lead to further damage to skin and open wounds.
- Utilizing large amounts of water by itself is very effective (limit pressure in infants).
- If water supplies are limited, and showers are not available an alternative form of decontamination is to use 0.5 % sodium hypochlorite solution, or absorbent powders such as flour, talcum powder, or Fuller's earth.
- Sodium hypochlorite is not recommended for use in infants and young children.
- Certification of decontamination is accomplished by any of the following: processing through the decontamination facility; M256A1 kit, M18A2, M90 chemical agent detectors.
- If still contaminated, repeat shower procedure.
Decontamination of First Responder:
- Begin washing PPE of the first responder using soap and water solution and a soft brush. Always move in a downward motion (from head to toe). Make sure to get into all areas, especially folds in the clothing. Wash and rinse (using cold or warm water) until the contaminant is thoroughly removed.
- Remove PPE by rolling downward (from head to toe) and avoid pulling PPE off over the head. Remove the SCBA after other PPE has been removed.
- Place all PPE in labeled durable 6-mil polyethylene bags.
Decontamination of Infants and Children
- Video: Decontamination of Infants and Children (HHS/AHRQ, Children's Hospital Boston) (Watch video)
- Decontamination of Children (HHS/AHRQ) provides a step-by-step decontamination demonstration in real time, and trains clinicians about the nuances of treating infants and children, who require special attention during decontamination.
Wound Management
References
- Medical Management of Chemical Casualties Handbook, 2nd edition, September, 1995
- Braue EH, Boardman CH. Decontamination of Chemical Casualties
- Jagminas L. CBRNE - Chemical Decontamination (eMedicine)
Treatment Area
Following decontamination the patient should be reassessed; noting changes in triage category (if any), the need for or the modification of supportive therapy (See ABC reminders/Advanced Treatment) .
Enforce rest - Even minimal physical exertion may shorten the clinical latent period and increase the severity of respiratory symptoms and signs in a lung-damaging agent casualty. Physical activity in a symptomatic patient may precipitate acute clinical deterioration and even death. Strict limitation of activity are strongly recommended for patients suspected of having inhaled phosgene.
ABC Reminders
Quickly access airway patency. If trauma is suspected, maintain cervical immobilization manually and apply a cervical collar and a backboard when feasible. Ensure adequate respiration and pulse. Document oxygen saturation. Place on a cardiac monitor.
Link to Primary and Secondary Survey
If the patient is symptomatic, immediately institute emergency life support measures.
Supportive - Link to supportive treatment in the hot zone
Clinical Signs and Symptoms - Link to clinical signs and symptoms
Medical Management
- The diagnosis of acute phosgene toxicity is primarily clinical, based on symptoms of irritation and breathing difficulty. However, laboratory testing is useful for monitoring the patient and evaluating complications.
- If cough or difficulty in breathing develops, evaluate for hypoxia, respiratory tract irritation, bronchitis, or pneumonitis.
- Chest radiography and pulse oximetry (or ABG measurements) are recommended if significant inhalation exposure is suspected. Serial chest x-rays may be necessary as effects may be delayed.
- Pulmonary edema visible on chest x-ray has developed within 1 to 2 hours of high exposure, 4 to 6 hours of moderate exposure, and approximately 8 to 24 hours after low dose exposure, but onset time can vary. Blurred perihilar enlargement and diffuse opacities are common findings.
- Routine laboratory studies for all exposed patients include CBC, glucose, and electrolyte determinations. ECG monitoring is useful for patients exposed to phosgene.
- Plasma phosgene levels are not clinically useful.
- Acute Lung Injury (ALI), Acute Respiratory Distress Syndrome (ARDS)
- ALI/ARDs is a process of nonhydrostatic pulmonary edema with resultant arterial hypoxemia associated with a variety of causative etiologies (including severe phosgene toxicity). Left atrial hypertension should be excluded.
- The standard definition of ALI identifies those patients as having bilateral pulmonary infiltrates and arterial hypoxemia using the concentration of arterial oxygen in the blood divided by the inspired fraction of oxygen (i.e. a PaO2 ratio of less than 300).
- If the patient's Pa02/Fi02 is less than 200, then a diagnosis of ARDS can be made
- Link to Overview literature for diagnosis and management of ALI and ARDS
Preventative Treatment
Inhalation of higher phosgene doses (e.g., > 150 ppm/min) causes immediate biochemical changes that lead to alterations of the air-blood barrier, but several hours may elapse until enough extravascular fluid has accumulated to produce the signs and symptoms of pulmonary edema. A major goal in victim management has been to block the phosgene-induced inflammatory cascade during the latency phase, before the development of clinical edema. (Such early therapy is often called prophylactic treatment, even though prophylaxis more correctly refers to treatments given before the exposure has occurred). Specific treatments proposed for post-exposure prophylaxis, including steroids, ibuprofen, NAC, and positive airway pressure ventilation, are described below (off label usage)‡*. However, a specific antidote for phosgene exposure is not known.
Animal experiments and anecdotal human experience suggests that the drugs listed in the prophylactic drug therapy and drug therapy sections below might be effective in preventing and/or treating phosgene-induced pulmonary edema. Optimal doses of these agents have not been established (off label usage)‡*.
Prophylactic Drug Therapy
- Exposure to a total dose of 50 ppm x minutes may cause delayed pulmonary edema. Prophylactic treatment should be considered in patients with an exposure of 50 ppm x min or more. Optimal doses of these agents for phosgene exposure have not been established.
- Methylprednisolone 15 mg/kg (max dose 1 gram) intravenously (or equivalent corticosteroid) or dexamethasone phosphate 10 milligrams aerosol (may be less effective than intravenous administration).
- Aminophyline 5- 6 milligrams/kilogram loading dose followed by 1 milligram/kilogram every 8 to 12 hours to maintain a serum level of 10 to 20 micrograms/milliliter.
- Ibuprofen 800 milligrams (at least one dose). Pediatric 10mg/kg
- N-Acetyl-cysteine - up to 10 milliliters of a 20 % solution aerosolized.
- Terbutaline 0.01 mg/kg (max dose 0.25 milligrams) subcutaneously.
Non-Pharmacologic Treatment
- Administer 100 % humidified supplemental oxygen, perform endotracheal intubation and provide assisted ventilation as required.
- Positioning - Improvement in oxygenation has been associated with a change to the prone position. .
- Maintain adequate ventilation and oxygenation with frequent monitoring of arterial blood gases, pulse oximetry and end tidal CO2 monitoring. If a high FIO2 is required to maintain adequate oxygenation, mechanical ventilation and positive-end-expiratory pressure (PEEP) may be required; ventilation with small tidal volumes (6 milliliters/kilogram) and acceptance of permissive hypercarbia is preferred if ARDS develops.
- To minimize barotraumas and other complications, use the lowest amount of Peak airway pressure and PEEP possible while maintaining adequate oxygenation.
- Use of smaller tidal volumes (6 milliliters/kilogram) and lower plateau pressures (30 cm water or less) has been associated with decreased mortality and more rapid weaning from mechanical ventilation in patients with ARDS (Brower et al, 2000). Despite the lack of a specific pharmacologic treatment, lung protective ventilation has reduced the mortality of ALI from 40% in 2000 to 25% in 2006.
- Link to Overview Literature for diagnosis and management of ALI and ARDS
Drug Therapy‡*
- Inhaled beta adrenergic agonists if bronchospasm develops - Consider racemic epinephrine aerosol for children who develop stridor. Dose 0.25-0.75 mL of 2.25% racemic epinephrine solution in 2.5 cc water, repeat every 20 minutes as needed, cautioning for myocardial variability. Consider the health of the myocardium before choosing which type of bronchodilator should be administered. Cardiac sensitizing agents may be appropriate; however, the use of cardiac sensitizing agents after exposure to certain chemicals may pose enhanced risk of cardiac arrhythmias (especially in the elderly). Phosgene poisoning is not known to pose additional risk from such drug therapies. The use of bronchial sensitizing agents in situations of multiple chemical exposures may pose additional risks.
- IV Aminophylline is a second line agent that might be helpful - 5-6 milligram/kilogram loading dose followed by 1 milligram/kilogram every 8 to 12 hours to maintain a serum level of 10 to 20 micrograms/milliliter.
- Methylprednisolone - children 2 mg/kg loading then 2 mg/kg divided Q6h¸ adults 250 mg Q6H, steroids are not recommended in patients without latent or overt reactive airway disease.
- Beta2 adrenergic agonists such as terbutaline, isoetharine at conventional doses.
- N-acetylcysteine - up to 10 milliliters of a 20 % solution aerosolized.
- Ibuprofen 800 milligrams (15 mg/kg in children) every 8 to 12 hours for at least one dose.
- Na Bicarbonate therapy - The utility of nebulized bicarbonate has not been firmly established, and the optimal dose has also not been delineated. A reasonable dose is 3.75-5% nebulized over 20 minutes and may be repeated. A 3.5% solution can be prepared by taking 2 mL of a 7.5% intravenous preparation of sodium bicarbonate solution and combining with 2 mL of normal saline. Because precipitates can form if combined, it is important that nebulized sodium bicarbonate be administered separately from nebulized albuterol sulfate
- Antibiotics are indicated only when there is evidence of infection. More than 60% of ARDS patients experience a (nosocomial) pulmonary infection
Fluids
- Crystalloid solutions must be administered cautiously, AVOIDING a net positive fluid balance. Monitor fluid status through a central line or Swan Ganz(R) catheter.
- Diuretics may be needed to avoid a net positive fluid balance but are almost always contraindicated. Pulmonary edema due to phosgene inhalation is not hypervolemic in origin; patients tend to be hypovolemic and hypotensive. Dopamine may be required for treatment of hypotension, bradycardia, or renal failure.
Observe patients who are in respiratory distress for up to 48 hours and periodically re-examine their chests and order other appropriate studies. Follow up as clinically indicated.
Eye Exposure
- Remove contact lenses and irrigate exposed eyes with copious amounts of room temperature 0.9 % saline or water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persists after 15 minutes of irrigation, an ophthalmologic examination should be performed.
Dermal Exposure
Frostbite has not been commonly reported but is a potential risk
- Re-warming
- Do not institute re-warming unless complete re-warming can be assured; re-freezing thawed tissue increases tissue damage. Place affected area in a water bath with a temperature of 40 to 42 degrees Celsius for 15 to 30 minutes until thawing is complete. The bath should be large enough to permit complete immersion of the injured part, avoiding contact with the sides of the bath. A whirlpool bath would be ideal. Some authors suggest that an antibacterial (hexachlorophene or povidone-iodine) be added to the bath water (Murphy et al, 2000).
- Correct systemic hypothermia.
- Re-warming may be associated with increasing pain, requiring narcotic analgesics.
Wound Care
- Digits should be separated by sterile absorbent cotton; no constrictive dressings should be used. Protective dressings should be changed twice per day.
- Perform daily hydrotherapy for 30 to 45 minutes in warm water 40 degrees Celsius. This helps debride devitalized tissue and maintain range of motion.
- The injured extremities should be elevated and should not be allowed to bear weight.
- Prophylactic antibiotics are recommended by some authors.
- Clear blisters should be debrided but hemorrhagic blisters left intact.
- Further surgical debridement should be delayed until mummification demarcation has occurred (60 to 90 days). Spontaneous amputation may occur.
- Analgesics may be required during the re-warming phase; however, patients with severe pain should be evaluated for vasospasm. Arteriography and noninvasive vascular techniques (e.g., Doppler ultrasound, digital plethysmography, isotope scanning), have been useful in evaluating the extent of vasospasm after thawing.
- Tetanus prophylaxis as indicated.
- Topical aloe vera may decrease tissue destruction and should be applied every 6 hours.
- Ibuprofen is a thromboxane inhibitor and may help reduce tissue loss. Adult dose of 200 milligrams every 12 hours is recommended.
- Adjunct pharmacological agents (heparin, vasodilators, prostacyclins, prostaglandin synthetase inhibitors, thrombolytics, dextran) are controversial and not routinely recommended.
Delayed Effects
Because pulmonary edema may not occur for up to 48 hours after exposure, patients who have known exposure should be observed and re-examined periodically before confirming the absence of toxic effects. Patients who have bronchospasm or pulmonary edema should be watched carefully for signs of impending respiratory failure and should be managed accordingly. Patients who survive for 48 hours usually recover.
Link to Basic and Advanced Life Support
‡ Not FDA approved for this indication/Off-label use
* Pregnancy Categories: Refer to DailyMed regarding Pregnancy Categories and additional pregnancy-related information.
Antidotes - there are no specific antidotes for phosgene.
Disposition and Follow-up
Patient Release
Asymptomatic patients who have normal initial examinations and no signs of toxicity after observation for 48 hours may be discharged with instructions to seek medical care promptly if symptoms develop (see the Phosgene-Patient Information Sheet below).
Follow-up
Patients may have long term damage to the lungs and increased susceptibility to infection. Sensitivity to irritants may persist, causing bronchospasm, chronic inflammation of the bronchioles and Reactive Airway Dysfunction Syndrome (RADS), a chemically- or irritant-induced type of asthma.
Patients who have corneal injuries should be reexamined in 24 hours.
Follow-up Instructions
![Follow-up instructions in PDF format](chemmimages/pdf.gif)
Adapted from Medical Management Guidelines for Phosgene (ATSDR/CDC)
PDF documents can be viewed with the free Adobe® Reader™
Acute Patient Care Guidelines References
|