MANAGING CHEMICAL EXPOSURES: THE ENGINE COMPANY PERSPECTIVE
ROB SCHNEPP
It`s 2 p.m. on a hot Tuesday afternoon, and your engine company is responding to a call for difficulty in breathing at a nearby industrial park. You`ve been to this complex a few times, but the name of the business is not familiar and you can`t picture the exact address. A minute or so before you arrive, the dispatcher gives you an update: “Engine 22, be advised the reporting party states that the patient has been exposed to a small amount of arsine gas.” Frantically, you dig out the North American Emergency Response Guidebook (NAERG) and look up arsine. It refers you to Guide fifty-something-or-other, which explains that an inhalation exposure to this material can be fatal and that your turnouts will not offer any real protection. On top of that, the ambulance is delayed for 10 minutes, and you`re now on-scene with a bunch of people who are expecting you and your crew to do something spectacular. After deciding that early retirement is not an option, you work your way through the facility to find an obviously distressed victim. Now what?
The good news is that you don`t have to be a haz-mat expert or a doctor or a combination of the two to remain safe and render some useful care. And although you may not be familiar with the chemical in question, there are some universal principles you can employ in a situation like this.
Following is a five-point checklist for the basic management of a chemically exposed patient.
Secure the scene, and provide for your own safety first!
Assist or remove the patient from the contaminated environment. Make sure your protective gear is adequate if effecting a rescue.
Decontaminate the patient.
Provide the appropriate basic life support (BLS) or advanced life support (ALS) measures.
Package the patient, and transport.
These concepts are certainly not ground-breaking revelations, but I encourage you to really think about them for a moment and understand how some basic actions can have a profound effect on the well-being of your patient. Remember that it`s your job to assume control of the chaos and confidently take the appropriate actions to minimize the exposure and get the patient moving toward the hospital. That`s a key concept in dealing with chemical exposures and is certainly worth repeating. Everything you do should be aimed at moving the patient toward the hospital. This is where the most definitive care will take place.
Your job in the field, from a medical standpoint, is to gather accurate information about the chemical and the nature of the exposure, remove gross contamination, provide the necessary basic and/or advanced life support, and get on the road.
SECURE THE SCENE AND PROVIDE FOR YOUR OWN SAFETY
It should go without saying that you must ensure your own safety first. If a responder is accidentally exposed and suddenly turns into a patient, then he has done nothing but further complicate an already stressful situation. To effectively secure a scene, simply refer to the basic principles of hazardous-materials response: isolate the area and deny entry. By staking out your claim and determining safe zones from the outset, the risk of further exposure to responders and civilians will be reduced. Never take more real estate than you can control, but be liberal in setting your initial safe zones. If possible, use site personnel or law enforcement to guard outlying perimeters to free up your own trained responders.
Accurately identifying the released chemical is also important. If site personnel are around, they may be a valuable resource. Take care, however, not to be lulled into complacency by people who claim to be familiar with the chemical. Those who work with “that stuff” on a daily basis may have lost some respect for it over time and could lure you right into their mindset. A person with a serious chemical exposure is a true emergency, and it is up to you to get all the facts available.
Obtain a current material safety data sheet (MSDS) or some other reliable reference for the material, and make sure it exactly represents the chemical in question. For example, if your patient was exposed to hydrofluoric acid at a two-percent concentration that was mixed with some other chemical, an MSDS representing a pure 50 percent concentration would not be pertinent. The reverse is true in terms of concentration or mixture, and you should use a very discerning eye when matching your reference source with the chemical you are researching.
Additionally, most MSDSs will have basic first aid or other recommendations for dealing with exposures. This can be a very useful guide for initial actions and a potential lifesaver for you. It`s always nice to have a little guidance when negotiating unsure territory.
Also listed are possible signs and symptoms of exposure. Compare them with what you are seeing and with what the patient is telling you. It may be useful in confirming the exposure or as an aid in determining how critical the exposure may be. This step also becomes very important in saving time once the patient arrives at the emergency room. There aren`t many emergency room doctors who treat chemical exposures off the top of their heads. Most will call poison control centers or refer to reference books when faced with chemical exposures. If you can walk in the door with accurate information on the chemical, it will ultimately speed up the treatment.
In many cases, structural firefighting gear provides limited protection from chemicals. Before rushing in to save the day, it is wise to evaluate the anticipated effectiveness of your protective clothing. Remember that personal protective clothing is there in case you need it, not to make you invincible against all hazards. If the environment is not safe to enter with the protective gear you have, then don`t go in! You may end up waiting for a haz-mat team to arrive, make entry, and bring the patient to a safe location prior to treatment. This will take a long time in most cases, but the alternative to waiting may not be very desirable.
SAFETY POINTS WHEN REMOVING A PATIENT
There are some important safety points to consider when removing a patient from a contaminated environment. First of all, most patients who can self-evacuate will do so. Luckily for us, a safe perimeter will oftentimes establish itself before our arrival if the release or exposures are significant. When was the last time you noticed anyone willingly walking around in a chlorine cloud? What we are usually faced with is the patient who has been exposed, has left the area of the release, and is now in some distant part of the building or complex. Murphy`s Law tells us that he will be in the most remote or inaccessible part of the building or complex and will have spread contamination for miles in all directions. It then becomes our job to isolate the victim(s) and the con-taminated areas. Murphy`s Law also has it that if one person is receiving treatment for an exposure, other victims will be likely as the incident progresses. You may have already found that once “the show” begins and a person is being given oxygen or some other treatment, others will come forward for treatment. It will be to your benefit to round up anyone who may have been exposed and move them to a more secluded area for treatment. This will reduce the spread of panic or phantom symptoms that may occur later.
It becomes important then to select a place that is conducive to the work you have ahead of you. You know that you`ll have to decontaminate the patient, treat him, and eventually transport, so find a spot with good ventilation, a water source like safety showers or eye wash stations, and some sort of containment for the decontamination runoff. Additionally, try to position yourself near access areas for ambulances or other emergency vehicles. The small amount of time you spend finding the best location will speed things up later in the incident.
In the early stages of the event, even before you have begun patient care, you should have completed at least the following steps:
Make sure you are not being exposed or will not likely become exposed.
Locate all your patients.
Isolate the anticipated release area, and secure it.
Remove your patient from the contamination if it is safe to do so. If not, back off, and wait for those who can make entry and bring the patient to you.
Obtain an MSDS or other reliable source of information for the chemical in question.
DECONTAMINATION
Before a patient can be treated, he must be free of the chemicals to which he was exposed. To effectively decontaminate a patient, use a systematic approach while keeping this thought in mind: Emergency rooms will not accept contaminated patients. Most hospitals have decon areas set up somewhere on the premises, but if a patient has gotten all the way to the hospital without being decontaminated, you have not done your job.
This is true for a number of reasons. First, you would have spread contamination from the scene to the hospital, including the transport vehicle, and all the personnel who came in contact with the patient. Second, you have allowed the exposure to continue well past the point it should have. Clothing soaked with contamination will increase the extent of the exposure through its constant contact with the skin. Generally speaking, the longer the contact with the chemical, the worse the exposure. Last, but also important, you may cause a great deal of harm to the patient by starting IVs at contaminated sites or allowing the patient to inhale vapors emitting from contaminated clothing.
Keep in mind this important fact: Decontamination is as much a part of patient care as any other procedure you may perform. In fact, it can be the single most crucial thing you do before transport.
Which agent? How much? So how do you know which type of decon is right or how much is enough? These are tough questions to which there are no standard answers. The basic concept is this: Water is the universal decon agent, and you should not be stingy about using it. Most chemicals can be adequately diluted or washed away by using copious amounts of water. The rule of thumb is to wash the affected area for at least 15 minutes. Sometimes, it takes a little longer, but, generally speaking, you should irrigate the area for a minimum of 15 minutes. This includes eyes, which are difficult to cleanse; hands; feet; arms; and face or back–you name it. If it has been contaminated, remove any affected clothing, and wash it off.
Secondary contamination. Be aware of secondary contamination. When washing the chemical from the patient, the contaminated water will flow to other parts of the body, thereby causing another exposure. Granted, it may not be as significant because of the dilution that has occurred, but, if you do not pay attention, you may find that your situation has become complicated. It is, therefore, necessary to position your patient in such a fashion that the water runoff does not contact you or other areas of the patient`s body. Safety showers are great for this because the patient can stand upright while being decontaminated. This allows for proper runoff and the prevention of a secondary exposure. If the patient is unconscious or unable to stand, place him on a backboard or wire stokes basket, and start rinsing. The stokes allows for better drainage and can be manually held on either end or supported by stools or five-gallon buckets.
Whatever the case, strip the patient as much necessary, and get the decon going. Modesty is secondary to living, so if your patient`s clothes need to come off, off they come. Provide as much privacy for the patient as possible, but be aggressive in dire circumstances, and take the appropriate action. If the best thing you have available is a booster line from the engine, then so be it. Whatever the method, make sure it`s safe for you, effective for the job at hand, and quick.
Some chemicals, like solvents, are difficult to remove with water. They tend to permeate the skin and stay there. You may not even see any visible damage at the site of exposure. Therefore, it may be necessary to use a mild soap solution to remove large amounts of gross contamination prior to a good long dousing with water. This is not a good idea for the eyes, though, as soap is very irritating to those delicate tissues.
Eye irrigation. A good method for irrigating eyes in the field necessitates only an IV bag of normal saline and a nasal cannula. First, spike the bag with your primary IV tubing minus the extension set. Next, fit the end of the IV tubing into the port that would normally attach the cannula to the oxygen cylinder. Fit the cannula with the prongs across the bridge of the patient`s nose, and snug it up behind the head. Flood the line, and titrate the flow to whatever looks effective. A good stream of saline will run from the prongs, down the bridge of the nose, and into the corners of both eyes. You may have to fold your patient`s eyelids open with a cotton swab or by some other method, but do whatever it takes to keep the eyes open. Also keep in mind that the IV bag will be emptying and running all over the place, so make some provision to control the flood.
Saponification. Most acids and bases are water soluble, so water is an effective decon agent. Bases, however, tend to be absorbed through the skin and liquefy the subcutaneous fat. This process is called saponification. It`s painful, and you can do nothing about it in the field. The patient may report a slick or slippery feeling on the skin, the result of the action caused by the chemical. Common bases like sodium and potassium hydroxide will certainly cause this to happen. Your only course of action is to continue the decontamination, although you may find that 15 minutes does not complete the process. The saponification reaction may go on well past your 15-minute time frame, so you may find yourself leaving the scene feeling that the decon was inadequate. This may be the best you can do under the circumstances. Unfortunately, some chemicals will continue to do their damage well beyond the initial exposure. A golden rule in dealing with acids and bases is, never try to neutralize the material on the skin. A lot of heat is generated during a neutralization reaction, and you don`t want to complicate an already undesirable situation.
State of matter. Additionally, it is important to determine the state of matter of the chemical to which your patient was exposed. Solids tend to stick to the skin and turn into pancake batter if mixed with water. It`s better to lightly brush off as much of the solid as you can before flushing with water. Gases are typically inhaled by the victim and, therefore, are not subject to traditional methods of decon. The good thing about gaseous substances is that they want to be gases at normal temperatures and will readily diffuse once released. It is usually not necessary to make a big production about decontamination for this reason. By the time you get there, the gas has probably diffused away and is no longer an issue. This is not true for all gases or prolonged releases, but keep in mind that a gas wants to be a gas–so let it. You may only need to remove the patient`s clothes and do a quick flush with water before starting treatment and transport. Again, consult the MSDS to find the particulars on the chemical. It will be time well spent.
It is also wise to consult an MSDS to determine if your patient has been exposed to a chemical that is doing damage internally. Chemicals such as organophosphate pesticides, for example, disrupt the nervous system. Decontamination will clean the outside of the patient but do nothing to treat the exposure. Drug therapy and other invasive actions are required in this type of exposure. If this happens to be the case, decon the best you can, and move on toward the hospital. Local protocols will dictate which therapies you can provide in these situations.
Here are some important questions to ask when preparing to decontaminate a patient:
What has he been exposed to, and for how long?
Is it a solid, liquid, or gas?
Where on the body is the exposure?
Was the patient wearing any protective equipment prior to the exposure? Did it fail?
Will water be effective?
Do I need any protective equipment to perform decon?
PROVIDING PATIENT CARE
We have finally arrived at the point where it may be necessary to do something on the patient`s behalf. It may seem as if a lot of time has passed before we enter this phase, but taking the above steps will ensure that you are working safely.
The interesting thing about dealing with a chemical exposure is that it presents some unique hazards not encountered in a standard medical call. Of course, if you`re treating a seizure patient, you don`t expect to begin seizing if you inadvertently touch him. You don`t expect to “catch” chest pain from a cardiac patient either. With chemical exposures, however, one wrong move or a touch with an unprotected hand and suddenly you are an exposure patient just as the person you`re working on is. It`s not a great position to be in, but it`s a fact of life when dealing with chemical exposures. Therefore, make sure you use every bit of personal protective equipment you have when rendering care under these circumstances. Be sure that your medical gloves and whatever else you are using will offer adequate protection. As a rule, the latex medical gloves that are standard in the industry are effective against blood and guts but not so good against aggressive solvents or strong corrosives. Refer to the appropriate reference source to confirm that your protective gear will work.
The initial actions for dealing with chemical exposures are no different from those for dealing with other patients–that is, it is necessary to ensure an open airway and to make sure that the patient is breathing adequately and has an effective heartbeat. After doing this, a multitude of paths may be taken. It is virtually impossible to cover all exposure scenarios in a single text, so we will concentrate on three exposure types–inhalation injuries, corrosive exposures, and organophosphate pesticide exposures–and explore some BLS and ALS actions that may be employed.
INHALATION INJURIES
Inhalation, or exposure through the lungs, is one of the most potentially damaging ways a chemical can enter the body. Because of the large surface area of the lungs (approximately 700 square feet), we can take in an overwhelming amount of contamination. In a single breath, we can bring in enough of the wrong material to cause a fluid buildup in the lungs, an altered level of consciousness, or even death. Take, for example, the arsine gas mentioned earlier. An inhalation exposure to as little as 500 parts per million (ppm) can be fatal. That is not a lot of material, and the downside is that once a person has been significantly exposed, there is little that can be done.
Water-soluble gases and vapors, like ammonia, cause the worst damage in the upper airway, whereas less soluble vapors, like hydrochloric acid, work deeper in the lung tissue. The sensitive linings of the trachea, bronchioles, and alveoli may be damaged, thereby causing fluid to be secreted. Additionally, the irritation may cause such substantial swelling in the upper airways that ventilation with a bag valve mask or intubation becomes virtually impossible.
The inhalation of a large concentration of hydrocarbon vapors may induce a chemical pneumonia. The mortality rate for chemically induced pneumonia is quite high and may occur if the patient has aspirated any vomit secondary to the exposure.
Suspect an inhalation exposure if the patient has been splashed on the chest or anterior part of the body with any vaporous liquid chemicals. There may be a secondary exposure from the emitted vapor, which may end up being more dangerous than what was spilled on the skin.
The goals in treating inhalation injuries are to assess the extent of the damage and to prepare for the patient to get worse. For example, a person exposed to hydrochloric acid vapors may initially be coughing a little, only to become so full of pulmonary edema that he literally drowns. In some cases, the respiratory distress may not be apparent for hours, but always be ready for a rapid change. Be tuned into the patient`s current status, and monitor constantly for any changes in breathing patterns, pulse oximetry readings, or levels of consciousness.
Signs and symptoms of inhalation. If you suspect that your patient may have sustained an inhalation injury, tune into the signs and symptoms such as the following:
A complaint of tightness in the chest or an acute onset of shortness of breath
Rapid, shallow breathing
Tachycardia
Productive coughing, especially blood-tinged sputum
Eye irritation–if the eyes are irritated, there is a strong possibility of an inhalation exposure
Redness or irritation around the nose or mouth
Also, carefully evaluate lung sounds. The patient may be wheezing like an asthmatic or have crackly sounding lungs like a congestive heart failure (CHF) patient. Then, ask yourself the million dollar questions: Is the asthma attack unrelated to the exposure or because of the exposure? Or, are the asthma-like symptoms related to the exposure? Are the wet lungs due to heart failure, or is it chemically induced pulmonary edema? Good history taking, the patient`s medications, and accurate vital signs may help you make a differential diagnosis.
At any rate, the patient may be struggling to breathe or may have wet sounding lungs. These are big clues you should not miss.
Here are some initial actions you may take after you ensure your own safety and the patient has been decontaminated.
BLS Actions
A good primary and secondary survey
High flow oxygen (don`t be cheap here; use a mask)
A full set of vital signs
A determination of respiratory effort and rate
A baseline mental status
Position of comfort for the patient
Transport
ALS Actions (including all the above)
Pulse oximetry, if within your scope–any reading below 93 percent indicates respiratory compromise.
ECG–monitor for tachycardias or other abnormal rhythms. Hydrocarbons, especially chlorinated solvents like chloroform, chlorobenzene, and chlorotoluene, can cause significant tachycardias whether inhaled or absorbed through the skin. Heart rates can easily go above 200 beats per minute and may be refractive to any drug therapy. Much like a patient who has taken methamphetamines, the patient may be tachycardic but not hemodynamically compromised. Whether to treat is a judgment. In most cases, adenosine or verapamil will not convert the rhythm. If it does convert, chances are it will not be maintained.
Large-bore IV, if applicable. Should the patient crash, you will have a line established.
Track respirations with a bag valve mask, or intubate, if necessary. Watch out for your own lungs when intubating or ventilating a patient with significant inhalation exposures. There is evidence that positive end expiratory pressure (PEEP) may be effective in driving fluids back into the vasculature. If this is in your scope of practice, it may be a useful tool for the patient with pulmonary edema.
Treat bronchospasms with nebulized albuterol, alupent, or other appropriate bronchodilators. If the bronchospasm is refractive to the nebulized treatments, it may be necessary to use subcutaneous epinephrine or brethine, depending on your scope of practice. Treat a cardiac arrest as any other nonchemically induced code.
Standard drug regimens for cardiogenic pulmonary edema can be used in pulmonary edema of noncardiac origin. Diuretics like lasix may have some effects, whereas nitroglycerin and morphine may help to reduce preload and assist in capillary pooling.
CORROSIVE EXPOSURES
As a group, corrosives comprise an extremely large group of chemicals. Both acids and bases are defined as corrosive and combined. They represent the potential for hundreds of thousands of chemical compounds. Acids and bases can be concentrated or diluted, weak or strong, water reactive or water soluble, and range from highly vaporous to virtually vaporless. The point is that you could find just about any type of chemical variation imaginable in this class of chemicals. Because of this, the extent of the injury may vary according to the specifics of the chemical, and it becomes critical to do everything possible to accurately identify the material to which your patient was exposed. To help nail down the potential injury your patient may have sustained, you need to ask a few important questions.
What is the concentration of the chemical?
How long did the material contact the patient?
Was it heated?
Is there a possibility that the patient inhaled any vapors?
The point of these questions is that concentration matters in a corrosive exposure. The general rule is that the higher the concentration, the more extreme the injury. Take battery acid, for example. It is made up of a solution containing sulfuric acid at approximately 30 percent concentration. Semiconductor facilities, on the other hand, traditionally use concentrated sulfuric acid in 97 percent concentration. The difference in exposures will be vast. Given identical exposure scenarios, the battery acid will cause tingling and itching of the skin, whereas the 97 percent concentration will cause deep and painful chemical burns that will cause substantial tissue damage. Chemical burns oftentimes are worse than the thermal burns a patient may sustain in a fire. The good news, however, is that many acid burns are somewhat self-limiting. The damage caused by the exposure makes the tissues thick and rubber-like and actually slows further exposure. Additionally, most patients do not suffer any long-term health effects as a result of the exposure. For the most part, if they survive the event, they will not develop cancer or liver failure or some other chronic disease as a result of the exposure. This is not to say there may not be scars or some other lasting reminder of the exposure, but usually there are no long-term health effects. Keep in mind, though, that this is only a generality and that, like almost everything else in the chemical world, there are exceptions.
Duration of exposure. The duration of the exposure is also an important factor that affects the patient. Again taking the sulfuric acid example, a longer exposure is certainly worse than a brief one. In fact, concentrated sulfuric acid is so dense that if it is washed off the skin immediately after the exposure, the damage is very minimal. Leave it on the skin, however, and the outcome will be quite different. This is the reason it is so important to remove any wet or con-taminated clothing as soon as possible: to reduce the ability of the clothes to wick the chemical onto your patient`s skin for a prolonged amount of time.
Keep in mind the diversity of this class of chemicals, however, because many acids and bases do not behave like sulfuric acid and will quickly absorb into the skin no matter how fast decontamination occurs.
Material temperature. The temperature of the material at the time of exposure is also important information. First of all, many chemical processes heat the materials to pump them or obtain a specific reaction. The result may be that the patient suffered thermal burns along with the chemical burns and you now have another dimension of injury to address. Additionally, hot chemicals are more reactive than cold ones, so whatever has gotten on the patient is going to be more aggressive if it has been heated. Exposures to the lungs are especially bad because of the tissues` sensitivity. There is a sort of synergism that occurs in these cases. The fluid buildup is caused by a combination of the chemical irritation and the heat. Watch out here because your patient could go downhill in a real hurry.
Inhalation exposure. Finally, determine if there has been a possibility of an inhalation exposure. Doing this is always important, no matter what the exposure scenario happens to be. If inhalation exposure has occurred, carefully evaluate the danger of respiratory compromise, and treat accordingly. Corrosives are notorious for irritating or damaging mucous membranes, and it is not uncommon for a small exposure to cause substantial respiratory problems.
Hydrofluoric Acid
One corrosive important to note is hydrofluoric acid. It behaves differently than other typical acids and can kill a person with a relatively small exposure. In the chemical world, hydrofluoric acid is referred to simply as “HF” and has gotten the nickname “the bone seeker.” This alone should give you a really big clue about the danger of the chemical! It should not be confused with hydrochloric acid, even though the names sound somewhat similar. The fact is that the two could not be more dissimilar in how they affect the body.
HF is an inorganic mineral acid characterized by a strong bond between an atom of hydrogen (H+) and an atom of fluorine (F-). When exposed to bodily tissues, it has a strong affinity for calcium. To that end, it commonly binds with calcium in the bones to form a salt compound called “calcium fluoride.” The bad thing about HF is that it is toxic by inhalation, ingestion, injection, and skin absorption and may cause full body or systemic health effects if the exposure is substantial. It is nonflammable, soluble in water, and incompatible with anything that contains silica, especially glass. An important point about HF is that the health effects of an exposure may be delayed for many hours. Low concentrations of the material (below 20 percent) may not even cause redness, pain, or itching at the site of exposure. Essentially, a person may feel like he has nothing worse than water on his skin. The danger here is that HF can kill at a 20-percent concentration just as it can at a 50-percent concentration. The only real difference is that at concentrations above 50 percent, a person would probably feel some discomfort at the exposure site. The problem is that we may not be called until the victim has progressed passed the point of no return. (See “Hydrofluoric Acid Causes Death of Sanitation Worker,” Haz Mat: On the Line, Fire Engineering, June 1999.)
Most people who work with HF on a regular basis are tuned into the hazards, but human nature being what it is, they may initially decide that the exposure was not really a big deal, and they may take a “wait and see” attitude. By the time you get involved, they may be exhibiting severe muscle pain due to calcium depletion; nervous system disturbances; and, worst of all, cardiac problems.
Due to systemic calcium depletion, the heart may become irritable and ultimately deteriorate to ventricular fibrillation. This is almost always fatal if unrecognized because we end up doing nothing for the underlying cause–calcium deficiency. There is probably an ALS provider or two who just began thinking, “Well now, a calcium deficiency–calcium chloride should fix that!” That is the wrong answer, unfortunately. The treatment for HF exposures revolves primarily around calcium gluconate. It can be applied topically, administered in a nebulizer like albuterol, or run into IV fluids. It is considered to be the best antidote for an HF exposure and must be applied immediately to be effective.
Most facilities that use HF have a topical cream available and are trained in how to use it. Most likely, it is not within your scope of practice to apply, and you will have to allow the patient (if he is able) to rub it on the skin. This may not be all bad considering the danger of this stuff! The bottom line, however, is that if you respond to a suspected HF exposure, be very careful not to become exposed yourself. Fortunately, latex gloves, PVC, and neoprene are recommended barriers against HF, but you should wear more than one pair of gloves to provide redundancy in your level of protection. Here are some guidelines you may find useful in dealing with an HF exposure.
Guidelines for HF Skin Exposure
Anyone with a suspected area of exposure greater than 25 square inches to any solution greater than 10 percent should be considered critical and will likely end up in the intensive care unit.
Remove affected clothing and perform decontamination. Pay close attention to the runoff.
Apply topical 2.5-percent calcium gluconate cream to the affected area. Be liberal with the cream, and keep applying it until the patient gets to the hospital. If it`s not within your scope, allow the patient to apply the gel. Wear gloves!
At the hospital, the topical gel may be followed by injections of 5 percent calcium gluconate given at .5 cc per square inch of exposed surface area. This is incredibly painful for the patient.
Do not give morphine or other pain medications in the field. The mitigation of pain by calcium gluconate therapy is an indication of how effective the treatment is. As the pain subsides, the exposure subsides.
Guidelines for HF Eye Exposure
Remove affected clothing and perform decontamination.
Always suspect an inhalation exposure in this type of injury. Monitor for pulmonary edema. If you suspect an inhalation, do not do mouth-to-mouth or mouth-to-mask ventilations. The hospital may opt for a 2.5-percent solution of calcium gluconate administered by positive-pressure ventilation.
Do not put calcium gluconate in the eyes.
Irrigate the eyes with normal saline, and watch the runoff.
Guidelines for HF Ingestion
This does not happen frequently.
Do not induce vomiting. It may rupture the esophagus or lead to the aspiration of vomitus.
Monitor lung sounds and swelling in the upper airway.
Rapid transport is always the goal with an HF exposure. Definitive treatment occurs in the hospital. What we do in the field is largely supportive, so do not delay leaving the scene. It is also important to let the hospital know that an HF exposure is on the way. It will need to plan for some specific therapies, and if you can speed up that process, all the better.
Organophosphate Pesticide Exposures
This last group of chemicals also contains many different compounds and can be very toxic. Along with pesticides there are rodenticides, fungicides, and herbicides. Although each group performs a different function, all groups have one very distinct thing in common: the suffix “cide,” which literally means “to kill.” In short, that is the part we should be worried about. Even though pesticides are designed to kill pests, they are certainly more than effective on humans. This group has profound health effects on exposed victims.
There are several categories of pesticides. We will focus only on organophosphates. Some common organophosphates you may have heard about, or even run into, are parathion and diazinon. The sarin and soman chemical nerve agents are also in this class.
These nasty pesticides are very dangerous. First of all, they are fairly common in the farming industry and are very effective in doing their job. Second, most pesticides are toxic by all routes of entry into the body and have systemic effects. This means that an external exposure to the skin or eyes may result in full body tremors or perhaps cardiac disturbances.
These substances act on the central nervous system inside the body, primarily as a cholinesterase inhibitor. In laymen`s terms, this means that the pesticide affects the way our nerves conduct an impulse throughout the body. Imagine for a moment that your body is wired somewhat like your house. The brain serves as the main service panel, and the nerves branch out through the body like runs of wiring. Some go to the kitchen, while others go to the living room and den. When everything works right, the lights go on and off when you flick the switch, and all the appliances are getting power. But what if the wiring arcs, shorts out, or becomes compromised? Maybe the lights come on, maybe they don`t. Maybe they even stay on and cannot be turned off no matter what you do.
Basically, this is what an organophosphate does. It interferes with the uptake of the chemical compound cholinesterase, which turns off some of the chemical “switches” in your body. In short, a chemical called acetylcholine is secreted by a nerve and travels across a tiny gap to another nerve or an organ that is to be stimulated. Once acetylcholine has completed its mission, the cholinesterase is supposed to break it down and stop the stimulation. This happens a zillion times a day without a problem in a normal healthy adult, and the whole cycle is completed in the blink of an eye.
If a person becomes exposed to parathion, however, things change. What happens now is that the acetylcholine does its job, but the parathion bonds to the cholinesterase and holds it hostage so it can`t break down the acetylcholine like it`s supposed to. The stimulated cells then go into a sort of hyperdrive and essentially burn themselves up. The manifestations of that overexcitement are a group of symptoms called SLUDGE, which stands for
Salivation
Lachrymation
Urination
Defecation
Gastric disturbance
Emesis
The patient may also appear anxious and have muscle tremors, diarrhea, bradycardia or even tachycardia, hypotension, and pinpoint pupils. There may also be huge amounts of saliva in the mouth and upper airway, which could ultimately lead to airway compromise. All in all, the patient is in big trouble, and the drugs you administer may not even help. Severe overdose cases necessitate immediate and aggressive therapy; even then, you may lose the patient.
Identifying signs of exposure. How do you determine if your patient has been exposed to an organophosphate? A good scene survey may give you this information, but, more than likely, you will determine this by the patient presentation. This group of symptoms is unique to an organophosphate poisoning, and you will need to fit the puzzle together to pick up on it. Pinpoint pupils are a big clue, so make sure your secondary survey includes a pupil check. The patient may also be wheezing with no history of asthma or other respiratory disease. Keep in mind that it may be the subtle things that tip you off in cases of mild overexposure.
Treatment. So now you have determined that you have an organophosphate poisoning. What next? The treatment is aimed largely at breaking the hold on cholinesterase. This is not an easy proposition and has to be done with drug therapy. Here again, thorough and safe decontamination must be completed to ensure your own safety. Assuming the scene is safe and you have done a good job of decontamination, here are some guidelines.
BLS Actions
A good primary and secondary survey
High-flow oxygen–the airway may also require lots of suctioning
A full set of vital signs
A determination of respiratory effort and rate
A baseline mental status
Position of comfort for the patient
Transport
ALS Actions (including all the above)
Pulse oximetry, if within your scope. Any readings below 93 percent should indicate respiratory compromise.
ECG. Monitor for tachycardia or bradycardia. The rhythm will be helped only by drug therapy.
Large-bore IV, if applicable. You may be pushing huge amounts of IV fluids and drugs, so make sure the line is patent.
Track respirations with a bag valve mask, or intubate if necessary. Watch out for your own lungs when intubating or ventilating a patient with significant inhalation exposures. There may be swelling in the upper airway, so intubate early if it is indicated.
Administer 2 to 5 mg of atropine IVP every two to five minutes. Your therapy is directed at drying up the secretions. Dilated pupils are an indicator of the drug`s effectiveness as well as the restoration of effective heart rate and the diminished effects of the SLUDGE. If administering the atropine by the endotracheal tube, double the IV dose, and use high-dose atropine diluted in 10 cc of saline. This keeps from adding a bunch of fluid to what may already be there. Atropine has no contraindications in this setting.
The patient may also be seizing. If this occurs, treat for seizures per your local protocols.
In case of cardiac arrest, treat it like any other nonchemically induced code.
AFTER THE RESPONSE
So now it`s 3 p.m. on that hot Tuesday afternoon, and you`ve managed to respond to the incident, stay safe, intervene properly, and turn your patient over to the ambulance or hospital. Now what? Well, like most other critical medical calls, your gear is scattered everywhere, and it`s time to get back in service. The fact is that you and your gear may need substantial decontamination. Residues left on equipment, especially corrosives, will render the gear useless if it is not properly cleaned. Cables for the heart monitor, blood pressure cuffs, stethoscopes, and backboards must all be thoroughly decontaminated or thrown away. Most of the waste, if contaminated with chemicals, can be bagged up and hauled to the waste site with other disposable items from the response. Take care to inspect all rubber fittings and gaskets, as well as metallic pieces, for any signs of corrosion or wear. It is a good policy to take everything that was used, whether you suspect it is “dirty” or not, and decontaminate it before putting it back in service. This also includes you. So, take a shower, and put on clean clothes. It may seem a little excessive, but spend some time putting yourself and your equipment back into good working order. It will benefit you and the next patient you treat.
ROB SCHNEPP is a career firefighter/paramedic with the Alameda County Fire Department in the San Francisco Bay area. He also serves as a Hazardous Materials Specialist with the Region 4 Task Force of the FEMA Urban Search & Rescue team based in Oakland, California. He is the primary author of Hazardous Materials: Regulations, Response and Site Operations (Delmar Publishing, Albany, NY, 1998).
