Notes from the Chair
Michael Hewitt, RRT-NPS, FAARC, FCCM
Greetings from Florida. I hope this finds you all well and busy. With spring rapidly approaching—and likely not soon enough for my friends in those parts of the country slammed with all the snow and cold—we find ourselves immersed in another year of activity and change. 2010 has been designated as the “Year of the Lung” around the country and globe. There are a number of activities and initiatives around this focus, which can be explored on the AARC’s Year of the Lung web pages.
As I write this column in early March, the AARC’s Political Advocacy Contact Team is getting ready to visit our members of Congress in Washington, DC. This is always a very busy and productive series of events that go a long way in getting us to the forefront as primary caregivers. Take a moment to thank these individuals for their hard work and dedicated efforts in this initiative.
There are so many other activities and events ramping up as spring and summer approach, including the annual Summer Forum in July as well as many of the regional and state respiratory conferences. Every year, I have the privilege of speaking at a number of these, and it is always a fun experience. I’d like to encourage each of you to check the calendars of the state societies in your area and try to attend.
Speaking of conferences, I am very excited to let you know that our section submitted an overwhelming number of proposals for presentations at the AARC International Respiratory Congress. Mike Gentile and the busy Program Committee have the enviable task of finding room on the agenda for as many of these presentations as possible. This speaks well of the growing interest of our section members in being active on the “big stage.” I personally wish to thank all of your for your continued and ramped up interest in the section and the advancement of our practices in adult care.
Finally, two other items to comment on:
- As you are aware, a small and very busy group of folks within the section has been working on our version of the “Swap Shop.” A lot of effort has gone into this project over the past year. We are now ready for the launch. However, we are holding off as there is some exciting news coming from the staff at the AARC regarding a new “social media” web site called “AARConnect” that will include all of the various section publications and activities — including our new Swap Shop — along with many other resources for the AARC membership. I have been involved in the beta testing for this new benefit of membership and can tell you that it is going to be a great tool for us. Stay tuned for more information as the site is launched.
- We also have a small group involved in reviewing one of the current AARC Clinical Practice Guidelines to assess its need for revision. We are excited about this as well. Going forward, it is my desire that we get involved in more of these reviews and revisions. As those opportunities present themselves, I will be reaching out to recruit some interested parties to participate.
There are a lot of exciting things going on for us here in Tampa, as I’m sure there are for all of you around the country. We have ordered our first two adult oscillators and are taking a lead role in rapid response, implementing robust protocols on ventilated patient transports, launching a comprehensive and proactive approach to lung expansion and secretion clearance, etc. As I’ve said many times before in this column, it is OUR time, as a profession, to step up and become recognized as a primary caregiver discipline rather than an ancillary add on. Never has the time been better. We should all embrace the opportunity.
That’s about it for now. I hope to see you all as I travel around the country and want to wish each of you a safe, fun, and productive spring and summer. Please call on me at any time if I can be of service or help in any way.
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Radiological Exposure
by Joe Hylton, RRT-NPS, CPFT, NCEMT-B
Deliberate or accidental exposure to ionizing radiation is a source of great concern worldwide. Detection of ionizing radiation without specialized equipment is very difficult, making exposure even more concerning. Even if treated quickly and correctly, whole body radiation can be devastating, with substantial morbidity and mortality.
Types of radiation
There are two types of radiation, ionizing radiation (any electromagnetic or particulate radiation capable of producing ions by interaction with matter) and non-ionizing radiation (lasers, microwaves, radio frequencies), which does not create ions or charged particles. Ionizing radiation is the focus in radiologic exposures, as it is absorbed or slowed down by human tissue and causes damage by transferring its energy to the tissue.
There are different types of ionizing radiation:
- Alpha rays and alpha particles: Alpha particles are positively charged ions that have mass and can be easily blocked by thin protective barriers such as paper, or even your hand. They are released by very heavy nuclei, such as that found in radon. They do not pose an external threat, but if inhaled or ingested can cause notable organ damage.
- Beta rays and beta particles: Beta particles are negatively charged electrons. They can travel through the air and pass through paper, tissue (such as your hand), and aluminum, but are blocked by lead barriers. Beta particles can result in external hazards if exposure is prolonged. They will penetrate a short distance into tissue and promote a beta burn, similar to a thermal burn.
- Gamma rays and gamma particles: Gamma rays are electromagnetic in nature. The nucleus of a gamma ray can emit excess energy as a pouch or packet called a photon. Depending on the duration of exposure, the distance from the source, and the type of shielding involved, they can present a significant external hazard. They can pass through tissue, aluminum, and lead barriers, but can be blocked by thick barriers of concrete. Gamma rays are similar to x-rays, the major difference being gamma rays originate from inside the nucleus, whereas x-rays originate from outside the nucleus.
- Neutrons: Neutrons, like gamma rays, possess no electrical charge. They are emitted only when a nuclear detonation or a nuclear reactor accident occurs. Neutrons do not cause direct cell and tissue damage, but they do have significant mass, allowing them to interact with nuclei of atoms, severely disrupting atomic structures. Neutrons interact with the hydrogen in water molecules in the human body, potentially causing up to ten times more damage to tissue than gamma rays.
Ionizing radiation in the body
Ionizing radiation affects the body through direct and indirect mechanisms. Radiation directly interacts with the body by altering critical biological molecules in the human cell. The cell’s nucleus is especially sensitive to radiation, as DNA is the most critical target of direct radiation. Radiation indirectly affects human tissue by producing ions and free radicals that interact with critical cell components. Many of the free radicals and ions are produced through interactions with water molecules, especially the hydroxyl (OH-) radical. Two hydroxyl free radicals can combine to form hydrogen peroxide, a strong oxidizing agent that can damage molecules in the body.
Ionizing radiation is measured in the human body in rads (radiation absorbed dose); the measurement for assessing radiation exposure is rem (roentgen equivalent man). One thousand millerems (mrem) will equal one rad, and 100 rads will equal one gray (one gray is the absorption of one joule of energy, in the form of ionizing radiation, by one kilogram of matter). Rems and rads are equivalent in x-rays and gamma rays. For example, a chest x-ray emits approximately 10–20 mrem; flight emits 0.5 mrem/hour; smoking 1.5 packs of cigarettes per day emits 16,000 mrem/year. For neutrons, rems are ten times higher than rads, due the fact that neutrons are much more harmful than gamma rays or x-rays.
Radiation exposure occurs in one of the following ways: irradiation, external contamination, or internal contamination. Irradiation occurs when someone is exposed to ionizing radiation but did not come in contact with radioactive isotopes. External and internal contamination occur when radioactive isotopes have contaminated the patient through ingestion, inhalation, or wounds. Irradiation of tissue may present several potential adverse affects. Organs that possess a rapid cell turnover are most frequently affected. In order of most sensitive to least sensitive, these body systems can be affected by radiation: the hematopoietic system, gastrointestinal system, vascular system, and nervous system.
Acute radiation syndrome presents itself in four phases:
- Prodromal phase (phase one): This usually consists of nausea, vomiting, and diarrhea. Severe abdominal pain, eye burning, and fever may also be present.
- Latent phase (phase two): The patient will experience an asymptomatic period. The length of this phase depends on the level of exposure. This is superficial, as the replacement of mature cells is impaired. The deficits will present in phase three.
- Illness or manifest phase (phase three): The deficits of mature cell replacement present, with possible skin sloughing, blood vessel damage, GI system damage, and hematopoietic cell damage.
- Recovery/death phase (phase four): If stem cells can recover and proliferate, a positive response may ensue, reducing the effects of radiation and potentially allowing a recovery. If they can’t recover, then the patient will most likely die from exposure.
The severity and duration of the phases will depend on the amount of radiation the patient was exposed to, with higher doses of exposure related to shorter latent phases. Higher doses will be lethal in most patients. Doses of 3–8 grays can cause a lethal hematopoietic syndrome due to the overwhelming death of hematopoietic precursor cells, with death occurring in 1–3 months. Doses of 10–40 grays are almost always fatal. At 100 grays, death will usually occur in 1–2 days.
Detection and decontamination
Patients suffering from radiation injury do not die immediately from their exposure; they usually die from associated trauma or burns. Treatment for these patients begins with proper identification and decontamination.
Detection and identification of radiation exposure is performed with a Geiger-Mueller counter. The dose absorbed by the patient depends on three factors: the distance of the patient from the source, exposure time, and shielding. Exposure can be decreased by a factor of 4 by doubling the distance from the radiation source.
Patients with exposure to radiation must be decontaminated prior to entering the EMS/health care system to prevent contamination of health care workers and the health care facility. Removal of clothing and washing with soap and water is effective in the removal of over 95% of contaminants. Clothing should be labeled and preserved for further investigation.
Health care workers providing care will be adequately protected if they observe universal precautions. Health care workers should be monitored for exposure times and radiation counts following care of a contaminated patient. Any items utilized in the care of the patient should be bagged, labeled, and disposed of in an appropriate manner. Water used for decontamination should be stored and not allowed to enter any municipal water system.
Patients who have been internally contaminated by a radioactive substance are treated differently. The methods used for treatment are dilution with water, blocking with iodine, chelation with DTPA or EDTA, or mobilization and elimination of the radionuclide with the use of Insoluble Prussian Blue or Uranyl Nitrate. The treatment received is a function of the specific isotope and the route of contamination.
Course of treatment
Patient management of the exposure continues after pre-hospital care and decontamination. Upon arrival at the health care facility, patients who received the highest doses of radiation and have a high risk for acute radiation syndrome must be identified for timely care. A good history of the radiation source, distance from the source, and time of exposure are of utmost importance.
The onset of the prodromal phase symptoms and their duration is another good indicator of the amount of whole body radiation received by the patient. For example, a patient who has received 2–4 grays of exposure will not show symptoms for 1–2 hours, whereas an exposure of greater than 8 grays will lead to symptoms within ten minutes of exposure. Total lymphocyte counts can be measured at presentation and again at 24 hours and 48 hours; the drop in the lymphocyte count will be proportional to the dose of radiation received by the patient. The Biological Assessment Tool (BAT) can be used to achieve an accurate estimate of the radiation exposure. The BAT analyzes the radioactivity of bodily fluids, swabs, and clothing in relation to exposure history.
Once the suspected level of exposure has been identified, the patient should be placed where he will receive the level of care that will provide the best chances for survival. Patients who have exposure levels of less than 1 gray will have the highest chances for survival and present with minimal symptoms and injuries; they can be cared for as outpatients or in a ward setting.
Patients who have received 2–8 grays of exposure may benefit most from aggressive treatment provided in the ICU setting. This patient population can present with significant cutaneous, gastrointestinal, and neurovascular symptoms, along with third or fourth degree hematologic changes.
Patients who have received more than 10–12 grays of exposure will likely present with early symptoms and multi-organ failure. In this patient population, aggressive ICU care will most likely not affect the outcome; these patients should be provided comfort care due to their very high mortality. Patients who present with trauma plus radiation exposure are at an increased risk, as trauma increases the mortality associated with radiation exposure.
ICU treatment of radiation exposure will consist of aggressive fluid resuscitation to correct hypovolemia, antiemetics, antidiarrheal agents, correction of electrolyte abnormalities, and analgesics. Infection control, immune reconstitution, and bone marrow transplants are likely needed for whole body radiation. Antibiotic therapy may be indicated.
Patients with significant hematopoietic toxicity may benefit from packed red blood cells and platelet therapy. If blood products are given, they must be irradiated and leukoreduced to minimize the risk of graft versus host disease.
For patients with exposure levels between 3–7 grays, recombinant granulocyte macrophage colony stimulating factor, granulocyte colony stimulating factor (G-CSF), and pegylated G-CSF may be administered. Patients with exposure levels of 7–10 grays who do not demonstrate significant co-morbidities may benefit from stem cell transplantation.
If traumatic injuries are present, the radiation syndrome must be considered when planning the treatment course. Due to the presence of bone marrow suppression, infections, and delayed wound healing, surgery more than 48 hours after injury/exposure is associated with an increased mortality up until the bone marrow recovers from the irradiation. This process can take up to 120 days. If at all possible, any reparative treatment for fractures, burns, and associated trauma should be completed before the 48 hour mark to minimize mortality from surgery.
Pre-planning a must
Radiation exposure is a rare event, with potentially devastating effects. Efforts must be made to pre-plan for radiation events to optimize the ability of pre-hospital caregivers to recognize and detect a potential radiation event and decontaminate patients on a potentially large scale so they can receive rapid transportation to the appropriate health care facility.
Hospital caregivers must pre-plan as well, to be able to provide a second layer of decontamination in case the patient did not receive appropriate decontamination at the scene. Caregivers should be trained to recognize signs and symptoms of radiation exposure, estimate the level of exposure, and triage the patient to the appropriate level of care in the health care facility. EMS and hospital systems that are able to implement effective training programs will provide caregivers with a safe approach to protect themselves, keep affected patients safe from further injury, and recognize and place patients in the best places for appropriate care.
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