hello and welcome to chapter 21 allergy and anaphylaxis of the emergency care and transportation of the sick and injured 12th edition after you complete this chapter and the related coursework you will understand the anatomy physiology and pathophysiology of hypersensitivity disorders and anaphylactic reactions additionally you will have knowledge and skills to recognize and manage hypersensitivity disorders and anaphylactic reactions okay so let's get started emts often respond to calls involving allergic reactions allergy related emergencies involve acute airway obstruction and cardiovascular collapse you must be able to treat these life-threatening complications and you must be able to distinguish between the body's usual response to an allergen and an allergic reaction this chapter describes immunology which is the study of the body's immune system and the five categories of stimuli that may provoke an allergic reaction okay so let's talk about the anatomy and physiology the immune system protects the body from foreign substances and organisms when a foreign substance invades the body the body initiates a series of responses to active inactivate the invader so a little bit about the pathophysiology an allergic reaction is an exaggerated immune response to a substance it is not caused directly by an outside substance such as a bite or sting it is caused by the body's immune system which releases chemicals to combat the stimulus these chemicals include histamines and leukotrienes both of which contribute to an allergic reaction some patients may not know what is causing their allergic reaction so you must be able to recognize the signs and symptoms and maintain a high index of suspicion an allergic reaction may be mild and local characterized by itching redness and tenderness or severe and systemic a condition known as anaphylaxis anaphylaxis is an extreme life-threatening allergic reaction it involves multiple organ systems and in severe cases it can rapidly result in shock and death there are three common signs first you have the uticaria and that's hives then you have the angioedema and then wheezing strider may be heard on inspiration if there's an upper airway narrowing you could have hypotension due to vasodilation as well as an increased capillary permeability and patients may experience nausea vomiting and abdominal cramps okay so let's talk about some common allergens the most common allergen falls into one of the following five categories so you have food food allergies and that certain foods such as shellfish and peanuts may be the most common trigger of anaphylaxis the symptoms include it may take more than 30 minutes to appear and may not include skin signs such as hives the reaction may be severe and involve respiratory and or cardiovascular systems then a common allergy the second one is medications so medications are the second most common source of anaphylactic reactions particularly antibiotics such as penicillin or non-steroidal anti-inflammatory drugs such as nsaids if the medication is injected the reaction may be immediate and severe reactions to oral medications may take more than 30 minutes to appear but can also be very severe okay so then the third most common allergen is going to be plants and this includes dust pollens and other plant material can cause rapid and severe allergic reactions okay so common plant allergens include ragweed rye grass maple and oak okay chemicals are the fourth most common allergen and certain chemicals such as makeup soap paradigm latex and various other substances can cause severe allergic reactions latex is of particular concern to healthcare providers so use latex alternatives such as nitrile gloves and then finally insect bites and stings and venomation that's the process of the insect injecting its venom the reaction can be localized or may be severe in systemic insect stings approximately 2 million americans are allergic to the venom of bees wasps and hornets and allergic reactions to stings account for at least 62 deaths in the united states per year in about half of these deaths the victim had never experienced a reaction prior the stinging organ of most insects is a small hollow spine and it projects from the abdomen honey bees cannot withdraw their stinger if the stinger is not removed it can continue to inject venom for up to 20 minutes and wasp and hornets they can sting multiple times some ants especially fire ants strike repeatedly signs and symptoms include sudden pain swelling localized heat widespread urticaria redness in light-skinned individuals itching and possibly a wheel in more severe such as anaphylactic cases patients may experience stridor bronchiospasm and wheezing test tightness and coughing dyspnea anxiety gastrointestinal complaints and hypotension occasionally they can experience respiratory failure and if untreated an anaphylactic reaction can rapidly proceed to death more than two-thirds of patients who die of anaphylaxis do so within the thirst first 30 minutes so let's start talking about the patient assessment aspect okay so seeing size up of course scene safety that's most important to us in the patient's environment or recent activity may indicate the source of an allergic reaction a respiratory problem reported by dispatch may be an allergic reaction until a field impression of a allergic reaction is firmly established be mindful of other potential causes of respiratory distress traumatic injury may also be present secondary to the medical emergency so follow standard precautions with a minimum of gloves and eye protection consider the need for additional resources such as advanced life support personnel so then you're going to do your primary assessment and quickly identify and treat any immediate or potential life threats your abc's should be reassessed repeatedly throughout transport you want to form your general impression allergic reactions may be present as a respiratory condition or a cardiovascular distress in the form of shock if the patient is anxious and in distress immediately call for advanced life support backup if available look for a medical identification tag if the patient is found unresponsive or unable to answer questions airway breathing of course is a major concern and anaphylaxis can rapidly swelling of the upper airway not all allergic reactions though are anaphylactic reactions quickly assess for increased work of breathing use of accessory muscles head bobbing tripod position nasal flaring and abnormal breath sounds assist the patient into a comfortable position which is generally in the high fowler's position to minimize ventilations so if signs of shock emerge immediately place the patient in the supine position as tolerated for a patient in severe respiratory distress you may have to assist ventilations using a bag valve mask attached to high concentration of oxygen now after the a and the b we're going to talk about c some patients in anaphylaxis may present with signs and symptoms of circulatory stress such as hypotension assess for signs of hypoperfusion treat for shock the definitive treatment for anaphylaxis is epi your transport decision if it's an anaphylaxis is suspected or if a round relatively mild allergic reaction appears to be worsening immediate transport is warranted if the patient is calm and does not exhibit signs and symptoms consider continuing the assessment but err on the side of emergency transport next is the history taking of the assessment so investigate the chief complaint or history of the present illness and identify the signs and symptoms the table above shows additional signs and symptoms of an allergic reaction and then obtain your sample history if the patient is responsive obtain the history from them and ask him or her the following questions specific to allergic reaction has and have any interactions already been completed in our interventions and has the patient experienced a severe allergic reaction in the past the alert for any statements regarding the ingested ingestion of foods commonly causing which cause allergic reactions inquire about the presence of gastrointestinal complaints such as nausea and vomiting next your secondary assessment so when you do that physical exam if indicated perform a rapid exam from the body of the body from the head to the toe or conduct a physical exam focus on the areas of the chief complaint if the patient is unconscious or otherwise unable to communicate removes clothing as necessary and look for the presence of bee stingers signs of contact with chemicals or other clues suggestion of suggestive of the reaction look for a medical alert tag that could indicate a severe allergy auscultate for abnormal breast sounds such as wheezing or strider and carefully inspect the skin for swelling rashes or uticarian next you're going to check your vital signs so you're going to bait you're going to assess the baseline including pulse and respiratory rate blood pressure pupillary response and oxygen saturation skin signs may be unreliable indicators of hypoperfusion as they may be widely or hidden by rashes and swelling next you're monitoring devices so a pulse ox can be very useful for assessing the patient's perfusion status the decision to apply oxygen should be based on airway patency work of breathing and abnormal lung sounds on auscultation not solely on your pulse oximetry readings and your reassessment so enroll to the hospital repeat the primary assessment reassess the patient's vital signs and repeat a focus exam of the affected body system if the patient is unable or unstable reassess every five minutes if the patient's stable every 15 and watch for signs of shock and treat immediately if present now your interventions so treatment is determined by the severity of the reaction mild reactions may require only supportative care and monitoring anaphylaxis requires more aggressive treatment including epi and ventilatory support so recheck your interventions even if the patient is experiencing relief transport to the emergency department is still warranted because the medications effect will wear off and symptoms will return communication and documentation so documents should include signs and symptoms found during the assessment reasons why you chose to provide the care you did and the patient's response to the treatment emergency care and of an immunologic emergency so if the patient appears to be having a severe allergic or anaphylactic reaction administer bls and provide prompt transport to the hospital if the stinger is present scrape this skin with a sharp edge stiff object such as a credit card do not use tweezers or forceps gently wash the area with soap or mild anesthetic remove jewelry from the area before sweat swelling begins position the injection site slightly below the level of the heart apply ice or cold packs to the area but not directly to the skin and not for more than 10 minutes at a time be alert for signs of swelling airway and other signs of anaphylaxis such as nausea vomiting and abdominal cramps and do not give the patient anything by mouth place the patient the supine physician as indicated and give oxygen if needed monitor the patient's vital signs and be prepared to provide further support if needed let's talk about epi epi is a sympathomimetic hormone okay it mimics the sympathetic fight or flight response it causes the blood vessels to constrict which reverses vasodilation hypotension caused by the anaphylactic reaction other properties of epi increase cardiac contractility and relieves bronchospasms in the lungs it can rapidly reverse this effects of anaphylaxis epi is prescribed by a physician and comes pre-dosed in an an automatic fb injector some ems systems are authorized to carry epi as part of their regular onboard medications and in others ems providers may be permitted to help patients self-assist our medicine refer to local product protocols or consult online medical control the adult epipen system delivers 0.3 milligrams of epi via spring-loaded needle and syringe system the infant child system delivers 0.15 milligrams we're going to see skill drill 21-1 to use the epi auto injector epinephrine can have an effect within one minute so it is the primary way to save the life of someone with a severe allergic reaction but there are side effects and they include high blood pressure increased pulse rate anxiety cardiac arrhythmias polar dizziness chest pain headache nausea and vomiting patients without signs of respiratory compromise or hypotension and who do not meet the criteria for a diagnosis of anal anaphylaxis should not be given epi okay so that concludes chapter 21 anaphylaxis reactions and now we're to the review slide so let's see what we've learned the signs and symptoms of an allergic reaction are caused by the release of it's both histamine and leukotrienes the two chief chemicals okay the negative effects associated with anaphylactic shock are a result of we know it's vasodilation and bronchial constriction all right you are called to a local baseball park for a 23 year old man with difficulty breathing he states that he ate a package of peanuts 30 minutes ago and denies any allergies your assessment reveals widespread uticarian tachycardia and the blood pressure of 90 over 60. you can hear him wheezing even without the stethoscope you should be most suspicious of i think it's an anaphylactic reaction see what is a wheel and it's a raised swollen or well-defined area on the skin you're treating a woman who was stung numerous times by hornets on assessment you note that some of the stingers are still embedded in her skin you should we're not going to leave them in we're going to scrape them we're not going to use tweezers because that could inject more and venom into her and cover the stings with tight dressings no so we're going to scrape them a young male is experiencing signs and symptoms of anaphylactic shock after being stung by a scorpion his level consciousness is diminished his breathing is severely labeled and you can hear inspiratory strider and his face is cyanotic the patient has for has a prescribed epi auto injector what should you do first it's a system the patient's not breathing so you want to therefore you need to assist with the bvm the most reliable indicator of an upper airway swelling during a severe allergic reaction is so upper airway right away is going to be strider right strider wheezes our lower airway the most common trigger of anaphylaxis is remember what we saw the very first one foods okay the adult epipen delivers it's a 0.3 and the infant child delivers 0.15 so that's going to be b when administering an epi by auto injector the empty should hold the injector in place and i don't know if we talked about this but it's going to be b for at least 10 seconds as the medication is injected okay thank you for 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