Silver Cross EMS September 2012 3 rd Trimester CME

1. Silver Cross EMS September 2012 3rd Trimester CME Allergies and Anaphylaxis Presented by Silver Cross staff

2. System Updates! • Please remember… Region VII does not give Lidocaine for EZ-IO pain, even though your sales rep may have told you otherwise. • The Region VII SMO Code 12 “Suspected Cardiac Patient” has added pregnancy as a contraindication to Aspirin • Region VII has also added a new SMO for Suspension Trauma, Code 21b. • As of September 1st – license and renewal fees are in place. • Sign up for our e-mail list for even more information! • Info on all these and more on the website… www.silvercrossems.com

3. Our agenda • Physiology and discussion of allergic reaction process. • Physiology and discussion of anaphyaxis. • Specific information on anaphylactic shock. • Treatment of allergies and anaphylaxis • Drug of the month – Epinephrine • Strip of the month – Ventricular rhythms

4. Allergies • An allergy is an exaggerated immune response or reaction to substances that are generally not harmful.

5. Anaphylaxis • Immediate, systemic, life-threatening allergic reaction - major changes in cardiovascular, respiratory, and cutaneous systems

6. Antigens • Antigen - induces formation of antibodies • Enters body by injection, ingestion, inhalation, or absorption • Examples of common antigens associated with anaphylactic reactions: • Drugs (penicillin, aspirin) • Envenomation (wasp stings) • Foods (seafood, nuts) • Pollens

7. Antibodies • Protective protein substances developed by body in response to antigens • Bind to the antigen that produced them • Neutralizes antigens and removes from the body • Antigen-antibody reaction protects body from toxins by activating immune response

8. Immune Response • Immune responses are normally protective • Can become oversensitive or be directed toward harmless antigens to which we are often exposed • When this occurs, the response is termed “allergic” • Antigen causing allergic response called an “allergen” • Common allergens include drugs, insects, foods, and animals

9. Immune Response • Healthy body responds to antigen challenge through collective defense system – immunity. • Natural, present at birth • Acquired, resulting from exposure to a specific antigenic agent or pathogen • Artificially induced (immunization) • Immunity may be active or passive

10. Allergic Reaction • Increased physiological response to antigen after previous exposure (sensitization) to same antigen • When circulating antibody combines with specific foreign antigen, results in hypersensitivity reactions • Or to antibodies bound to mast cells or basophils (IgE)

11. Hypersensitivity Reactions • Divided into four distinct types • Type I (IgE-mediated allergic reactions) • Type II (tissue-specific reactions) • Type III (immune-complex-mediated reactions) • Type IV (cell-mediated – localized allergic reactions)

12. Hypersensitivity Reactions • Agents that may cause hypersensitivity reactions (including anaphylaxis) • Drugs and biological agents • Insect bites and stings • Foods

15. Localized Allergic Reaction • Localized allergic reactions (type IV) do not manifest multi-system involvement • Common signs and symptoms of localized allergic reaction include: • Conjunctivitis • Rhinitis • Angioedema • Urticaria • Contact dermatitis

16. Histamines • Promote vascular permeability • Allows plasma to leak into interstitial space • Cause dilation of capillaries and venules • Profound vasodilation further decreases cardiac preload, compromising stroke volume/cardiac output • Cause contraction of nonvascular smooth muscle in GI tract and bronchial tree • Associated increase in gastric, nasal, and lacrimal secretions, resulting in tearing and rhinorrhea

17. Histamines • These physiological effects lead to: • Cutaneous flushing • Urticaria • Angioedema • Hypotension • Onset very rapid • But short lived, quickly broken down by plasma enzymes

18. Other Chemical Mediators • Other chemical mediators (heparin, neutrophil chemotactic factor, and kinins) cause: • Fever • Chills • Bronchospasm • Pulmonary vasoconstriction • These chemical processes can rapidly lead to: • Upper airway obstruction and bronchospasm • Dysrhythmias and cardiac ischemia • Circulatory collapse and shock

19. Don’t be shocked…. • But this discussion has a lot to do with shock!

20. Anaphylactic Shock • The body needs oxygen carried by blood for cellular metabolism • Perfusion • Delivery of O2, other nutrients to cells • Shock • Inadequate tissue perfusion causes too little oxygen to cells

21. All Kinds of Shock are caused by one of three things… • Causes: pump failure (heart) container failure (vessels) fluid failure (volume) • Failure of heart = inadequate cardiac output • Failure of blood vessels = significant changes in systemic vascular resistance • Inadequate blood volume = inadequate delivery of oxygen to cells

22. Imagine a power steering pump • Your car’s power steering needs a functioning pump, intact lines and enough fluid to work. • Failure of any one will cause power steering to fail. • Our bodies work the same way… Failure of our heart (pump), our vessels (lines) or our blood flow (fluids) will cause the body to fail

23. Distributive shock – a vessel failure • Anaphylaxis is a form of distributive shock. • Vessels dilate so much, blood stagnates in them and can never fill them up properly. • Also called “container” failure • It's like replacing the power steering lines in your car with lines that are twice as big. • They would need more fluid to fill them. • If not enough fluid, it will not flow properly.

24. Normal Circulation vs. Distributive Shock

25. Anaphylactic shock/anaphylaxis • Etiology/causes • Dust, pollen, mold, animal dander • Foods: milk, eggs, nuts, shellfish, beans • Latex/rubber products • Blood components • Antibiotics • Insect venom (hymenoptera) • Local anesthetics • Vitamins • NSAIDS (ASA, ibuprophen), IV contrast dyes • Radiocontrast media • Aspirin

26. Early (compensated) shock • Early (compensated) shock • Physical exam • Assess heart rate – probably elevated • Assess presence & volume of peripheral pulses • Assess blood pressure – may still be normal • Reversible if cause identified, corrected • Uncorrected progresses to next stage

27. Late (decompensated) shock • Compensatory mechanisms fail • Epinephrine & norepinephrine – vasoconstriction • Precapillary sphincters dilate • blood rushes into capillary beds • Postcapillary sphincters constricted • causing stagnation of blood • Blood pressure falls • Altered mental status • Anaerobic metabolism occurs (acidosis)

28. Anaphylactic shock/anaphylaxis • Findings • Angioedema • Inability to speak, tightness in throat, stridor, DIB, wheezing, hoarseness, cough • Retractions, accessory muscle use, ↓ breath sounds • Tachycardia, ↓ BP • Diaphoresis, urticaria/flushing, pruritis, pallor/cyanosis • N/V/D, abdominal pain/cramps, incontinence • AMS, anxiety, restlessness, feeling of impending doom

29. Anaphylactic shock/anaphylaxis • Skin • Diaphoresis • Urticaria • Flushing • Pruitis • Angioedema • Pallor • Cyanosis

30. Urticaria as a result of an allergic reaction.

31. Angioedema of the Eyes

32. Bee Sting and Angioedema Bee Sting and Angioedema of the Lips

33. Anaphylactic shock/anaphylaxis • Respiratory findings • FBAO • Pulmonary embolism • Reactive airway disease • Tension pneumothorax • Panic attack • Vasovagal syncope

34. Anaphylactic shock/anaphylaxis • Gastrointestinal & genitourinary findings • Nausea, vomiting and diarrhea • Abdominal pain • Cramping • Incontinence

35. Initial Assessment • Airway and breathing • Airway assessment critical • Most deaths from anaphylaxis from upper airway obstruction • Evaluate for voice changes, stridor, barking cough • Tightness in neck, dyspnea suggest airway obstruction • Airway of unconscious patient should be evaluated, secured • If airflow impeded, perform endotracheal intubation. • If severe laryngeal/epiglottic edema, needle cricothyrotomy indicated • Monitor patient closely for signs of respiratory distress • Circulation • Assess pulse quality, rate, and location frequently

36. History • May be difficult to obtain but critical to rule out other medical emergencies • Question patient regarding the chief complaint and the rapidity of onset of symptoms • Signs and symptoms of anaphylaxis usually appear within 1 to 30 minutes of introduction of the antigen

37. Significant Past Medical History • Previous exposure and response to the suspected antigen • Not always reliable • Method of introduction of the antigen • Chronic or current illness and medication use • Preexisting cardiac disease or bronchial asthma • Prescribed Epi-Pen

38. Physical Examination • Assess and frequently reassess vital signs • Inspect face and neck for angioedema, hives, tearing, and rhinorrhea. • Note presence of erythema or urticaria on other body regions • Assess lung sounds frequently to evaluate effectiveness of interventions • Monitor ECG

39. EMS Drug Therapy • Epinephrine • Fluid resuscitation for hypovolemia • Antihistamines to antagonize the effects of histamine • Benadryl (diphenhydramine) • 50mg IVP slowly over 2-3 minutes • 50mg IM if no IV • Beta agonists to improve alveolar ventilation • Albuterol nebulizer • Corticosteroids to prevent a delayed reaction • Solu-medrol (methylprednisolone) • 125mg IVP • No longer just for long transports

40. ALS

41. ILS

42. BLS

43. Prevention and Patient Education • Clearly document allergic reactions • Always ascertain history of allergies before administering any medication • Medications that are highly allergenic should be given orally rather than parenterally • When parenteral medication is given, the patient should be observed for 20 to 30 minutes

44. Prevention and Patient Education • Patients with known allergies should: • Receive information regarding medical identification tags, bracelets, or cards • Contact their physician for Epi-pen prescription for epinephrine if they have a history of anaphylaxis.

45. Drug O’ the Month - Epinephrine • Sympathetic agonist • Epinephrine is a naturally occurring catecholamine. It is a potent α- and β-adrenergic stimulant; however, its effect on β-receptors is more profound.

46. Mechanism of Action • Epinephrine acts directly on α- and β-adrenergic receptors. Its effect on β-receptors is much more profound, and includes the following: • Increased heart rate (Beta) • Increased cardiac contractile force (Beta) • Increased electrical activity in the myocardium (Beta) • Increased systemic vascular resistance (Alpha) • Increased blood pressure (Beta) • Increased automaticity (Beta)

47. Pharmacokinetics • Onset • < 2 minutes (IV/ET) • Peak effects • < 5 minutes (IV/ET) • Duration • 5-10 minutes (IV/ET) • Half-life • 5 minutes

48. Indications • Cardiac arrest • Asystole • Ventricular fibrillation • Pulseless ventricular tachycardia • PEA (pulseless electrical activity) • Severe anaphylaxis • Severe reactive airway disease

49. Precautions • Should be protected from light • Can be deactivated by alkaline solutions such as sodium bicarbonate • The IV line must be adequately flushed between administrations of epinephrine and sodium bicarbonate.

50. Side Effects • Palpitations • Anxiety • Tremulousness • Headache • Dizziness • Nausea • Vomiting • Increased myocardial oxygen demand