CURRENT Essentials of Critical Care.pdf

Chapter 7 Pulmonary Disease 83■■■AnaphylaxisEssentials of Diagnosis• Urticaria, pruritis, flushing, shortness of breath, localized edema;onset 5–60 minutes after exposure to inciting antigen• Wheezing, laryngeal edema, respiratory failure, pulmonaryedema• Hypotension (anaphylactic shock)• Causes in ICU: antibiotics (penicillins), radiocontrast media,food, blood products; rarely to latex or other allergens• Antigen exposure through air, contact, blood or other injectionwith immediate, life-threatening allergic reaction; usually IgEmediated immediate hypersensitivity; may be non-antibody-mediated• Release of histamine, complement components, prostaglandins,and leukotrienes from mast cells and basophils through boundIgE• May or may not have history of previous anaphylaxisDifferential Diagnosis• Angioedema• Asthma• Urticaria• VasculitisTreatment• Maintain airway and cardiopulmonary function; endotrachealintubation• Remove antigen; discontinue drug or blood products• Epinephrine, 0.5–1.0 mL of 1:10,000 IV for severe airway compromiseor shock; otherwise 0.3–0.5 mL of 1:1000 subcutaneously• Hydrocortisone, 100 mg every 6–8 hours• Diphenhydramine, 25–50 mg IV every 4–6 hours plus cimetidine,300 mg IV every 8–12 hours• May require large volumes of IV crystalloids (0.9% NaCl); epinephrine,dopamine for persistent hypotension• Observe for late or persistent reactions■ PearlRadiocontrast agents are the most common cause of anaphylaxis inthe ICU.ReferenceKemp SF et al: Anaphylaxis: a review of causes and mechanisms. J AllergyClin Immunol 2002; 110:341 [PMID: 12209078]