| Diagnosis is made clinically: |
| The most common signs and symptoms are cutaneous (eg, sudden onset of generalized urticaria, angioedema, flushing, pruritus). However, 10 to 20% of patients have no skin findings. |
| Danger signs: Rapid progression of symptoms, respiratory distress (eg, stridor, wheezing, dyspnea, increased work of breathing, persistent cough, cyanosis), hypotension, dysrhythmia, chest pain, collapse. |
| Acute management: |
| The first and most important therapy in anaphylaxis is epinephrine. There are NO absolute contraindications to epinephrine in the setting of anaphylaxis. |
| Airway: Immediate intubation if evidence of impending airway obstruction from angioedema. Delay may lead to complete obstruction. Intubation can be difficult and should be performed by the most experienced clinician available. Cricothyrotomy may be necessary. |
| Call for help. This might involve a multispecialty resuscitation team (anesthesiologist, obstetrician, neonatologist) in a hospital setting or emergency medical services in a community setting. |
| Promptly and simultaneously, give: |
| IM epinephrine (1 mg/mL preparation): Give epinephrine 0.3 to 0.5 mg intramuscularly, preferably in the mid-anterolateral thigh. Can repeat every 5 to 15 minutes, as needed. If symptoms are not responding to epinephrine injections, prepare IV epinephrine for infusion (see below). |
| Oxygen: Give 6 to 8 liters per minute via facemask or up to 100% oxygen, as needed. |
| Place the woman on her left side (or in a position of comfort if there is respiratory distress and/or vomiting), and elevate her lower extremities. Manual displacement of the gravid uterus to the left might be necessary. Positioning on the back might lead to inferior vena caval compression and reduced venous return to the heart. Fatality can occur within seconds if she stands or sits suddenly. |
| Normal saline rapid bolus: Treat hypotension with rapid infusion of 1 to 2 liters IV. Repeat, as needed. Massive fluid shifts with severe loss of intravascular volume can occur. |
| Start continuous electronic monitoring of maternal blood pressure, cardiac rate and function, respiratory status, and oxygenation, and start continuous electronic fetal monitoring. If continuous electronic monitoring is not available, monitor maternal vital signs and fetal heart rate every five minutes or more frequently. Maintain a minimum maternal systolic blood pressure of 90 mmHg. |
| Consider administration of: |
| Albuterol (salbutamol): For bronchospasm resistant to IM epinephrine, give 2.5 to 5 mg in 3 mL saline via nebulizer. Repeat, as needed. |
| H1 antihistamine*: Consider giving diphenhydramine 25 to 50 mg IV or cetirizine 10 mg IV (for relief of urticaria and itching only). |
| H2 antihistamine*: Consider giving famotidine 20 mg IV. |
| Glucocorticoid*: Consider giving methylprednisolone 125 mg IV. |
| When indicated at any time, perform emergency cesarean delivery for anaphylaxis refractory to medical management as outlined above or for fetal distress. |
