Practice Essentials
Anaphylactic reactions in the operating room (OR) present unique diagnostic concerns. In this setting, signs and symptoms that alert the provider to a potential problem and that are apparent under other circumstances are often missing, as a consequence of the absence of an alert and communicative patient.
Surgical drapes obscure any visible signs, making bronchospasm and cardiovascular compromise the first indicators likely to be noted.
The use of multiple potential allergens in an abbreviated period of time further complicates the diagnostic process.
Although these reactions are rare, the anesthesia provider must nevertheless be well prepared for them, and the best defense is a good offense.
A thorough patient history is required. In the OR, the ready availability of supplemental oxygen and emergency drugs is obligatory. For the intubated patient, as in all cases, the recommended alarms on the anesthesia machine should be set. Once it has been determined that the patient is having an anaphylactic reaction, there are several critical steps that must be taken, many of which can occur simultaneously.
Communicate – Alert the OR personnel to the exigent circumstances, and have the OR nurse send out an overhead page
Ensure the presence of the code cart and defibrillator in the OR; these reactions may proceed to cardiovascular collapse
Mentally review the potential causes, with a focus on the timing of exposure in relation to the anaphylactic event
Discontinue any potential offending agents; this includes disconnecting intravenous (IV) lines and flushing them to prevent any inadvertent administration of the potential offending agent(s)
Administer
epinephrine intravenously (IV) as a bolus of 10-100 μg, depending on the severity of the symptoms, and repeat bolus administration as necessary; if the patient requires continued bolus administration of epinephrine, consider infusion of epinephrine 1-10 μg/min or administration of
vasopressin 0.4-1 units/kg IV (maximum, 40 units)
Place the patient on 100% oxygen, and intubate if a secure airway has not yet been established
Open IV fluids
Consider the use of the following agents:
diphenhydramine 25-50 mg/kg IV;
ranitidine 50 mg IV or
famotidine 20 mg IV;
hydrocortisone 100 mg IV or
methylprednisolone 1-2 mg/kg IV;
albuterol 4-10 puffs
For children, the protocol remains the same, but drug dosages are altered as follows: epinephrine bolus 1-10 μg/kg; epinephrine infusion 0.02-0.2 μg/kg/min, if needed; vasopressin 0.3-2 milliunits/kg/min IV (maximum, 40 units); diphenhydramine 1-5 mg/kg IV (maximum, 300 mg/day; famotidine 0.5 mg/kg IV; hydrocortisone 2 mg/kg IV (maximum, 100 mg/day); methylprednisolone 0.25-2 mg/kg IV (maximum, 60-80 mg, depending on age); albuterol 4-10 puffs
Follow advanced cardiac life support (ACLS)/pediatric advanced life support (PALS) protocol in the event of complete cardiovascular collapse