What medications are used to manage anesthesia emergencies such as cardiac arrest, anaphylaxis, severe hypotension, and bradycardia?

Anesthesia Emergency Medications

Core Emergency Medications by Clinical Scenario

Epinephrine (adrenaline) is the single most critical emergency medication in anesthesia, serving as first-line treatment for anaphylaxis, cardiac arrest, and severe hypotension, with immediate IV administration at 50 mcg (0.5 mL of 1:10,000 solution) for adults being the definitive intervention. 1, 2

Anaphylaxis Management

Primary medication:

• Epinephrine IV: 50 mcg (0.5 mL of 1:10,000 solution) for adults, repeated every few minutes as needed 1, 2
• Multiple doses are frequently required for severe hypotension or bronchospasm 1, 2
• If multiple boluses needed, start continuous IV infusion (epinephrine has short half-life): 1 mg in 250 mL D5W = 4 mcg/mL, infuse at 1-4 mcg/min initially, titrate up to 10 mcg/min 2
• Pediatric dosing: 1 mcg/kg (0.1 mL/kg of 1:10,000 solution), titrated to response 1

Adjunctive medications (secondary management):

• Chlorphenamine 10 mg IV (adult dose) 1, 2
• Hydrocortisone 200 mg IV (adult dose) 1, 2
• Alternative vasopressors (metaraminol) if blood pressure fails to recover despite epinephrine infusion 1, 2

For persistent bronchospasm:

• Salbutamol IV infusion 1, 2
• Metered-dose inhaler if appropriate connector available 1, 2
• Aminophylline or magnesium sulfate IV as additional options 1, 2

Critical context: Cardiovascular collapse occurs in 50.8% of anaphylaxis cases during anesthesia and may be the sole presenting feature in 10% of patients, often without cutaneous signs 2. Bradycardia occurs in approximately 10% of cases, not just tachycardia 2. The absence of skin manifestations does not exclude anaphylaxis—28% of cases lack cutaneous signs 2.

Cardiac Arrest

Primary medication:

• Epinephrine 1 mg IV every 3-5 minutes during CPR according to Advanced Life Support Guidelines 1
• For anaphylaxis-induced cardiac arrest, the same epinephrine dosing applies but may require higher cumulative doses due to severe vasoplegic state 3, 4

Important caveat: In anaphylaxis-associated cardiac arrest, patients may remain profoundly hypotensive even after standard epinephrine doses, requiring aggressive fluid resuscitation and potentially vasopressor infusions 3, 4.

Severe Hypotension (Non-Anaphylactic)

Primary medications:

• Epinephrine infusion as described above for refractory hypotension 2
• Norepinephrine (Levophed): Initial rate 2-3 mL/minute (8-12 mcg/min of base), then adjust to maintain systolic BP 80-100 mmHg; average maintenance 0.5-1 mL/minute (2-4 mcg/min of base) 5
• Metaraminol as alternative vasopressor 1, 2

Critical consideration: Occult blood volume depletion should always be suspected and corrected when hypotension persists despite vasopressors 5. Central venous pressure monitoring is helpful in detecting and treating this situation 5.

Bradycardia

Primary medication:

• Atropine 0.5-3 mg IV for severe bradycardia 6, 7
• Glycopyrrolate 0.1 mg IV as alternative anticholinergic 7

Critical context: Bradycardia during anesthesia emergencies may represent severe hypovolemia in conscious individuals, particularly in hypotensive insect sting anaphylaxis where relative bradycardia (falling heart rate despite hypotension) is a consistent feature 4. Bradycardia can also occur with sugammadex administration 7.

Essential Supportive Medications

Fluid Resuscitation

• Normal saline 0.9% or lactated Ringer's solution at high rate through large-bore IV 1, 2
• Adults: 1-2 L at 5-10 mL/kg in first 5 minutes, up to 7 L may be required 2
• Children: up to 30 mL/kg in first hour 2
• Avoid dextrose solutions (rapidly extravasated); use normal saline preferentially 2

Rationale: Increased vascular permeability in anaphylaxis can transfer 50% of intravascular fluid to extravascular space within 10 minutes 2.

Critical Pitfalls to Avoid

Never delay epinephrine administration—it is the definitive treatment with combined alpha-agonist (vasoconstriction), beta-agonist (inotropy, bronchodilation), and mediator release inhibition properties 1, 2.

Do not exclude anaphylaxis based on absence of cutaneous signs—28% of cases lack skin manifestations 2.

Do not assume tachycardia will be present—bradycardia occurs in 10% of anaphylaxis cases 2.

Always exclude equipment failure (misplaced tracheal tube) before attributing symptoms solely to anaphylaxis 1.

Avoid IM route when IV access is available in the anesthesia setting—IV allows for precise titration 2.

Position matters: Upright posture has been associated with death from anaphylaxis; maintain supine/Trendelenburg position 4.

Diagnostic Confirmation

Mast cell tryptase sampling protocol:

• First sample: As soon as feasible after resuscitation starts (do not delay resuscitation) 1, 2
• Second sample: 1-2 hours after symptom onset 1, 2
• Third sample: At 24 hours or in convalescence (establishes baseline) 1, 2
• Collect 5-10 mL clotted blood, label with time and date 1

Evidence shows: Repeated measurements of mast cell tryptase are more sensitive and specific than a single measurement for diagnosing anaphylaxis 4.