What is the epinephrine (epi) titration strategy in mcg/min for an adult patient with acute hypotension in the cath lab setting, already on high-dose norepinephrine?

Epinephrine Titration Strategy for Acute Hypotension in the Cath Lab

For an adult patient with acute hypotension in the cath lab already on high-dose norepinephrine, start epinephrine at 3.5-14 mcg/min (0.05-0.2 mcg/kg/min for a 70 kg patient) and titrate every 10-15 minutes in increments of 3.5-14 mcg/min (0.05-0.2 mcg/kg/min) to achieve a mean arterial pressure of 65 mmHg or higher. 1

Initial Dosing and Preparation

• Dilute 1 mg of epinephrine in 1,000 mL of 5% dextrose solution to create a 1 mcg/mL concentration. 1
• Start the infusion at 0.05 mcg/kg/min (3.5 mcg/min for a 70 kg patient), which is the FDA-approved starting dose for hypotension associated with septic shock. 1
• Administer through a large vein whenever possible; central venous access is strongly preferred to minimize extravasation risk and tissue necrosis. 2, 3

Titration Protocol

• Adjust the dose every 10-15 minutes in increments of 0.05-0.2 mcg/kg/min (3.5-14 mcg/min for a 70 kg patient) to achieve the desired blood pressure goal. 1
• The maximum dose is 2 mcg/kg/min (140 mcg/min for a 70 kg patient), though doses this high are associated with poor outcomes and should prompt consideration of alternative strategies. 1, 4
• Target a mean arterial pressure of 65 mmHg as the primary endpoint, though patients with chronic hypertension may require higher targets. 2, 3

Clinical Context for Adding Epinephrine

This recommendation assumes you are adding epinephrine because norepinephrine has reached 0.25 mcg/kg/min (approximately 17.5 mcg/min for a 70 kg patient) and hypotension persists despite adequate fluid resuscitation. 5, 3 In the cath lab setting with acute hypotension on high-dose norepinephrine, epinephrine is the appropriate second-line vasopressor. 5, 3

Monitoring Requirements

• Monitor blood pressure every 5-15 minutes during initial titration with continuous cardiac monitoring for arrhythmias, which are more likely with epinephrine than norepinephrine. 3, 1
• Assess tissue perfusion markers including capillary refill, urine output (target >50 mL/h), and mental status to ensure adequate end-organ perfusion beyond just achieving a MAP target. 5, 3
• Place an arterial catheter for continuous blood pressure monitoring if not already present, as this is strongly recommended for all patients requiring vasopressors. 5, 2

Critical Pitfalls to Avoid in the Cath Lab

• Do not start epinephrine without ensuring adequate volume resuscitation first (minimum 30 mL/kg crystalloid bolus), as vasoconstriction in a hypovolemic patient causes severe organ hypoperfusion despite "normal" blood pressure. 5, 3
• Never mix epinephrine with sodium bicarbonate or other alkaline solutions in the IV line, as adrenergic agents are inactivated in alkaline solutions. 5, 3
• Use extreme caution in patients with ischemic heart disease (which is likely in the cath lab population), as epinephrine significantly increases myocardial oxygen consumption and may worsen ischemia or precipitate arrhythmias. 2, 3
• Watch for extravasation; if it occurs, immediately infiltrate 5-10 mg of phentolamine diluted in 10-15 mL of saline into the site to prevent tissue necrosis. 2

Alternative Push-Dose Strategy for Immediate Stabilization

If you need immediate blood pressure support while establishing a continuous infusion, push-dose epinephrine at 10-20 mcg IV every 2 minutes can be used until systolic blood pressure reaches 90 mmHg or MAP reaches 65 mmHg. 6 This approach showed a median MAP increase of 13 mmHg with rare adverse events in critically ill transport patients. 6

Weaning Protocol

• After hemodynamic stabilization, wean incrementally over 12-24 hours by decreasing doses every 30 minutes rather than abrupt discontinuation. 1
• Monitor closely during weaning, as rebound hypotension can occur.

When Epinephrine Fails

If epinephrine reaches high doses (>0.5 mcg/kg/min or >35 mcg/min) without adequate response, consider adding vasopressin 0.03-0.04 units/min as a third agent rather than continuing to escalate epinephrine, as prolonged high-dose catecholamine therapy is associated with poor survival. 5, 4 Alternatively, if arrhythmias develop with epinephrine, consider switching to phenylephrine or vasopressin. 3