Intravenous Phenylephrine

Emergency Resuscitation for cardiovascular collapse while performing other interventions
1. Example: Septic Shock refractory to fluid Resuscitation, temporizing while obtaining central access
2. Can be used via peripheral IV for hours until central access is available for other Vasopressors (e.g. Norepinephrine)
Conscious Sedation
1. Commonly used by anesthesiology for Hypotension secondary to Propofol and other agents

Direct selective alpha-Adrenergic Agonist
Push Dose Pressor (Bolus Phenylephrine)
1. Vasopressor without direct inotropic (contractility) or chronotropic (Heart Rate) activity
Increases cardiac perfusion via Vasoconstriction and secondary increase in venous return

Local infiltration effects (extravasation)
1. Risk of tissue ischemia, necrosis and gangrene
2. Less local toxicity to tissue and vascular structures compared with other pressors
Reflex Bradycardia
1. Unlikely to occur during cardiovascular collapse in which adrenergic response is expected to be strong
2. Baroreceptor reflex to increasing BP is typically outweighed by a stronger adrenergic response

See Push Dose Pressor
Precautions
1. Limit Push Dose Pressors to emergency use
2. Mixing errors are common (Exercise caution)
3. When adequate time is available, pharmacy prepared solutions are preferred
4. Push Dose Pressors are a temporizing measure to stabilize Hypotension
  1. In some cases, Push Dose Pressor alone may be sufficient (e.g. Propofol induced Hypotension)
  2. Prepare for Vasopressor infusion (e.g. Norepinephrine, Epinephrine) if expected persistent Hypotension
Preparation
1. Dilute 1 ml (10 mg) from Phenylephrine vial (10 mg/ml) in Normal Saline 100 ml bag
2. Resulting solution: Phenylephrine 100 mcg/ml
3. Draw solution into labeled syringe for use as Push Dose Pressor

Phenylephrine IV bolus
1. Bolus (100 mcg/ml) 50 to 200 mcg (0.5 to 2 ml) IV bolus as needed every 10 to 15 min
2. May initially be needed every 2-5 minutes in severe Hypotension
Phenylephrine IV Infusion
1. Prepare 20 mg Phenylephrine in 250 ml D5W (80 mcg/L)
2. Start 100 to 180 mcg/min (75 to 135 ml/h)
3. Maintain typically at 40 to 60 mcg/min

Phenylephrine IV bolus
1. Bolus (100 mcg/ml) 5 to 20 mcg/kg IV bolus as needed every 10 to 15 min
Phenylephrine IV Infusion
1. Prepare 20 mg Phenylephrine in 250 ml D5W (80 mcg/L)
2. Infuse 0.1 to 0.5 mcg/kg/min IV, titrating to target Blood Pressure and perfusion