II. Indications: Hypotension (intravenous)
- Emergency Resuscitation for cardiovascular collapse while performing other interventions
- Example: Septic Shock refractory to fluid Resuscitation, temporizing while obtaining central access
- Can be used via peripheral IV for hours until central access is available for other pressors (e.g. Norepinephrine)
-
Conscious Sedation
- Commonly used by anesthesiology for Hypotension secondary to Propofol and other agents
III. Mechanism: Intravenous
- Direct selective alpha-adrenergic agonist
-
Push Dose Pressor (Bolus Phenylephrine)
- Vasopressor without direct inotropic (contractility) or chronotropic (Heart Rate) activity
- Increases cardiac perfusion via Vasoconstriction and secondary increase in venous return
IV. Pharmacokinetics: Intravenous
- Onset: 1 minute
- Duration: 10-20 minutes
V. Adverse Effects: Intravenous
- Local infiltration effects
- Less local toxicity to tissue and vascular structures compared with other pressors
- Reflex Bradycardia
- Unlikely in cardiovascular collapse in which adrenergic response is likely to be strong
- Baroreceptor reflex to increasing BP is typically outweighed by a stronger adrenergic response
VI. Preparation: Intravenous
- Dilute 1 ml (10 mg) from Phenylephrine vial (10 mg/ml) in Normal Saline 100 ml bag
- Resulting solution: Phenylephrine 100 mcg/ml
- Draw solution into labeled syringe for use as Push Dose Pressor
VII. Dosing: Intravenous
- Phenylephrine (100 mcg/ml) 50 to 200 mcg (0.5 to 2 ml) every 2-5 minutes
VIII. Resources
- EM-Crit Blog (Scott Weingart)
- NLM Daily Med
IX. References
- Mattu and Weingart in Majoewsky (2013) EM:Rap 13(4): 9-10
