Why Use Push Dose Pressors?

To buy yourself some time with your super hypotensive patients!!

Ensure your patient's perfusion status while you are trying to:

intubate

managing transient hypotension

preparing a drip

preparing a central line

Know which medication to use based on clinical presentation of patient.

Dr. Scott Weingart's Easy Push Dose Printout (It has photos!)

Epinephrine

alpha 1&2, beta 1&2 agonist = inopressor

(Increase in myocardial contraction, heart rate, and peripheral vascular resistance)

Epinephrine Push Dose Concentration 10mcg/mL (1:100,000) vs. cardiac dose (1:10,000)

Onset Immediate - 1 minute

Duration 5-10 minutes

Dose 5-20mcg every 2-5 minutes (0.5-2mL)

 

Preparation

Draw up 9mL of Normal Saline in an empty 10mL syringe (updated - see below)

Attach a syringe and draw up 1mL of epinephrine from the pre-filled cardiac dose amp (Epinephrine 100mcg/mL)

Shake a little, Place a label: Epinephrine 10mcg/mL

Phenylephrine

alpha 1 agonist = increase in peripheral vascular resistance

Heart rate remains the same. Watch out for reflex bradycardia.

 

Phenyelphrine Push Dose Concentration 100mcg/mL

 

Onset Immediate - 1 minute

Duration 10-20 minutes

Dose 50-200mcg every 2-5 minutes (0.5-2mL)

 

Preparation

Draw up 1mL of phenylephrine (10mg/mL concentration vial)

Inject into NS 100mL bag

Shake a little, Place a label: Phenylephrine 100mcg/mL

Use as a drip or draw up in a syringe.

Super Nerdy Receptor Information

Beta Receptors

Tissue

Receptor Subtype

Heart

beta1

Adipose Tissue

beta1, beta3?

Vascular Smooth Muscle

beta2

Airway Smooth Muscle

beta2

Beta1 Agonist

Increases contractile force & HR. Activation of beta1 receptors in the atria and ventricles but the ventricles are really effected - thus increasing myocardial contraction. HR increases because SA node, AV node and the His-Purkinjie system are activated.

 

Beta 2 Agonist

Relaxes smooth muscles

 

Alpha1 & Alpha 2 Agonist

Constriction of vascular smooth muscle.

Myocardial Alpha 1 may have a positive inotropic effect.

No clear understanding on Alpha 2 receptors at this moment.

Epinephrine & NE has equal affinity to both alpha 1 and alpha 2 receptors.  However, Epinephrine has a higher affinity to beta 2 receptors. So effects are dose dependent. Initially will activate beta 2 receptors so relaxes vascular smooth muscle and decrease peripheral resistance, but at higher doses, epinephrine will also bind to alpha 1 receptors which is a potent vasoconstrictor and will dominate as epinephrine concentrations are higher.

 

Phenylephrine is a pure alpha 1 agonist.

Vasoconstriction of both arterial and venous vessels.

Great for someone who has tachycardia/tachyarrhythmia but also hypotensive.

Can cause reflex bradycardia.

Update 8/6/2017 "Concentration" used to differentiate final concentration versus dosing, to have clear language.

Update 8/8/2017 Brought to my attention by Craig Button, RN - There have been reported cases of serious medication errors due to mixing medications using pre-filled saline flushes and not labeling them. Therefore, I am going to change the recommended preparation of mixing epinephrine push dose concentrations. The LAST thing I want is to hear about unlabeled saline flushes with epinephrine lying around, and/or causing harm to patients. These medications should be respected so PLEASE LABEL ALL PREPARATIONS!! Original text is here. Blog post has been updated above.

Original Text: Epinephrine Push Dose Concentration Preparation

Take a NS 10mL flush and squeeze out air bubbles and saline so 9mL remains

Attach a syringe and draw up 1mL of epinephrine from the pre-filled cardiac dose amp (Epinephrine 100mcg/mL)

Shake a little, Place a label: Epinephrine 10mcg/mL

Now listen to the episode....

References:

Scott Weingart. EMCrit Podcast 6 – Push-Dose Pressors. EMCrit Blog. Published on July 10, 2009. Accessed on August 3rd 2017. Available at [https://emcrit.