Vasopressors: Difference between revisions
Line 21: Line 21:
*↑SV
*↑SV
===Dosing===
===Dosing===
*Start 2mcg/min
''Based on Glomerular Filtration Rate [GFR (ml/min)]''
**Incr by 1-2mcg/min  
*<10:  0.2mcg/kg/min
**Max dose is 40mcg/min
*10-40:  0.3mcg/kg/min
*Replace volume before starting
*>40-50:  0.4mcg/kg/min
 
*For CVVHD: dose at 0.4mcg/kg/min
*For HD: dose 0.2mcg/kg/min
 
===Rate of Titration===
===Rate of Titration===
*Q2-5 min
*Q2-5 min

Revision as of 04:18, 3 December 2014

Background

The goal of vasopressor use is to reach critical organ perfusion pressure. Estimated required mean arterial pressures (MAP) are listed below. It is generally safe to aim for a goal map of 65 mmHg. Vasopressors also promote increased venous return.

  • Brain: MAP of 50 mmHg [1]
  • Heart: MAP of 65 mmHg[2]
  • Kidneys: MAP 65-75 mmHg[3]

IV Vasopressor have not been shown to be unsafe when used peripherally[4] If running peripherally perform frequent site check via institutional protocol. [5]

Norepinephrine

Indication

  • Septic shock (1st line)
  • Cardiogenic shock:
    • If marked hypotension (SBP <70)
    • If used with dobutamine

Primary Receptor

  • α1 >> β1

Relative Effects

  • ↑↑↑SVR
  • ↑HR
  • ↑SV

Dosing

Based on Glomerular Filtration Rate [GFR (ml/min)]

  • <10: 0.2mcg/kg/min
  • 10-40: 0.3mcg/kg/min
  • >40-50: 0.4mcg/kg/min
  • For CVVHD: dose at 0.4mcg/kg/min
  • For HD: dose 0.2mcg/kg/min

Rate of Titration

  • Q2-5 min

Adverse Effects

  • If extravasation occurs use phentolamine 0.1 to 0.2 mg/kg (maximum dose 10 mg) subcutaneous in affected site[6][7]
    • Consult plastic/general surgery service to follow the patient and eval for need for intervention[8]

Notes

More potent vasoconstrictor than dopamine and phenylephrine.

Dopamine

Indication

  • Hypotension caused by:
    • Septic shock
    • MI
    • Trauma/spinal shock
    • Heart failure

Primary Receptor

  • Low dose: DA, β1
  • High dose: DA, α1 >> β1

Relative Effects

  • Low dose: Natriuresis, ↑↑HR, ↑↑SV
  • High dose: ↑SVR and ↑SV

Contraindication

  • Tachyarrhythmias

Dosing

  • Low dose:
    • 1-5 mcg/kg/min - Vasodilation (renal, mesenteric, coronary)
    • 5-10 mcg/kg/min - predominant β1
  • High dose: 10-20 mcg/kg/min - predominant α1
  • Titrate to clinical effect
    • Use lowest dose possible (prevent tachyphylaxis)
  • May use in peripheral IV temporarily
    • Avoid using in same line as alkaline infusions

Rate of Titration

  • Q2-5 min

Adverse Effects

  • Low doses:
    • Hypotension
  • High doses:
    • Hypertension, ectopic beats
  • Tissue necrosis (if extravasates)
    • If occurs use phentolamine 5-10mg in affected area

Dobutamine

Indication

  • Cardiogenic shock
  • Low-output heart failure
  • Tricyclic overdose

Primary Receptor

  • β1
  • β2

Relative Effects

  • ↑↑↑SV
  • ↑↑HR
  • ↓SVR (transient, from β2 agonism)

Dosing

  • 2-20mcg/kg/min
    • 10mcg works for most
  • May use in peripheral IV

Rate of Titration

  • Q2-5 min

Adverse Effects

  • Tachyarrhythmias
  • Myocardial ischemia
  • Hypotension as β2 effect may result in vasodilation
    • Caution if SBP <90

Phenylephrine

Indication

  • Neurogenic Shock

Primary Receptor

  • α1

Relative Effects

  • ↑SVR
  • ↓HR (reflex bradycardia)

Dosing

  • Start 100-200mcg/min then taper down
    • 40-60mcg/min works for most

Adverse Effects

  • Baroreceptor-mediated reflex bradycardia
  • If extravasates use phentolamine

Notes

  • Use with caution in pts with spinal cord injury-related bradycardia
  • Useful for treatment of vasodilatory shock when norepinephrine or dopamine have precipitated tachyarrhythmias
  • In pts with ↓LV function, unopposed α1 may lead to decreased CO or myocardial ischemia
    • However clinical trials do not support these effects when used in clinically appropriate dose range

Vasopressin

Indication

  • Adjunct for septic shock

Primary Receptor

  • V1

Relative Effects

  • ↑SVR
  • ↓HR

Dosing

  • 0.04 units/min

Rate of Titration

  • Fixed dose (do not titrate)

Adverse Effects

  • Bradycardia
  • Limb ischemia
  • Myocardial ischemia
  • Splanchnic ischemia

Notes

  • Adverse effects are dose-dependent
  • Acts on V1 receptors leading to ↑vasoconstriction and

↑sensitivity to catecholamines in pts with shock

Epinephrine

Indication

  • Anaphylaxis

Primary Receptor

  • β1
  • α1
  • β2

Relative Effects

  • ↑↑↑HR
  • ↑↑↑SV
  • ↑↑↑SVR
  • Bronchodilation (β2)

Dosing

  • Dose-dependent effects:
  • 1-10 mcg/min - increase HR and SV
  • 10-20 mcg/min - increase SVR

Rate of Titration

  • Q2-5 min

Adverse Effects

  • Tachyarrhythmias
  • Myocardial ischemia
  • ↑Serum lactate
  • Splanchnic ischemia

Notes

  • ↑lactate occurs primarily from ↑glycolysis/glycogenolysis within skeletal muscles not tissue hypoperfusion
  • Use with caution in pts with CAD
    • However clinical trials have not demonstrated worsened outcomes


Milrinone

Indication

low cardiac output states due to impaired myocardial contractility

Primary Receptor

  • PDE-3 inhibitor

Relative Effects

  • ↑HR
  • ↑↑↑SV
  • ↓SVR

Dosing

  • Normal renal function:

0.25 - 0.75 mcg/kg/min

  • Creatinine clearance < 50mL/min, reduce infusion rate

Rate of Titration

  • Q2H; slower titration rate if renal insufficiency

Adverse Effects

  • Tachyarrhythmias
  • Hypotension
  • Myocardial ischemia

Notes

  • Can use as alternative to dobutamine in pts with cardiogenic shock and on b-blockers
  • Causes pulmonary vasodilation, may be good choice in pts with RV failure
  • ↑cAMP in cardiac myocytes and vascular smooth muscle, thereby ↑HR and ↑SV while decreasing ↓SVR
  • Use with caution in pt with renal failure and hypovolemia

Push Dose Pressors

  • Use when need temporary BP or CO boost
    • Post-intubation hypotension
    • Propofol-induced hypotension
    • A-fib w/ hypotension
      • Easier to convert well-perfused heart

Epinephrine

  • Mix 9mL of NS with 1mL of 1:10,000 epi
    • Now have 10mL of 10mcg/mL
      • Use 0.5-2mL q2-5min (similar to epi drip)
      • Same as 2% lido with epi
        • Ok to give peripherally
  • Onset - 1min
  • Duration - 5-10min

Phenylephrine

  • Pure alpha (no effect on heart)
  • Place 1mL of 10mg/mL vial in 100mL NS
    • Now have 100mcg/mL
    • Draw up 10mL
    • Use 0.5-2mL q2-5min (50-200mcg)
  • Onset - 1min
  • Duration - 20min

Source

  1. ↑ Plöchl, W, D J Cook, T A Orszulak, and R C Daly. 1998. Critical cerebral perfusion pressure during tepid heart operations in dogs. The Annals of thoracic surgery, no. 1. http://www.ncbi.nlm.nih.gov/pubmed/9692450
  2. ↑ Emcrit Vasopressor basics http://emcrit.org/podcasts/vasopressor-basics/
  3. ↑ Bellomo, Rinaldo, Li Wan, and Clive May. 2008. Vasoactive drugs and acute kidney injury. Critical care medicine, no. 4 Suppl. doi:10.1097/CCM.0b013e318169167f. http://www.ncbi.nlm.nih.gov/pubmed/18382191.
  4. ↑ Ricard JD. et al. Central or peripheral catheters for initial venous access of ICU patients: a randomized controlled trial. Crit Care Med. 2013 Sep;41(9):2108-15
  5. ↑ Chen J. et al. Extravasation injury associated with low-dose dopamine.. Ann Pharmacother. 1998 May;32(5):545-8
  6. ↑ ZUCKER G. et al. Treatment of shock and prevention of ischemic necrosis with levarterenol-phentolamine mixtures. Circulation. 1960 Nov;22:935-7.
  7. ↑ PELNER L. et al. The problem of levarterenol (levophed) extravasation an experimental study.. Am J Med Sci. 1958 Dec;236(6):755-66
  8. ↑ Emcrit peripheral vasopressors http://emcrit.org/podcasts/peripheral-vasopressors-extravasation/
  • EmCrit Podcast 6
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