Levo vs. Neo: A Change of the Guards?

Vancomycin IV infiltration, yet we still give through PIV

From A&A May 2016: Should Norepinephrine, Rather than Phenylephrine, Be Considered the Primary Vasopressor in Anesthetic Practice?

http://www.ncbi.nlm.nih.gov/pubmed/27101504

GA = Sympathectomy, decreased NE and Epi concentrations

Phenylephrine (PE, trade name Neosynephrine aka Neo)
pure alpha 1 agonist
increase ABP, decrease HR
CO effect mixed +/- venous return, decreased HR

Norepinephrine (NE, trade name Levophed aka Levo)
alpha1 and beta1, some beta2
relaxation of venous resistance
NE enhances venous return +CO
+ionotropy, little chronotropy
+arterial vasoconstrict
+HR, +SV, +CO

Potency of NE:PE 20:1

NE levels increased in cardiac failure

PeriOp circulating Catecholamine levels

NE and Epi decreased by
-diazepam
-thiopental (even more in uremic)
-midazolam
-pancuronium
-spine surgery + prop or iso

NE and Epi increased by
-Ketamine
-1.5 mac Desflurane
-succinylcholine
-rapid increase in Isoflurane
-intubation
-abdominal surg + sevo/n2o
-emergence/extubation

little effect from roc/vec

Comparing NE to PE in specific studies and circumstances

Aortic stenosis
-PE resulted in higher MAP, no differencve in LV fx vs. Levo

CABG
-PE imparied LV function, unchanged with levo

Pulmonary HTN cardiac surgery pts
-CI maintained with NE, decreased with PE
-NE improved (reduvced) ratio of mean PA pressure to SBP

General Surgery, isoflurance
-NE increased LV performance
-PE decreased LV performance

General Surgery, prop+remi
-both PE/NE decreased CO and HR, increased MAP

C/S Spinal
-PE vs. NE infusion
-NE had same sbp, higher HR, higher CO c/w PE

If LV fx impaired, enhanced afterload from PE -> decreased CO and systemic perfusion

but what about infiltration? Largely overblown as, yes NE 7x more constrictive in radial ARTERY, yet only 76% more vasoconstrictive in veins and concentration of Levo is 20x less than PE

if infiltrate -> give phentolamine