Miscellaneous
"This used to be merely intuition...even a minute or two at low MAPs may be too much and certainly waiting 20 minutes for pharmacy to send up a drip is probably way too long...and your kidneys may actually be getting damaged in that short period of time." - Scott Weingart, MD Who is Scott Weingart, MD? Courtesy of Scott Weingart, MD Scott D. Weingart, MD FCCM FUCEM DipHTFU Scott is an ED Intensivist from New York. He did fellowships in Trauma, Surgical Critical Care, and ECMO. He is currently an attending in and chief of the Division of Emergency Critical Care at Stony Brook Hospital. He is a clinical associate professor of emergency medicine at Stony Brook Medicine and an adjunct associate professor at the Icahn School of Medicine at Mount Sinai. He is best known for talking to himself about Resuscitation and Critical Care on a podcast called EMCrit, which has been downloaded > 19 million times. EMCrit Twitter Team @emcrit What is a MAP? (Mean Arterial Pressure) Average pressure in a patient’s arteries during one cardiac cycle Really good number to measure organ perfusion Systolic BP is a useless measurement in super hypotensive patients Calculations: MAP = CO x SVR MAP = SBP + 2(DBP)/3 Low MAPs should be treated as an Emergency = Requires Good Nursing!! What is a minimal MAP for adequate perfusion? No one knows!! Minimal MAPs (what we think and have made up) to adequately perfuse 3 main organs. Use this as a loose guideline. May have to individualize for each patient. Brain MAP 60-65 but can go lower for a bit of time before damage MAP 40 starts to have altered mental status Heart MAP 60-65 Kidney MAP 65 super sensitive to low MAPs May not be able to measure output in ED if kidneys were hit hard and due to shunting In the ED, we like MAP 65... because the organs will have minimal perfusion and we often don't know what the medical history is or have had 24 hours of patient observation. Normal MAP + Low SBP + Normal DBP = Okay Organs are being perfused Low MAP + Normal SBP + Low DBP (Ex: 100/20) = Badness Can be in cardiac arrest if you don't pay attention and do something ASAP Low MAP, How long is too long? New Anesthesia literature that shows a minute or two may be too much. Concern for kidney injury Hearts may dislike low MAP esp. Pts with cardiac history. React quickly to low MAPs (MAP 40s and 50s) No barrier to treating low MAPs No Harm in treating low MAPs Can start peripheral NE drip and if in 45 minutes, NE drip is titrated off - no harm done to Pt Wait and See approach with fluids doesn't work Fluids don't last to maintain MAPs, it will drop 30-60 minutes later Harm to keep Pt at low MAPs "Permissive Hypotension" A confusing term No one is really in a permissive hypotension state lower than the minimal MAP 65 Trauma A confusing term because the trauma studies still show that a Pt is being perfused and hovering around MAP 60-65 Term came about because fluids were restricted instead of giving bunch of fluids - but BPs were normal Some say the clot is formed so don't break the clot - still BPs are at MAPs that we talked about Bickell study on penetrating trauma Scott mentioned Permissive hypotension/hypotensive resuscitation and restricted/controlled resuscitation in patients with severe trauma by D. Kudo Rick Dutton Approach for penetrating trauma management as described by Scott Keep your patient from being vasoconstricted Organs are not being perfused with higher MAP but in fact exsanguinating due to vasoconstriction Manage by hovering around a MAP 60-65 and perfuse organs MAP 80 (or whatever upper limit you decide), give them some anesthetic and dilate them. Fentanyl is an indirect vasodilator Read more about Richard Dutton and trauma at emcrit.org Hemostatic Resuscitation Hemorrhagic Shock Patient in Trauma Neuro - term doesn't really apply