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233Septic shock Pathophys: infection/inflammatory state --> release of mediators (heparin, bradykinin, LTE, PG) --> vasodilation --> SVR decrease --> afterload decrease --> easier for blood to be ejected from the heart --> CO increases --> LA/RA = PCWP/CVP pressures decrease (blood is moving forward through the heart)Mixed venous oxygen saturation = increased= O2 sat of blood that is in the RA = blood that has returned from all the veins in the body Fixed principle: CO = O2 delivery/(O2 content of arteries - O2 content of veins)Septic shock: CO increases --> difference in O2 artery-venous should decrease --> O2 content of veins goes up (MVO2 goes up)*CO and SVR go in opposite directions in shock*(only exception is neurogenic shock)SIRS+ criteria: >= 2 criteria Temperature <36C or >38CHR >90 bpmRR >20 bpmPaCO2 <32WBC >12000 or <4000with source of infection = septic shock + lactic acidosis (low HCO3 or pH) or end-organ damage = severe sepsisTxBroad spectrum abx (make sure to cover MRSA or pseudomonas)Fluids MAP increasesNorepinephrine Remove indwelling catheter if that is source of infection Neurogenic shockPathophys: high spinal injury, spinal cord surgery, SEA --> @spinal cord thoracic levels --> take out sympathetic nervous system --> lose vascular tone --> SVR decrease, CO decrease*the only kind of shock where SVR AND CO are low*Cardiogenic shockPathophys: cardiac tamponade, CHF, post-MI --> CO decreased (heart cannot pump fluid forward), SVR increased --> fluid backs up in the heart --> CVP/PCWP increasedCO is low --> tissues get very efficient at extracting oxygen --> O2 sat of blood returning to RA is very low (MVO2 decreased)TxPositive inotrope = digoxin, dobutamine (b1 agonist), milrinone Milrinone = PDE inhibitor --> increased cAMP --> increased cardiac contractility, decreased vascular resistancePulse pressure increases due to increased SBP + decreased DBP Hypovolemic shockPathophys: bleeding out --> body volume goes down --> preload goes down --> CO decreased, SVR increased --> PCWP/CVP decreased, MVO2 decreasedTx: fluids *QSOFA criteria (1+): AMS, RR >=22, SBP<=100* used clinically ??? ................
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