Shock

1. Shock Tad Kim, M.D. UF Surgery tad.kim@surgery.ufl.edu (c) 682-3793; (p) 413-3222

2. Overview • Definitions • Initial Assessment – ABC • Stages of Shock • Physiologic Determinants of Shock • Types of Shock • Common Features of Shock • H & P / Work-up • Case scenarios and Management • Take Home Points

3. Definitions • Shock is a physiologic state characterized by systemic reduction in tissue perfusion, resulting in decreased tissue oxygen delivery • Hypotension is not a requirement • Poor tissue perfusion

4. Initial Assesment - ABC • Airway: • Does pt have mental status to protect airway? • GCS less than “eight” means “intubate” • Airway is compromised in anaphylaxis • Breathing: • If pt is conversing with you, A & B are fine • Place patient on oxygen • Circulation: • Vitals (HR, BP) • 2 large bore (#16g) IV, start fluids (careful if cardiogenic shock), put on continuous monitor

5. ABC “DE” • In a trauma, perform ABCDE, not just ABC • Deficit or Disability • Assess for obvious neurologic deficit • Moving all four extremities? Pupils? • Glascow Coma Scale (M6, V5, E4) • Exposure • Remove all clothing on trauma patients

6. Stages / Spectrum of Shock • “Preshock” aka compensated/warm shock • Body is able to compensate for ↓perfusion • Up to ~10% reduction in blood volume • Tachycardia to ↑cardiac output & perfusion • “Shock” • Compensatory mechanisms overwhelmed • See signs/symptoms of organ dysfunction • ~20-25% reduction in blood volume • “End-organ dysfunction” • Leading to irreversible organ damage/death

7. Physiologic Determinants • Global tissue perfusion is determined by: • Cardiac output (CO) • CO = Heart rate (HR) times Stroke Volume (SV) • SV = function of Preload, Afterload, Contractility • Systemic vascular resistance (SVR) • Variables: Length, Inverse of Diameter, Viscosity

8. Types of Shock • Hypovolemic shock – from ↓preload • Hemorrhage • Fluid Loss (Vomiting, Diarrhea, Burns) • Cardiogenic shock – pump failure or ↓SV • MI, arrhythmia, aortic stenosis, mitral regurg • Extracardiac obstructive causes such as PE, tension pneumothorax, tamponade • Distributive (vasodilatory) shock - ↓SVR • Septic, anaphylactic, and neurogenic shock • Pancreatitis, burns, multi-trauma via activation of the inflammatory response

9. Common Features of Shock • Hypotension (not an absolute requirement) • SBP < 90mm Hg, not seen in “preshock” • Cool, clammy skin • Vasoconstrictive mechanisms to redirect blood from periphery to vital organs • Exception is warm skin in early distrib. shock • Oliguria (↓kidney perfusion) • Altered mental status (↓brain perfusion) • Metabolic acidosis

10. H&P / Work-up • History to determine etiology • Bleeding (recent surgery, trauma, GI bleed) • Allergies or prior anaphylaxis • Sx consistent with pancreatitis, EtOH history • Hx of CAD, MI, current chest pain/diaphoresis • Physical examination • Mucous membranes, JVD, lung sounds, cardiac exam, abdomen, rectal (blood), neuro exam, skin (cold & clammy or warm) • Labs/Tests directed toward suspected dx’s

11. Case 1 • 55yo male otherwise healthy who is fresh post-op from a colon resection for CA • Called for tachycardia, hypotension, altered mental status, and abd distension • On exam: pale, dry mucous membranes, disoriented, abdomen is tender and tense • UOP is 15mL over past hour • What else do you want to know? • What is the most likely diagnosis?

12. Case 1 • The one thing you want to know: Hct (Hgb) • Dx: Hemorrhagic (hypovolemic) shock • Management • ABC (need intubation? IV access?) • Wide open fluids and T&C 6 units PRBC • Send coags when sending for CBC • Make sure it’s not an MI (chest pain, EKG) • Give blood & prepare for re-exploration in OR

13. Case 2 • 75yo male PMH CAD, PVD, DM who is post-op from AAA repair complains of crushing substernal chest pain • Stat 12-lead EKG shows ST elevation in 2 contiguous leads • What do you do? • What is the diagnosis?

14. Case 2 • ABC, get good access, continuous monitor • Dx: Acute ST elevation MI • Treatment: “MONA” • Oxygen, Aspirin, Nitroglycerin, Morphine • Beta-blockade (no heparin or tPA due to surg) • Plavix & GP IIb/IIIa inhibitor (i.e. eptifibatide) • Stat cardiology consult for cardiac cath

15. Case 2, continued • Cath reveals critical stenosis of left main s/p balloon angioplasty • 24 hrs later, in ICU intubated • Vitals: 80/50 • On exam: cool, clammy extremities • Echocardiogram: severe LV dysfunction • What is the diagnosis & management?

16. Case 2, continued • Dx: Cardiogenic shock 2ndary to STEMI • Management • Ventilator support (remember, ABC) • Aspirin, Heparin (maintain coronary patency) • Inotropes and Vasopressors • Pulmonary artery catheter to optimize volume status and cardiac function • May need intra-aortic balloon pump

17. Case 3 • 60yo male heavy drinker brought in by EMS with nausea, vomiting, severe epigastric pain radiating to the back • Tachycardic, hypotensive • Altered mentation, dry mucous membranes, minimal UOP after Foley • What is the most likely diagnosis? • Differential diagnosis? • How do you manage this patient?

18. Case 3 • Acute pancreatitis • DDx of acute abdomen: Perforated viscus, acute mesenteric ischemia, cholecystitis, SBO, Ruptured AAA, MI • Hypovolemic shock from vomiting and Distributive shock from the inflammation: vasodilation, vasopermeability (3rd-space) • These pts require heavy, heavy fluid resus • Treatment: Push heavy fluids, NPO, NGT • Can feed post-pyloric, consider CT scan

19. Case 4 • 55yo male also post-op from colon resection for CA, epidural placed for post-operative pain control • Called by nurse for hypotension and bradycardia • Abdomen soft, no pallor, altered mentation • Hct is 38 • Most likely diagnosis?

20. Case 4 • Neurogenic shock 2ndary to epidural • Differentiated from hypovolemic due to bradycardia • Treatment is: • IVF • Turn down or turn off epidural • If BP does not respond, then alpha-agonist such as phenylephrine until above measures stabilize patient, then wean the vasopressor

21. Case 5 • 25yo male presents with diffuse abdominal pain of 1day duration, started initially as epigastric pain after a meal. Takes ibuprofen 3x a day. • Vitals: hypotensive, tachycardic • Tense abdomen, involuntary guarding, altered mental status, oliguric • What is the diagnosis & management?

22. Case 5 • Septic shock 2ndary to perf duodenal ulcer • This patient has diffuse peritonitis • Management: • ABC, IV & resuscitation (requires heavy fluids) • Broad-spectrum IV antibiotics • Emergent OR for ex-lap, washout & repair • If pt does not respond to fluids, may need vasopressors (norepinephrine, dopamine) • Have beta-agonist effects to help pump function as well as alpha-agonist for periph vasoconstriction

23. Take Home Points • Shock = poor tissue perfusion/oxygenation • Know difference btw compensated/uncomp shock • 3 types are based on physiology of shock • Hypovolemic due to decreased preload • Cardiogenic due to decreased SV or CO • Distributive due to decreased SVR • Know the common signs a/w shock • Oliguria, AMS, cool/clammy skin, acidosis • Work-up & management starts with ABC • Aggressive resuscitation except if cardiogenic • Vasopressors if hypotensive despite fluids