1. Undifferentiated Shock diagnosis and management
As part of Lady Minto Hospital Emergency Rounds and
All Day Emergency Simulation Workshop
Saturday May 14, 2016
Prepared by Shane Barclay

2. Goals and objectives Review the types of shock.
Review the clinical approach to diagnosis of undifferentiated shock.
Review the management of undifferentiated shock
Practice clinical scenarios for shock.

3. Overview
Patients presenting with shock often have obvious causes of their shock – multiple fractures etc. However patients can present with shock and no obvious cause. The approach to these patients must be a simultaneous resuscitation along with diagnosis. We typically equate shock with hypotension – this is NOT always the case initially. Failure to recognize shock states early increase the chance of bad outcomes.

4. Overview
Even transient or a single episode of hypotension (systolic below 100 mg Hg) is associated with increased mortality. Remember, shock is a time-dependent disorder. These patients need continual monitoring and repeated clinical assessment.

5. Overview
We will cover the initial assessment and stabilization as this is the most critical. We will then cover actual fluid management.

6. Initial assessment of Shock
Standard history and physical. However all undifferentiated shock patients should also have: - Blood glucose - Pregnancy test in females of child bearing age. - ECG to look for arrhythmias - Assessment of feet and hands for abnormal vasodilation. - Examine neck veins for paradoxical increased CVP. - Rectal exam for melena - CXR (+/- EDE) for pneumonia, pneumothorax or pulmonary edema.

7. Initial stabilization of Shock
Ensure patent airway and oxygenation. Use devices as required to maintain O2Sats > 93%. Large bore IVs in antecubital fossa. Intraosseous device if needed, but tend to not allow same fluid volumes quickly like IV access. Remember to use pressure bag on IV. Give 1 – 2 liters of N/S in all but hemorrhagic shock patients. In hemorrhagic shock, the new ATLS guidelines recommend 1 liter of N/S and if fluid support still needed go immediately to Packed Red Blood cells.

8. Initial stabilization of Shock
Goal of fluid resuscitation is to achieve Mean Arterial Pressure (MAP) of 65. Values higher than 65 mm Hg are not associated with better outcomes and can predispose the patient to complications. Trendelenburg position may have some transitory benefit for increasing BP but should not be uses as a resuscitation position. All critically ill patients should be placed with the head up 30 degrees (with the exception of anaphylaxis – supine with feet elevated) If the MAP is very low (35 – 40) then temporary use of vasopressors can be used while fluids are being administered.

9. b1 b1 b1 Drug a1 Inotr Chron Dromo b2 V/C V/D
Vasopressors
b b b1 Drug a Inotr Chron Dromo b V/C V/D
Phenylephrine
Epinephrine
Norepinephrine
Dobutamine
Dopamine +/

10. Vasopressors
Norepinephrine: start mcg/min (0.03 mcg/kg/min) titrate 1-2mcg/min. Max 30 mcg/min Phenylephrine: start 100 – 180 mcg/min titrate 100 mcg/min. Max 10 mcg/kg/min Epinephrine: start 1 mcg/min titrate 1 mcg/min. Max 10 mcg/min Dobutamine: 2.5 mcg/kg/min titrate 2.5 mcg/kg/min. Max 20 mcg/kg/min Vasopressin: start 0.01 units/min titrate 0.01 units. Max 0.04 units/min

11. Mixing Push Dose Phenylephrine
With a 5 ml syringe, draw 1 ml of 50mg/ml (1 vial) Phenylnephrine. Mix it in 100 cc minibag of normal saline Draw out 3 – 5 cc of solution. This is now Phenylephrine of 100 mcg/ml Put labels on both the minibag and the syringe Dose is 50 – 100 mcg/min ie give 0.5 – 1 ml q2-5 minutes. Action is within 1 minutes and lasts for min.

12. Mixing Push Dose Epinephrine
Take a 10 cc N/S syringe. Discard 1 cc. Take a preloaded syringe of Epi 1:10,000 from the cardiac drawer. Take the bottom stopper off the syringe. With the 9 cc Saline syringe, draw out 1 cc Epi (1:10,000) You now have 10 mls of Epinephrine 10 mcg/ml Dose is 0.5 – 2 ml (5-20 mcg) q 2-5 min Onset 1 minute, duration 2-5 minutes.

13. Calcium
Calcium is a positive inotrope. When given IV will cause increase vasoconstriction and inotropy, especially in patients who are hypocalcemic. Dose: Calcium Gluconate 3 – 6 gm slowly IV through peripheral line (Calcium chloride 1 – 3 gm through central line)

14. Differential Diagnosis
Shock can be viewed like a simple pump. The four components are: - a pump - reservoir - inflow pipes - outflow pipes

15. Differential Diagnosis

16. Differential Diagnosis
Pump failure: Cardiogenic shock, arrhythmia, PE.
Reservoir: Hemorrhage, Hypovolemia.
Inflow pipes: Cardiac tamponade, tension pneumothorax.
Outflow pipes (vasodilation): Anaphylaxis, Sepsis, Neurogenic shock.

17. Differential Diagnosis
Some clues to the diagnosis mentioned at the beginning in the clinical exam: Warm extremities in a hypotensive patient point to abnormal vasodilation from such things as sepsis, anaphylaxis, overdose or poisoning. Cold extremities and hypotension can indicate hypovolemia, hemorrhage and cardiogenic causes. Clear lungs nearly always exclude cardiogenic shock unless right ventricular infarction is the cause of hypotension.

18. Differential Diagnosis
Some clues to the diagnosis mentioned at the beginning in the clinical exam: Females of child bearing age with undifferentiated shock should be assumed to be an ectopic pregnancy until proven otherwise. Jugular vein distention with hypotension, one should consider PE, Tension Pneumothorax, Pericardial Tamponade or Pump Failure.

19. EDE and Point of care ultrasound (POCUS)
There are many protocols (eFAST, RUSH) for examining hypotensive patients. EDE 1 ‘graduates’ have covered most but not all of the views used. The EDE 2 course covers the remaining cardiac views.

20. EDE and Point of care ultrasound (POCUS)

21. Summary of undifferentiated Shock assessment
The first priorities are ABC. After that the list is not necessarily in order, as resuscitation and diagnosis must proceed simultaneously. 1. Airway – determine if patent. If needed, apply jaw thrust, chin lift. As indicated apply nasal cannula, NRBM, BMV, OPA, NPA, LMA. Suction prn 2. Breathing - establish if breathing spontaneously or not. Apply above as necessary. EtCO2 monitor. Keep SaO2 > 93% 3. Circulation – BP, MAP. Establish IV’s. or IO. Start Normal Saline

22. Summary of undifferentiated Shock assessment
4. Patient position – head elevated 30 degrees unless anaphylaxis suspected. 5. Need for pressors? Epinephrine push 10 mcg or Start Norepinephrine drip. ? Calcium Gluconate 3 – 6 gm IV slowly.

23. Summary of undifferentiated Shock assessment
6. Exposure – remove clothing, cover with warm blanket. Log roll. Primary survey exam: Heart – rhythm?, muffled. JVP – elevated consider Tension Pneumo, PC tamponade, pump failure. Chest – unilateral or bilateral, (clear = not cardiogenic) Abdomen – soft or rigid? Neuro – sensation below T8 ? If hypotensive and bradycardic consider neurogenic shock. Examine extremities: warm (sepsis, anaphylaxis, OD, poison) vs cold (hypovolemic, hemorrhage, cardiogenic) Rectal exam - ? melena

24. Summary of undifferentiated Shock assessment
7. Consider etiology Pump – cardiogenic failure, PE, arrhythmia Reservoir – hemorrhage, hypovolemia Inflow – cardiac tamponade, tension pneumothorax Outflow – anaphylaxis, sepsis, neurogenic shock 8. Labs: ECG, CBC, lytes, glucose, GFR, Trop, preg test, urine drug screen. 9. NG tube 10. Foley 11. CXR

25. Summary of undifferentiated Shock assessment
12. FAST/RUSH exam Substernal view of heart – PCE (if able, do parasternal long view and Apical 4 chamber view) AAA Inferior vena cava view Free fluid in RUQ and LUQ. Also check lungs for fluid/air Left and Right Pneumothorax view on anterior chest (use linear array probe)

26. Fluid resuscitation in shock

27. Shock
Shock is defined a state of inadequate tissue perfusion. This does not equal ‘perfusion pressure’ Thus blood pressure is not a reliable indicator of adequate oxygen delivery to tissues, nor perfusion. Shock can occur in patients with normal or even elevated blood pressure. Inadequate tissue perfusion in the setting of normotension is called ‘compensated shock’.

28. Shock
Decompensated shock on the other hand is a late sign of shock. MAP of < 65 or a Systolic < 90 mm Hg should raise concerns of hypotension even in the absence of overt clinical hypotension. Brief, self limited episodes of hypotension represent depletion of CV compensation and are the first signs of decompensated shock. Remember, automated BP cuffs can overestimate BP in low flow states. As well, direct auscultation can underestimate SBP by as much as 30 mm Hg in low flow states.

29. Shock – Classes I - IV Importance of serial vital monitoring.
% blood loss blood loss Signs
I < 15% <750 mls none, + HR
II 15 – 30 % 750 – 1500 ml HR, RR, no syst. change
III 30 – 40 % 1500 – 2000 ml HR, RR, Syst BP, PPres
IV > 40 % > 2000 ml HR, RR PPres
Syst BP, + no Dias BP
Importance of serial vital monitoring.

30. IV access and choice of fluids
This is covered in the Power Point “Fluid Resuscitation in the ER” Points to remember: - flow is related to diameter and length of the IV - doubling the catheter size increases flow by 16 fold, whereas doubling cannula length decreases flow by half. - use large short IV in the antecubital veins, with pressure bags.

31. END point of resuscitation
Traditionally restoration of systolic BP or a MAP of was considered an end point. Recent data suggests such end points don’t necessarily guarantee optimal organ perfusion. Serum lactate helps predict morbidity and mortality independent of hemodynamics. Lactate clearance can be reassuring that resuscitation efforts are being successful. However no optimal end point of resuscitation is currently available.

32. END point of resuscitation
Historically the rule of 3:1 (3 units of volume for every 1 unit lost in hemorrhage) was taught. However experimental models of severe hemorrhage/hypotension show that the 3:1 rule is often quite inadequate. Also, CVP measurement is an unreliable predictor of fluid status, preload or response to fluid therapy. Although not exact, respiratory collapse of the inferior vena cava greater than 50% can be a helpful and easily identified sign in the rural setting with ultrasound, that the patient is volume depleted.

33. END point of resuscitation
Passive leg raising. Volume responsive patients respond to passive leg raising of 3 minutes, with a temporary improvement in stroke volume greater than 15%. However such monitoring is not available to us so not of value.

34. Summary
Even a transient drop in BP can signal significant hypotension and is associated with poorer outcomes. Be systematic in examination and the approach to shock. IV Normal Saline should be provided to virtually all ER critically ill patients. Be familiar with pressor agents. Goal is to achieve a MAP of 65 mm Hg. However a MAP of 65 does not ensure adequate organ perfusion. Lactate clearance is one marker of favorable resuscitation.

35. Clinical Scenario 1
78 year old woman is found collapsed on the floor at home by her neighbor. ‘Down time’ unknown. EHS bring her in saying patient responding to pain, spontaneous respirations. BP 90/44 RR 20, HR 110. Unknown medication or medical history.

36. Clinical Scenario 1
What are you going to do?

37. Clinical Scenario 2
40 year old woman is found outside her house by her car by her sister who came over from Victoria to visit for the weekend. EHS brings her saying at scene she was moaning incoherently, diaphoretic, BP 100/45 HR 150 RR 22, Sats 90%, glucose at scene 8.5 Past Med Hx: Diabetes – diet controlled HTN – on hydrochlorothiazide 25 mg od

38. Clinical Scenario 2
What are you going to do?