Undifferentiated Shock diagnosis and management Prepared by Shane Barclay MD

Goals and objectives Review the types of shock. Review the clinical approach to diagnosis of undifferentiated shock. Review the management of undifferentiated shock

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.

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.

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

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.

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.

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 used 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.

b1 b1 b1 Drug a1 Inotr Chron Dromo b2 V/C V/D Vasopressors b1 b1 b1 Drug a1 Inotr Chron Dromo b2 V/C V/D Phenylephrine +++ Epinephrine ++ +++ ++ ++ ++ Norepinephrine +++ ++ ++ ++ + Dobutamine ++ ++ + Dopamine +/- + +

Vasopressors Norepinephrine: start 0.5 -1 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

Mixing Push Dose Phenylephrine With a 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 10-20 min.

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.

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 – 2 gm through central line)

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

Differential Diagnosis

Differential Diagnosis Pump failure: Cardiogenic shock, Arrhythmia, PE. Reservoir: Hemorrhage, Hypovolemia. Inflow pipes: Cardiac tamponade, Tension Pneumothorax. Outflow pipes (vasodilation): Anaphylaxis, Sepsis, Neurogenic shock.

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.

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.

Point of care ultrasound (POCUS) There are many protocols (eFAST, RUSH) For further information, view the page “Ultrasound in the ER” on the REMSTARBC.ca site

Point of care ultrasound (POCUS)

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

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.

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

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

Summary of undifferentiated Shock assessment 12. eFAST/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)

The end