Shock

Question 1

Define shock

Answer 1

• Inadequate tissue perfusion
• Leads to anaerobic metabolism (lactic acidosis)
• Eventually, end organ damage/failure

Question 2

Oxygen delivery is a factor of:

Answer 2

• Lung function
• Hgb concentration
• Cardiac output (preload, afterload, contractility, HR)

Question 3

What are most cases of shock associated with? What are the exceptions?

Answer 3

• Hypotension

- Exceptions: hypertensive emergencies, CO poisoning (may be normo or hypertensive)

Question 4

PE to evaluate shock

Answer 4

• Airway
• Breathing (effort, rate, sounds, pulse ox, ABG)
• Circulation (BP, HR, MAP)
• Disability/Neuro status (GCS)
• Exposure (head to toe assessment)

Question 5

Signs of end organ damage

Answer 5

• Confusion
• Decreased urine output
• CP or ischemic EKG changes
• Diffuse abd pain
• Generalized muscle pain

Question 6

Define hypovolemic shock

Answer 6

More than 15% loss of intravascular volume causing hypotension that leads to decreased end-organ perfusion

Question 7

What is the MC cause of shock?

Answer 7

Hypovolemia

Question 8

Etiology of hypovolemic shock

Answer 8

• Fluid loss (vomiting, diarrhea, 3rd degree burns, DKA urine)
• Hemorrhagic (trauma, GI bleed)
• 3rd spacing (ascites 2/2 cirrhosis, cancer, pancreatitis)

Question 9

Treatment of hypovolemic shock

Answer 9

• IVF (until MAP over 65)
• Transfusion (preferred if cause is hemorrhagic)
• Vasopressors (initiate if IVF cannot get MAP over 65)

Question 10

When should vasopressors be avoided in treating hypovolemic shock?

Answer 10

If cause is hemorrhagic

Question 11

Preferred vasopressor in treating hypovolemic shock

Answer 11

Norepi

Question 12

What is the preferred volume expander if hypovolemic shock is caused by hemorrhage?

Answer 12

Blood transfusion

Question 13

Define cardiogenic shock

Answer 13

Decreased cardiac output 2/2 abnormal cardiac function in the setting of NORMAL intravascular volume

Question 14

Etiology of cardiogenic shock

Answer 14

• MI (50% of cases)
• Arrhythmias (tachy or brady)
• Mechanical (cardiomyopathy, ventricular septum or wall rupture)

Question 15

Treatments of cardiogenic shock

Answer 15

• Norepi for hypotension
• Dobutamine for wet/cold HF
• Cath lab or CABG for MI
• Intra-aortic balloon pump (temporizing measure)
• Atropine and pacemaker for bradycardia
• Electrical cardioversion for AFib/VFib-tach

Question 16

Define neurogenic shock

Answer 16

• Hypotension and bradycardia 2/2 sympathetic ganglion chain injury
• Sometimes considered a component of distributive shock (d/t significant vasodilation)

Question 17

What type of injury MC causes hypotension and bradycardia (i.e. neurogenic shock)?

Answer 17

C-spine injuries

Question 18

Etiology of neurogenic shock

Answer 18

• Trauma (MC)

- Improper location of regional anesthesia delivery

Question 19

Key signs of neurogenic shock

Answer 19

• Bradycardia and hypotension in setting of trauma or injection
• Limbs are warm, rest of body is cold
• Neuro symptoms (urine retention, paralysis)

Question 20

Treatment of neurogenic shock

Answer 20

• ABCDE and spine immobilization
• Treat or avoid hypothermia
• IVF, vasopressors, atropine
• IV steroids
• Neurosurgery/ortho consults

Question 21

Define obstructive shock

Answer 21

• Decreased CO despite normal cardiac function

- Can be 2/2 obstructive decrease in preload OR increase in ventricle outflow resistance

Question 22

Etiology of obstructive shock

Answer 22

• Tension PTX
• Pericardial tamponade
• Massive PE
• Aortic stenosis
• Pulm HTN
• Atrial myxoma
• HTN emergency

Question 23

Treatment of obstructive shock

Answer 23

• Needle decompression for PTX/tamponade
• Thrombolytics/thrombectomy for massive PE
• NO inhalation for pulm HTN
• Valve replacement for AS
• Operative resection for atrial myxoma
• IV anti-HTNs for HTN emergency

Question 24

Define hypertensive urgency

Answer 24

Asymptomatic severe HTN (SBP over 220 or DBP over 125)

Question 25

Define hypertensive emergency

Answer 25

Severe HTN with signs of end organ damage (encephalopathy, nephropathy, aortic dissection, pulm edema, MI, etc)

Question 26

Define malignant/accelerated HTN

Answer 26

Severe HTN involving retinopathy (papilledema)

Question 27

Etiology of HTN urgency/emergency

Answer 27

- Noncompliance or med withdrawal (clonidine) - RAS or chronic renal dz progression - Thyroid storm - Pheochromocytoma - Cocaine - Pregnancy - CNS (head injury, ICB, CVA) - Intra/postop

Question 28

Treatment goal of HTN urgency

Answer 28

Mild BP reduction initially with a focus on long term control

Question 29

Treatments of HTN urgency and what to monitor for each

Answer 29

- Captopril (30 min onset) - Labetalol (monitor for bradycardia) - Clonidine (potential for rebound HTN) - Nifedipine (unpredictable response)

Question 30

Treatment goal of HTN emergency (and exceptions to this)

Answer 30

BP reduction of 25% within 1 hour and then to 160/100 within 6 hours *Exceptions: CVA (maintain SBP 160-165) and ICB (target SBP under 130 or 20% below pt's baseline)

Question 31

Treatments of HTN emergency

Answer 31

- Nicardipine IV (caution in CAD) - Labetalol IV - Nitro infusion - Hydralazine IV (mostly for pregnancy related) - Furosemide

Question 32

Define distributive shock

Answer 32

Hypotension 2/2 decreased vascular resistance despite NORMAL circulatory volume

Question 33

Etiology of distributive shock

Answer 33

- Sepsis - Anaphylaxis - Intoxication - Acute adrenal insufficiency - Neurogenic shock

Question 34

How can pregnancy cause shock?

Answer 34

- Increases BV and CO due to increased HR and SV - Decreases systemic resistance * Net result: 5-10 mmHg decrease in MAP (either WNL or early signs of shock)

Question 35

When is shock in pregnancy MC?

Answer 35

3rd trimester - when the pathophysiologic factors are most prominent

Question 36

Explain hypotension in pregnancy

Answer 36

- Pregnancy causes increased BV and CO with decreased systemic resistance - These changes could be normal OR early signs of shock

Question 37

Etiology of shock in early pregnancy

Answer 37

Ruptured ectopic pregnancy

Question 38

Etiology of shock in late pregnancy

Answer 38

- PE - Amniotic fluid emboli - Uterine rupture - Postpartum hemorrhage - Postpartum cardiomyopathy - Septic shock

Question 39

Reasons why intubation of a critically ill person can cause shock

Answer 39

- Vasodilation from induction meds - Increased vagal tone from hypopharyngeal stimulation - Decreased RV preload from positive pressure ventilation

Question 40

Describe central venous catheter

Answer 40

Lengthy catheter passed through a vein to end up in thoracic portion of vena cava or RA of heart

Question 41

Insertion locations of CVC

Answer 41

1. Internal jugular vein 2. Subclavian vein 3. Femoral vein

Question 42

Potential complications a/w CVC placement

Answer 42

- Hematoma - PTX, hemothorax - Air embolism - Misguided or kinked catheter - Wire migration - Infection

Question 43

Indications for CVC

Answer 43

1. Provide vasopressors or other centrally administered meds 2. Measure CVP 3. Measure central venous O2 saturation (ScvO2) 4. Inadequate peripheral venous access

Question 44

What does CVP under 5 mmHg suggest?

Answer 44

Hypovolemia

Question 45

What does CVP over 18 mmHg suggest?

Answer 45

Tamponade Overload Pulm HTN

Question 46

Which site(s) are preferable for measuring ScvO2?

Answer 46

Internal jugular or subclavian

Question 47

What does ScvO2 under 70% indicate?

Answer 47

Oxygen delivery is inadequate to meet oxygen uptake in the tissues