Shock/Hypotension

Question 1

What is shock?

Answer 1

Circulatory failure

Question 2

What is the cellular mechanism of shock?

Answer 2

1. Inadequate O2 delivery or utilization or too much consumption
2. Cellular/tissue hypoxia
3. cell membrane ion pump dysfunction -> intracellular edema -. leakage to extracellular -> inadequate regulation of pH
4. systemic acidosis, endothelial dysfunction, inflammatory cascade -> ant-inflammatory cascade
5. Decreased tissue perfusion

Question 3

What are the four key types of shock?

Answer 3

Distributive

Cardiogenic

Hypovolemic

Obstructive

(plus Combination)

Question 4

Which forms of shock are primarily

due to decreased systemic vascular resistance?

Answer 4

Distributive Shock

Question 5

Which forms of shock are primarily due to

decreased cardiac output?

Answer 5

Cardiogenic

(late) Hypovolemic
(late) Obstrucitve

Question 6

What can cause shock (decreased perfusion) but with normal cardiac output and normal systemic vascular resistance ?

Answer 6

Carbon monoxide poisoning

Cyanide poisoning

Mitochondrial disease

Question 7

What are the three stages of shock and what are they symptoms of each?

Answer 7

Pre-shock aka Compensated Shock aka Cryptic Shock:

SX: tachycardia, cool skin, hypotension

Shock: compensatory mechanisms inadequate

SX: tachycardia, dyspnea, restlessness, diaphoresis, N/V, thirst, pallor, narrow pulse pressure, decreased mental status, hypotension, oliguria, cool clammy skin

Decompensated Shock aka End Organ Dysfunction

SX: hypotension, anuria, labored irregular breathing, thready, weak or absent peripheral pulses, ashy/cyanotic skin, decreased body temp and mental status, dilated pupils

Question 8

A patient has an infection and then develops signs and Sx of shock. What is the likely type of shock?

Answer 8

Septic

which is a kind of distributive shock

Question 9

A patient suffering from severe aortic stenosis develops signs/Sx of shock. What type of shock is likely?

Answer 9

Mechanical Cardiogenic

Question 10

A patient with the flu who has severe N/V/D for several days followed by shock Sx. Which is the likely type of shock?

Answer 10

Non-Hemorrhagic Hypovolemic

Question 11

A patient develops trouble breathing after a long flight from Kenya, and then develops Sx of shock. Which type is likely?

Answer 11

Pulmonary Vascular Obstructive Shock

(from a PE)

Question 12

What type of shock is anaphylaxis?

Answer 12

Non-septic distributive shock

Question 13

A patient has complete heart block and develops shock Sx. Which kind?

Answer 13

Arrhythmogenic Cardiogenic shock

Question 14

A patient is in a car accident and develops pericardial tamonade and Sx of shock. Which kind?

Answer 14

Mechanical Obstructive

Question 15

What is the pathophysiology of cardiogenic shock

caused by an MI as pertains to Systolic and Diastolic function?

Answer 15

Systolic:

• Decreased cardiac output and stroke volume -> hypotension -> decreased coronary perfusion -> ischemia -> progressive myocardial dysfunction -> Death
• Decreased cardiac output and stroke volume -> decreasesd systemic perfusion -> compensatory vasoconstriction -> progressive myocardial dysfunction

Diastolic:

• Increased LVEDP and pulmonary congestion -> hypoxemia -> ischemia -> progressive myocardial dysfunction -> Death

Question 16

How do you work up a patient with shock?

Answer 16

• Cover your ABCs: airway, breathing, circulation
• Determine the underlying cause (may need tests)
• Initiate life-saving maneuvers re underlying cause (Chest tube for tension pneumothorax, Epinephrine for anaphylaxis, IV antibiotics for sepsis, coronary revascularization for MI, steriods for adrenal crisis)
• Once stable do focussed Hx and PE, general and targetted lab studies, plus possible Echo and pulmonary artery catheterization for definitive Dx and Tx
  
  • Treat the cause (eg: steriods for adrenal crisis, IV ABX for sepsis)
    *

Question 17

What are some causes of cardiogenic shock?

Answer 17

Ischemia or MI

LV failure

Ventricular Septal Rupture

Papillary m or chordea t. rupture re severe mitral regurg

ventricular free wall rupture

Question 18

How to you treat cardiogenic shock?

Answer 18

• General: ventilation, IV fluids, sodium bicarb re acidosis, aspirin, IV heparin, possible glycoprotein IIb/IIIa Inhib, possible insertion of pulmonary artery catheter
• Specific:
  
  • Meds: sympathomimetic inotropes, Norepi
  • Revascularization: PCI, CABG, thrombolytics
  • Mechanical: intra-aortic balloon pump, left ventricular or biventricular assist device, percutaneous cardiopulmonary bypass

Question 19

What is the 30-day survival rate for patients with cardiogenic shock?

Answer 19

about 50%

Question 20

What are the Sx and ETX of orthostatic hypotension?

Answer 20

Sx: dizziness, blurred vision, weakness, syncope, confusion, nausea upon standing

ETX:

Acute: dehydration, prolonged bedrest, hypoglycemia, overheated, post-prandial

Chronic: heart problems (rate, valve, HF), endocrine (DM, thryroid, adrenal), regulation problems (neuro or baroreceptor)

Question 21

How do you diagnose and treat orthostatic hypotension?

Answer 21

Dx: Orthostatic blood pressure testing, blood tests re anemia, hypoglycemia, EKG/Holter, Echo re structure, ETT, Tilt Table, Valsalva maneuver

Tx: depends on cause

• Lifestyle changes: hydration, less alcohol, more salt, elevate head of bed
• Compressive stockings
• Medications: fludrocortisone, midodrine

Question 22

What is cardiogenic syncope?

Answer 22

Sudden drop in heart rate and BP causing fainting causes by cardiac arrhythmia or structural heart problem

Question 23

What are the Sx of cardiogenic syncope

Answer 23

Fainting plus possibly:

Chest tightness

SOB

Sweating

Apprehension

Palpiation

Question 24

Who is likely to get cardiogenic syncope?

Answer 24

Older patients with heart disease

Question 25

How do you diagnose and treat cardiogenic syncope?

Answer 25

Dx: EKG, Holter or Event Recorder and possible electrophysioligy testing

Tx: depends on cause:

Bradycardia: pacemaker

Tachycardia: meds, ablation, implanted defribrillator