Shock Flashcards
What is shock?
inadequate tissue perfusion resulting in decreased oxygen delivery & oxygen consumption leading to cell death
What is the pathophysiology of shock?
1) inadequate perfusion
2) cell hypoxia
3) lactic acid accumulation & fall in pH -> anaerobic
metabolism
4) metabolic acidosis
5) cell membrane dysfunction & failure of sodium pump
6) intracellular lysosomes release digestive enzymes ->
efflux of potassium & influx of sodium & water
7) toxic substance enter circulation
8) capillary endothelium damaged
9) further destruction, dysfunction & cell death
What are the pro-inflammatory mediators of shock?
- IL-1 alpha & beta
- IL-2
- IL-6
- IL-8
- interferon
- TNF
- Platelet activating factor
What are the anti-inflammatory mediators of shock?
- IL-4
- IL-10
- IL-13
- Prostaglandin E2
- TGF beta
What is the main trigger of shock?
loss of blood volume
What are the types of shock?
- hypovolemic (reduced preload)
- restrictive (obstructive)
- redistributive (severe peripheral vasodilatation0
- cardiogenic
What are the causes of hemorrhagic hypovolemic shock?
HEMORRHAGIC
- traumatic vascular injury
- multiple fractures
- ruptured abdominal aortic or left ventricle aneurysm
- gastrointestinal bleeding
- aortic-enteric fistula or ruptured hematoma
- hemorrhagic pancreatitis
- postpartum hemorrhage
What are the non-hemorrhagic causes of hypovolemic shock?
- diarrhea or vomiting
- burns
- diabetes (urinating a lot)
- third space losses into extravascular space or body
What is the normal amount of blood in an average person?
80cc per kg
losing <750mL of blood will lead to what stage of hypovolemic shock?
Class I
<15%
How much blood is lost in Class II hypovolemic shock?
750-1500mL 15-30% tachycardia BP is orthostatic patient is anxious
What are the 3 vital organs?
brain
heart
kidney
What’s the normal urine output?
1mL-2mL / Kg / hour
How do we know a patient is in class III hypovolemic shock?
patient is confused tachycardia hypotension loss of 1500-2000mL of blood 30-40%
What occurs in class IV of hypovolemic shock?
loss of >2000mL of blood >40% tachycardia severe hypotension obtunded patient
What are the causes of obstructive shock?
pulmonary vascular (right ventricular failure)
- hemodynamically significant pulmonary embolism
- severe pulmonary hypertension
- severe stenosis of pulmonary or tricuspid valve
mechanical
- tension pneumothorax
- pericardial tamponade
- constrictive pericarditis & restrictive cardiomyopathy
- abdominal compartment syndrome
What is the most common cause of distributive shock?
SIRS —> septic shock (infection)
vasodilation
What are the causes of distributive (septic) shock?
- burns
- pancreatitis
- post-myocardial infarction, cardiac arrest, or coronary bypass
- viscus perforation
- fat embolism, idiopathic systemic capillary leak syndrome
What are the types of distributive shock?
- SIRS
- Septic shock
- Neurogenic shock
- Anaphylactic shock
What occurs in neurogenic shock?
- spinal injury at or above thoracolumbar sympathetic nerve roots leading to interruption of autonomic pathways
- loss of sympathetic tone to vascular system causing vasodilation
What is the cause of anaphylactic shock?
severe IgE mediated allergic reactions to insect stings, food, & drugs
What are the cardinal signs of anaphylactic shock?
bronchospasm & increased airway resistance
hemodynamic collapse
What are the types of cardiogenic shock?
- cardiomyopathic
- arrhythmic
- mechanical
What are the causes of cardiomyopathic shock?
- MI is most common
- severe right ventricular infarction
- acute heart failure with severe dilated cardiomyopathy
- myocardial depression due to advanced septic or
neurogenic shock - myocarditis
What is the cause of arrhythmic cardiogenic shock?
Atrial & ventricular tachyarrhythmias & bradyarrhytmia may induce hypotension
- when CO is severely compromised by significant rhythm disturbances, cardiogenic shock may develop
What are the causes of mechanical cardiogenic shock?
- severe aortic or mitral valve insufficiency
- acute valvular defects due to rupture of a papillary
- mitral valve defect or retrograde dissection of ascending aorta into aortic valve ring
- abscess of aortic ring
- severe ventricular septal defects
- acute rupture of intraventricular septum or ventricular free wall aneurysm
What is the presentation of ruptured ventricular aneurysm?
- cardiogenic shock
- obstructive shock
- hemorrhagic shock
What are the manifestations of shock?
- tachycardia
- tachypnea
- hypotension
- oliguria or anuria
- abnormal mental status
- cool, clammy, cyanotic skin
- weak peripheral pulses & prolonged capillary refill
- narrowing of pulse pressure <25mmHg
What is the first step in management of shocked patient?
ABC
- stabilize airway & breathing with oxygen & mechanical ventilation when necessary
- if patient has respiratory distress or hemodynamic instability -> INTUBATE
- IV access should be secured to treat with fluids to restore tissue perfusion (14 to 18 gauge catheters or intraosseous)
How should tension pneumothorax be managed?
Needle decompression using 14 or 16 gauge IV catheter followed by immediate tube thoracostomy
How should pericardial tamponade be treated?
Pericardiocentesis (should not be attempted in patients with pericardial effusion due to aortic dissection or myocardial rupture)
How should MI be treated?
- Administration of anti platelet agents & heparin
- coronary revascularization procedures (balloon angioplasty)
- intraaortic balloon pump
How should a patient presenting with hemorrhagic shock be treated?
- External hemorrhage controlled with direct pressure
- internal hemorrhage requires further diagnostic tests & surgical interventions
How should a patient presenting with anaphylactic shock be managed?
- intramuscular 0.3mg of 1:1000 epinephrine every 5 to 15 minutes as needed
- anti histamines, nebulized albuterol, & methyprednisolone
