Cardiology 2 - States of Shock

___ shock is caused by inadequate circulating blood/fluid volume

hypovolemic

Hemorrhage, dehydration and burns will cause ___

hypovolemic shock

___ shock is caused by peripheral vasodilation and maldistribution of blood

distributive

Sepsis and spinal cord injury will cause ___ shock

distributive

___ shock is cause by an extra-cardiac obstruction

obstructive

Pulmonary emboli and cardiac tamponade will cause ___

obstructive shock

___ shock is caused by inadequate heart pumping function

Cardiogenic

What are the three main etiologies of shock?

- vascular

- pump

- volume

In broad terms, shock is caused by ___

inadequate perfusion of tissues

Insufficient O2 demand is first compensated by ___

increased CO

If increased CO does not suffice, the amount of oxygen extracted from ___ increases

hemoglobin

Compensatory mechanism failure will lead to ___

anaerobic metabolism and lactic acidosis

What are some compensatory mechanisms the body will attempt to use before going into shock?

- arterial peripheral vasoconstriction (shunting)

- increased HR/CO

- increased O2 extraction from Hgb

- tachypnea

- venous vasoconstriction

- vasoactive hormone release

- release of ADH and RAAS activation

What are some things that happen when compensatory mechanisms fail?

- SIRS (inflammatory cytokines and free radicals)

- metabolic acidosis

- global tissue hypoperfusion

- multiorgan dysfunction syndrome

- death

What are the features of the classic presentation of shock?

- tachycardia

- ABG deficit (> 6mEq/L)

- MAP (<60)

- late manifestation systemic hypotension

What is the first acid-base abnormality in shock?

respiratory alkalosis

As organ perfusion gets progressively worse metabolic ___ develops

acidosis

Which class of hypovolemic shock is asymptomatic?

Class I (15% or 750cc)

Which class of hypovolemic shock presents with mild tachycardia?

Class II (15-30% or 750-1500cc)

Which class of hypovolemic shock presents with mild hypotension and significant tachycardia?

Class III (>30% or >1500cc)

Which class of hypovolemic shock presents with significant tachycardia and profound hypotension?

Class IV (>40% or >2000cc)

Management of hypovolemic shock?

- secure airway, stop hemorrhage, protect C-spine if appropriate

- breathing/oxygen

- control external bleeding

- fluid (blood) resuscitation

If a patient is losing blood in hypovolemic shock, ___ can increase mortality rates rather than help

crystalloids (saline)

What is the lethal triad of shock?

- hypothermia

- acidosis

- coagulopathy

Which type of shock is most commonly caused by bacteria?

Distributive (septic)

Cardiovascular changes in septic shock?

- Increased CO

- decreased LV EF

- decreased peripheral vascular resistance

- myocardial depression (free radicals and NO)

Testing ordered for distributive (septic) shock?

- CBC w/ diff

- CMP

- blood culture before abx

- CXR

- ABD X-ray

- LP

- CT (chest/abd/pelv)

Tx of septic shock?

- airway management

- hemodynamic stabilization (saline/blood/inotropes)

- abx

- remove infectious source

What are the types of distributive shock?

- septic

- neurogenic

- anaphylactic

What are some potential causes of obstructive shock?

tamponade, PE

What are two CXR findings of pulmonary embolus?

Hamptons hump & Westermark sign

Tx of PE?

- anticoagulation (heparin and warfarin, or oral anticoags)

- thrombolytics

- embolectomy, thrombolysis

- IVC filter

What are some etiologies of cardiogenic shock?

- MI

- contractility depression (sepsis, contusion)

- mechanical obstruction (AS, hypertrophy)

- LV regurg

Characteristics of hypertrophic cardiomyopathy?

- asymmterical septal hypertrophy w/ >15mm thickness

- hyper dynamic systolic function

- small LV

- reduced diastolic fxn

- LVOTO

Tx for papillary muscle rupture?

- aggressive medical therapy with vasodilators

- IABP bridge to surgery

Tx of cardiogenic shock?

- reperfusion

- thrombolytics

- IABP

- PCA (percutaneous coronary angiography)

- CABG

- inotropes (dobutamine, dopamine, norepinephrine)

- sympathomimetics (epi)

- vasopressor (phenylephrine)

___ provides selective beta 1 adrenergic antagonist effects without side effects of tachycardia

Dobutamine

Low doses of dopamine with cause ___ dilation

renal, myocardial and mesenteric artery

Doses of dopamine higher than 10mcg/kg/min will cause ___

increased BP and SVR (alpha adrenergic)

___ is indicated in acute MI and sepsis during acute episodes of hypotension

Norepi(both alpha and beta action)

___ is a potent vasoconstrictor and vascular smooth muscle relaxant

epinephrine

___ is a potent vasoconstrictor with alpha-1 action but little to no beta adrenergic properties. This drug has a rapid onset of action with short duration.

Phenylephrine