Overview of Shock

Definition
Acute, widespread process of impaired tissue perfusion
Imbalance btwn cellular oxygen supply and demand
An impaired cardiac pump, circulatory system, and/or volume can lead to compromised blood flow to tissues
Causes problems with: cellular, metabolic or hemodynamic alteration
Etiology
Hypovolemic = ↓ in circulating volume
Cardiogenic = heart not pumping enough blood to organs
Distributive
Septic = invasion of bacteria that causes misdistribution of blood
Anaphylactic
Neurogenic
Pathophysiology of Stages
Initial – ↓CO…↓ tissue perfusion
Compensatory – kicks in quickly (attempt to ↑CO…maintain BP and tissue perfusion)
Progressive – compensatory mechanisms begin to fail, body cannot meet metabolic needs
Refractory – unresponsive to tx/therapy (there’s no going back)
[Results in MODS; failure of 2 or more body systems] – Will ultimately die
Assessment and Diagnosis
Shock state
Clinical Manifestations
Global indicators – MAP 40% (>2000ml)
Medical Management
Correct cause of Hypovolemia
Restore tissue perfusion
Prevent complications
Nursing Management
Give fluids! – NS (#1 thing to give for volume)
Continuous evaluation
Strict I&O’s
Daily weights
Physical assessment

Cardiogenic Shock

Description
Failure of heart to pump effectively
Inability of ventricle to pump blood forward…↓SV…↓CO…↓ cellular O2 supply…↓ tissue perfusion
Etiology
Mechanical failure
Most common cause = MI (results in destruction of >40% of functioning myocardium)
Assessment
Decline in CO (and CI)
Chest pain
Tachycardiac
Tachypnea
Resulting in respiratory alkalosis
Then as LV fails : hear crackles and rhonchi, so…
Pulmonary edema, then
Hypoxemia
[As compensatory mechanisms fail: other s/s come  change to respiratory & metabolic acidosis, dysrhythmias, ↓LOC and renal failure]
Diagnosis
Echo confirms dx!*
Medical Management
Requires aggressive approach
Treat underlying cause
Enhance pump effectiveness & Improve tissue perfusion
Dobutamine (only affects beta-receptors) – causes heart to beat stronger & faster
If drugs don’t help
Intra-aortic balloon pump
LV assist device

Anaphylactic Shock (Distributive)

Description
Hypersensitivity reaction (Antibody-Antigen response)
[IgE mediated or non-mediated response]
Food
Bee sting
Venom
Etiology
Immunologic
Nonimmunologic
**Emergent! Requires prompt intervention!!**
Assessment and Diagnosis
Severe systemic reaction hoTn & tachycardia (almost immediately)
Pruritis
Erythema
Urticaria (hives)
Angioedema
↓LOC
↓Preload
↓CO
Biphasic reaction
Protracted anaphylaxis
Eventual outcome = circulatory failure
Medical Management
Removal of offending agent
Reverse effects of the biochemical mediators (Epinephrine)
Promote adequate tissue perfusion
Nursing Management
Volume replacement (NS)
Look @ history of allergies
Will need emergency epi kit
[Requires lots of teaching from RN]

Neurogenic Shock (Distributive)

Description
Loss or suppression of sympathetic tone
Etiology
Disruption of sympathetic nervous system
Massive peripheral vasodilation (relative Hypovolemia)
[Causes pooling of blood…↓preload, SV and CO]
Effects baroreceptors response (inhibition) resulting in bradycardia…↓tissue perfusion
[Impairs thermoregulation – body temp!!!]
#1 patient affected is SCI
Assessment and Diagnosis hoTN Bradycardia
Warm extremities (r/t vasodilation)
Medical Management
Remove cause
Prevent cardiovascular instability
Promote tissue perfusion
Nursing Management
Fluids! (observe for fluid