15 - Shock

Circulatory Shock

Generalized hypoperfusion that fails to deliver sufficient O2 to tissues

Circulatory Shock Diagnosis

- MAP: <70 mmHg

- Cold and Clammy

- Decreased Urination

- Elevated Lactate levels

What are the 4 types of Shock?

- Hypovolemic

- Cardiogenic

- Obstructive

- Distributive

Hypovolemic Shock

Loss of Blood Volume

Hypovolemic Shock can be caused by ____ or ____.

hemorrhaging/dehydration

Symptoms of Hypovolemic Shock

- Increased Respiration

- Increased HR

- Low Temp.

- Low BP

- Cool Skin

Cardiogenic Shock

Inadequate functioning of the Heart

Causes of Cardiogenic Shock

Anything that interferes with Heart Function

ie. Myocardial Infarction or Arrythmias

Cardiogenic Shock has similar symptoms to Hypovolemic Shock, but is characterized by ____.

Chest Pain

Obstructive Shock

Impaired Cardiac filling via physical obstruction

What are the two most common causes of Obstructive Shock?

- Cardiac Tamponade

- Tension Pneumothorax

Cardiac Tamponade

Accumulation of fluid in the Pericardium, decreasing ventricular filling

Obstructive Shock has similar symptoms to Hypovolemic Shock, but is characterized by ____ and ____.

distension of Jugular Veins/weak Radial Pulse

Distributive Shock

Abnormal distribution of Blood Volume due to widespread peripheral vasodilation

What is the most prevalent form of Shock?

Distributive

What are the three types of Distributive Shock?

- Anaphylactic

- Septic

- Neurogenic

Anaphylactic Shock

Drastic Histamine release that causes widespread vasodilation

Typically severe allergy

Anaphylactic Shock has similar symptoms to Hypovolemic Shock, but is characterized by ____ and ____.

Airway Narrowing/Facial Edema

Septic Shock

Bacterial endotoxins and Cytokine Storm cause widespread vasodilation

Septic Shock has similar symptoms to Hypovolemic Shock, but is characterized by ____ and ____.

Fever/Warm Skin

Who is at increased risk of Septic Shock?

- Immunocompromised Patients

- Burn Patients

- GI Injury Patients

- Meningitis Patients

Neurogenic Shock

Loss of sympathetic ability to vasoconstrict in the periphery due to a traumatic injury in the CNS

Neurogenic Shock has similar symptoms to Hypovolemic Shock, but is characterized by ____.

Warm Skin

Lack of SNS Vasoconstriction

What are the 4 stages of Shock?

- Initial

- Compensatory

- Decompensatory

- Refractory

Initial Stage of Shock

Reduction in perfusion decreases O2 delivery; Metabolic requirements of cells are not met

In the Initial Stage of Shock, the body switches from ____ metabolism to ____ metabolism.

Aerobic/Anaerobic

Hence, Lactate accumulation

Compensatory Stage of Shock

Reversible Cellular Injury

In the Compensatory Stage of Shock, the SNS is activated to release ____ and increase ____.

Catecholamines/Cardiac Contractility

The body attempts to regain control during the Compensatory Stage of Shock by increasing ____ release as well.

Aldosterone

RAAS - Increased Blood Volume, Peripheral Vasoconstriction

What reflex causes the body to respond to Shock?

The Baroreceptor Reflex

Chemoreceptors within the periphery (Carotid Sinus & Aortic Arch) sense ____, ____, and decreased ____ during Shock.

[CO2]/[H+]/[O2]

Peripheral Chemoreceptors signal to the Medulla to increase ____ and ____.

Respiration/CO

Central Chemoreceptors sense decreased ____ and signal to the Medulla to increase Respiration and CO.

pH

What happens to the Capillary Beds during the Compensatory Stage?

Hydrostatic Pressure within the Capillaries decreases; Filtration is decreased in an attempt to increase Blood Volume

Decompensatory Stage of Shock

Progressive Cellular Injury marked by...

- Electrolyte Imbalance

- Metabolic Acidosis

- Respiratory Acidosis

- Hypotension

- Noticeable Symptoms like Cool and Clammy Skin

Acidosis

pH below 7.35

What 3 effects does Acidosis have on the body during Shock?

- Reduced sensitivity to circulating Catecholamines (Decreased SVR)

- Depressed Myocardial Function and impaired responsiveness to SNS (Decreased CO)

- Relaxation of Arterioles (Capillary Damage)

In the Decompensatory Stage of Shock, the SNS and RAAS have been stimulating vasoconstriction for a prolonged amount of time. What happens to the body during prolonged vasoconstriction?

- Disruption of Intestinal Barrier

- Systemic Inflammation due to Bacterial products and endotoxins

- Decreased Renal Blood Flow

Decreased circulating volume leads to increased ____ within the Capillaries.

Blood Viscosity

Increases risk of Clot formation and Damage

Blood Flow to the ____ and ____ is decreased during the Compensatory Stage of Shock.

Brain/Heart

Reduced function of Control Centers (SNS and Reflexes)

Refractory Stage of Shock

Irreversible Cellular Injury (Organ Failure & Death)

During the Refractory Stage of Shock, organ damage has occurred ____.

everywhere