Week 5: Shock

Shock Definition

• life-threatening condition that results in adequate tissue perfusion

  • affects all body systems

What happens when tissues are not adequately oxygenated?

• cell dysfunction

• cell death

Why is shock highly unpredictable?

• can be slow or rapid onset

What is Multiple Organ Dysfunction Syndrome?

• altered dysfunction of 2 or more organs

• medical interventions are required to support organ function

• may result in death

When does Multiple Organ Dysfunction Syndrome (MODS) occur?

• if shock isn’t treated

Types of Shock

1. Hypovolemic

2. Cardiogenic

3. Obstructive

4. Distributive

ALL shock types result in

• hypoperfusion of tissue

• stimulation of the sympathetic nervous system

  • ↑ HR, ↑ RR, "fight-or-flight" response

Compensatory Stage of Shock: Cardiovascular + Circulation

• BP remains WNL

• vasoconstriction → ↑ HR maintains CO

• RR ↑ to remove CO2 to compensate for metabolic acidosis

Compensatory Stage of Shock: Other Effects

• "fight or flight” response

• bowel sounds = may be hypoactive

• urine output ↓

Compensatory Stage: Nursing Management

• Identify “warning” signs/symptoms

• Identify and treat underlying causes

• IV fluids and/or supplemental oxygen might be needed

• Frequent vital signs, GCS, measure lactic acid, urine output

• Clarify advanced directives

• Ensure patient safety - reorient patient, frequent rounding, fall precautions

Progressive Stage of Shock

• SBP: less than 100mgHG or 40mmHg decrease from baseline

• declining mental status

• rapid, shallow respirations

• ↑ HR: dysrhythmias and cardiac ischemia might occur

• abnormal clotting might occur

• risk for stress ulcer/GI bleeding

Progressive Stage of Shock: Nursing Managment

• Require ICU level nursing care

• Treatment varies by shock type

• Support airway/ventilation

• Continuous ECG monitoring and often invasive monitoring (arterial line, CVP)

• Might require advanced treatments (dialysis, mechanical ventilation, intra-aortic balloon pump etc.)

Irreversible Stage of Shock

• patient does not respond to treatment

• worsening acidosis

• multiple organs begin to fail

Irreversible Stage of Shock: Nursing Management

• initially similar to progressive stage

• might qualify for experimental interventions

• comfort measures

• engage with palliative care services

• support for patient’s family

Hypovolemic Shock

• due to loss of intravascular volume

• reduced by 15-30%

• can be related to external fluid loss, blood loss, or internal fluid shifts

External: Fluid Losses

• trauma

• surgery

• hemorrhage

• vomiting

• diarrhea

Internal: Fluid Shifts

• burns

• ascites (excess fluid inside the peritoneal cavity)

• peritonitis (inner wall of your abdomen)

• dehydration

• necrotizing pancreatitis

Hypovolemic Shock: Treatment

• treat underlying cause

  • stop bleeding, stop fluid loss, etc

• fluid and/or blood replacement

  • 2 or more large bore peripheral IVs

  • and/or large bore central venous access

  • non-hemorrhagic: 0.9%NS or LR

  • hemorrhagic shock: might given 1L crystalloids then switch to a massive transfusion protocol

• passive leg raise test (PLR)

Crystalloids

• have an osmolarity similar to plasma; they expand the extracellular space without causing fluid shifts into or out of cells

• 0.9% NS or LR

Hypovolemic Shock: Continued Treatment

• monitor for effectiveness of treatment and complications of tretament

  • (fluid overload, transfusion reactions, etc)

Passive Leg Raise Test (PLR)

• Raising the legs shifts approximately 300 to 450 mL of venous blood from the lower extremities to central central venous compartment

• temporary volume shift acts as an "internal fluid bolus" without actually giving fluid, avoiding the risks of fluid overload

• tests to see if they will benefit from IV fluids

Passive Leg Raise Position

• 45-degree semi-recumbent position (head and upper body elevated)

  • gives baseline

• lay the patient flat, elevating the lower extremities passively to 45 degrees

Cardiogenic Shock

• occurs when the heart is unable to effectively contract and pump blood

• can be coronary and noncoronary in etiology

  • coronary → e.g. MI

  • noncoronary → e.g. arrhythmia, valvular disease, cardiomyopathies

Cardiogenic Shock Patho

↓ cardiac contractility → ↓ stroke volume and CO → pulmonary congestion, ↓ systemic tissue perfusion, ↓ coronary artery perfusion

↓ coronary artery perfusion

• goes back to ↓ cardiac contractility

Cardiogenic Shock: Treatment

• treat underlying cause

  • correct dysrhythmia, IABP therapy, percutaneous coronary intervention

  • cautious use of IV fluids

• inotropes (dobutamine, dopamine)

• vasodilators (nitro)

• neurovascular checks if IABP in place

How does inotropes help cardiogenic shock?

• increasing the force of the heart's muscle contractions

• which raises cardiac output

• restores blood flow to vital organs

What is Distributive Shock?

• occurs when intravascular volume pools in peripheral blood vessels

Types of Distributive Shock

1. Septic Shock

2. Neurogenic Shock

3. Anaphylactic Shock

Septic Shock Risk Factors

• chronic illness

• emergent and multiple surgeries

• extremes of age

• immunosuppression

• invasive procedures

• malnourishment

Neurogenic Shock Risk Factors

• depressant action of medications

• lack of glucose (ex. insulin reaction)

• spinal anesthesia

• spinal cord injury

Anaphylactic Shock Risk Factors

• food allergies

• history of medication insensitivity

• history of reaction to insect bites/stings

• latex sensitivity

• transfusion reaction

Distributive Shock Progression

1. precipitating event

2. vasodilation

3. activation of inflammatory response

4. maldistribution of intravascular volume

5. decreased venous return

6. decreased cardiac output

7. decreased tissue perfusion

Septic Shock Care

• early recognition

• measure lactate

• obtain blood cultures prior to antibiotics

• rapid administration of crystalloids for HoTN

• vasopressors if HoTN during or after IVF bolus

• antibiotics (3 hours ED, 1 hour inpatient)

Neurogenic Shock

• loss of balance between parasympathetic and sympathetic nervous systems

• presents with HoTN ↓ HR

Neurogenic Shock Care

• treat underlying cause

  • (stabilize spinal cord injury)

• IV crystalloids and vasopressors

Anaphylactic Shock: Severe Allergic Reaction

• IgE mediated response

• Antigen-antibody reaction → provokes mast cells to release potent vasoactive substances

  • histamine, bradykinin, cytokines

• results in widespread vasodilation and capillary permeability

Anaphylactic Shock: Common Triggers

• foods (peanuts)

• medications

• insect stings

Anaphylactic Shock: Defining Characteristics

• acute onset

• 2 or more symtpoms that include:

  • respiratory compromise

  • reduced BP

  • GI distress

  • skin/mucosal irritation

• cardiovascular compromise mins - hrs after exposure to antigen

Anaphylactic Shock: Care

• rapid administration of IM epinephrine

  • after epi. admin. must go to ED for 4 hours of observation for “rebound reaction”

• antihistamines and corticosteroids

• bronchodilators (if needed)

• IV crystalloids

• ensure patent airway

Obstructive Shock

• shock secondary to a physical obstruction that prevents blood from flowing into or out of the heart

  • PE

  • tension pneumothorax

  • cardiac tamponade

  • severe vena cava syndrome

• must quickly treat underlying cause to remove the physical obstruction