Path chap 6 prep + case studies

Chapter 6 Summary

• Perfusion: Defined as the delivery of oxygen and nutrients to cells, organs, and tissues through the circulatory system.

  • Hypoperfusion: Occurs when tissue perfusion decreases below normal.

  • The body activates compensatory mechanisms in response to hypoperfusion, but severe disease or injury can overwhelm these mechanisms, leading to deterioration.

  • Catecholamines (e.g., epinephrine, norepinephrine) are released during hypoperfusion, causing:

    • Vasoconstriction (increased systemic vascular resistance).

    • Activation of the peripheral renin-angiotensin-aldosterone system and antidiuretic hormoneleading to:

      • Salt and water retention.

      • Increased peripheral vasoconstriction.

  • Results in increased blood pressure and cardiac output.

  • Normal compensatory responses include increases in preload, stroke volume, and heart rate, which typically enhance cardiac output.

  • Insufficient compensatory mechanisms worsen myocardial function, leading to decreased cardiac output and ejection fraction.

• Shock: An abnormal state characterized by inadequate delivery of oxygen and nutrients to cellular metabolism.

  • Can arise from issues in either central circulation (heart and great vessels) or peripheral circulation(remaining vessels).

  • Types of shock:

    • Central Shock:

      • Cardiogenic Shock: Heart's inability to pump sufficient blood.

      • Obstructive Shock: Blockage of blood flow in heart or vessels.

    • Peripheral Shock:

      • Hypovolemic Shock: Insufficient circulating blood volume.

      • Distributive Shock: Widespread dilation of small arterioles and venules.

  • Characterized by reduced cardiac output, circulatory insufficiency, rapid heartbeat, and pallor. Treatment focuses on underlying conditions.

• Multiple Organ Dysfunction Syndrome (MODS):

  • A progressive condition marked by failure of multiple organs (lungs, liver, kidneys) after severe illness or injury.

  • Triggered by injury or infection (e.g., septic shock), leading to systemic immune, inflammatory, and coagulation responses.

  • Release of inflammatory mediators via complement, coagulation, and kallikrein/kinin systems.

  • As MODS progresses, organ systems exhibit dysfunction; renal failure and myocardial depression may occur.

  • Failure to remediate the underlying cause generally leads to patient death.

Vital Vocabulary

• Angioedema: Sudden, recurrent areas of subcutaneous edema, often related to allergies, especially in young women.

• Capacitance Vessels: Small venules involved in blood volume control.

• Cardiogenic Shock: Condition from loss of 40% or more myocardium; insufficient blood circulation for oxygen delivery.

• Central Shock: Shock due to central pump failure (cardiogenic + obstructive).

• Distributive Shock: Widespread dilation of resistance vessels, impacting blood delivery.

• Endogenous Hypovolemic Shock: Fluid loss contained internally, like in anaphylactic shock.

• Exogenous Hypovolemic Shock: External fluid or blood loss.

• Hypoperfusion: When tissue perfusion drops below levels needed for normal cell function.

• Hypovolemic Shock: Inadequate blood volume to supply oxygen and nutrients.

• Multiple Organ Dysfunction Syndrome (MODS): Progressive organ failure following severe illness or injury.

• Obstructive Shock: Blockage of blood flow in the heart or vessels.

• Perfusion: Delivery of oxygen and nutrients through circulation.

• Peripheral Shock: Shock from peripheral circulatory abnormalities (hypovolemic + distributive).

• Primary MODS: MODS results from an immediate insult (e.g., pulmonary contusion).

• Resistance Vessels: Small arterioles regulating peripheral vascular resistance.

• Secondary MODS: Organ dysfunction as part of the immune response.

• Shock: Abnormal state with inadequate metabolic oxygen and nutrient delivery.

• Urticaria: Raised skin areas (hives), potential symptom of anaphylaxis.

Case Study Overview

Incident Description:

• Dispatch to a motor vehicle collision on a high-speed road.

• Traffic light recently installed; multiple collisions reported.

Case Study Part 1 Scene Assessment:

• Two vehicles identified with significant front-end damage.

• One individual trapped undergoing extrication by the fire department.

Patient Overview:

• Older male (~75 years old).

• Symptoms: Disoriented, pale, difficulty breathing, chest pain.

• High-priority for rapid extrication and transport.

Initial Assessment:

• Time Recorded: 0 minutes

• Vital Signs:

  • Pulse: 100 beats/min, regular, strong.

  • Blood Pressure: 110/50 mm Hg.

  • Respiratory Rate: 24 breaths/min, labored.

  • Appearance: Disoriented, alert only to verbal stimuli.

  • Airway: Open.

• Questions:

  • Signs of shock?: Yes, confusion, pale skin, high pulse rate, labored breathing.

  • Type of shock?: Suspected hypovolemic shock due to trauma.

  • What happens during tissue hypoperfusion?: Compensatory mechanisms activate to maintain blood pressure and perfusion.

Case Study Part 2 Patient Management:

• Cervical collar applied; rapid extrication performed.

• Extra driver assigned for ambulance transport (15 minutes to trauma center).

In-Transit Assessment:

• Remove clothing: conducted for rapid assessment.

• Breathing: Labored, decreased breath sounds (right side).

• Circulation: Pale, moist skin; rapid, weak distal pulse.

• Tenderness noted:

  • Chest (right side)

  • Abdomen lower quadrants

  • Unstable pelvis.

• Extremities appear uninjured.

Vital Signs Post-Assessment:

• Pulse: 110 beats/min, regular, weak.

• Blood Pressure: 100/48 mm Hg.

• Respiratory Rate: 30 breaths/min, shallow and labored.

Diagnostic Tools:

• ECG: Sinus tachycardia.

• SpO2: 93%.

• Blood glucose: 140 mg/dL.

• Questions:

  • Outcome of persistent hypoperfusion?: Further organ dysfunction and deterioration.

  • Treatment goals?: Rapidly transport for surgery, manage blood loss and maintain airway.

Case Study Part 3 Critical Moment:

• Patient loses consciousness 5 minutes from trauma center.

• Prepares for intubation; partner reassesses vitals.

Ongoing Assessment:

• Mental Status: Unresponsive.

• Airway: Intubated for breathing support.

• Circulation: Pale, weak pulse.

• Vital Signs:

  • Pulse: 110 beats/min, regular, weak.

  • Blood Pressure: 80/40 mm Hg (after 1.5 L saline).

  • Respiratory Rate: Good breath sounds with bagging.

Diagnostic Tools:

• ECG: Sinus tachycardia.

• SpO2: 95%.

• Questions:

  • Definition of MODS?: Yes, patient likely experiences it due to multiple failing organ systems.

  • Patient's Age & Deterioration?: Increased age likely contributed due to diminished physiological reserve.

Case Study Part 4 Outcome:

• Patient enters cardiac arrest en route to operating suite.

• 20 minutes of aggressive resuscitation efforts yield no response.

• Injuries Identified:

  • Right lung injury.

  • Fractured ribs.

  • Lacerated liver.

  • Unstable pelvis.

  • Significant blood loss.