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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.