shock

Instructor Information

• Mark Malesker, Pharm.D., FCCP, FCCM, FASHP, BCPS
  Professor of Pharmacy Practice and Medicine
  Creighton University

Course Information

• Course Title: Hemodynamic Monitoring and Shock
• Course Code: PHA 416
• Semester: Spring 2026

Learning Objectives

• Define shock and recognize the four common categories of shock.
• Recognize the basic principles of hemodynamic monitoring.
• Compare and contrast the pharmacologic profiles of vasopressors and inotropes.

Course Outline

• Clinical manifestations of shock
• Classification of shock
• Types of vascular access devices
• Hemodynamic basics
• Specific treatments of shock
  • Vasopressors
  • Inotropes
  • Angiotensin II
  • Methylene blue

Recommended Reading

• Textbook: Pharmacotherapy: A Pathophysiologic Approach, 13e
  • Chapter e45 Circulatory Shock

Shock Overview

• Definition: Physiologic state characterized by reduced systemic tissue perfusion.
• Consequences: Decreased tissue oxygen (O2) delivery leading to cellular hypoxia and biochemical dysfunction.
• Pathophysiological Progression:
  • Cell injury/death → End-organ damage → Multiple organ dysfunction syndrome → Death
• ICU Relevance: Shock is common in Intensive Care Units (ICU) and associated with significant mortality rates.

Clinical Manifestations of Shock

• Classic Findings:
  • “Low” Blood Pressure
  • Tachycardia
  • Cool, clammy skin
  • Warm, flushed skin (in distributive shock)
  • Altered mental status
  • Oliguria
  • Metabolic acidosis

Hypotension in Shock

• Hypotension Criteria:
  • Mean Arterial Pressure (MAP) < 70 mm Hg
  • Systolic Blood Pressure (SBP) < 90 mm Hg or acute reduction of 40 mm Hg from baseline.
• Relative Nature of Hypotension:
  • BP of 100/50 may be abnormal in a hypertensive patient (baseline 160/80)
  • BP of 80/40 may be normal in patients with conditions like CHF or cirrhosis.
• MAP Calculation: ext{MAP} = rac{(2 imes ext{DBP}) + ext{SBP}}{3}

Clinical Parameters in Shock

• Possible Evaluations and Monitoring:
  • Encephalopathy
  • Tachy- or bradycardia
  • Ventricular ectopy
  • Myocardial ischemia/generation
  • Acute respiratory failure
  • Acute respiratory distress syndrome
  • Acute renal failure
  • Gut ischemia
  • Erosive gastritis, pancreatitis
  • Thrombocytopenia
  • Altered glycemic states: hyper/hypoglycemia

Physiologic Determinants of Shock

• Blood Pressure Equation:
  $ext{BP} = ext{CO} imes ext{SVR}$
• Expanded form: $ext{BP} = ( ext{HR} imes ext{SV}) imes ext{SVR}$
  • Where:
  • BP = blood pressure
  • CO = cardiac output
  • SVR = systemic vascular resistance
  • HR = heart rate
  • SV = stroke volume

Approach to Shock

• When low blood pressure is observed, assess:
  • Heart rate too fast/slow (pump issue)
  • Stroke volume is low (fluid issue)
  • Systemic vascular resistance is low (container issue)

Classification of Shock

• Categories:
  • Cardiogenic shock
  • Hypovolemic shock
  • Obstructive shock
  • Distributive shock
• Note: More than one type of shock may be present simultaneously.

Major Types of Shock

• Distribution of Shock Types (Statistics):
  • Distributive shock (septic) - 62%
  • Cardiogenic shock - 16%
  • Hypovolemic shock - 16%
  • Obstructive shock - 4%
  • Distributive (nonseptic) - 2%

Characteristics of Different Shock Types

Extracardiac Obstructive Shock

• Etiology:
  • Decreased diastolic filling caused by afterload or obstruction (e.g., tension pneumothorax, pericardial tamponade).

Cardiogenic Shock

• Physiological Foundation:
  • Causes include myocardial infarction, arrhythmias, etc.
• Significance of BP:
  $ext{BP} = ext{CO} imes ext{SVR}$

Hypovolemic Shock

• Etiology:
  • Resulting from significant internal or external fluid loss.
• Low cardiac index

Distributive Shock

• Characterized by peripheral vasodilation, resulting in hypotension despite normal or sometimes increased cardiac output (high CI).

Vascular Access Devices

Types of Vascular Access Devices

• Peripheral IV Catheter:
  • Used for short-term access
• Midline Catheter:
  • Longer catheter, providing access for weeks
• Central Venous Catheter (CVC):
  • Access to the central venous system
• PICC (Peripherally Inserted Central Catheter):
  • Inserted into the upper arm
• Arterial Catheter:
  • Used for blood pressure monitoring and blood gas sampling

Key Information on IV and Flow Rates

• IV Catheter Sizes:
  • Orange (14G) - 240 mL/min
  • Gray (16G) - 180 mL/min
  • Green (18G) - 90 mL/min
  • Pink (20G) - 60 mL/min
  • Blue (22G) - 36 mL/min
  • Yellow (24G) - 20 mL/min
  • Violet (26G) - 13 mL/min

Hemodynamic Monitoring

Definition of Hemodynamic Monitoring

• Measurement of pressure, flow, and oxygenation within the cardiovascular system to evaluate:
  • Vascular capacity
  • Blood volume
  • Pump effectiveness
  • Tissue perfusion

Types of Hemodynamic Monitoring

• Non-invasive assessment
• Direct measurement of arterial pressure
• Invasive hemodynamic monitoring

Initial Steps in Managing Shock

• Clinical Monitoring:
  • Signs: tachycardia, peripheral hypoperfusion, hypotension, etc.
• Laboratory Monitoring:
  • Hemoglobin, white blood cells, electrolytes, lactic acid, and others as listed.
• Imaging/Monitoring Techniques:
  • Continuous ECG, arterial line, imaging methods, etc.

Normal Hemodynamic Parameters

• Standard Values:
  • SBP: 90-140 mm Hg
  • DBP: 60-90 mm Hg
  • MAP: 70-100 mm Hg
  • HR: 60-100 beats/min
  • CO: 4-7 L/min
  • CI: 2.8-3.6 L/min/m²
  • EF: 50-70%

Response Assessment in Shock

Stable Hemodynamic Profile Measurements

1. MAP Target: > 65 mm Hg
2. PCWP (Pulmonary Capillary Wedge Pressure): 15-18 mm Hg
3. CI (Cardiac Index): > 2.1 L/min/m² for cardiogenic or obstructive shock.
4. CI Targets for Septic/Hemorrhagic Shock: > 4.0-4.5.

Management of Shock

Strategies of Resuscitation in Shock

• The VIP Rule:
  • V: Ventilate
  • I: Infuse (fluid resuscitation)
  • P: Pump (administration of vasoactive agents)

Phases of Treatment of Shock

1. Salvage Phase: Establish a minimum acceptable BP, and perform lifesaving measures.
2. Optimization Phase: Improve oxygen availability while minimizing complications.
3. Stabilization Phase: Provide organ support.
4. De-escalation Phase: Gradually wean from vasoactive agents.

Cardiogenic Shock

• Severe reduction in cardiac function (pump failure) due to myocardial issues.

Treatment Options:

• Rate/rhythm control
• Mechanical assist devices
• Coronary revascularization
• Surgical valvular repair
• Use of venoarterial ECMO
• Vasopressors and inotropes with MAP > 60 mm Hg and CI > 2.2 L/min/m².

Hypovolemic Shock

• Treatment:
  • Fluid replenishment and transfusions are essential.
  • Hemorrhagic shock management involves addressing the source of bleeding aggressively.

Obstructive Shock

Characteristics:

• Caused by obstruction of flow in the circulatory system leading to inadequate filling.

Treatments include:

• Thrombolytic therapy for PE
• Needle thoracostomy for tension pneumothorax
• Pericardiocentesis or surgery for cardiac tamponade.

Distributive Shock

• Associated with vasodilation and often linked to sepsis or anaphylaxis.

Treatments:

• Fluids and vasopressors are foundational treatments.

Vasoactive Agents Overview

Types of Vasopressors:

• Categories:
  • Norepinephrine, epinephrine, dopamine, phenylephrine, angiotensin II, dobutamine, etc.

Characteristics:

• Each agent has distinct mechanisms and effects on blood pressure and cardiac output.
  • Norepinephrine: Alpha and beta-1 agonist effects; first-line for septic shock (starting at 0.1-2.0 mcg/kg/min).
  • Epinephrine: Used for anaphylaxis and severe shock.
  • Dopamine: Variable effects and used at different doses depending on desired outcome.

Angiotensin II (Giapreza)

• Noncatecholamine vasopressor; increased BP through vasoconstriction.
• Dosing: 20 ng/kg/min with titration protocols for continued infusion.

Methylene Blue

• Treatment for refractory vasoplegic shock; it acts by inhibiting excessive nitric oxide signaling.
• Side effects may include hypertension and other complications.

Patient Case Studies

1. Case of Anaphylaxis after Antibiotic Change:

   • Type of Shock: Anaphylactic Shock
   • Recommended Treatment: Immediate epinephrine administration.

2. Gunshot Victim:

   • Type of Shock: Hypovolemic Shock due to hemorrhage.
   • Recommended Treatment: Volume resuscitation and surgical intervention.

3. Chest Pain with ST Elevation:

   • Type of Shock: Cardiogenic Shock
   • Recommended Treatment: Emergency revascularization and supportive measures.

Summary of Shock

• Definition: A state of cellular and tissue hypoxia from inadequate oxygen delivery or utilization.
• Stages:
  • 1: Pre-shock
  • 2: Shock
  • 3: End-organ dysfunction
• Management Overview:
  • Administer appropriate IV fluids; maintain hemodynamics and treat underlying etiologies such as hemorrhage or sepsis.