What parameters predict hyperdynamic sepsis?

Parameters to Predict Hyperdynamic Sepsis

Hyperdynamic sepsis is predicted by a cardiac index >7.0 L/min/m² combined with systemic vascular resistance <370 dynes·s·cm⁻⁵ after adequate volume resuscitation, representing an extreme hemodynamic state with particularly poor prognosis. 1

Defining Hyperdynamic vs. Extreme Hyperdynamic States

The hemodynamic spectrum in septic shock ranges from hypodynamic to hyperdynamic states, with critical distinctions:

Moderate Hyperdynamic State (More Common)

• Cardiac index: 3.5-7.0 L/min/m² after volume expansion to adequate filling pressures 1
• Systemic vascular resistance index: ~658 dynes·s·cm⁻⁵ 1
• Stroke index: ~46 mL/m² 1
• Mortality rate approximately 35% 1

Extreme Hyperdynamic State (EHS) - Distinct High-Risk Subset

• Cardiac index: >7.0 L/min/m² despite adequate preload 1
• Systemic vascular resistance: <370 dynes·s·cm⁻⁵ (profoundly decreased) 1
• Pulmonary vascular resistance: ~52 dynes·s·cm⁻⁵ (vs. 119 in moderate hyperdynamic) 1
• Stroke index: ~67 mL/m² (significantly elevated) 1
• Mortality approaches 100% in this subset 1

Key Predictive Parameters

Hemodynamic Markers (Require Invasive Monitoring)

After volume resuscitation to adequate filling pressures:

• Cardiac index >7.0 L/min/m² is the primary defining parameter for extreme hyperdynamic sepsis 1
• Systemic vascular resistance index <370 dynes·s·cm⁻⁵ indicates excessively low peripheral resistance 1
• Stroke index >67 mL/m² despite similar right atrial pressures compared to moderate hyperdynamic patients 1
• Response to phenylephrine: In hyperdynamic sepsis, cardiac index and stroke index increase (rather than decrease) with phenylephrine-induced afterload, demonstrating preserved cardiac function despite high output 2

Metabolic Markers

Extreme hyperdynamic state is associated with:

• Lactate levels >6.5 mmol/L (vs. 2.1 mmol/L in moderate hyperdynamic sepsis) 1
• More severe metabolic acidosis 1
• More pronounced coagulation disorders 1

The elevated lactate in extreme hyperdynamic sepsis reflects severe tissue hypoperfusion despite supranormal cardiac output, indicating profound mismatch between oxygen delivery and utilization 1, 3

Clinical Predictors of Extreme Hyperdynamic State

Three major risk factors predispose to EHS:

• Underlying liver cirrhosis (present in 3 of 5 EHS patients vs. 2 of 31 moderate hyperdynamic patients) 1
• Fulminant meningococcemia 1
• Prolonged polymicrobial bacteremia before adequate treatment 1

Practical Assessment Algorithm

Step 1: Initial Clinical Recognition

Use NEWS2 score for risk stratification: 4

• Score ≥7 indicates high risk of severe illness or death from sepsis 4
• Score 5-6 indicates moderate risk 4
• Single parameter score of 3 may indicate increased sepsis risk 4

Clinical signs suggesting hyperdynamic state: 4

• Warm extremities with flash capillary refill 4
• Bounding peripheral pulses 4
• Wide pulse pressure 4
• Altered mental status despite warm perfusion 4

Step 2: Volume Resuscitation and Reassessment

Administer at least 30 mL/kg IV crystalloid within first 3 hours 4

Assess cardiac reserve with fluid challenge: 5

• Increase left ventricular preload to 12-13 mm Hg 5
• Survivors demonstrate normal cardiac response with change in left ventricular stroke work index for given increase in pulmonary capillary wedge pressure 5
• Hyperdynamic survivors show CI increase from 4.4 to 6.9 L/min/m² with volume 5

Step 3: Hemodynamic Monitoring (If Available)

Measure cardiac index and systemic vascular resistance after adequate volume resuscitation:

• CI >7.0 L/min/m² with SVR <370 dynes·s·cm⁻⁵ defines extreme hyperdynamic state 1
• CI 3.5-7.0 L/min/m² represents moderate hyperdynamic state 1
• CI <3.5 L/min/m² indicates hypodynamic shock 1

Step 4: Metabolic Assessment

Measure lactate immediately in all suspected sepsis patients: 3, 6

• Lactate ≥4 mmol/L indicates severe tissue hypoperfusion requiring immediate protocolized resuscitation 3
• Lactate >6.5 mmol/L in hyperdynamic patient suggests extreme hyperdynamic state 1
• Repeat lactate within 6 hours if initially elevated 6

Clinical Course and Prognosis

Extreme hyperdynamic state follows a characteristic pattern:

• Patients maintain extremely high cardiac index until death 1
• Death supervenes after brief episode of sinus bradycardia 1
• This clinical course is rarely observed in moderate hyperdynamic sepsis 1
• Mortality in extreme hyperdynamic state approaches 100% vs. 35% in moderate hyperdynamic sepsis 1

Critical Pitfalls to Avoid

Do not assume adequate perfusion based on warm extremities and high cardiac output alone - extreme hyperdynamic patients have profoundly elevated lactate despite supranormal cardiac indices 1

Do not delay hemodynamic assessment in high-risk patients - survivors are evaluated within 2.3 hours of sepsis onset vs. 12 hours in nonsurvivors 5

Do not interpret normal or elevated blood pressure as adequate resuscitation - blood pressure alone is inadequate marker of tissue perfusion in sepsis 3

Do not wait for hypotension to diagnose severe sepsis - tissue hypoperfusion (lactate ≥4 mmol/L) can occur with normal blood pressure 3

Recognize that underlying liver disease dramatically increases risk of extreme hyperdynamic state - 60% of EHS patients had cirrhosis 1