1. Clinical Assessment for Sepsis and Septic Shock

Early recognition of sepsis is paramount and relies on a synthesis of patient history, vital signs, physical examination, and the use of rapid screening tools. A high index of suspicion is critical, especially in patients with subtle or atypical presentations.

A. Risk Profile and History

• Infection Risk: Recent or suspected infection, presence of invasive devices (e.g., central lines, urinary catheters), and known or suspected immunosuppression.
• Comorbidities: Chronic conditions such as diabetes, chronic kidney disease (CKD), heart failure, and malignancy significantly increase risk.
• Demographics: Extremes of age (very young and elderly) and adverse social determinants of health, like limited access to care, are key risk factors.

B. Vital Signs and Physical Examination

Look for a constellation of findings, as no single sign is definitive. Trends over time are more informative than a single snapshot.

• Systemic Inflammatory Response: Temperature >38.0°C or <36.0°C; heart rate >90 bpm; respiratory rate >20 breaths/min.
• Hemodynamic Instability: Systolic blood pressure (SBP) <100 mm Hg or a mean arterial pressure (MAP) <65 mm Hg.
• Signs of Organ Hypoperfusion: Altered mental status (new confusion, lethargy), oliguria (<0.5 mL/kg/h), or cutaneous signs like mottling, cool extremities, and delayed capillary refill (>2 seconds).

C. Rapid Screening Tools

Screening tools help identify at-risk patients but do not replace clinical judgment.

• SIRS (Systemic Inflammatory Response Syndrome): Requires ≥2 criteria related to temperature, heart rate, respiratory rate, or white blood cell count. It is sensitive but highly non-specific.
• qSOFA (Quick SOFA): Uses three bedside criteria: altered mentation (GCS <15), respiratory rate ≥22, and SBP ≤100 mm Hg. A score ≥2 is specific for poor outcomes but has low sensitivity for identifying sepsis itself.
• NEWS/MEWS (National/Modified Early Warning Score): These are aggregate scores incorporating multiple vital signs, including oxygen saturation and level of consciousness. They offer a more balanced sensitivity and specificity for detecting patient deterioration.

2. Laboratory Diagnostics

Laboratory biomarkers are crucial for confirming tissue hypoperfusion, identifying organ dysfunction, guiding therapy, and monitoring the patient’s response to resuscitation efforts.

3. Microbiologic and Imaging Studies

Identifying the infectious source is a cornerstone of sepsis management. This requires prompt collection of appropriate cultures before antibiotic administration and targeted imaging to locate any focus of infection that may require source control.

A. Microbiologic Cultures

• Blood Cultures: Obtain at least two sets (one aerobic, one anaerobic bottle per set) from separate venipuncture sites before starting antibiotics. Aim for ≥20 mL of blood per set in adults to maximize diagnostic yield.
• Site-Specific Cultures: Collect samples from suspected sources (e.g., urine, sputum, wound drainage, cerebrospinal fluid) using aseptic technique to minimize contamination.

B. Imaging for Source Identification

• Chest X-Ray/CT: To identify pneumonia or pleural effusions.
• CT Abdomen/Pelvis: Essential for detecting intra-abdominal abscesses, cholecystitis, or other deep-seated collections.
• Ultrasound: A valuable bedside tool (POCUS) for rapid assessment of the heart, lungs, and abdomen, especially in hemodynamically unstable patients.
• MRI: Reserved for specific indications where it offers superior detail, such as suspected spinal epidural abscess or deep soft-tissue infections.

4. Classification and Severity Scoring Systems

Standardized definitions and scoring systems are vital for clear communication, risk stratification, and guiding the intensity of care. The Sepsis-3 consensus definitions are the current standard.

A. Sepsis-3 Definitions

• Sepsis: Defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. Operationally, this is identified by an acute increase in the total Sequential Organ Failure Assessment (SOFA) score of ≥2 points.
• Septic Shock: A subset of sepsis with profound circulatory, cellular, and metabolic abnormalities. It is clinically identified by the need for vasopressors to maintain a MAP ≥65 mm Hg AND a serum lactate >2 mmol/L, despite adequate fluid resuscitation.

B. Comparison of Scoring Systems

5. Integrating Diagnostics into Early Management

Effective sepsis care involves a systematic, time-sensitive approach that integrates diagnostic tools into a clear action plan. This process is often guided by institutional protocols and sepsis “bundles.”