Sepsis Sources and Management in Intubated ICU Patients

Primary Infection Sources

• The American Thoracic Society and Infectious Diseases Society of America recommend that ventilator-associated pneumonia (VAP) is the most ubiquitous cause of fever and infection in mechanically ventilated patients, with the majority of ICU-acquired pneumonia cases occurring in this population 1
• The cumulative incidence of VAP increases with intubation duration: approximately 3% per day in the first week, 2% per day in the second week, and 1% per day thereafter, according to the Society of Critical Care Medicine 2
• The Infectious Diseases Society of America suggests that clinical diagnosis of VAP is challenging because purulent secretions are almost inevitable in patients receiving prolonged mechanical ventilation and do not specifically indicate pneumonia 2
• The American College of Chest Physicians recommends looking for new or progressive radiographic infiltrates, particularly unilateral air bronchograms which have the best predictive value, though no single radiographic finding is highly predictive 1
• Risk factors for VAP include witnessed aspiration, neurological disease, paralytic agents, nasogastric tubes, enteral feeding, and drugs that raise gastric pH, as stated by the European Respiratory Society 2
• The Centers for Disease Control and Prevention recommend that if there is evidence of tunnel infection, embolic phenomenon, vascular compromise, or septic shock, the catheter should be removed immediately and cultured 1
• The Society of Critical Care Medicine suggests examining daily for inflammation or purulence at the exit site, along the tunnel, and assessing for signs of venous thrombosis or embolic phenomena 1
• The Infectious Diseases Society of America recommends that any expressed purulence from the insertion site should be Gram stained and cultured 1
• The American College of Surgeons suggests that with short-term catheters, if catheter-related sepsis is likely, remove the suspect catheter and culture a 5-7 cm intracutaneous segment 1
• The Centers for Disease Control and Prevention recommend obtaining at least two blood cultures: one peripherally by venipuncture and one from the suspected catheter 1
• The European Society of Intensive Care Medicine states that local inflammation and frank purulence around insertion sites predict systemic infection, though marked local signs can occur without systemic infection 2
• The World Health Organization recommends that intra-abdominal infections are among the most common sites requiring source control interventions 3
• The Society of Critical Care Medicine suggests that undrainable foci such as abscesses or necrotic tissue can perpetuate bacterial seeding even with appropriate antibiotics 3
• The American College of Radiology recommends rapidly identifying the anatomical source through CT imaging within 12 hours of sepsis diagnosis 4, 3
• The Infectious Diseases Society of America suggests that intervention for source control should be undertaken within the first 12 hours when feasible 5, 4
• The American Urological Association recommends considering urinary catheters as potential sources, particularly in patients with prolonged catheterization 1
• The European Association of Urology states that two-thirds of patients with nosocomial pneumonia have at least one other focus of infection, usually urinary or catheter-related 2

Critical Diagnostic Approach

• The American College of Emergency Physicians recommends obtaining at least two sets of blood cultures before starting antimicrobials if no significant delay occurs 1, 6
• The Society of Critical Care Medicine suggests performing daily physical examination for catheter site inflammation, purulence, or signs of thrombosis 1
• The American College of Radiology recommends obtaining portable chest radiograph in erect sitting position during deep inspiration if possible 1
• The European Respiratory Society suggests considering CT imaging for posterior-inferior lung bases, which are particularly sensitive for parenchymal or pleural disease 1
• The American Thoracic Society recommends obtaining respiratory secretions via expectoration, nasopharyngeal washing, deep tracheal suctioning, or bronchoscopic sampling 1
• The Infectious Diseases Society of America suggests sending samples for Gram stain, culture, and fungal stains 1, 2
• The American College of Chest Physicians recommends that if pleural effusions larger than 10 mm are present, aspirate and send for immediate Gram and fungal stains, culture, and biochemistry 2
• The Society of Critical Care Medicine suggests culturing a 5-7 cm intracutaneous segment of short-term catheters; with longer central venous catheters, culture both the intracutaneous segment and tip 1
• The European Society of Intensive Care Medicine recommends using quantitative culture systems or differential time to positivity to diagnose catheter as the source 1

Common Pitfalls and Caveats

• The American College of Physicians states that clinical diagnosis of pneumonia using fever, leukocytosis, purulent sputum, and new infiltrates is too nonspecific in intubated patients 2
• The Society of Critical Care Medicine suggests that the absence of infiltrates on portable chest radiograph does not exclude pneumonia, abscess, or empyema 1
• The Infectious Diseases Society of America recommends that immunocompromised patients may have severe pneumonia without fever, cough, sputum production, or leukocytosis 1
• The European Respiratory Society states that between 3-12% of bacteremias in ICU patients have a respiratory tract source, but only one-quarter of VAP cases are associated with bacteremia 2
• The American College of Surgeons recommends that the most critical factor in sepsis recurrence is failure to identify and control the anatomical source within 12 hours 3
• The Society of Critical Care Medicine suggests that infected intravascular devices remaining in place serve as persistent sources of bacteremia 3
• The Infectious Diseases Society of America states that undrainable foci of infection perpetuate bacterial seeding despite appropriate antibiotics 3
• The American College of Physicians recommends that patients with prolonged ICU stays are at highest risk for multidrug-resistant organisms including MRSA, vancomycin-resistant Enterococci, and resistant gram-negative bacilli (Acinetobacter, Pseudomonas) 7, 3
• The European Society of Clinical Microbiology and Infectious Diseases suggests that recent antimicrobial exposure, prolonged hospitalization, and prior colonization with resistant organisms increase risk 7
• The Infectious Diseases Society of America recommends that empiric therapy must be broad enough to cover healthcare-associated pathogens, typically requiring broad-spectrum carbapenems or extended-range penicillin/β-lactamase inhibitor combinations 7

Prevention Strategies

• The American Thoracic Society recommends using orotracheal rather than nasotracheal intubation 8
• The European Society of Intensive Care Medicine suggests maintaining semi-recumbent positioning (30-45 degrees) unless contraindicated 8
• The American College of Chest Physicians recommends considering subglottic secretion drainage and oral chlorhexidine gluconate for oroph