What are aspiration and aspiration pneumonia in the Cardiovascular Intensive Care Unit (CVICU), their signs and symptoms, treatment, and relevant CVICU tips?

Aspiration and Aspiration Pneumonia in CVICU: Signs, Symptoms, Treatment, and Tips

Aspiration is a common event in CVICU patients that can lead to aspiration pneumonia, significantly increasing morbidity and mortality. Prompt recognition, appropriate treatment, and preventive measures are essential to improve patient outcomes. 1

Definitions and Pathophysiology

• Aspiration refers to the inhalation of oropharyngeal or gastric contents into the lower respiratory tract 1, 2
• Aspiration pneumonitis is a chemical injury resulting from aspiration of sterile gastric contents, causing inflammation without infection 3
• Aspiration pneumonia is an infectious process resulting from aspiration of colonized oropharyngeal contents 2, 4

Risk Factors in CVICU

• Decreased level of consciousness (post-cardiac surgery, sedation) 1
• Impaired swallowing or gag reflex 2
• Presence of endotracheal tubes or tracheostomy 5
• Supine positioning 5
• Enteral feeding, especially with gastric distention 5, 1
• Reintubation 5
• Prolonged mechanical ventilation 5, 6

Signs and Symptoms

• New or worsening hypoxemia 7
• New infiltrates on chest radiography 1, 7
• Increased respiratory secretions, often purulent 1
• Fever and leukocytosis 7
• Increased work of breathing 5
• Auscultatory findings (crackles, rhonchi) 7
• Deterioration in hemodynamic parameters in CVICU patients 1

Diagnosis

• Clinical suspicion based on risk factors and symptoms 1
• Chest radiography showing new infiltrates, typically in dependent lung segments 1, 7
• Arterial blood gas analysis showing hypoxemia 7, 8
• Gram stain and culture of lower respiratory tract samples 1
• Consider Clinical Pulmonary Infection Score (CPIS) for assessment 1
• CT scan may be needed in equivocal cases 1

Prevention Strategies

Positioning and Airway Management

• Maintain patients in semi-recumbent position (30-45° head elevation), especially during enteral feeding 5, 1
• Use orotracheal rather than nasotracheal intubation 5, 1, 6
• Maintain endotracheal tube cuff pressure >20 cm H₂O to prevent leakage 5, 1
• Consider endotracheal tubes with subglottic secretion drainage capability 5, 1
• Avoid reintubation whenever possible 5, 1

Ventilation Strategies

• Use noninvasive ventilation when appropriate 5, 1
• Implement weaning protocols to reduce duration of mechanical ventilation 5, 1
• Minimize sedation through protocol-guided administration and daily interruption 5, 1
• Change ventilator circuits only for each new patient or when soiled 5
• Carefully empty condensate from ventilator circuits 5

Enteral Feeding Management

• Verify appropriate placement of feeding tubes before initiating feeds 1
• Consider post-pyloric feeding in high-risk patients 5
• Avoid gastric overdistention during enteral feeding 1
• Monitor gastric residual volumes 1

Treatment Approach

Aspiration Pneumonitis

• Provide supportive care with oxygen therapy 7, 8
• Implement aggressive pulmonary care to enhance lung volume and clear secretions 3
• Selective intubation for severe cases 8, 3
• Avoid prophylactic antibiotics 1, 3
• Avoid corticosteroids (not indicated) 3

Aspiration Pneumonia

• Initiate prompt empiric antibiotic therapy when aspiration pneumonia is suspected 1, 7
• Base antibiotic selection on:
  • Time of onset (early vs. late) 1
  • Risk factors for multidrug-resistant pathogens 1, 7
  • Local pathogen epidemiology and resistance patterns 1, 9
• For community-acquired aspiration pneumonia: amoxicillin/clavulanic acid or other regimens covering oral anaerobes 7, 9
• For hospital-acquired aspiration pneumonia: broader coverage including Pseudomonas aeruginosa and other gram-negative bacilli 1, 7
• De-escalate antibiotics based on culture results and clinical response 1, 7
• Treat for 7 days if good clinical response and no complications 1, 7

Special Considerations in CVICU

• Maintain glycemic control as hyperglycemia increases aspiration risk 1
• Consider the impact of blood transfusions on pneumonia risk 1
• Monitor for ventilator-associated pneumonia in intubated patients 5
• Ensure adequate staffing levels to implement preventive measures 5

Common Pitfalls to Avoid

• Failing to distinguish between aspiration pneumonitis (non-infectious) and aspiration pneumonia (infectious) 1, 2
• Treating aspiration pneumonitis with antibiotics (not indicated) 1, 3
• Delaying appropriate antibiotic therapy for true aspiration pneumonia 1
• Failing to de-escalate antibiotics once culture results are available 1, 7
• Using prolonged courses of antibiotics when shorter durations would be sufficient 1, 7
• Neglecting to maintain head elevation at 30-45° 1
• Overlooking the importance of oral care in preventing aspiration pneumonia 1, 6