How to manage ARDS secondary to pneumonia?

From the Guidelines

Management of ARDS secondary to pneumonia requires a multifaceted approach centered on lung-protective ventilation strategies, as recommended by the most recent guidelines 1. Implement low tidal volume ventilation at 6 ml/kg of predicted body weight with plateau pressures maintained below 30 cmH2O to prevent ventilator-induced lung injury, as supported by the 2017 guideline 1 and the 2016 Surviving Sepsis Campaign guidelines 1. Some key points to consider in the management of ARDS secondary to pneumonia include:

• Use of PEEP titration starting at 8-10 cmH2O and adjust based on oxygenation response, typically ranging from 10-20 cmH2O, with a suggestion to use higher PEEP without lung recruitment maneuvers in patients with moderate to severe ARDS 1.
• Prone positioning for 16+ hours daily is recommended for patients with PaO2/FiO2 ratios below 150 mmHg, as recommended by the 2016 Surviving Sepsis Campaign guidelines 1.
• Treatment of the underlying pneumonia with appropriate antibiotics, such as ceftriaxone and azithromycin for community-acquired pneumonia, as guided by culture results and clinical judgment.
• Conservative fluid management to minimize pulmonary edema while maintaining adequate perfusion, with consideration of the FACTT protocol and FACTT-lite protocol for fluid management in ARDS patients 1.
• Consideration of neuromuscular blockade with cisatracurium for the first 48 hours in severe cases with P/F ratios below 120 mmHg, as suggested by the 2024 guideline 1.
• Consideration of rescue therapies like inhaled nitric oxide or ECMO for refractory hypoxemia, as recommended by the 2024 guideline 1. These interventions work together to improve gas exchange, reduce inflammatory damage, and support recovery while the underlying pneumonia resolves with appropriate antimicrobial therapy.

From the FDA Drug Label

In a randomized, double-blind, parallel, multicenter study, 385 patients with adult respiratory distress syndrome (ARDS) associated with pneumonia (46%), surgery (33%), multiple trauma (26%), aspiration (23%), pulmonary contusion (18%), and other causes, with PaO2/FiO2 <250 mm Hg despite optimal oxygenation and ventilation, received placebo (n=193) or INOmax (n=192), 5 ppm, for 4 hours to 28 days or until weaned because of improvements in oxygenation. Despite acute improvements in oxygenation, there was no effect of INOmax on the primary endpoint of days alive and off ventilator support. INOmax is not indicated for use in ARDS.

The management of ARDS secondary to pneumonia is not directly supported by the use of nitric oxide (INH), as stated in the drug label. The study showed no effect of INOmax on the primary endpoint of days alive and off ventilator support in patients with ARDS, including those associated with pneumonia 2.

From the Research

Management of ARDS Secondary to Pneumonia

To manage ARDS secondary to pneumonia, several strategies can be employed:

• Lung Protective Ventilation: This approach focuses on using lower tidal volumes and maintaining plateau pressures at or below 30 cm H2O to minimize lung injury 3.
• Fluid Management: Conservative fluid management is recommended to avoid fluid overload, which can exacerbate lung injury 4.
• Diagnosis and Treatment of Pulmonary Infections: Accurate diagnosis of pneumonia is crucial, and techniques such as protected specimen brushing and bronchoalveolar lavage can help establish the diagnosis 5.
• Prone Positioning: While prone positioning can improve oxygenation, its impact on the incidence of ventilator-associated pneumonia (VAP) is unclear, and it may not reduce the incidence of VAP in ARDS patients 6.
• Inhaled Nitric Oxide: Inhaled nitric oxide may improve oxygenation in ARDS patients, but its effectiveness in reducing mortality is unclear 3, 7.
• Antibiotic Therapy: Broad-spectrum antibiotics may be harmful if used empirically in mechanically ventilated patients without pneumonia, and their use should be guided by diagnostic testing 5.

Ventilator-Associated Pneumonia

Ventilator-associated pneumonia (VAP) is a common complication in ARDS patients and is associated with increased mortality:

• Diagnosis: VAP can be diagnosed using quantitative cultures of bronchoalveolar lavage fluid or tracheal aspirate 6.
• Incidence: The incidence of VAP in ARDS patients can be high, with one study reporting a cumulative probability of VAP at 90 days of 46.5% in the prone group and 33.5% in the supine group 6.
• Mortality: VAP is associated with increased mortality in ARDS patients, with a hazard ratio of 1.65 (1.05-2.61) in one study 6.