Different Methods of Aerosolized Polymyxin B Inhalation for Treating Carbapenem-Resistant Gram-Negative Bacterial Pneumonia.

Condition(s) studied

Investigational drug(s) / intervention(s)

Polymyxin B Sulfate 25mg Jet Nebulization / Vibrating Mesh Nebulization: * Group A: 25mg polymyxin B sulfate dissolved in 5ml sterile water, administered via jet nebulizer under mechanical ventilation. * Group B: 25mg polymyxin B sulfate dissolved in 5ml sterile water, administered via vibrating mesh nebulizer under mechanical ventilation.

Study summary

Study Design:

A randomized, open-label, parallel-group clinical trial comparing the efficacy and safety of jet nebulization versus vibrating mesh nebulization of sulfate polymyxin B in mechanically ventilated patients with carbapenem-resistant Gram-negative bacterial pneumonia.

Participants:

144 patients (72 per group) will be enrolled from December 2023 to December 2025.

Interventions:

Group A: 25mg polymyxin B + 5ml sterile water via jet nebulizer (respirator-assisted).

Group B: 25mg polymyxin B + 5ml sterile water via vibrating mesh nebulizer (respirator-assisted).

Both groups receive additional intravenous polymyxin B (2.0mg/kg loading dose, followed by 1.25mg/kg every 12h) starting 12h after nebulization.

Treatment duration: 14 days.

Key Procedures:

Nebulization parameters: Fixed ventilator settings (SIMV+PSV mode, tidal volume 8ml/kg, PEEP 6cmH₂O).

Bronchoalveolar lavage (BAL) and blood sampling:

BAL fluid (BALF) and blood collected pre-nebulization (baseline), 1h post-nebulization, and at steady-state (days 3-7).

BALF analyzed for polymyxin B concentration, urea nitrogen, and inflammatory mediators (IL-6, TNF-α, etc.).

Primary Outcomes:

Clinical efficacy:

Total response rate (cure + improvement). 28-day survival rate. Time to fever resolution and bacterial clearance.

Drug exposure:

Polymyxin B concentration in alveolar epithelial lining fluid (ELF) and blood.

Secondary Outcomes:

Inflammatory response: Changes in BALF and serum IL-6, TNF-α, CRP levels.

Safety:

Nephrotoxicity (changes in serum creatinine/urea nitrogen). Airway complications (bronchospasm incidence).

Assessment Timeline:

Clinical monitoring: Daily evaluation of vital signs, sputum volume, and ventilator parameters.

Lab tests: Blood tests (hematology, renal function, inflammatory markers) at baseline, days 3/7/14.

Microbiological evaluation: Sputum cultures on days 3/7/14.

Statistical Analysis:

Efficacy and safety endpoints compared between groups using t-tests or chi-square tests.

A p-value \<0.05 will be considered statistically significant.

Eligibility

Primary outcome measure(s)

• Clinical efficacy — Baseline (pre-treatment); End of Treatment (EOT, 14 days after starting polymyxin B)
  Percentage of patients with cure or improvement based on symptom resolution, microbiological clearance, and radiographic findings.

Trial sites (1)

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