Overview

Acute respiratory distress syndrome (ARDS) is characterized by acute diffuse alveolar injury caused by a variety of pulmonary and extrapulmonary factors, leading to refractory hypoxemia. It has high incidence and mortality rates. Neuromuscular blocking agents (NMBAs) play a crucial role as adjunctive therapy for ARDS, aiding in lung-protective ventilation by inhibiting excessive spontaneous breathing, improving patient-ventilator synchrony, and reducing barotrauma.

Determining the appropriate depth of muscle relaxation in moderate to severe ARDS patients receiving NMBAs remains a clinical challenge. Research has shown that partial neuromuscular blockade is feasible in certain ARDS patients. However, large randomized controlled trials (RCTs) and clinical practices often use higher doses of NMBAs to ensure complete cessation of spontaneous breathing. This indicates an ongoing debate regarding the optimal depth of neuromuscular blockade necessary for lung-protective ventilation in ARDS patients. It also raises the question of whether the optimal depth of neuromuscular blockade varies among patients with different severities of ARDS.

This study aims to investigate changes in respiratory mechanics and other physiological parameters in moderate to severe ARDS patients under different depths of neuromuscular blockade. The investigators will evaluate the impact of targeted neuromuscular blockade depth on lung protection in these patients.

Eligibility

Inclusion Criteria:

1. Patients with moderate to severe ARDS requiring the use of NMBAs, as assessed by clinicians (Berlin definition 2012: PaO2/FiO2 < 150 mmHg, PEEP ≥ 5).
2. Age: 18-85 years.
3. Signed informed consent.

Exclusion Criteria:

1. History of allergy to NMBAs.
2. Open chest or abdominal injuries.
3. Patients with pulmonary masses, lung transplantation, or lung resection.
4. Contraindications to esophageal catheter placement.
5. Pregnant patients.
6. Contraindications to TOF measurement (e.g., history of neuromuscular disease, presence of a cardiac pacemaker).
7. Severe dysfunction of other organs with an expected short-term mortality (within 7 days) or palliative care.
8. Previous inclusion in this study.