Critically ill patients need reasonable and moderate analgesic and sedative treatment to eliminate or reduce pain, anxiety and restlessness, improve patient comfort and cooperation, reduce patients' stress response, protect organ function and optimize prognosis. As a semi-synthetic opioid receptor agonist-antagonist, nalbuphine can bind to μ, κand δ receptors, has partial antagonistic effect on μ receptor, and is fully activated on κreceptor, with very weak δ receptor activity. Results of a study on the efficacy and safety of nalbuphine for analgesia in ICU patients showed that nalbuphine has sustained and stable analgesic effect for patients with mild to moderate analgesic needs in ICU, the onset time is comparable to sufentanil, and excessive sedation caused by sufentanil can be avoided, and the effect on hemodynamics is small. It can be used as a new choice of analgesic drugs in ICU.

A single-center, randomized, single-blind, prospective study was designed to compare nalbuphine and sufentanil in patients with ARDS after surgery. Sixty patients with ARDS after surgery to be admitted to ICU were randomly divided into experimental group (Nalbuphine group) and control group (Sufentanil group). This study aims to determine the analgesic efficacy and safety of nalbuphine hydrochloride in patients with Acute Respiratory distress syndrome (ARDS) after surgery. The successful development of this study will provide more theoretical basis for the individualized analgesic sedation program for surgical patients.

Severe patients need reasonable and moderate analgesic sedation to eliminate or reduce pain, anxiety and agitation, improve comfort and cooperation, reduce stress response, protect organ function and improve prognosis. As a semi-synthetic opioid receptor agonist-antagonist, nalbuphine can bind to μ, κand δ receptors, has partial antagonistic effect on μ receptor, and is fully activated on κreceptor, with very weak δ receptor activity. Nalbuphine exerts powerful analgesic and sedative effects at the spinal cord level, with rapid analgesic effect and long duration, almost no cardiovascular adverse reactions, mild respiratory depression and capping effect, low incidence of nausea, vomiting and skin pruritus, and low addiction. Results of a study on the efficacy and safety of nalbuphine for analgesia in ICU patients showed that nalbuphine has sustained and stable analgesic effect for patients with mild to moderate analgesic needs in ICU, the onset time is comparable to sufentanil, and excessive sedation caused by sufentanil can be avoided, and the effect on hemodynamics is small. It can be used as a new choice of analgesic drugs in ICU. Moreover, nalbuphine theoretically has no σ-receptor excitability, is not hallucinogenic, and the chance of inducing delirium is lower. Studies have shown that nalbuphine can reduce postoperative inflammation and oxidative stress and has a lung protective effect.

This study aims to determine the analgesic efficacy and safety of nalbuphine hydrochloride in patients with Acute Respiratory distress syndrome (ARDS) after surgery, and to explore the effects of nalbuphine hydrochloride on respiratory function, gastrointestinal function and cognitive function. To provide more theoretical basis for individualized analgesic and sedation program for surgical patients. Sixty patients were included and randomly divided into 1:1 groups, with 30 patients in each group. All patients were included according to strict inclusion criteria.

The experimental group was given nalbuphine analgesia and the control group was given sufentanil analgesia. The number of patients reaching the target level of analgesia and sedation at each time node, invasive mechanical ventilation time, oxygenation index change, mortality and other indicators were compared between the two groups.

Inclusion Criteria:

• Had undergone surgical treatment within 7 days before enrollment;
• Meet the diagnostic criteria for ARDS proposed at the 2011 Berlin ARDS Definition Conference;
• Age ≥18 years old, gender unlimited;
• Patients admitted to ICU with CPOT score ≥3;
• Stay in ICU ≥48h;
• Sign the informed consent form.

Exclusion Criteria:

• APACHE II score ≥23 points;
• Patients with esophageal reflux disease and severe gastrointestinal injury have AGI score ≥3;
• Long-term use of narcotic analgesics, hypnotics and psychotropic drugs;
• Alcohol withdrawal symptoms;
• Severe liver dysfunction (Child-Pugh grade C);
• Patients with bronchial asthma and myasthenia gravis;
• Patients with severe craniocerebral injury, brain tumor, and increased intracranial pressure are prone to respiratory depression;
• Patients undergoing cardiac surgery under cardiopulmonary bypass;
• Patients who have been enrolled in other clinical trials;
• Study patients with drug allergy or other contraindications;
• Pregnant or lactating women;
• The patient himself or his legally authorized representative is unwilling to sign the informed consent;