Study of Xuanbai Shengmai Decoction in the Treatment of Acute Respiratory Distress Syndrome

Mortality was calculated on day 28 of treatment.

Clinical scores were assessed before treatment, on day 3 of treatment, and on day 7 of treatment.

Serum IL-6 levels (pg/mL) are measured at baseline, Day 3, and Day 7 as a marker of systemic inflammatory response.

The concentration of angiopoietin-2 in peripheral blood (pg/mL) will be measured at baseline (pre-treatment), Day 3, and Day 7 of treatment, as a biomarker of pulmonary vascular permeability.

Arterial blood gas samples will be collected at baseline (pre-treatment), Day 3, and Day 7 of treatment to determine the ratio of arterial partial pressure of oxygen (PaO₂) to the fraction of inspired oxygen (FiO₂), which will be used to assess the patient's oxygenation status.

The ventilator-set tidal volume (in mL) will be recorded directly from the ventilator interface at baseline (pre-treatment), Day 3, and Day 7 of treatment.

Duration of mechanical ventilation within 28 days

Time of staying in ICU within 28 days

Throat swabs, fecal samples (10g), and peripheral blood (3mL) will be collected at baseline, day 3, and day 7 of treatment. Multiplex PCR will be performed to detect the nucleic acid load of target pathogens, with the unit of copies/mL, to evaluate changes in infection burden.

Assessed using the full APACHE Ⅱ scale at baseline (pre-treatment), Day 3, and Day 7 of treatment. The scale consists of three components: acute physiology score, age score, and chronic health evaluation score, with a total score ranging from 0 to 71. Higher scores indicate greater severity of illness and higher risk of mortality.

Assessed using the full Sequential Organ Failure Assessment scale at baseline (pre-treatment), day 3, and day 7 of treatment. The score evaluates the function of six organ systems: respiratory, coagulation, hepatic, cardiovascular, neurological, and renal, with a total range of 0-24. Higher scores indicate more severe organ dysfunction and a worse prognosis.

Static lung compliance ( mL/cmH₂O) will be calculated via the ventilator monitoring platform under constant tidal volume and plateau pressure conditions at baseline (pre-treatment), Day 3, and Day 7 of treatment, to assess respiratory mechanics function.

Peripheral blood samples will be collected at baseline (pre-treatment), Day 3, and Day 7 of treatment to measure serum sRAGE levels (pg/mL), which serves as a biomarker of pulmonary epithelial injury.

Lung ventilation distribution will be monitored by EIT at baseline (pre-treatment), Day 3, and Day 7 of treatment to assess lung injury-related indicators including lung collapse, overdistension, and ventilation inhomogeneity.

The pressure support level provided by the ventilator (in cmH₂O) will be recorded directly from the ventilator interface at baseline (pre-treatment), Day 3, and Day 7 of treatment.

The positive airway pressure maintained at the end of expiration (in cmH₂O) will be recorded directly from the ventilator interface at baseline (pre-treatment), Day 3, and Day 7 of treatment.

The fraction of inspired oxygen set on the ventilator (in %) will be recorded directly from the ventilator interface at baseline (pre-treatment), Day 3, and Day 7 of treatment.

The number and distribution of B-lines are assessed and scored by lung ultrasound at baseline (pre-treatment), Day 3, and Day 7 of treatment. A higher number and more diffuse distribution of B-lines indicate more severe pulmonary edema. This score is used to evaluate pulmonary vascular permeability and the severity of pulmonary edema.

Serum TNF-α levels (pg/mL) are measured at baseline, Day 3, and Day 7 as a marker of systemic inflammatory response.

Serum CRP levels (mg/L) are measured at baseline, Day 3, and Day 7 as a marker of systemic inflammatory response.

Serum PCT levels (ng/mL) are measured at baseline, Day 3, and Day 7 as a marker of systemic inflammatory response.

Fecal samples (10g) will be collected at baseline, day 3, and day 7 of treatment. 16S rRNA high-throughput sequencing will be performed to analyze gut microbiota alpha diversity (Shannon index, unitless) to evaluate changes in intestinal microecological homeostasis.

Peripheral blood (3mL) will be collected at baseline, day 3, and day 7 of treatment. Untargeted metabolomics will be performed to detect the concentration of target serum metabolites, with the unit of μmol/L, to evaluate changes in the body's metabolic status.