Clinical Study on the Efficacy of Subglottic Suction in Mechanically Ventilated Patients Guided by Bedside Ultrasound

Exclusion Criteria

• •1\) Severe cervical deformity, extensive subcutaneous emphysema, thick dressing coverage, or severe obesity that prevents clear visualization of the subglottic region by ultrasound.
• •2\) Coagulopathy (platelets \<50×10⁹/L) or active bleeding tendency, which may induce airway bleeding due to suctioning procedures.
• •3\) Presence of organic airway disease or previous cervical surgery history, affecting assessment of the subglottic region.
• •4\) Tracheostomy patients. 5) Patients allergic to ultrasound coupling agents, or those unable to cooperate with cervical ultrasound examination due to severe agitation.
• •6\) Patients with existing pulmonary infection upon admission. 7) Patients intubated for treatment of known aspiration. 8) History of lung cancer or head and neck cancer that may produce alpha-amylase in the lungs.
• •9\) History of conditions affecting salivary secretion (e.g., Sjögren's syndrome).