Pneumonia is a significant global and national health issue, particularly posing a notable threat to elderly population. Accumulation of sputum in pneumonia patients often results in impaired airway clearance, negatively impacting disease management and recovery. Clinically, nebulization therapy is widely employed to facilitate sputum clearance; however, evidence regarding the comparative effectiveness of different nebulized solution concentrations remains limited and inconsistent. Therefore, this study aims to evaluate and compare the clinical effects of nebulized solutions with various osmotic concentrations (3% hypertonic saline, 0.9% normal saline, 0.45% hypotonic saline, and distilled water) on airway clearance in patients with pneumonia. A randomized, double-blind controlled trial design will be used, recruiting 80 patients with pneumonia from a regional teaching hospital in northern Taiwan. Participants will be randomly assigned into four groups, receiving nebulized therapy four times daily over a period of seven days. This study outcome including the length of hospital stay, venous blood gas analysis, routine sputum examination, and arterial oxygen content. The findings of this the study are anticipated to provide evidence-based recommendations for the clinical application of nebulized solutions with different concentrations, aiming to enhance airway clearance efficiency, improve clinical care outcomes for pneumonia patients, and serve as a practical reference for healthcare professionals.

Inclusion Criteria:

1. Diagnosed with pneumonia, defined by ICD-10 codes, including:

   J18: Pneumonia, unspecified organism J180: Bronchopneumonia, unspecified organism J181: Lobar pneumonia, unspecified organism J182: Hypostatic pneumonia, unspecified organism J188: Other pneumonia, unspecified organism J189: Pneumonia, unspecified organism

2. Aged 18-100 years

3. Clinical respiratory score > 3

4. Patients unable to expectorate sputum spontaneously and requiring assisted suctioning

Exclusion Criteria:

1. Diagnosis of influenza-associated pneumonia, defined by ICD-10 codes, including:

   J09X1: Influenza due to identified novel influenza A virus with pneumonia J1001: Influenza due to other identified influenza virus with the same identified influenza viral pneumonia J100: Influenza due to other identified influenza virus with pneumonia

2. Diagnosis of COVID-19 infection, defined by ICD-10 code:

   U07.1: COVID-19, virus identified

3. History of chronic obstructive pulmonary disease (COPD) (ICD-10 code: J44)

4. History of lung cancer or metastatic cancer involving the lungs

5. Current use of bronchodilators

6. Patients requiring oral suctioning only

7. Oxygen therapy with a flow rate > 10 L/min

8. Clinical respiratory score > 8 (Table 2)