This is a stepped-wedge, cluster-randomized, two-arm, open-label, clinical trial of an electronic clinical decision support tool (eCDST) for the diagnosis and treatment of lower respiratory tract infection (LRTI) among patients at three sites in Southern Province, Sri Lanka.

The primary objective of this trial is to determine the impact of an electronic clinical decision support tool (eCDST) on clinical outcomes and antibacterial prescription in subjects with LRTI in the intervention group compared to the control group.

The study will enroll 765 patients ≥ 14 years of age. Medical wards will be randomized in clusters to the intervention at intervals of 3-6 months until all clusters cross over. Participants will be followed for 30 days from enrollment to record clinical outcomes and any antimicrobials prescribed (a maximum of 14 days).

Inclusion Criteria:

1. Admitted within prior 48 hours

2. Have evidence of new acute respiratory illness (<14 days of symptoms), as indicated by at least one of the following:

   1. New cough or sputum production
   2. Chest pain
   3. Dyspnea or tachypnea (respiratory rate >20 breaths/minute)
   4. Abnormal lung examination

3. Have evidence of acute infection, as indicated by at least one of the following:

   1. Self-reported fever or chills
   2. Documented fever ≥38 ̊ C (100.4 ̊ F)
   3. Documented hypothermia <35.5 ̊ C (95.9 ̊ F)
   4. Leukocytosis (white blood cell count >10,000/mm3)
   5. Leukopenia (white blood cell count <3000/mm3)
   6. New altered mental status

4. Ability and willingness of patient, parent or legally authorized representative (LAR) to give informed consent

5. Ability of children 14-17 years of age to provide assent

6. Ability to complete follow-up encounter at 30 days in person or by telephone

Exclusion Criteria:

1. Hospitalized recently (within last 28 days)

2. If they have been enrolled into this clinical trial previously

3. Surgery in the past 7 days

4. If they are unable or unwilling to complete the follow-up encounter

5. If they will likely be transferred from the medical wards within 24 hours of enrollment (to another ward or to another hospital)

6. If they have underlying conditions or circumstances for which physicians would be unlikely to withhold antibacterials:

   1. Vasopressor therapy
   2. Cystic fibrosis
   3. Known severe immunosuppression (i. Cancer or another condition with neutropenia (absolute neutrophil count <1000/ microL; ii. Solid- organ or hematopoietic stem-cell transplant within the previous 90 days; iii. Active graft-versus-host disease or bronchiolitis obliterans; iv. On chronic steroids equivalent to prednisone 20mg daily for ≥ 2 weeks or other targeted cytotoxic or biologic immunosuppressants within the prior 4 weeks; v. Human immunodeficiency virus infection with a CD4 cell count <200/mm3)
   4. Have an accompanying non-respiratory infection
   5. Have evidence of a lung abscess or empyema
   6. Have respiratory failure at enrollment, evidenced by use of non-invasive or invasive ventilation