Table 1 Study outcomes

Primary outcome measure

Proportion of patients prescribed an antibiotic in each arm by day 28

Secondary outcome measures

Clinical outcomes

   By day 7

 Proportion of patients with clinical failure, defined as:

 • admission to hospital OR

 • death OR

 • absence of amelioration or worsening of relevant symptoms (fever and/or dyspnoea)

   By day 28

 Proportion of patients with an adverse outcome, defined as:

 • admission to hospital OR

 • death OR

complications due to LRTI (persistence of pneumonia, lung abscess, lung effusion, empyema or sepsis)

 Duration of restricted daily activities due to a respiratory tract infection

 Duration of the episode (defined by the total daily symptom score)

 Number of medical visits for the episode of LRTI

 Number of days with side effects related to antibiotics

Consultation process outcomes

 • Time spent by the patient in the practice, time required for the whole consultation

 • Patient satisfaction with diagnostic process and consultation outcome

 • Quality of the ultrasound images and of their interpretation

 • Provider adhesion, level of trust and perceived usefulness of the algorithm recommendation

 • Identification of barriers and facilitators to the implementation of UltraPro algorithm in primary care

Economic outcomes

 Cost / effectiveness ratio