Advanced Ultrasound in Pleural Infection (AUDIO)

Pleural infection is a potentially serious infection of the fluid normally found around the lung and current evidence suggests its incidence is increasing in both adult and paediatric populations. Identification of bacterial pathogens causing pleural infection is of paramount importance in the clinical care of patients are currently, only 40% of patients have a laboratory confirmed microbiological diagnosis for their pleural infection. An unclear diagnosis can be due to various reasons such as a small sample volume therefore the aim of the AUDIO study is to ascertain the capacity of pleural biopsies in improving the microbiological yield of pleural infection. Currently, there are no well validated methods for identifying patients presenting with pleural infection on the basis of initial ultrasound imaging. The AUDIO study will define the role of baseline thoracic ultrasound in predicting the radiographic, clinical and surgical outcomes of patients with pleural infection. The AUDIO study aims to recruit 50 patients from 2 centres with specific pleural expertise and these patients will be followed up over a 12 month period. Investigators hope that through the information gathered from ultrasound imaging and pleural biopsies, it will aid physicians' clinical and therapeutic decision making when treating patients with pleural infection.

6 - 8 pleural biopsy samples will be taken before the insertion of the chest drain. These samples will be sent to microbiology for examination.

Positive microbiological results on pleural biopsy at baseline compared with positive microbiological results on pleural fluid.

Radiographic improvement in area of pleural collection measured by the percentage of the ipsilateral hemithorax occupied by effusion on chest radiography.

Inclusion Criteria: A clinical presentation compatible with pleural infection A pleural fluid collection that may or (rarely according to clinical judgement) may not require drainage that meets at least one or more of the following criteria: Purulent Gram stain positive for bacteria Bacterial culture positive Acidic with a pH <7.2 Low pleural fluid glucose <3mmol/L (<55mg/dL) CT evidence of pleural infection (consolidation of underlying lung with enhancing pleural collection on contrast-enhanced CT) Exclusion Criteria: Age <18 years No pleural fluid available for analysis Previous pneumonectomy on the side of pleural infection Expected survival <3 months due to co-morbid disease Inability to give informed consent.