Pleural Effusion Case 2

John is a 45-year-old male who attends the ED with a 5-day history of productive cough, fever, mild shortness of breath and right pleuritic chest pain. He had thoracic surgery following a road traffic accident 20 years ago. His observations are as follows:

• Blood pressure 126/76 mmHg
• Pulse 96bpm
• Respiratory rate of 24
• Oxygen saturations 94% on room air
• Temperature 37.9°C

His ECG is normal. His chest radiograph is shown on the right. Click the image to see a larger version.

With regards to the nature of the aspirate in this case, choose the options that are most likely to be true:

Which of the following factors are indications for therapeutic chest drainage in cases of para-pneumonic effusion?