Please help! what is the risk factors of ventilator associated pneumonia?

Risk factors...: Ventilator-associated pneumonia risk factors include the presence of oral bacteria, gastroesophageal reflux, interruption of the ventilator circuit, meds that decrease stomach acidity, prolonged oral/nasal intubation, etc. Various measures are taken to prevent this including weaning from mechanical ventilation as quickly as possible, keeping the head of the bed raised, good oral hygiene, etc.