The risk factors for silent aspiration: A retrospective case series and literature review.

What is already known on the subject Clinical signs of penetration or aspiration include coughing, throat clearing and voice changes, while silent penetration or aspiration patients aspirate without demonstrating any clinical symptoms. The most common consequences of silent aspiration include aspiration pneumonia, recurrent lower respiratory tract infections and respiratory failure. Additionally, malnutrition and dehydration can be indicators of silent aspiration. Patients may unknowingly reduce their oral intake and lose weight. Retrospective studies have shown that 20%-30% of patients aspirate silently (e.g. patients after stroke, acquired brain injury, head and neck cancer treatment, prolonged intubation). Clinical examination of swallowing can miss up to 50% of cases of silent aspiration. What this paper adds to existing knowledge Currently, silent aspiration is often discussed in neurological literature, but its applications to head and neck surgery are limited. In this study, we identify head and neck surgery patients who should be prioritised or considered to be in higher need of instrumental swallowing evaluation due to a higher risk of silent aspiration. What are the potential or actual clinical implications of this work? Post-treatment structural changes can result in lower cranial nerve paresis (IX, X, XII) and face injury, in which vagus and glossopharyngeal nerves are injured. After tracheostomy and radiotherapy, patients with problems swallowing saliva need careful clinical examination, particularly cranial nerve examination.