Excessive endotracheal tube cuff pressure can cause mucosal ischaemia leading to tracheal stenosis or tracheooesophageal fistulae 1).

1)
Stauffer JL, Olson DE, Petty TL. Complications and consequences of endotracheal intubation and tracheotomy. A prospective study of 150 critically ill adult patients. Am J Med. 1981 Jan;70(1):65-76. PubMed PMID: 7457492.