Ketamine–dexmedetomidine total intravenous anaesthesia with NIRS-guided oxygenation in an adult with cyanotic congenital heart disease undergoing craniotomy: A case report - Seham Syeda; Suneela Channabasappa Biradar; Geetha Lakshminarasimhaiah; Madhusudhana Rao (Indian Journal of Clinical Anaesthesia, 2026)