Preoperative oral caffeine as prophylaxis against post-spinal hypotension in patients undergoing orthopedic lower limb surgery: A randomized, placebo-controlled, double-blinded study. - Antar SS; Metaweh A; Neamatallah H; Abdelfattah M; Abdelbaser I; Awad KA (Anaesthesia, critical care & pain medicine, 2025)