Hairui Liu, Shan Hu, Lianqin Zhang, Zihao Zhang
BACKGROUND We aimed to compare postoperative oxygenation and dorsal lung ventilation between supine and prone positions in patients undergoing craniotomy and to provide clinical evidence for lung-protective ventilation strategies. MATERIAL AND METHODS Eighty-four patients scheduled for elective craniotomy under general anesthesia were assigned to supine (S group) or prone (P group) according to different positions required for surgery (observational, non-randomized). All received volume-controlled ventilation with tidal volume set at 7 mL/kg predicted body weight, I: E=1: 2, and respiratory rate adjusted to maintain PetCO₂ at 30-40 mm Hg. The decline in oxygenation index (ΔPaO₂/FiO₂) was calculated 24 hours after extubation. Dorsal lung ventilation proportion (ROI34) was measured before anesthesia (T1), after intubation (T2), before extubation (T3), 10 min after extubation (T4), and 24 hours after extubation (T5). Lung ultrasound score (LUS) was assessed at T1, T4, and T5. RESULTS ΔPaO₂/FiO₂ was significantly higher in the S group than P group (45.5 [34.7-58.0] vs 36.8 [30.5-40.8] mm Hg, P<0.05). Compared with P group, ROI34 was lower in the S group at T3 (26.2%±9.2% vs 30.7%±9.8%, P<0.05) and T4 (41.5%±12.4% vs 48.5%±11.4%, P<0.05). At T5, total LUS (4.0 [3.0-5.0] vs 2.0 [1.0-3.0], P<0.05) and posterior LUS (3.0 [3.0-4.0] vs 1.0 [0.0-1.0], P<0.05) were significantly higher in the S than P group. CONCLUSIONS General anesthesia with mechanical ventilation reduced postoperative oxygenation and dorsal lung ventilation in patients undergoing craniotomy, most notably in supine patients at 24 hours. Ventilation strategies should be individualized according to surgical position, with enhanced lung-protective strategies for supine patients.