Objective To systematically evaluate the effects of different durations of nil per os (NPO) on perioperative electrolyte balance, acid-base balance, blood glucose changes, intraoperative circulatory stability, and postoperative recovery in patients undergoing gynecologic laparoscopic surgery, so as to provide clinical evidence for optimizing perioperative management.

Methods A retrospective cohort study was conducted. Patients who underwent elective gynecologic laparoscopic surgery at Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, from March to August 2025 were included. According to NPO duration, the patients were divided into three groups: the NPO ＜ 14 h group (n = 90), the NPO 14-20 h group (n = 145), and the NPO ＞ 20 h group (n = 27). General patient data, intraoperative conditions, arterial blood gas analysis indicators, incidence of electrolyte disorders, and postoperative recovery indicators were collected, and differences among the groups were compared.

Results A total of 262 patients undergoing gynecologic laparoscopic surgery were included. Upon entry to the operating room, the incidence of hypokalemia was 80.53%, hypocalcemia 41.60%, and hyponatremia 24.81%, with no statistically significant differences among the three groups (all P ＞ 0.05). Before leaving the operating room, the incidence of hypokalemia (46.56% vs. 80.53%) and hyponatremia (23.66% vs. 24.81%) decreased compared with that upon entry, whereas hypocalcemia did not improve. With prolonged NPO duration, pH value, base excess, hemoglobin, and hematocrit upon operating room entry showed decreasing trends (all P ＜ 0.05). The incidence of metabolic acidosis differed significantly among the three groups (P = 0.035). Intraoperative urine output decreased with prolonged NPO duration (P = 0.011), while there were no statistically significant differences in the incidence of intraoperative hypotension, use of vasoactive drugs, or postoperative C-reactive protein levels among the groups (all P ＞ 0.05). Time to first out-of-bed activity, time to first flatus, and postoperative length of stay differed significantly among the three groups (all P ＜ 0.05).

Conclusions Under a preoperative fluid supplementation strategy, prolonged NPO duration did not further aggravate electrolyte disorders upon operating room entry. However, the risk of metabolic acidosis increased with prolonged NPO duration, especially in patients with NPO duration exceeding 20 h. Reduced intraoperative urine output suggested that prolonged fasting may affect renal perfusion. When the fasting regimen recommended by enhanced recovery after surgery (ERAS) cannot be implemented, preoperative electrolyte supplementation should be strengthened, the risk of acid-base imbalance should be closely monitored, and intraoperative monitoring of renal perfusion should be enhanced to promote postoperative recovery.