Background: The aim of this post hoc analysis of a large cohort study was to evaluate the association between night-time surgery and the occurrence of intraoperative adverse events (AEs) and postoperative pulmonary complications (PPCs). Methods: LAS VEGAS (Local Assessment of Ventilatory Management During General Anesthesia for Surgery) was a prospective international 1-week study that enrolled adult patients undergoing surgical procedures with general anaesthesia and mechanical ventilation in 146 hospitals across 29 countries. Surgeries were defined as occurring during 'daytime' when induction of anaesthesia was between 8:00 AM and 7:59 PM, and as 'night-time' when induction was between 8:00 PM and 7:59 AM. Results: Of 9861 included patients, 555 (5.6%) underwent surgery during night-time. The proportion of patients who developed intraoperative AEs was higher during night-time surgery in unmatched (43.6% vs 34.1%; P<0.001) and propensity-matched analyses (43.7% vs 36.8%; P¼0.029). PPCs also occurred more often in patients who underwent night-time surgery (14% vs 10%; P¼0.004) in an unmatched cohort analysis, although not in a propensity-matched analysis (13.8% vs 11.8%; P¼0.39). In a multivariable regression model, including patient characteristics and types of surgery and anaesthesia, night-time surgery was independently associated with a higher incidence of intraoperative AEs (odds ratio: 1.44; 95% confidence interval: 1.09e1.90; P¼0.01), but not with a higher incidence of PPCs (odds ratio: 1.32; 95% confidence interval: 0.89e1.90; P¼0.15). Conclusions: Intraoperative adverse events and postoperative pulmonary complications occurred more often in patients undergoing night-time surgery. Imbalances in patients' clinical characteristics, types of surgery, and intraoperative management at night-time partially explained the higher incidence of postoperative pulmonary complications, but not the higher incidence of adverse events. Clinical trial registration: NCT01601223.

In this study we aimed to explore the effects of epidural analgesia achieved by a combination of low-dose bupivacaine and fentanyl infused through an epidural catheter on mother, foetus and labour process in nulliparous at-term pregnant women during vaginal delivery. This study was designed in a prospective, randomised controlled manner. Epidural analgesia was achieved in 50 nulliparous women. Fifty nulliparous women did not undergo epidural analgesia procedure. The duration of the first stage of labour was significantly shortened, while the second stage was significantly lengthened in pregnant women who underwent epidural analgesia (p < 0.05). In conclusion, starting epidural analgesia application during the active phase of the first stage of labour may shorten the duration of the first stage compared with the group of nulliparous women not undergoing epidural analgesia. The factor that has an impact on this may be the addition of fentanyl to bupivacaine used for epidural analgesia.