Title: Unanticipated admissions following day case gynaecological surgery - a retrospective audit.

Background and aims: 
Effective pre-operative preparation and protocol-driven admission and discharge procedures are fundamental to safe and effective day case surgery. The incidence of unanticipated admission following day case procedures has been reported between 0.3%-9.5%.The KK Women's and Children's Hospital is a tertiary centre for Obstetrics and Gynaecology in Singapore that performs around 5000 day case procedures annually. We conducted a retrospective audit to identify the risk factors for unanticipated admission following day case surgery.
Methods: 
This is a retrospective audit with the data gathered from the "unanticipated admission audit forms" of all the patients with unanticipated admission following day surgery in the period, 2 January to 31 December, 2015 at our institution.
Results and discussion: 
A total of 4079 day case procedures were performed during the study period, of which 118 unanticipated admissions occurred, giving an incidence of 2.89%. Among the admissions, high body mass index (BMI) accounted for 42 cases (35.59%) followed by anaesthesia-related causes (n=33; 27.97%), medical causes (n=31, 26.27%) and procedure-related causes (n=10; 8.47%).Most of the admissions for high BMI were decided preoperatively after anaesthetic review. The main reason for admission under this category is the perceived risk of obstructive sleep apnoea and requirement for postoperative respiratory monitoring.Pain is the most important reason among the anaesthesia-related admissions, related to prolonged surgery. Use of multiple doses of opioid-based analgesia and subsequent drowsiness resulted in the need for admission. Thirty-one admissions were classified under medical causes. Most of the medical admissions were secondary to poor control of pre-existing comorbidities. These admissions could have been avoided had patients been referred to the preanaesthesia assessment clinic before the procedure. 
Conclusions: 
There is a need to review and reinforce patient selection criteria for daysurgery, with regard to BMI cut-off, adequacy of medical optimisation and anticipated duration of surgery. Multimodal analgesia, using local anaesthetic techniques and non-opioid based protocols, is recommended to enhance effectiveness and safety.

Unanticipated admissions following day case gynaecological surgery – a retrospective audit