The Nigerian Surgical Outcome Study is a national 30-day observational cohort study of complications after surgery. Various institutions across Nigeria will be involved. The study aims at providing detailed data describing post-operative complications, requirement for intensive care and mortality. All patients undergoing either elective surgery during a 7-day study period with a planned overnight stay will be recruited.

It is widely known that complications after surgery are responsible for a good number of morbidity and mortality following surgery. This national cohort study will help contribute to, and allow a better computation of data on post-operative complications and mortality following elective surgery in Nigeria.

This study therefore has important public health implications for Nigeria. This study will also provide a baseline for other similar studies in future being the first of such in Nigeria.

Objectives are:

1. To determine the mortality rate on the day of surgery for patients undergoing surgery in Nigeria.
2. To determine the in-hospital mortality rate for patients undergoing surgery in Nigeria.
3. To describe the relationship between anaesthetic complications and postoperative mortality.
4. To describe the relationship between postoperative complications and postoperative mortality.
5. To describe the proportional contribution of communicable, non-communicable diseases and traumatic injuries to critical care admissions and in-hospital mortality in Nigeria. We plan to recruit a minimum of 5 centres per state, made up of federal, state and private hospitals. The national coordinating centre shall be the University College Hospital, Ibadan. Regional coordinating centres shall be in Lagos, Kwara, Enugu, Kaduna, Port-Harcourt, Maiduguri and Abuja.The plan is to recruit all eligible patients during the recruitment week.

All recruited patients would have had the routine preoperative surgical and anaesthetic review. Since the study is purely observational, all basic intraoperative procedures as it relates to surgery and anaesthesia will not be altered. Following informed written consent by the patient, the following information will be obtained.

• Results of preoperative Haemoglobin, Total white cell count, and Creatinine.
• Patient's socio-demographics.
• Co-morbid conditions
• Type of anaesthesia and surgical procedure.
• Anaesthetic and Surgical details
• Critical care admission post-operatively, and
• Postoperative complications observed till discharge or up to 30 days if on admission.

Inclusion Criteria:

All consecutive patients admitted to participating centres undergoing elective surgery with a planned overnight hospital stay following surgery during a seven-day study period. The recruitment week will run between June and July 2018.

Exclusion Criteria:

Patients undergoing planned day-case surgery or procedures outside the operating theatre.

Adults or Paediatrics coming for elective surgical procedures

Data will be pseudo-anonymised by generation of a unique numeric code and transcribed by local investigators onto an internet based electronic CRF. Each patient will only be identified on the electronic CRF by their numeric code; thus the co- ordinating study team cannot trace data back to an individual patient without contact with the local team.