The 30-day serious

complication rate will be used as a third Receptor Tyrosine Kinase Signaling Pathway main outcome measure. These outcomes represent grade III and V of the internationally standardised and validated Clavien-Dindo classification16 and chiefly occur during the index stay at the hospital, minimising the risk of loss to follow-up. Although not all centres have the critical care facilities necessary to treat grade IV complications, the scale will provide a measure of the reintervention rate. These outcomes are in keeping with those recommended by WHO Safe Surgery Saves Live Measurement and Study Groups.13 The primary and secondary outcomes measures are summarised in box 2. Box 2 Study inclusion and exclusion criteria Primary outcome measure A 24 h perioperative mortality rate. This is defined as the number of deaths during operation or within 24 h of conclusion of an operation, divided by the number of operations performed

during the same time period. Secondary outcomes measures A 30-day perioperative mortality rate. This is defined as the total number of deaths within 30 days of a surgical operation divided by the total number of emergency abdominal operations performed during the same time period. A 30-day serious complication rate. These outcomes represent grades III and V of the internationally standardised and validated Clavien-Dindo classification.16 Data points In addition to the main outcome measures, data points related to the patient, surgeon, operation, hospital, operative method and postoperative period will be collected (table 1). In order to maximise completion, the minimum required data set has been designed to be brief and to test only those factors that are likely to be relevant. Descriptions of included data points are provided in online supplement 1. Data will be entered by local investigators via a secure online webpage, provided using the Research Electronic Data Capture (REDCap) system17 hosted at the University

Cilengitide of Edinburgh, Scotland. All patient data will be transmitted and held anonymously; the data will not be analysed at identifiable hospital or surgeon level. Identification of individual hospital or surgeon performance will not be reported. To test outcome variation across different contexts, explanatory variables including the 2012 Human Development Index (HDI) and Healthcare Expenditure Per Capita will be retrieved for each of the participating countries and included in statistical analysis. Table 1 Required data fields Investigators This study will be carried out by investigators from around the world that will disseminate the study protocol, collect data at hospitals, coordinate the study on national levels and finally analyse and write the manuscript.