The Role of Concomitant Diseases in Postoperative Complications Risk Stratification - a Prospective Observational Multi-center Cohort Study

Advances in modern anesthesiology have significantly reduced the risk of anesthesia compared to the last century, however, the level of perioperative hospital mortality of planned operations at the moment is on average about 0.5% (ISOS group, 2016). Weiser et al. (2016) estimated that more than 313 million adults worldwide are subject to surgery each year. Thus, the number of deaths may result in several million each year worldwide. However, the study of the mortality risk is associated with certain difficulties, because over the past half century, this figure has decreased a hundred times and the study requires studies that include a large number of participants.

Current research focuses on other outcome criteria - postoperative complications. Thus, anesthetic risk often refers to the risk of postoperative complications. The frequency of these complications varies in a wide range, ranging from 3 to 18 % (Gawande AA, 1999, Kable AK, 2002, Malik OS, 2018). The differences in the data are explained by the lack of clear definitions and differences in the design of studies, but the fact that the development of postoperative complications increases the risk of death several times (ISOS group, 2016) can be considered undoubted. However, despite the importance of this issue, in modern literature there is no clear idea of what is considered a high risk and which of the patients corresponds to this category.

Understanding whether a patient is at high risk is an essential task - it allows you to obtain meaningful informed consent of the patient, as well as to understand whether to apply strategies for the prevention of complications (targeted infusion therapy, protective respiratory support, especially monitoring in the postoperative period, etc.).

Attempts at preoperative risk stratification have been made for many decades, some scales estimate the initial physical status (ASA scale) (Young J, 2015) and predict mortality, others estimate the risk of specific complications (Lee index, respiratory risk scale, etc.) .

Scales including intraoperative and postoperative parameters such as the POSSUM series of scales (Whiteley MS, 1996) are also being developed. The analysis shows that in routine clinical practice, these scales are not used very often, due to their limitations: subjectivity, technical complexity and often - low specificity and sensitivity.