Perioperative risk factors and outcomes

Sammanfattning: Perioperative complications is an increasing issue worldwide, as surgical volume continues to grow. Myocardial and kidney injury, and myocardial infarction (MI), are known complications in non-cardiac surgery. Hemodynamic instability during anaesthesia and surgery, the association with perioperative complications, and optimal blood pressure threshold in the perioperative period, have been topics of increasing interest since this thesis idea was formed. The thesis aim is to increase our knowledge of perioperative organ injury and to understand its aetiology: to evaluate the relation between preoperative risk factors – comorbid burden – and intraoperative risk factors, with a special focus on intraoperative hemodynamic variability. All studies are observational by design and epidemiologically approached. Regional and national registers, and medical records, are used in the data collection. Study I is a descriptive, registry-based, cohort study of more than 400 000 operated adult patientes in 22 Swedish hospitals between 2007 and 2014. Study II and III are cohort studies enrolling adult patients undergoing major non-cardiac surgery att the Karolinska University Hospital, 2012 to 2013 and 2015 to 2016. Study IV use a case-control study design, nested within the cohort collected in study I. In summary, this thesis illuminates how comorbid patients, undergoing major non-cardiac surgical procedures, are at increased risk of perioperative cardiac and kidney morbidity. Development of myocardial or kidney injury, or clinically significant MI in the perioperative period is associated with short- and longterm mortality. This elderly, high-risk surgical population should be targeted to improve perioperative outcomes. Intraoperative hypotension is associated with myocardial and kidney injury and is a major contributor to clinically significant perioperative MI. The high absolute risk of MI development associated with intraoperative hypotension, among a growing population of patients with a high risk-burden, suggests that increased vigilance of blood pressure control in these patients is beneficial