Peripheral Perfusion Index in Acute Surgical Patients

Introduction Perioperative haemodynamic instability is associated with postoperative morbidity and mortality. Macrocirculatory parameters, such as the conventionally obtained mean arterial blood pressure and cardiac output, may be uncoupled from the microcirculation during sepsis and severe blood loss and may not necessarily be optimal resuscitation parameters. The peripheral perfusion index (PPI) is derived from the pulse oximetry signal and reflects perfusion. Reduced peripheral perfusion is associated with morbidity in critically ill patients and in patients following acute surgery. We hypothesize that patients with low intraoperative PPI demonstrate high frequency of postoperative complications and mortality regardless of blood pressure. Methods and analysis We plan to conduct a prospective observational cohort study in patients undergoing acute non-cardiac surgery (November 1st, 2017 to October 31st, 2018) at two University Hospitals. Data will be collected prospectively from patient records including patient demographics, comorbidity and intraoperative hemodynamic values, with PPI as the primary exposure variable, and postoperative complications and mortality within 30 and 90 days as outcome variables. We primarily assess association between PPI and outcome in multivariate regression models. Secondly, the predictive value of PPI for outcome, using area under the receiver operating characteristics curve is assessed. Ethics and dissemination Data will be reported according to The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE). Results will be published in a peer reviewed journal. The study is approved by the regional research ethics committee, storage and management of data has been approved by the Regional Data Protection Agency, and access to medical records is approved by the hospital board of directors at the involved hospitals and departments.