DANS study - diabetic autonomic neuropathy in patients undergoing surgery

Diabetes mellitus (DM) is associated with a two- to threefold increase in perioperative cardiovascular morbidity and mortality, compared to patients without DM. In addition to well-known complications of DM, diabetic autonomic neuropathy may contribute to the perioperative cardiovascular morbidity and mortality. Cardiovascular autonomic neuropathy (CAN) is one of the most serious forms of diabetic autonomic neuropathy. Patients with CAN are at increased risk of perioperative hemodynamic instability, cardiopulmonary arrest, (postoperative) silent myocardial infarction and postoperative mortality.
There are different tests to determine CAN. Ewing’s battery of tests are simple, inexpensive and reliable bedside tests for CAN. If these bedside tests can help us to predict perioperative cardiovascular instability in patients with DM, it might be important to assess patients with DM for the presence of CAN during their preoperative screening, for more vigilant perioperative management.
Objective:
1) What is the prevalence of CAN in patients with DM scheduled for major abdominal / cardiothoracic surgery?
2) Does the severity of CAN relate to perioperative hemodynamic changes?

patients with diabetic cardiovascular autonomic neuropathy are more prone to hypotension during surgery and therefore require more inotropic/vaspressor medication perioperatively

Day before surgery: autonomic function tests
Day of surgery: standardized induction. Collection of perioperative data via chart review
Days after surgery: collection of postoperative data via chart review

On the day before surgery, patients will be subjected to 5 non-invasive tests to assess diabetic CAN, there will be no invasive test performed for study purposes.