Continuation of Metformin to Improve And Keep Peri-operative Glycemic Control

ContinuAtioN of meTformin to Improve And KEep Peri-operative Glycemic Control: A Randomized, Double-Blind, Placebo-Controlled Pilot Study.

Type II Diabetes Mellitus patients having surgery who adhere to their regular scheduled metformin dosing and take this medication on the morning of surgery will have better glycemic control peri-operatively and potentially suffer less morbidity compared to individuals taking a placebo.

Peri-operative hyperglycemia has been linked to numerous negative adverse consequences, including wound infection, impaired wound healing, endothelial dysfunction, neurocognitive dysfunction, sepsis, prolonged hospital stay and increased mortality. This has been shown in numerous studies as outlined in our detailed research proposal. The peri-operative period includes a timeframe ranging from 12 to 72 hours around the time of surgery according to definition. Our study is examining glycemic control in the peri-operative period which we are defining as approximately 48 hours around the time of surgery. The majority of the patients with type II diabetes take oral medications, such as metformin, to control their blood sugar. These patients have historically held their doses on the day of the surgery to avoid possible low blood sugar and lactic acidosis while fasting. However, numerous recent studies have shown that individuals who are fasting without renal, heart and liver failure are safe to take metformin. The most recent guidelines from the American diabetes association suggest that patients should take their dose of metformin on the day of surgery. Despite these recommendations most anesthesiologists continue to withhold metformin on the day of surgery, as no studies exist to show the benefit of continuing metformin. If we are able to show that patients taken metformin have better glycemic control during this time we can extrapolate that result mean they may have a lower incidence of the consequences linked to poor glycemic control.

Inclusion Criteria:

• ages 18 - 75, using metformin for control of Type II Diabetes mellitus, American Society of Anesthesiologists(ASA) I, II and III, informed consent, surgery in which less than 1000 mL of blood loss is expected.

Exclusion Criteria:

• renal failure, liver failure, Congestive heart failure (CHF), previous episodes of hypoglycemia, conditions which mask symptoms of hypoglycemia (autonomic neuropathy or chronic high dose beta-blocker usage), low capillary blood sugar (CBG) (≤4.0 mmol/L) at pre-operative appointment date, same day surgery, any patient who received contrast dye within 2 days of the planned surgery or requires intra-operative contrast dye and same day surgery.