How To Achieve Optimal Perioperative Glycemic Control In Patients With Diabetes
At our institution, we divide patients into two groups when it comes to managing glucose. The first group includes all patients with type 1 diabetes or type 2 diabetes who require multiple daily insulin injections (sliding scales). The second group includes the remainder of patients who are not in the first group, namely those with type 2 diabetes who have a controlled diet, those taking oral hypoglycemics and those who take subcutaneous insulin once or twice daily. Regardless of which group a patient fits into, we strongly recommend surgery first thing in the morning, if at all possible, in order to avoid prolonged fasting.
A Guide To Preoperative And Perioperative Measures
Both groups require little intervention prior to the day of surgery. Emphasize continued outpatient insulin regimens and diets without alterations. For those taking oral hypoglycemics, no change is required until the day of surgery. Remind patients to check fingerstick glucose levels before every meal and at bedtime.
If the glucose is poorly controlled, a common occurrence in the face of infection, use a sliding scale of short-acting insulin (regular or lispro for example) to supplement control. The BIDMC podiatry service utilizes a weight-based sliding scale developed by the Joslin Diabetes Center. One may need to adjust and individualize sliding scales for each patient to optimize glucose control. Also, if the patient is on a basal-bolus regimen of insulin, one should continue the basal rate (glargine, detemir).
On the day of surgery, the patient should begin fasting at midnight. One may administer D5W or D5 1/2NS unless the blood glucose level is >200 mg/dL. In these cases, the surgeon can usually administer normal saline instead if there are no contraindications. However, there are exceptions to this guideline and medical judgment should override this recommendation as needed.
For patients in group one, one should withhold all scheduled fast- or very fast-acting insulin. Cut intermediate or long-acting insulin in half. Typically, one would reduce peakless or relatively peakless insulins such as glargine or detemir into two-thirds of the usual dose. However, if the glucose levels have been high, give the entire dose. If a patient receives an insulin mixture, hold the fast-acting portion of the mixture and cut the intermediate portion in half. Monitor glucose levels every two hours before and during surgery.
For group two, hold all oral hypoglycemic medications and all scheduled fast-or very fast-acting insulins. If the patient takes intermediate or long acting insulin as an outpatient, reduce the dose by half. If a patient receives an insulin mixture, hold the fast-acting portion of the mixture and cut the intermediate portion in half.
For both groups, an insulin sliding scale supplements glucose control. When it comes to preoperative and perioperative measurements, one should use the bedtime portion of the sliding scale since the patient is not eating. If the glucose cannot be controlled, then one may initiate an insulin intravenous infusion. If the glucose levels fall below 80 mg/dL, give 100 cc of D10W IV and recheck the glucose in 30 minutes.
What You Should Know About Post-Op Management
Following surgery, manage both groups similarly. Check the glucose levels when the patient reaches the postoperative care unit. Continue the bedtime insulin sliding scale until the patient can tolerate at least 50 percent of his or her prescribed diet. If the patient takes metformin, draw a serum creatinine prior to resuming that medication. If the serum creatinine is elevated, hold this medication until you have identified the cause for this and continue coverage with the sliding scale.
Special circumstances, such as insulin pump management and IV insulin infusions, warrant further discussion and are beyond the scope of this article. In general, physicians maintain insulin pump use for these patients while they are inpatients and adjust this use as needed. If the patient is unable to manage the pump (due to illness, medications, anesthesia, etc.), then he or she will usually receive an insulin infusion or a calculated basal-bolus or subcutaneous insulin regimen.