SCOTTSDALE, ARIZ. – Controlling hyperglycemia before and after surgery in patients with diabetes is a balancing act, but when done properly, it can reduce infections and wound complications, according to Dr. David Baldwin.
The key to preoperative planning for patients with diabetes is a full list of medications and an understanding of how well (or how poorly) patients’ glycemia is controlled, said Dr. Baldwin, an endocrinologist at Rush University Medical Center in Chicago.
He discussed strategies for perioperative management of patients with diabetes and thyroid disorders at the Perioperative Medicine Summit 2014."You definitely want to write down exactly what they are and aren’t taking. We find that the medication list for people getting admitted for surgery is often fraught with a lack of little details," he said.
For patients with type 2 diabetes, it’s important to record an accurate description of antidiabetes medications, especially combination oral agents such as Actoplus MET (metformin and pioglitazone) or Janumet (sitagliptin and metformin). For patients with type 1 and 2 diabetes, it is important to record not just the type of insulin but the regimen the patient uses.
Dr. David Baldwin
Dr. Baldwin noted that many intake staff make the mistake of reporting that patients take "Novolin" or "Humulin," which are brand families of insulin and not specific insulin types.
"We often find, probably at least half of the time, that until we actually go and ask the patients what they take for insulin post-op, the correct information won’t have been in the medical record," he said.
The best way to determine whether a patient has good control of chronic hyperglycemia is with a hemoglobin A1c (HbA1c) level. A value above 6.5% is diagnostic for diabetes; well-controlled patients have HbA1c levels from 6% to 8%. HbA1c values not more than 2 months old should be a routine part of preoperative evaluations for patients with diabetes or newly discovered hyperglycemia, Dr. Baldwin said.
Preoperative medications
The Rush University protocol for the preoperative management of antidiabetic therapies other than insulin notes that sulfonylureas, metformin, pioglitazone, exenatide, liraglutide, sitagliptin, linagliptin, saxagliptin, alogliptin, alpha-glucosidase inhibitors, and canagaflozin may all be taken with food on the eve of surgery, but none should be taken on the morning of surgery.
Specific rules also apply for patients who use insulin, depending on the insulin type, as follows:
• For long-acting insulins (glargine or detemir), the patient should take the full dose on the evening before surgery or the morning of surgery if the dose is prescribed for either morning or evening administration. Patients with prescriptions for a b.i.d. dose should take the full dose both the evening before and the morning of surgery.
• With intermediate-acting insulin (NPH), the patient should take the full dose on the evening before surgery and 80% of the morning dose on the morning of surgery.
• For rapid-acting insulins (aspart, lispro, glulisine, or regular) and premixed insulins (NPH or rapid acting), the patient should take the full dose with dinner the night before, and none on the morning of surgery.
Dr. Baldwin emphasized that except in rare circumstances, patients on subcutaneous insulin pumps should not use the pumps during surgery, and should get special instructions from their endocrinologists.
Ideally, the patient can convert to insulin glargine the night before surgery, with the dose equivalent to the total 24-hour basal insulin dose delivered by the pump. Two hours after the glargine dose is given, the patient should disconnect the pump and leave it at home.
Glycemic control in the hospital
As noted before, poor glycemic control can lead to poor wound healing from impaired leukocyte function, which can lead to decreased chemotaxis, phagocytosis, and bacteriocidal activity.
The risk of bacteremia is especially high among patients who are on total parenteral nutrition with poorly controlled glucose levels, he noted.
Forces conspiring against glucose control in the hospital can include elevated levels of hormones that counterregulate glucose; nausea/vomiting, anorexia, or nothing-by-mouth orders; erratic meal timing due to tests or interventions; intravenous glucose; glucocorticoid therapy; and "physician indifference and lack of attention to required adjustments in therapy," Dr. Baldwin noted.
Evidence from a randomized study showed that in patients with type 2 diabetes undergoing general surgery, basal-bolus treatment with insulin glargine once daily plus insulin glulisine before meals both improved glycemic control and reduced hospital complications compared with sliding-scale insulin therapy, he reported.
Hyper- and hypothyroid patients
Switching endocrinology hats, Dr. Baldwin said that patients who have significant weight loss or resting tachycardia before surgery should be evaluated for hyperthyroidism. A good rule of thumb is that in patients with hyperthyroidism, all but emergency procedures should be postponed until the condition can be controlled with methimazole.