Glucose Control and Surgery
Diabetics and Surgery
Diabetics who need surgery present some unique challenges for the patient, anesthesiologist and surgery team. Optimal management of blood sugar levels starts with the patient under the guidance of the doctor who follows their diabetes. The surgeon will encourage good glucose control prior to surgery. The anesthesiologist may need to manage, or at least be aware of, glucose levels, depending on the type and length of surgery and the patient will need to be in good control of blood sugar after surgery to ensure the best recovery possible.
Post-Surgical Risks for Diabetics
Because blood glucose fluctuations affect many body systems, diabetic patients have some risk from surgery related to the diabetes. There may be major variations in these risks depending on whether the diabetes is type I or type II, how longstanding it is, how tightly the glucose has been controlled and whether or not there is organ damage throughout the body from the disease. Some people with well-controlled diabetes may have little extra risk beyond baseline.
The highest risk will be in those patients who have long-standing, poorly controlled diabetes (especially if it is type I or insulin-requiring) with damage to organs such as the heart, nerves or kidneys.
INFECTION: Diabetics have a higher risk for postop infection at the surgical sites. Great care must be taken to control glucose levels, adhere to diet and recovery recommendations and report any possible signs of infection like fever, redness, increased pain, pus and so on.
IMPAIRED HEALING: There are a whole host of factors that contribute to impaired wound healing in diabetics. Many of these factors are at the biochemical or molecular level. The Journal of Clinical Investigation says that "Over 100 known physiologic factors contribute to wound healing deficiencies in individuals with diabetes," in the article "Cellular and Molecular Basis of Wound Healing in Diabetes" from May of 2007. These include deficiencies in growth hormone, changes in the blood vessels and inflammatory cells and many other abnormalities related to alterations in glucose metabolism.
Diabetes: Defintions and Statistics
Diabetes, Type I- is also called "juvenile diabetes" or insulin dependent diabetes. This is a genetically-linked disorder of autoimmune origin.
Diabetes, Type II- is often, but not always, related to obesity, inactivity and poor diet. Despite the traditional designation as "non-insulin dependent" diabetes, some type II diabetics may require insulin. Most, however, can be managed with oral medicines like glucophage or metformin, as well as lifestyle changes.
About 25 million Americans have diabetes, and 95 percent have type II diabetes
Anesthesia Risks for Diabetics
Likewise, there are specific issues related to giving anesthesia to diabetic patients. These risks are well-known to anesthesiologists and outlined in the authoritative text "Miller's Anesthesia, 7th ed". Diabetes is a systemic disease and the effects on the entire body must be considered by the anesthesia provider.
The risks include potential problems with the airway, the lungs, the digestive system, the nerves, blood electrolytes and cardiovascular system. Usually, serious complications do not occur because of the diabetes, but the risk increases in people who already have end-organ damage from the disease (such as kidney problems or heart disease). The anesthesiologist is the provider who will deal with blood sugar issues in the immediate preoperative, intraoperative and postoperative period.
Introduction to Diabetes
Miller's Anesthesia, 7th ed. Chapter 35: Anesthesia Implications of Concurrent Disease,
Blood Sugar Management for Surgery
Based on the risk of developing significant end-organ damage (kidney failure, heart disease and so on), obviously, it is ideal to keep good control of blood sugar levels from the time of diagnosis of diabetes. Good glucose control slows or prevents these diseases from developing, which in turn lowers surgical risk and makes diabetes easier to manage in the time around surgery.
How Should Blood Sugar be Maintained for Surgery?
There is still some debate about how best to manage blood sugar before and during surgery. Tight control in a lower range may improve healing and other potential issues related to diabetes, but it also may make it more likely to have complications related to hypoglycemia (too low blood sugar).
Other regimens allow for a wider range of glucose levels, but may increase the risk of postop complications with healing and infection.
There is no good consensus at this point and certainly, no one plan will be appropriate for all patients under all circumstances.
Oral Diabetes Medicines before Surgery
If you are diabetic, you must consult with your surgeon and preferably the anesthesia clinic or provider for guidance on when to take or not take oral diabetes medicine:
Below are examples of what may typically be asked of you with regards to your diabetes medicines.
The night before surgery, you will probably be instructed not to take
- Glucophage (Metformin) or glucophage XR
- Chlorpropamide (Diabinase)
- Ask about other medications
The morning of surgery, you will probably be instructed not to take:
- Glucophage or glucophage XR
- Any oral diabetes medicine such as glipizide, glyburide, precose, etc.
Also, get specific instructions for when to restart these medicines- usually it will be when you are able to eat a normal meal. The timing may be different depending on what type of surgery you are having. Also, if you are in the hospital before or after your surgery, your oral meds will likely be held and your blood sugar tested and managed with insulin.
Insulin before Surgery
If you use insulin to manage your diabetes, it means that your blood sugar is harder to control or you have Type I diabetes. In either of these cases, your pre, intra and post op blood sugar control may be more complicated.
Type I Diabetics:
Insulin considerations are much more complicated and may require a consultation with the doctor managing the diabetes. Each patient is different and have different needs in regards to insulin and blood sugar control. In general, basal insulin, whether by pump or intermittent injection will likely be continued. Short acting insulin will be held (not given) the morning of surgery.
During long or complicated procedures, the anesthesiologist may start an insulin infusion (continuous through the intravenous line) and take frequent measurements of blood sugar while you are under anesthesia to adjust the insulin to your needs.
Type II Diabetics on Insulin:
Some types of insulin may be given in 1/2 to 2/3 dose the night before surgery. These might include Lantus (glargine) insulin and Levemir (detemir) insulin.
No short acting insulin should be taken the morning of surgery.
Insulin infusions can be used during surgery (managed by the anesthesiologist) for type II diabetics if needed during long or complicated procedures or in difficult to manage diabetics.
Diabetic Ketoacidosis (Type I Diabetes Risk)
If you are a diabetic facing surgery…
- control your blood sugar as carefully as possible all the time and be extra-diligent in the time between when the surgery is scheduled and when it occurs
- consult with your medical doctor or endocrinology specialist as soon as you know you will be scheduled for surgery. They may be able to help optimize your control and make other helpful recommendations
- attend all preoperative appointments. Have recommended labs drawn and make sure you understand your instructions about eating and medications.
- ask to be scheduled early in the morning so that disruption of meals and medications is minimized. Some places do this automatically for diabetic patients, but it can't hurt to remind them of this need.