HELP ON DIABETES

Managing Your Diabetes During Medical Procedures

Having an outpatient medical procedure or being hospitalized can be a stressful experience. Planning for it can alleviate some of the stress and ensure that your dia­betes is well managed. In this section, I discuss how to adjust medicines for proce­dures that require you not to eat and how to talk to medical providers about your diabetes before the procedure or hospitalization, tell you what to take with you when you go into the hospital, and let you know how you can ensure that your dia­betes remains under control during the hospitalization and afterwards. 

OUTPATIENT PROCEDURES

Many medical procedures, such as colonoscopies, hernia repair, cataracts, cosmetic surgeries, and x-ray procedures such as angiograms are performed in an outpatient setting, where you go into the hospital in the morning and leave a few hours after the procedure.

If you need one of these procedures, talk to your medical care team beforehand about how to manage your diabetes. A lot of these procedures require you not to eat for several hours before and after the procedure. Therefore, you need to know how to adjust your diabetes medicines to avoid both low and high glucose levels. Ideally, the procedure should be scheduled early in the day so that your period of fasting is limited. There are also issues surrounding diabetes-related complications—gastro-paresis can become troublesome and can cause vomiting after the procedure. The contrast dyes used in x-rays can worsen kidney function, especially if you already have diabetic kidney disease.

The following are general recommendations for what to do regarding your diabe­tes medicines before, during, and after the procedure. Your medical team will pro­vide specifi c recommendations.

If You Take Oral Medicines

In most cases you can take your usual medicines the day before the procedure, but none on the day of the procedure, and then restart them when you start eating. If you are on metformin and you need a procedure where you get a special x-ray with contrast dye, you may be asked to stop your metformin for a couple of days until a serum creatine confirms that your kidneys are not affected by the contrast dye. When you stop metformin, your glucose levels may run high, and your doctor may ask you to take tolbutamide, repaglinide, or nateglinide, or even a little bit of insu­lin, to control the glucose levels until you can restart the metformin.

If You Take Insulin

 In most cases, you can take your usual insulin dose the day before surgery. How much insulin is injected on the day of the surgery will depend on your particular insulin regimen. Let me give you some scenarios:

• If you are on a basal-bolus insulin regimen—that is, you are using insulin glargine at night and a fast-acting insulin analog before meals— then you should continue your insulin glargine (perhaps reducing the dose just a little bit—about 10 percent) while fasting, and use fast-acting insulin to correct high glucose levels. For example, if you are going to get a colonoscopy: the day before the procedure, use fast-acting insulin for the liquid carbohydrates you consume and take your usual insulin glargine that night. On the day of the colonoscopy, do not take any fast-acting insulin until you have recovered from the procedure and are ready to eat. 
• If you are on a premixed insulin regimen, inject the usual insulin dose the day before the procedure. On the day of the procedure, your insulin dose will depend on your glucose levels and what happens if you miss an insulin injection. If your glucose levels tend to go up a lot if you miss an injection and do not eat, then you will need to take some insulin. On the other hand, if your glucose does not rise much if you do not eat and do not take insulin, then you can probably wait and hold off the insulin injection until after the procedure. Usually, you can restart the insulin with the evening meal. If you are going to eat less than usual that evening, cut back the insulin dose. 
• If you are on an insulin pump, switch to insulin injections a couple of days before the procedure, because while you are undergoing the procedure, the pump infusion cannula can get dislodged, interrupting the insulin flow. Also, the medical personnel who are looking after you may not be familiar with how to manage a pump. To come off the pump, just calculate the total amount of basal insulin you take in twenty-four hours and give that amount of insulin as one injection of insulin glargine. For example, if you are on a basal rate of 0.5 units per hour, then the total basal in twenty-four hours is 24  0.5  12 units. Take 12 units of insulin glargine and turn off the pump. Remember that insulin glargine takes a couple of hours to start working, so you may need to give a small bolus of your fast-acting insulin (1 to 2 units) to cover this two-hour interval.