Recently, an employee at Bottom Line Publications was scheduled for a colonoscopy, the screening test for colon cancer. The medical test turned into medical mayhem.

The day before the test, the woman followed her doctor's orders to start ingesting a "clear liquid" diet, which includes soft drinks, Jell-0 and other clear beverages and foods. But when she drank the "prep"-the bowel-cleaning solution that is consumed the evening before a colonoscopy (and sometimes also the morning oD-she vomited. Over and over. As a result, her colon wasn't sufficiently emptied to conduct the test, which had to be postponed.

What went wrong?

The woman has diabetes-and her glucose (blood sugar) levels had become unstable, triggering nausea and vomiting. Yet not one medical professional-not a doctor, not a nurse, not a medical technician-had warned her that people with diabetes need to take special precautions with food and diabetes medicine whenever they have any medical test that involves an extended period of little or no eating. Unfortunately, this lack of diabetes-customized instruction about medical tests is very common. What you need to know...

Do It Early

If you're undergoing a test that requires only overnight fasting, which includes many types of CT scans, MRIs and X-rays, make sure that the test is scheduled for early in the morning-no later than 9 am. That way, you will be able to eat after the test by 10 am or 11 am, which will help to stabilize your blood sugar as much as possible.

Don't expect your blood sugar levels to be perfect after the test. The important thing is to keep them from getting too high or too low.

The Right Clear Liquids

Conventional dietitians and doctors specify clear liquids and foods that reflect the conventional American diet, such as regular soda, sports drinks, Popsicles, Kool-Aid and Jell-0 (no red or purple). But the pH of these products is highly acidic. And that could contribute to diabetic ketoacidosis, a potentially life threatening condition where the body bums fat instead of glucose for fuel, producing ketones, substances toxic to the liver and brain.

When my clients with diabetes are on a clear liquid diet before a test, I recommend that they consume liquids with essential nutrients and a more balanced pH, such as apple juice, white grape juice and clear, fat-free broth (vegetable, chicken or beet). A typical "dinner" could include up to three-quarters cup of juice (to limit sugar) and any amount of broth. A bedtime "snack" could include one-half cup of juice and any amount of broth. Plenty of good pure water between "meals" also is important to stay well-hydrated

Check Blood Sugar Often

Many people with diabetes check their blood sugar a few times a day-typically right before a meal and again one to two hours afterward. But if you're on a dear-liquid diet or fasting before a medical test, you should check your glucose level every two to three hours. If it's too low, correct it with a fast-acting carbohydrate, such as four ounces of 100% fruit juice or a glucose gel (a squeezable, over-the-counter product).

Important: Take fruit juice or a glucose gel with you to the test-if the test is delayed for any reason, you can ingest the carb and keep your blood sugar on track.

Stop Taking Metformin

Your doctor likely will recommend that you stop taking the diabetes medication metformin 24 hours before the test. Metformin (Glucophage) also can contribute to acidosis and typically is stopped 24 hours before and up to 72 hours after any test that requires a contrast agent (an injected dye often used in an X-ray, CT scan or MRI that helps create the image). Talk to your doctor about when to stop taking your medication and when to resume or about the possible need for an alternative diabetes drug during this period.

An unexpected threat: Metformin is a component of many multi-ingredient diabetes drugs-so you may not realize you're taking it and therefore may need to discontinue it. Drugs that include metformin are Actoplus Met and Actoplus Met XR... Glucovance... Janumet and Janumet XR... Jentadueto... Kazano... Kombiglyze XR... and PrandiMet. New drugs are being developed constantly, so check with your pharmacist to see if yours contains metformin.

Also important: Many X-rays, CT scans and MRIs utilize an injected dye or a contrast agent that can damage the kidneys in people with diabetes (contrast-induced nephropathy). Before restarting metformin, have a kidney function test (such as BUN, which requires a blood sample, and creatinine clearance, which requires a urine sample and a blood sample) that confirms that your kidneys are working normally. These tests are recommended 24 to 48 hours after your procedure is completed and usually are covered by insurance.

Decrease Insulin

Insulin is the hormone used by the body to regulate blood sugar-and many people with advanced diabetes give themselves shots of short- and/or long-acting insulin to keep glucose levels steady. But if you're consuming only clear liquids or fasting before a medical test, you likely will need to take less insulin.

Excellent guidelines for insulin use before a medical procedure have been created by the University of Michigan Comprehensive Diabetes Center. In general, it recommends...

• Take one-half of your usual dose of long-acting insulin the evening before the procedure.

• Take one-half of your usual dose of long-acting insulin the morning of the test and no short-acting insulin the morning of the test.

You can find the complete guidelines in downloadable PDF form at pdf Print them out, and discuss them with your doctor.

Reduce Anxiety

Anxiety triggers the release of the stress hormone cortisol, which in turn sparks the production of glucose. To keep blood sugar balanced before a test, use these two methods to keep anxiety in check...

• Get all your questions answered. Fear of the unknown is the greatest stress. Before your procedure, create a list of questions to ask your doctor or nurse practitioner. Examples: What is going to happen during the procedure? What is it going to feel like? What are the potential side effects from the test, and how can I best avoid them? When will I be informed of the test results? How will the test results affect future decision-making about my health?

• Breathe deeply. Deep breathing is the easiest and simplest way to reduce anxiety. My recommendation, based on the approach of Andrew Weil, MD...

Repeat this breathing exercise three times, and do it three times a day every day: Inhale for a count of four... hold for a count of seven... exhale for a count of eight. (Don't worry if you can't do the entire count shorter counts also work.) Do this exercise when you get up in the morning, at midday and at bedtime. You can do it more often, but most people find three times simple and easy to integrate into their routines.

Also, you can use this breathing technique in any situation that you find anxiety-producing, such as before and during the test itself. Breathe deeply three times every 10 or 15 minutes, and be sure to keep the 4:7:8 ratio-inhale for four, hold for seven, exhale for eight.

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