Hyperglycemia is the medical term for blood glucose (sugar) that is too high. High blood glucose (HBG) is a common problem for people with diabetes. Blood glucose can also rise too high for patients in the hospital, even if they do not have diabetes. This patient guide explains why some patients develop HBG when they are hospitalized and how their HBG is treated.
Until recent years, doctors thought that HBG in hospitalized patients was not harmful as long as the blood glucose levels stayed at or below 200 milligrams per deciliter (mg/dL). Recent research studies show that HBG above 180 increases the risk of complications in hospital patients. Keeping blood sugar below this level with insulin treatment lowers the risk for these problems.
Most doctors agree that controlling blood sugar so it stays below 180 mg/dl but not below 140 mg/dl is best for very ill patients in intensive care units (ICU). Less clear is what the best target blood sugar should be for inpatients who are admitted for general surgery or non-critical medical conditions.
In some patients, some non-insulin therapies as well as insulin treatment can cause low blood sugar, called hypoglycemia. Just like blood sugar levels that are too high, blood sugars that are too low are not safe and should be avoided.
This patient guide for glucose control in the hospital is based on The Endocrine Society’s practice guideline for health care providers on preventing and treating HBG. This guide applies just to patients on a regular hospital floor, not those who are in an ICU.
Health care providers find HBG by doing a simple blood test. Blood sugar is usually measured by pricking the finger and testing a drop of blood with a glucose meter. The glucose meters used in hospitals are calibrated on a regular basis leading to more reliability and accuracy of results.
Your blood sugar should be measured either by fingerstick testing or testing blood from your veins when you are admitted to the hospital. You may need this test more than once if you are at high risk for HBG. For example, you have a higher risk for HBG if you have diabetes, are treated with medications that increase your blood sugar, or are receiving tube feeding or intravenous (IV) feeding.
In-hospital HBG is defined as a pre-meal blood sugar above 140 mg/dL. After finding HBG, your care providers will check your blood sugar before meals and at bedtime. You may need more testing in some cases. This includes if you are not eating, are receiving intravenous (IV) insulin, have a medication change that could affect blood sugar, or have frequent bouts of low blood sugar (hypoglycemia).
Health care providers want most ICU patients to have a blood sugar between 140 and 180 mg/dl. Outside the ICU, most providers aim to keep blood sugar between 100 and 140 mg/dl before meals and below 180 mg/dl at other times.
Insulin is the currently identified as the most reliable treatment for HBG in the hospital. This is true even if you do not have diabetes or if you do not use insulin at home. Insulin injection is the most effective way to control blood sugar.
Some non-insulin therapies that are used in the outpatient setting for diabetes treatment can cause low blood sugar or other health problems while you are sick. For these reasons, you may have to stop taking your non-insulin diabetes medicines during your hospital stay.
Hospital patients with HBG should receive insulin shots under the skin (subcutaneous injections). You should get basal (long- or intermediate-acting) insulin once or twice a day to keep blood sugar levels steady. The effect of these injections tends to be over 24 hours and should not be skipped if you do not eat, although doses may need to be adjusted if you are not eating. Before meals, getting bolus (rapid-acting) insulin helps prevent blood sugar levels from going too high after eating. Besides mealtime insulin, some patients with HBG may need additional insulin injections. This scheduled insulin treatment prevents HBG or, in some patients, a dangerous health problem called diabetic ketoacidosis (when acids and substances called ketones build up in the blood due to lack of insulin).
Intravenous insulin is another way that HBG is treated in the hospital. This is used when the blood sugar is extremely high or unstable or not responding to subcutaneous injections. This is a temporary way of treating HBG and is usually replaced by subcutaneous insulin when there is improvement in blood glucose levels or hospital discharge is anticipated.
For people who are on insulin pumps, your health care provider may decide to keep you on the pump during the hospital stay if you are admitted to a hospital that has a policy for this in place. Please inform your nurse and physician that you use an insulin pump so they can work with you to manage your blood sugar in the hospital. You will be fully responsible for the mechanics of managing the insulin pump. If you think you are unable to do so, let your team know. If you wear a continuous glucose monitor (CGM), check with your team if you are allowed to wear it in the hospital. You will have to remove pump and CGM devices for radiographic testing such as X-rays, CT scans or MRI scans.
There are situations when your health care team may decide to stop pumps or CGM devices. In this case, you will be started on standard subcutaneous insulin injections.
For all patients with HBG, good nutrition is important to help control blood sugar. A dietitian should work with you to plan your meals. The point is to make sure you get enough calories and eat the right amount and types of sugars or carbohydrates. These include whole grains, fruits, vegetables, and low-fat milk. Some hospitals may base your premeal insulin based on the amount of carbohydrates you will consume.
How should patients with diabetes who are having surgery be treated?
Before surgery, patients who take insulin should continue to receive insulin. If you do not take insulin, your care providers usually will sometimes stop or adjust non-insulin medicines and advise you to receive insulin if you develop HBG while in the hospital.
Before and after surgery, all patients with type 1 diabetes and most patients with type 2 diabetes should receive insulin especially basal insulin to prevent HBG. Insulin can be given through an IV or by multiple injections under the skin. When you can eat again, you should get mealtime (bolus or rapid-acting) insulin before meals.
Low blood sugar (defined as a blood sugar below 70 mg/dL) can occur with insulin treatment, if you are not eating, or after a sudden stop to tube or IV feedings. If you receive insulin or other diabetes medicines, your care providers will check your blood sugar often to make sure it does not drop too low. They may need to change the dose or timing of your insulin to prevent low blood sugar. Low blood sugar is treated with juice or glucose gels or tablets if you are able to take food by mouth. If not, you might get injections of glucose or glucagon if needed
If you have diabetes, let your nurse and doctor know this information when you go into the hospital. Ask your doctor to make sure this information goes into your patient chart. You will need to have your blood sugar checked at least four times a day (before each meal and at bedtime if you are eating regular meals or every six hours if you are not eating). So that your care providers know your usual blood sugar control, you should have a hemoglobin A1c test (blood test that shows your average blood sugar over the past three months). If you do not have diabetes but your blood sugar is above 140 mg/dL, you will need to have this test to determine if you have previously undiagnosed diabetes or are at risk for this in the future.
If your hospital provider diagnoses you with diabetes, you will need to learn how to do home glucose testing and how to recognize and treat high and low blood glucose levels. In some cases, you may also need to learn how to inject insulin. You may receive education while you are in the hospital and will likely need to arrange for additional diabetes education through your primary care provider following discharge.
When you leave the hospital, you will receive a written care plan for home diabetes management. It is important to fill the medications prescribed at time of your discharge. Please check back with your team if you have difficulty in filling medications at your pharmacy or if you have questions about the diabetes plan you were given. If you had HBG or low blood sugar in the hospital, your care plan should include how to control your blood sugar and when to see your doctor next. It also should explain how and when to take your diabetes medications. By following this advice, you will have the best chance of a good recovery after your hospital stay.
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