MORE THAN 375,000 Americans with diabetes are using insulin pumps, according to manufacturers' estimates.1 In the past, insulin pumps were used primarily by patients with type 1 diabetes. Now patients with type 2 and gestational diabetes are also choosing continuous subcutaneous insulin infusion (CSII) or insulin pump therapy because of its advantages compared with multiple daily insulin injection therapy.2 Used properly, insulin pump therapy can decrease the frequency and severity of hypoglycemia. (See Looking at the pros and cons of insulin pumps.)
|Figure. No caption available.|
This article will explain how to care for a hospitalized patient with an insulin pump, who's likely to be strongly motivated and involved in self-care. First, consider some background on these devices.
Boost your pump I.Q.
An insulin pump is a small battery-powered device, about the size of a small cell phone, that continuously delivers a subcutaneous infusion of short- or rapid-acting insulin 24 hours a day. Most insulin pumps are attached to an infusion set, which includes a soft plastic cannula inserted under the skin. This set must be changed every 2 or 3 days or according to the manufacturer's recommendation.
An insulin pump has a reservoir that's filled with insulin and a microcomputer that allows adjustment of the amount of insulin delivered to the patient. This basal insulin infusion keeps your patient's blood glucose levels in target range between meals and overnight. Additional insulin dosages can be programmed to be delivered at different times of the day and night (bolus insulin); for example, to cover carbohydrates in meals or to treat high blood glucose levels.3 The patient programs the pump according to the healthcare provider's orders. The patient then administers the insulin according to the amount of carbohydrates consumed, blood glucose level, or both.
When the basal rate is set correctly, the patient's blood glucose won't rise or fall between meals. Some insulin pumps can calculate bolus insulin doses after the user provides blood glucose readings or carbohydrates eaten.
Basal rates are set as units/hour. The average rate is between 0.4 and 1.6 units/hour.1 Variable basal rates can be set to accommodate fluctuations in insulin requirements during the night.
The correction factor is the amount of blood glucose (mg/dL or mmol/L) that will be reduced by one unit of insulin. To calculate the correction bolus, use the 2,000 rule if the basal rate is 50% of the patient's daily dose. Divide 2,000 by the total units of insulin per day. (If the patient's basal rate is 40% of the total daily dose, use the 1,800 rule. Divide 1,800 by the total units of insulin per day.)1 The healthcare provider makes these calculations when determining initial orders.
The second type of bolus covers the carbohydrates eaten at a meal or snack. The pump uses an insulin-to-carbohydrate ratio to determine the bolus amount. Carbohydrate bolus doses are established to match the carbohydrate content of foods. Usually, one unit of insulin will cover 8 to 20 grams of carbohydrates for most adults and adolescents, but this will vary based on the patient's insulin sensitivity and weight.
The insulin-to-carbohydrate ratio is based on the 500 (or 450) rule. Divide 500 (or 450) by the total units of insulin per day to get the number of grams of carbohydrate covered by one unit of insulin.1 The ratio may differ at different times of the day.
All insulin pumps provide the same basic functions, but features vary among models available. The pump keeps a history of insulin used.
While using these pumps, the patient needs to check blood glucose levels according to the healthcare providers' instructions; for example:
* before meals and at bedtime
* 2 hours after meals
* between 2 and 4 a.m. weekly
* before driving or operating machinery
* when the patient has signs or symptoms of hypoglycemia or feels nauseated or sick.4
Some pumps take blood glucose measurements every minute and then display a 5-minute average. Fingerstick measurements with a standard blood glucose meter are still needed before adjusting therapy and calibrating the system.4
Some meters can work with real-time continuous glucose monitoring. (See illustration on page 57.) Data from a tiny glucose sensor is sent to a transmitter, a small attached device. Using advanced radio frequency wireless technology, the transmitter sends the glucose data to the insulin pump. The glucose sensor, which can be worn for up to 3 days, is inserted with an automatic insertion device.5
How to assess the patient
Many hospitals have consents in place stating the nursing responsibilities as well as the patient's responsibilities during the inpatient stay. If you're caring for a hospitalized patient with an insulin pump, you'll need to assess the patient's ability to manage self-care to determine the appropriateness of continuing to use the device in the hospital. Relay the results of your assessment to the healthcare provider.
Patients using pump therapy must possess good diabetes self-management skills. They must also have a willingness to monitor their blood glucose frequently (at least four times per day) and record blood glucose readings, carbohydrate intake, insulin boluses, and exercise. Standards of practice include letting the patient self-monitor blood glucose in the hospital, but you should monitor it as well.
Besides assessing the patient's physical and mental status, review and record pump-specific information, such as the pump's make and model. Also assess the type of insulin being delivered and the date when the infusion site was changed last.
Assess the patient's level of consciousness and cognitive status. If the patient doesn't seem competent to operate the pump, notify the healthcare provider and document your findings. Consider any possible impairment related to the patient's medical condition or prescribed medications that prevent competent use of the pump.
An insulin pump doesn't guarantee good insulin control, so routinely evaluate self-care behaviors to determine the patient's willingness to manage the pump correctly. Some pump users get tired of managing the pump, which can be evident if the patient has been hospitalized for episodes of unstable blood glucose, such as diabetic ketoacidosis or severe hypoglycemia. Also assess the condition of the infusion site. If it's poor, this can also indicate lack of self-care.
Assess whether the patient needs more education about how to use the pump properly, especially if there have been problems in the past. Alert the healthcare provider if the patient doesn't seem competent to use it properly.
To regulate the insulin dosage delivered by a pump, your patient must be able to count carbohydrates. The first level is basic carbohydrate counting, which usually consists of carbohydrate servings, not grams of carbohydrates, as well as how to manage patterns of blood glucose levels. That is, the patient is able to match food eaten with glucose levels. For instance, the patient may say that after eating pizza, glucose levels are always higher.
The second level is advanced carbohydrate counting. In this level, the patient matches the prescribed insulin dose to personal carbohydrate consumption. The patient may also develop an understanding of the basal-bolus concept and provide food records to help demonstrate the ability to count carbohydrates. To use a pump, the patient must be able to count grams of carbohydrates and understand the basal-bolus concept.
If using the insulin pump in the hospital is appropriate for the patient, you'll need to obtain orders from the healthcare provider. See A tall order for insulin pumps.
Once you receive the orders, ask the patient to show you the set basal rates, how to suspend delivery, time and amount of last bolus, and review of history. The patient needs to demonstrate how to administer a bolus dose, change the infusion set, and rotate sites. Observe the patient administering all bolus insulin doses. Verify the amount of the bolus and that the patient is following orders.
You'll need to make arrangements with the patient or the patient's support person to bring in supplies needed. With all the equipment available, it's not practical for hospitals to stock pump supplies other than insulin and batteries (AA and AAA). Make sure the patient has enough supplies to change his infusion sites every 2 or 3 days throughout his hospitalization.
The insulin pump should be discontinued for certain tests, including magnetic resonance imaging and computed tomography scans. The patient can safely disconnect the pump and most infusion sets for up to 1 hour but he should check his blood glucose before disconnecting and after reconnecting.4 Never place the insulin pump in the direct line of X-rays. Take special care to avoid dislodging the catheter when transferring the patient for these procedures.
Finally, document all of your interventions. See Documenting the details.
Potential acute problems for patients with insulin pumps include hypoglycemia, hyperglycemia, diabetic ketoacidosis, and skin infections. Patients using insulin pumps don't seem to have a higher incidence of hypoglycemia than those managing their diabetes with multiple daily injections.2 Blood glucose levels should always be checked prior to giving any insulin (bolus or correction dose).
If the patient develops hypoglycemia, treat it according to hospital protocol. If the patient can swallow, the recommended treatment is 15 grams of carbohydrate (4 oz. [120 mL] of orange juice or 6 oz.[180 mL] of regular (not diet) soda or two glucose tablets or two doses of glucose gel). Repeat the blood glucose testing in 15 minutes. Repeat the same steps if necessary. If the patient is N.P.O. or can't swallow, administer 50 mL D50 I.V. (1 amp) and start I.V. D5W.
If insulin delivery is interrupted for any reason, hyperglycemia and diabetic ketoacidosis can occur within 2 hours. Treat the patient according to hospital protocol and assess the catheter site for problems. (See Looking for trouble.) Provide supplemental insulin by subcutaneous injection. If the patient has ketoacidosis, he'll need I.V. insulin.
If you encounter problems with pump operation, obtain a consult with a certified diabetes educator who's also a certified insulin pump trainer. The manufacturers of most insulin pumps provide a toll-free telephone number on the back of the device for round-the-clock technical support.
When patients who use an insulin pump are admitted to your unit, you'll now be better prepared to help them continue using the pump throughout hospitalization, if appropriate. This treatment option lets them continue to manage their own condition and may increase patient satisfaction.
Looking at the pros and cons of insulin pumps
Here are some advantages of insulin pump therapy:
* tighter glycemic control, which decreases the risks of long-term complications
* variable basal rates can be used to accommodate fluctuations in insulin requirements during the night caused by hormonal releases
* reducing basal rates during low physiologic requirements may lessen the frequency and severity of hypoglycemia
* improved convenience, flexibility, satisfaction, and lifestyle
* meals and snacks can be customized
* insulin needs can be tailored to changes in schedules
* more precise dosing because basal and bolus doses can be delivered in 0.5 units.
Here are some disadvantages of pump therapy:
* the pump is a constant reminder of the disease
* frequent self-blood glucose testing is required
* skin irritations and infections can occur if the patient fails to use proper insertion and skin care techniques
* possible technical and mechanical failures
* diabetes ketoacidosis can occur very quickly in patients with type 1 diabetes
* the insulin pump and supplies are costly.
A tall order for insulin pumps
The healthcare provider's orders should include the following information for a patient in the hospital with an insulin pump:
* type of insulin
* a schedule for monitoring blood glucose (the recommended testing for intensive insulin therapy is fasting, premeal, 2-hour postprandial, bedtime, and occasionally at 3 a.m.)
* when to test for ketones
* insulin injection schedule if pump failure occurs
* basal rate (specific time frames and the number of units for each basal rate)
* blood glucose targets
* correction factor, which is also called the insulin sensitivity factor
* insulin-to-carbohydrate ratio.
Documenting the details
Your documentation should include the following information:
* type and amount of insulin
* basal rate or rates
* bolus insulin doses (number of doses and units given)
* any supplemental insulin given by injection
* blood glucose levels, including any the patient checked with a personal monitor
* condition of the infusion site
* change of infusion site
* the make and model of the insulin pump
* when the insulin pump is suspended or removed, such as for showers or procedures, the time it was removed, and where the pump was placed while it was discontinued.
Looking for trouble
If the pump isn't delivering insulin as expected, check for the following:
* erythema, edema, or tenderness of the site
* leakage, breakage, or kinking of the tubing
* battery failure
* empty reservoir or cartridge
* improper basal rate programming
* air in the tubing
* omitted bolus or improper amount given
* ineffective insulin (past expiration date, exposure to heat or cold)
* crimped catheter or needle not penetrating the skin
* insulin leaks at site.
Source: Walsh J, Roberts R. Pumping Insulin. San Diego, CA: Torrey Pines Press; 2006.