AS YOU ENTER your patient's room, ready to administer his insulin, the unit secretary informs you that your patient has just been made N.P.O. Do you give the insulin? Hold it? Give a reduced dose? Ask three nurses, experienced or novice, and you'll probably get three different answers.
In this article, I'll help you make the right decision by reviewing insulin categories and discussing how to sort out the information to provide the best patient care based on the evidence. But first, consider these eye-opening facts about diabetes.
More than 23 million Americans have been diagnosed with type 1 or type 2 diabetes, and another 6 million have this complex disease but are undiagnosed. Even if a patient is hospitalized for another condition, his diabetes will affect his outcome while in your care.1 For a refresher on the role of insulin, see The glucose and insulin dance.
The types of diabetes are defined by what's happening at the cellular level:
With dozens of insulin products on the market and more on the way, administering insulin can be challenging, with a high risk of mix-ups and other errors. In fact, insulin is on the Institute for Safe Medication Practices' list of high-alert medications; this list is endorsed by the Institute for Healthcare Improvement as part of its 5 Million Lives Campaign. Understanding the categories of insulin and how they work in the body is the first step to preventing errors and administering safe and effective therapy.
NPH, the oldest formulation, is given twice a day, once in the morning and once in the evening. Lantus and Levemir, the newest generation of basal insulins, start to work within 30 minutes and maintain a consistent supply of insulin for 20 to 24 hours. Because of this peaklessness, they're given once a day. They can't be mixed with other insulins, so the safest time of day to administer Lantus and Levemir is before bedtime.
No matter what type of basal insulin your patient is using, find out what schedule he uses at home and make all attempts to mimic that while he's hospitalized. In general, hospitalized patients who are N.P.O. and on basal insulin need half of their usual dose.2
For example, a patient might take 5 units of NovoLog with breakfast, 8 units with lunch, and 10 units with dinner. If the breakfast dose is scheduled for and administered at 0800 but breakfast doesn't arrive until 0900, the patient is at risk for hypoglycemia.
To prevent this complication, ask your patient to inform you or the nursing assistant when he receives his meal and tell him not to start eating until you've administered his rapid-acting prandial insulin. If he needs assistance to eat, ask the nursing assistant to let you know when she'll be available to help him so you can give the insulin at the appropriate time.
What makes matters worse is that many of us don't administer this type of insulin correctly. In my experience, holding correction insulin for a patient who's N.P.O. is the most common mistake that healthcare providers make in relation to insulin management.
For example, using correction insulin, if your patient's blood glucose is 200 mg/dL you'd generally administer 4 units of regular insulin. But suppose the unit secretary informs you that the healthcare provider just made your patient N.P.O. Do you administer the correction insulin as ordered, or should you hold it because the patient is N.P.O.?
The correct answer is to administer the insulin as ordered. Correction insulin is designed to be given independent of nutritional intake. You may hesitate to give insulin to a patient who's not eating for fear of causing hypoglycemia. But more patients die of hyperglycemia (because of its negative effects on the healing process) than hypoglycemia. The challenge is to be vigilant for signs of hypoglycemia while also keeping the patient's blood glucose within the target range.
Hyperglycemia in hospitalized patients is predictive of poor outcomes. Other evidence indicates that ICU patients with blood glucose levels above 130 mg/dL are more likely to die.3 Research supports a target blood glucose under 110 mg/dL in a CCU; in a medical-surgical unit, research supports a fasting blood glucose level of 126 mg/dL or less and a nonfasting level of 130 to 180 mg/dL.4
However, fearing hypoglycemia, many nurses are still most comfortable when a patient's blood glucose level is just under 200 mg/dL and don't aggressively treat hyperglycemia.5 In the past, standard treatment for a patient with hypoglycemia was a big glass of orange juice with three packets of sugar, for a carbohydrate load of 45 grams. The nurse would encourage him to drink it rapidly and keep checking his blood glucose until it reached 200 mg/dL or more. Not understanding the importance of tight glycemic control, she overtreated the hypoglycemia and put the patient at risk for more serious complications.
The current recommendation for treating hypoglycemia in a conscious patient is to provide 15 to 20 grams of glucose.4 Follow your facility's hypoglycemia protocol and encourage all team members to follow this method for managing a patient's low blood glucose level.
Now let's look at a few common scenarios in which insulin may be incorrectly administered.
You can safely mix the two doses of rapid-acting insulin together in one syringe (for example, the prandial and the correction dose of NovoLog). Here's an example: Your patient is scheduled for NovoLog, 5 units with breakfast. His morning blood glucose is 200 mg/dL. The correction dose is 4 units of NovoLog, which you add to the 5 units already ordered. By giving one injection of 9 units, you've taken care of hyperglycemia before and after the meal.
Diabetes management is all about timingthe one thing that isn't always in your control. Use a team approach to keep your patient safe from complications.
In most hospitals, a patient's capillary blood glucose level is tested before each meal and at bedtime. Many hospitals still follow the classic 0700, 1100, 1600, and 2100 schedule. This is appropriate if meals arrive at 0730, 1130, and 1630, with a bedtime snack at 2130. Because the ideal time to check a capillary blood glucose level is 30 minutes before a meal, find out when meals are delivered in your unit. You'll need to know when a patient's capillary blood glucose level is tested because you have only 1 hour to give correction insulin based on that test result. If your facility uses electronic medical records, you should be able to get the precise time of the last blood glucose test. If you can't administer your patient's correction insulin dose on time, check his blood glucose level again to ensure that you're administering the appropriate dose.
By understanding the basics of diabetes and the types of insulin, and having the commitment to pull it all together, you can help ensure the best outcome for a hospitalized patient with diabetes.
As you know, diabetes is about the relationship between glucose and insulin. All body cells, including brain cells, require glucose for energy, which explains why early signs of hypoglycemia include altered neurologic function.
When a person without diabetes eats, the pancreas boluses the body with the insulin it needs to take care of the glucose contained in the meal. The insulin lets the glucose enter the cells. (When teaching patients about diabetes, you may use the analogy of how insulin acts as the key to unlock the door of the cell and let in the glucose.) When insulin levels are high, such as after a meal, the liver stores extra glucose.
Between meals, when insulin levels are low, the liver releases stored glucose to maintain normal blood glucose level and body functions. Twenty-four hours a day, 365 days a year, a healthy adult has glucose in his bloodstream whether he's eating or it's being produced by his liver. This concept is critical for you to understand and properly ensure that your patient is receiving the insulin needed to maintain homeostasis.
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Institute for Healthcare Improvement. 5 Million Lives Campaign. http://www.ihi.org . Accessed September 25, 2008.
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