Blood Glucose Targets
The literature reflects controversy about what constitutes an optimal blood glucose target range during hospitalization (Table 2). Study results reported in 2001 documented that blood glucose targets of 80 mg/dL to 110 mg/dL reduced morbidity and mortality among patients in a surgical ICU.3 However, a similar benefit was not documented for patients in the medical ICU in the same facility.4,5
A recent study found that intensive glucose control (target 81 mg/dL to 108 mg/dL) increased mortality among adult patients in the ICU. But a blood glucose target of 180 mg/dL or less resulted in lower mortality than the intensive glucose target.6
Based on collective research and expert clinical opinion, the American Association of Clinical Endocrinologists and the American Diabetes Association now recommend a glucose range of 140 mg/dL to 180 mg/dL for the majority of critically ill patients. For the majority of patients who are not critically ill, the organizations recommend a premeal blood glucose target of less than 140 mg/dL and a random blood glucose target of less than 180 mg/dL.7
The NP-PA Team
I am an adult nurse practitioner and certified diabetes educator who practices in the Diabetes Consulting Service at Mayo Clinic in Rochester, Minn. Our team consists of nurse practitioners, physician assistants, a physician consultant, a diabetes fellow and medical residents. We are responsible for the clinical management of inpatients who have been diagnosed with diabetes and inpatients who develop hyperglycemia but have not been diagnosed with diabetes.
The availability of our diabetes service allows the admitting service to focus on each patient's presenting needs, such as a surgery or other medical event. Our team provides all diabetes management while the patient is in the hospital.
Hospital-based diabetes management is a growing specialty that directly affects patient care. It is both a science and an art. Nurse practitioners and physician assistants are well suited for this team approach to focused care. A study conducted at Dartmouth-Hitchcock Medical Center found that a nurse practitioner-led glucose management service reduced patients' blood glucose levels with substantially less variation when compared to patients who were not followed by the service.8
The role of the nurse practitioner and physician assistant in an inpatient diabetes management service is autonomous, challenging and rewarding. We provide the following services:
• Assessment and evaluation of new consults and writing all orders related to diabetes management. We perform physical examinations with special attention to body systems that may be affected by diabetes.
• Examination of the previous 24 hours of blood glucose values and writing daily orders for diabetes medications. Daily dose adjustment is a critical component of keeping the patient's blood glucose in target range.
• Identification of discharge needs at the point of initial patient contact. Many patients are admitted with an HbA1c level that is too high. We initiate a new therapy to be continued after discharge or work with them to optimize their current plan. Sometimes we re-evaluate their entire discharge plan due to an elevated creatinine or some other factor that prohibits continuation of the current treatment plan.
• Coordination of nutrition and diabetes education. Our dietitians and diabetes educators make vital contributions to care. Working together as a cohesive team, the NPs, PAs, dietitians and diabetes educators assist each patient in improving diabetes self-management skills.
In conjunction with the duties described above, we confer with endocrinologists and fellows about patients whose conditions are difficult to manage. We sometimes consult NPs and PAs who specialize in endocrinology to obtain another viewpoint on our plan of care for a particular patient.
In a more system-wide capacity, we are involved in practice issues, staff education and research. Our supervising/consulting physician is an endocrinologist with a special interest in hospital-based diabetes management.
The NPs and PAs on our diabetes service come from a variety of backgrounds. Some were certified diabetes educators or registered nurses. Some had little experience in diabetes prior to joining our service. We all share the common goal of empowering our patients to achieve optimal or near optimal glycemic control without increasing hypoglycemia risk.
Historically, hospitalized patients with diabetes were often treated several times a day according to insulin correction scales, rather than with a basal/bolus (prandial) insulin program. A basal/bolus program works to prevent hyperglycemia. An insulin correction program simply treats the hyperglycemia once it has occurred.
We write insulin orders daily and review them several times a day. The team uses an electronic service list so that we can view our patients' insulin doses and blood glucose values at the push of a button. Variables that require monitoring and affect glycemic control are numerous and multidimensional. The primary ones are outlined in the sections that follow.
Most inpatients we see are on a basal dose of insulin plus mealtime coverage. When using a long-acting insulin analog such as glargine (Lantus) with a rapid-acting insulin analog for mealtime coverage, we simply hold the mealtime insulin and continue the glargine until the patient is able to eat again. If the patient takes only a long-acting insulin analog, we often reduce that dose based on the knowledge that he or she is using this single injection a day to cover both basal and prandial needs.
When a patient takes an intermediate-acting insulin such as NPH and has to stop eating and drinking prior to a procedure, we prescribe a reduced dose of insulin - commonly half the usual dose - the morning the NPO (nothing by mouth) status is required.
Things get complicated when a patient who has received insulin in the morning is then made NPO. In such cases, we monitor blood glucose levels more frequently and, if necessary, start intravenous dextrose-containing fluids to prevent hypoglycemia.
For patients receiving continuous tube feedings, we often prescribe NPH insulin two or three times daily to obtain optimal glycemic control. The literature contains little information to suggest a superior management plan for the patient who requires insulin coverage for tube feedings. A long-acting insulin analog such as glargine is an option, but it becomes a complicating factor in the event that the tube feedings are discontinued.
For intermittent bolus tube feedings, the use of a short-acting insulin, such as regular insulin dosed at the start of each feeding, usually works well. We consider adding a longer-acting basal insulin if the patient has underlying diabetes.
If tube feeding is stopped for any reason, we may start dextrose 10% at the same hourly rate of the tube feeding and continue until the time action of the last basal insulin injection is reached.
Continuous Parenteral Nutrition
Patients who have diabetes and require continuous parenteral nutrition (CPN) may benefit from the addition of insulin directly into the CPN bags. Typically, we start with a 1:1 dextrose:insulin ratio. For example, if the dextrose content is 15%, we start with an insulin addition of 15 units per liter. The typical maximum ratio is 1:2 (e.g., dextrose 15% and insulin 30 units per liter). Regular insulin is the only form of insulin suitable for CPN addition.
If the patient continues to experience hyperglycemia at a 1:2 ratio, subcutaneous basal insulin may be added to the management plan. However, should the CPN be stopped for any reason, we stay alert to the potential for hypoglycemia development.
Steroid therapy is necessary in the treatment of some conditions, but it wreaks havoc on blood glucose values in the person with diabetes. No evidence-based guideline for insulin dosing during steroid therapy has been published. Some healthcare providers dose NPH and regular insulin in the morning and again with the evening meal. Another insulin management plan for steroids includes a long-acting insulin analog, such as glargine, dosed with a mealtime rapid-acting insulin analog, such as aspart (NovoLog). A third insulin management option is to use short-acting insulin for each meal plus or minus basal insulin, depending on the patient's diabetes history. The insulin management plan varies based on whether or not the patient has pre-existing diabetes.
Stress hyperglycemia, a transient elevation of blood glucose resulting from the stress of illness, can occur in the hospitalized patient who has no prior history of diabetes. Many factors stress hospitalized patients, including sleep deprivation, medications and disruptive surroundings. We obtain an HbA1c reading for patients with stress hyperglycemia to determine whether they had high blood sugar levels prior to hospitalization. Follow-up testing of glucose levels several weeks after discharge is a vital component of continued management. We note the hospital occurrence of hyperglycemia in the discharge summary and state that it requires follow-up. For local patients who do not have a primary care provider, we schedule an appointment for them.
Most oral diabetes agents are not recommended for use in patients with a creatinine level of around 2.0 mg/dL or higher. For hospitalized patients with elevated creatinine levels, we choose a rapid-acting insulin analog such as aspart over regular insulin. This is because in the presence of an elevated creatinine, the time of action for the insulin is prolonged. This extends the insulin action time, and it's one of the reasons why oral diabetes agents are avoided in the presence of an elevated creatinine. Hypoglycemia in such a case could be prolonged and persistent.
The patient with compromised liver function may have both increased sensitivity to insulin and prolonged time of action for diabetes medications cleared through the liver. A slightly higher glucose target range may be appropriate for some of these patients.
When selecting diabetes medications for patients 70 and older, we evaluate creatinine clearance and ejection fraction. We also assess the ability to self-manage diabetes, level of hypoglycemia risk, and ability to eat regular and balanced meals. Most clinicians raise the target range for blood glucose values and HbA1c based on life expectancy and the wishes of the patient.
Attaining optimal glycemic control without increased hypoglycemia is a balancing act. Prevention of hypoglycemia is an important goal of treatment. Studies have demonstrated that hypoglycemia experienced during a hospital stay can lead to increased costs, longer stays, increased mortality and an increased possibility of being transferred to a skilled care facility.9 A hypoglycemia treatment protocol should be mandatory for any patient who requires treatment for hyperglycemia, for use in the event that he or she develops low blood sugar.
Another crucial function we perform is the assessment and amendment of each patient's diabetes management plan, as necessary. Diabetes educators strive to see each patient to assess individual needs and provide education on topics such as blood glucose monitoring, insulin administration, dose adjustment, hypoglycemia and use of oral agents.
We are fortunate to have diabetes education services available 7 days a week. Additionally, a diabetes nutritionist is available to provide instruction on topics ranging from dietary basics to detailed carbohydrate counting.
We thoroughly explain the discharge and home care plan to the patient and document the details in the discharge summary. Interpreters are available in a multitude of languages to assist us with communication, as necessary.
Preoperative diabetes management is a common need at our facility. Our diabetes consulting team performs consultations in the morning admission area for patients scheduled for surgery that day. We write orders for preoperative insulin and evaluate each patient's diabetes management to date.
We also act as a telephone resource for patients who undergo outpatient procedures. They can call us for advice about what to do with their diabetes medications the day before and the day of the procedure. This access contributes to the reduction of errors and episodes of hypoglycemia and hyperglycemia.
Insulin pumps present another special situation. A patient who uses an insulin pump may require pump removal for surgery that requires complete anesthesia. In such a case, we either start an insulin infusion (for type 1 diabetes) or administer a long-acting insulin analog, such as glargine (for type 2 diabetes).
As soon as the patient is fully alert and awake, we allow him or her to resume insulin pump therapy with self-management. This may take a day or two, depending on pain medication use and level of sedation.
Certain surgeries present unique concerns. The patient who undergoes a complete pancreatectomy immediately develops surgically induced type 1 diabetes and will always require exogenous insulin. For such a patient, insulin infusion should not be discontinued without first administering subcutaneous basal insulin. The patient with a partial pancreatectomy may or may not experience a change in insulin requirements. If the patient did not have diabetes before surgery, it may develop afterward.
Bariatric surgery patients may require less insulin due to decreased food intake and weight loss. Some may even stop requiring insulin. Most bariatric surgery patients do not require preadmission doses of insulin or oral diabetes medications at the time of discharge, and we monitor them closely to make necessary adjustments in postoperative therapy.
Each year, the American Diabetes Association publishes a document called Standards of Medical Care in Diabetes.10 Each edition includes a section on inpatient glycemic management. These standards guide our practice, and they can be helpful for NPs and PAs who encounter patients with diabetes in any setting.
Inpatient diabetes management is a unique medical subspecialty ideally suited to the skills, education and contributions of NPs and PAs. A multitude of factors within the hospital setting influence glycemic control. Patients with diabetes benefit from skilled healthcare professionals who focus on their diabetes management while they are hospitalized.
1. Centers for Disease Control and Prevention. National Center for Chronic Disease Prevention and Health Promotion. Diabetes successes and opportunities for population-based prevention and control. At a glance 2010. http://www.cdc.gov/nccdphp/publications/aag/ddt.htm. Accessed June 8, 2010.
2. Centers for Disease Control and Prevention. Diabetes data and trends - Diabetes surveillance system. Number (in thousands) of hospital discharges with diabetes as any-listed diagnosis, United States, 1980-2005. http://www.cdc.gov/diabetes/statistics/dmany/fig1.htm. Accessed June 8, 2010.
3. Van den Berghe G, et al. Intensive insulin therapy in critically ill patients. N Engl J Med. 2001;345(19):1359-1367.
4. Van den Berghe G, et al. Intensive insulin therapy in the medical ICU. N Engl J Med. 2006;354(5):449-461.
5. Van den Berghe G, et al. Intensive insulin therapy in mixed medical/surgical intensive care units: benefit versus harm. Diabetes. 2006;55(11):3151-3159.
6. The NICE-SUGAR Study Investigators. Intensive versus conventional glucose control in critically ill patients. N Engl J Med. 2009;360(13):1283-1297.
7. Moghissi E, et al. American Association of Clinical Endocrinologists and American Diabetes Association consensus statement on inpatient glycemic control. Endocr Pract. 2009;15(4):353-369.
8. Comi RJ, et al. Improving glucose management by redesigning the care of diabetic inpatients using a nurse practitioner service. Clinical Diabetes. 2009;27(2):78-81.
9. Curkendall S, et al. Economic and clinical impact of inpatient diabetic hypoglycemia. Endocr Pract. 2009;15(4):302-312.
10. American Diabetes Association. Standards of medical care in diabetes 2010. Executive summary. Diabetes Care. 2010;33(Suppl 1)S4-S10.