The Case

A 62-year-old man with type 1 diabetes mellitus was admitted to the hospital for coronary artery bypass graft surgery. His diabetes had been managed with an insulin pump while he was an outpatient. During his preparation for surgery, the patient asked the staff to leave his insulin pump in place and running at a basal rate. After surgery, he was transferred to the coronary care unit where orders were written to start him on a standard intravenous insulin infusion protocol. After he was extubated, the patient asked the nurse for his hourly finger stick blood glucose results. Unbeknownst to the nurse, the patient would then adjust his insulin pump in response to the glucose readings. At the same time, the nurse adjusted the intravenous insulin infusion rate based on the standardized protocol. The patient's blood glucose levels fluctuated, and he experienced hypoglycemia (with blood glucose levels in the range of 50-60 mg/dL) on several occasions. When the nurse mentioned the insulin pump at case management rounds, the medical director inquired further and, after discussion with the patient, the double dosing was discovered. The patient then agreed to turn off his insulin pump while he was receiving the intravenous insulin infusion.

The Commentary

Outpatient continuous subcutaneous insulin infusion (CSII or "insulin pump therapy") is an effective method of insulin delivery in select patients.(1-3) No national data are available regarding the exact number of users. However, it is likely that tens of thousands of people in the United States are employing CSII.(2) The recent proliferation of available devices is a testament to the ever-growing popularity of this therapy. Hence, it is likely that hospital staff will encounter individuals on CSII.

This case demonstrates some of the potential pitfalls and raises several questions regarding the safe use of CSII for hospitalized patients. Did the hospital have a policy to address insulin pump use? If so, was the staff aware of the policy and procedures? If a policy existed, were the appropriate procedures followed? Finally, was the presence of the pump recognized and addressed intraoperatively? Unless an acute care facility has a preestablished plan to address CSII therapy in patients who have an insulin pump in place at the time of admission, errors may occur. In this case, the apparent lack of a policy or set of procedures to guide management of the insulin pump patient during hospitalization seems to have contributed to inadvertent hypoglycemia.

Too often, the tendency of hospital staff is to require insulin pump users to disconnect from their pump during their inpatient stay. Given the time and treasure many patients invest in becoming educated in CSII treatment, they may become angry at being asked to surrender their technology—and their diabetes control and management—to individuals whom they may consider (sometimes quite correctly) far less expert in diabetes management. On the other hand, given the complexity of insulin pump therapy and the number of different devices available, inpatient staff and practitioners cannot be expected to become competent in all of the various technologies used in CSII therapy. Because of the high visibility of these patients when admitted, hospitals should have a plan in place that allows a standardized approach to care. Nursing staff will likely have first contact with insulin pump users, and they need to be part of any policy development.

Until recently, there has been very little information about how patients on outpatient CSII treatment fare during hospitalization. The number of insulin pump patients who require hospitalization each year and the frequency and types of inpatient errors involving CSII in these patients are unknown.

Despite the lack of published data—but with full recognition that hospitals will inevitably provide care to patients with an insulin infusion pump in place—our institution has published its guidelines outlining parameters for continued insulin pump use during the hospital stay.(4) These recommendations attempt to balance safety concerns with a desire to allow patients the option of continuing their CSII therapy (and their self-management independence) during hospitalization. The guidelines were developed by a team of endocrinologists, diabetes nurse educators, and representatives from hospital staff nursing and quality managers, and were subjected to repeated cycles of review and revisions until finally implemented. A basic theme permeates the recommendations: there must be daily collaboration and communication between the pump user and hospital staff, including practitioners on the primary team, diabetes consultants, and nurses.

Both the guideline and the written policy consist of three basic components: (i) a list of suggested contraindications to inpatient CSII, such as altered state of consciousness, critically ill patient, suicide risk, or other reason deemed appropriate by a physician; (ii) a set of rules to guide the medical staff in insulin pump management after patient admission, including use of a standard order set (see Table); and (iii) a requirement for signed patient informed consent that details the conditions for use of CSII in the hospital. Operationally, when a patient on insulin pump therapy is admitted to the hospital, the device is noted by the nurse and admitting physician, nurse practitioner, or physician assistant. If the patient is considered a candidate for continued use of CSII in the hospital, orders are written for basal insulin rates, insulin-to-carbohydrate ratios (if patient is allowed to eat), and correction factors. Initially, these orders correspond to the patient's home insulin regimen, and adjustments are made if needed on a daily basis according to the bedside glucose readings. Patients are required to provide their own insulin pump supplies (e.g., infusion sets and catheters) because it is not practical to stock items from various pump manufacturers. Patients who are not believed to be candidates for continued insulin pump treatment are switched to subcutaneous insulin therapy.(4,5) At our institution, we emphasize the use of basal-prandial-correctional insulin algorithms.

A recently completed analysis indicated that the above policy implemented by the hospital is generally performing as intended.(6) Between November 2005 and February 2008, there were 50 hospitalizations involving 35 patients who had been receiving outpatient insulin pump therapy. The mean age and duration of diabetes of the 35 patients were 55 and 32 years, respectively; 66% were women, and 91% had type 1 diabetes. Patients in 31 of the 50 hospitalizations (62%) were deemed candidates for continued insulin pump therapy after admission. Of the 31 hospitalizations, 80% had the presence of the pump documented at admission; 100% had an admission glucose value; 77% had documentation of signed patient consent; 81% had evidence of completed preprinted insulin pump orders; 77% received an endocrine consultation; and 68% had a completed bedside flow sheet. No adverse events (e.g., pump site infections, diabetic ketoacidosis, pump malfunction) were identified.

Although the above data indicate that implementing a formal policy on inpatient insulin pump use permits safe continued use of CSII in the hospital, there are insufficient data to address the effectiveness of CSII in controlling inpatient glucose levels—or to compare this mode of therapy to the substitution of CSII with physician-managed standard insulin treatment. However, the mean point-of-care glucose levels in patients with continued CSII were comparable to the values obtained in patients whose insulin pump was discontinued after admission. On the other hand, patients who continued insulin pump therapy were less likely to suffer episodes of hypoglycemia than patients switched to physician-managed insulin therapy.(6) There are no data that compare insulin requirements for patients on CSII in the hospital with those in the outpatient environment. More data are needed before it can be concluded that CSII therapy in the hospital offers any advantage in glucose control compared with standard insulin treatment, but these results are certainly promising and provide no hint of ill effects of allowing patients to continue their CSII as inpatients.

This analysis indicates that outpatient CSII users are likely to be encountered infrequently in the hospital (only 50 instances in little over 2 years). However, when they are admitted, these patients present unique challenges for communication and care coordination. With careful selection, patients receiving outpatient insulin pump therapy can safely continue to use the technology when hospitalized. To avoid the type of error illustrated by the case, hospitals should have in place a policy and set of standardized procedures that result in a systematic approach to evaluating and caring for this specialized group of patients.

Take-Home Points

• Outpatient insulin pump therapy is becoming increasingly popular as an alternative to standard insulin therapy with multiple daily injections.
• Patients on outpatient insulin pump therapy may be encountered in the hospital setting.
• Insulin pump therapy may be safely continued in the hospital in select patients.
• Hospitals should have a written policy and set of procedures regarding use of insulin pumps to ensure patient safety.
• The most successful inpatient insulin pump policy incorporates a sense of collaboration between the patient and the inpatient staff and providers.

Curtiss B. Cook, MD Professor of Medicine

Division of Endocrinology Mayo Clinic, Scottsdale, AZ

References

1. Lenhard MJ, Reeves GD. Continuous subcutaneous insulin infusion: a comprehensive review of insulin pump therapy. Arch Intern Med. 2001;161:2293-2300. [go to PubMed]

2. Pickup J, Keen H. Continuous subcutaneous insulin infusion at 25 years: evidence base for the expanding use of insulin pump therapy in type 1 diabetes. Diabetes Care. 2002;25:593-598. [go to PubMed]

3. Jeitler K, Horvath K, Berghold A, et al. Continuous subcutaneous insulin infusion versus multiple daily insulin injections in patients with diabetes mellitus: systematic review and meta-analysis. Diabetologia. 2008;51:941-951. [go to PubMed]

4. Cook CB, Boyle ME, Cisar NS, et al. Use of continuous subcutaneous insulin infusion (insulin pump) therapy in the hospital setting: proposed guidelines and outcome measures. Diabetes Educ. 2005;31:849-857. [go to PubMed]

5. Leonhardi BJ, Boyle ME, Beer KA, et al. Use of continuous subcutaneous insulin infusion (insulin pump) therapy in the hospital setting: a review of one institution's experience. J Diabetes Sci Technol. 2008;2:948-962. [go to PubMed]

6. Bailon RM, Partlow BJ, Miller-Cage V, et al. Continuous subcutaneous insulin infusion (insulin pump) therapy can be safely used in the hospital in select patients. Endocr Pract. 2009;15:24-29. [go to PubMed]

Tables

Table. Suggested Procedures for Patients Admitted to the Hospital While on Insulin Pump Therapy.

CSII, continuous subcutaneous insulin infusion.