Technology, education key to glucose control in ICU

Avoidance of hypoglycemia and keeping patients in target range are two barriers to control.

There is no current national standard of care regarding intensive glycemic control in the ICU. Nurse training, staff-to-patient ratios, tightness of glucose control, available technology and individualized treatment are some of the variables and issues surrounding the treatment of critically ill patients.

The challenges to intensive insulin therapy in the ICU are numerous, according to Jeffrey Mechanick, MD, director of metabolic support and associate clinical professor of medicine in the division of endocrinology, diabetes and bone diseases at Mount Sinai Medical Center in New York.

The barriers include “implementation, including coordination between nurses and physicians; the ability to check sugars and monitor them closely; avoidance of clinically significant and severe hypoglycemia; the ability to get patients in the target range of 80 mg/dL to 110 mg/dL as soon as possible; and the ability to conduct a proper analysis at the beginning to ensure the treatment is appropriate for the patient,” he said.

Endocrine Today interviewed a number of experts on the subject of intensive insulin therapy in the ICU and the current status of research into glycemic management of critically ill patients.

“Based on the available data that we have, we can say that intensive glucose management does reduce microvascular events, and that data comes from the Diabetes Control and Complications Trial and from the United Kingdom Prospective Diabetes Study,” Glenn R. Cunningham, MD, told Endocrine Today. Cunningham is professor of medicine, professor of Molecular & Cellular Biology at Baylor College of Medicine, and Medical Director at St. Luke’s Episcopal Hospital-Baylor Diabetes Program in Houston. He is also a member of the Endocrine Today Editorial Board. “However, those studies focus on outpatients, so to focus on inpatients, the best data come from Belgium, both in surgical and medical patients.”

Jeffrey Mechanick, MD, is the Director of Metabolic Support and Associate Clinical Professor of Medicine at Mount Sinai Medical Center. Photo by Stephen Fuller

“The landscape changed with the landmark papers of Van den Berghe of 2001 on patients in the surgical intensive care unit,” Mechanick said. “Prior to the Van den Berghe study, it was thought by many that increased glucose levels in the ICU were merely a marker of stress and did not need to be treated per se, as an acceptable range of glucose control in the ICU at that point was perhaps between 150 mg/dL and 200 mg/dL and not any lower due to fear of hypoglycemia.”

In the Van den Berghe study, researchers from the University of Leuven in Belgium demonstrated that treating hyperglycemia among ICU patients resulted in improved outcome and not only decreased mortality, but also decreased renal failure, infection and neuropathy. The insulin therapy used in the study has become the standard of care for many but not all practitioners, according to Mechanick.

The study was a prospective controlled trial. Researchers analyzed data from 548 patients who were admitted to the surgical ICU and were receiving mechanical ventilation. Patients were randomly assigned to either intensive insulin therapy or conventional treatment, according to the researchers.

At 12 months, intensive insulin therapy reduced mortality from 8% with conventional treatment to 4.6% (P<.04), according to the study. Among patients who remained in the ICU for more than five days, the mortality rate was 20.2% for conventional treatment compared with 10.6% for intensive insulin therapy (P=.005).

Intensive insulin therapy reduced overall in-hospital mortality by 34%. “Intensive insulin therapy to maintain blood glucose at or below 110 mg/dL reduced morbidity and mortality among critically ill patients in the surgical intensive care unit,” they wrote. The research was published in The New England Journal of Medicine. A subsequent study of patients treated in a medical ICU also was published by the same group in The New England Journal of Medicine (2006;354: 449-461).

Therapy recommendations

“Hospitals are expected to follow Joint Commission requirements regarding medication management and the competency of staff to order, use and manage that medication,” Kenneth A. Powers of The Joint Commission told Endocrine Today. “Hospitals determine their own patient needs and appropriate staffing ratios based on such resources as literature or FDA guidelines.”

The Joint Commission does not specifically address this therapy, but the standards are applicable systemwide, according to Powers.

In certain situations, such as a woman delivering a baby or perhaps cardiovascular surgery, tightness of control may be very strict, according to James L. Rosenzweig, MD. “But in most other ICU situations, for example, most major surgical procedures and cardiac events, our review of the literature indicates that if you keep the blood sugar between 100 mg/dL and 150 mg/dL with liberal use of intravenous insulin infusions, excellent outcomes can be achieved.” Rosenzweig is a staff physician at Beth Israel Deaconess Medical Center and assistant professor of medicine at Harvard Medical School.

There is still an open debate about how intensive control should be for usual perioperative care or treatment in the medical ICU, according to Rosenzweig. “Some endocrinologists would advocate control tighter than 100 mg/dL to 150 mg/dL; they might want blood glucose in the range between 80 mg/dL to 130 mg/dL,” he said. “Some endocrinologists who advocate for tighter control claim the problems associated with tight control, like low blood sugar, are not necessarily due to tightness of control but more due to the process by which the insulin infusions were set up; so, skill of managing IV insulin infusions may play a role in the failure of some of the large multicenter trials.”

Recommendations of the American Association of Clinical Endocrinologists and the American Diabetes Association include identifying elevated blood glucose in hospitalized patients, establishing a multidisciplinary approach to diabetes management, implementing structured protocols for aggressive control of blood glucose in the ICU and other settings, creating educational programs for all hospital personnel caring for patients with diabetes and planning for a smooth transition to outpatient care with appropriate diabetes management.

Indications for IV insulin therapy, according to AACE, consist of diabetic ketoacidosis, nonketotic hyperosmolar state, critical care illness (surgical and medical), postcardiac surgery, myocardial infarction or cardiogenic shock, NPO status in type 1 diabetes, labor and delivery, glucose exacerbated by high-dose glucocorticoid therapy, perioperative period, after organ transplant and total parenteral nutrition therapy.

AACE also recommends that concentrations be standardized throughout the hospital with regular insulin at 1 U/mL or 0.5 U/mL and infusion controller adjustable in 0.1-U doses. Additionally, they recommend that accurate bedside blood glucose monitoring be done hourly and, if stable, every two hours, and that potassium be monitored and given if necessary.

Some caveats

Joan Moshang

A possible difficulty surrounding the issue of glycemic control in the ICU is that, in the past, hyperglycemia may not have been taken as seriously, according to Joan Moshang, RN, BSN, MEd, CDE.

“For many years, some physicians and medical professionals did not look at blood sugar levels unless they were over 200 mg/dL, so there was not a lot of emphasis then — and in some cases now — on the management of patients with high blood sugar,” she told Endocrine Today.

Moshang is a Diabetes Clinical Nurse Specialist in the department of nursing at Thomas Jefferson University Hospital in Philadelphia.

Microvascular and macrovascular complications of diabetes are more understood now, and more attention is paid to the disease, according to Moshang. Although some recent research findings seem to suggest stricter glycemic targets may be dangerous to patients with cardiac conditions, diabetes organizations such as the ADA still assert that tight glycemic control is beneficial. “Glycemic control, blood pressure and lipid control have been and still are critically important,” she said.

Protocol implementation requires a multidisciplinary team, administration support, pharmacy and therapeutics committee approval, forms, education and monitoring, according to AACE. The common features leading to increased risk for hypoglycemia in an inpatient setting are advanced age, decreased oral intake, chronic renal failure, liver disease and beta-blocker use.

The factors increasing risk are lack of coordination between dietary and nursing possibly leading to mistiming of insulin dosage with respect to food; inadequate glucose monitoring; lack of coordination between transportation and nursing; unsafe work environment; and indecipherable orders, according to AACE.

Nurses’ perspective

Based on the studies by Van den Berghe and that sometimes more than a quarter of the people in the hospital can have diabetes, glycemic control is critical, according to Moshang. She helped develop an insulin infusion therapy program at Thomas Jefferson University Hospital.

“Step one was having a dedicated endocrine department who designed a team that included me, the ICU clinical nurse specialists, and representatives from nutrition, pharmacy, medicine and surgery to discuss the kinds of patients we treat, numbers, and so on,” she said.

Jefferson’s intensive insulin protocol is nurse managed. Training includes an online learning program, a power point presentation for ICU staff and, specifically, daily supervision by the ICU clinical nurse specialists, according to Moshang. “We performed trial runs on the computer program set in place to calculate the insulin dose based on current and previous blood glucose results,” she said.

Glenn R. Cunningham

Often when staff encounter problems with glycemic control in the ICU, it is due to lack of compliance to the protocol by both physicians and nurses, according to Moshang. “Without the background teaching, a program cannot be a success,” she said.

There are instances where nurses come to hospitals from other areas and have either not had the appropriate training or are rushed through training when they come to the hospitals, according to Moshang. “You can tell different institutions and organization have different philosophies,” she added.

“Different institutions and ICUs have different protocols and treatment is typically individualized; however, in general, glucose levels are checked every one to two hours and titrated accordingly,” she said. The target glucose level at Thomas Jefferson University Hospital on the floors is between 80 mg/dL and 180 mg/dL; and in the ICUs, it was initially 80 mg/dL to 140 mg/dL but is now between 100 mg/dL and 140 mg/dL despite the very low percentage of hypoglycemic events.

The future of therapy

“Even though the number of randomized trials is limited, the quality of the trials we have is good, and we have other supporting studies that were done with historical controls. The latter support the concept that more intensive glucose management is associated with better outcomes,” Cunningham said. “My understanding is that The Joint Commission on the Accreditation of Healthcare Organizations is moving toward wanting to see programs put into place in hospitals, at least for cardiovascular surgery.”

Irl B. Hirsch, MD, professor of medicine at the University of Washington Medical Center, Roosevelt, in Seattle, told Endocrine Today that in about five years from now, continuous glucose sensors may be the standard of care in critically ill patients in the ICU. “The only caveat is that we have to now test the current technology, specifically the subcutaneous sensors, since that is what we are using on the outpatient basis,” he said.

Continuous glucose monitoring systems would allow nurses to look at the trends, and if the glucose either went above or below the set target, the sensor would alarm, and the nurse could make an adjustment in the insulin, according to Hirsch. – by Christen Haigh

What is needed to help improve implementation of intensive insulin therapy in the ICU?