Improved Blood Sugar Management in Critically Ill Patients
Duke University Medical Center physicians and nurses have developed a new protocol to improve management of high blood sugar (hyperglycemia) in hospitalized patients and reduce errors in administering intravenous insulin.
While many people with diabetes manage their blood sugar with frequent insulin injections, hospitalized patients often require intravenous insulin to quickly reduce high blood sugar levels. Previous studies have demonstrated a link between high blood sugar and increased infection rates in hospitalized patients, said the researchers. Strictly managed blood sugar levels can contribute to a reduced infection rate in inpatients, they said.
"Under the old protocol, we measured patients' blood sugar every hour, and nurses determined how much insulin to give based on the current blood sugar level alone," said Lillian Lien, M.D., an endocrinology fellow in the department of medicine at Duke and lead author of the study. "Our protocol is different because in addition to the current blood sugar level we also consider the blood sugar reading from the previous hour and the current insulin dosage. Those three factors allow us to be more efficient in determining an insulin dose that will quickly and safely reduce the patient's blood sugar to the desired level," said Lien.
The Duke researchers presented data from a study of 28 patients treated under the new protocol in intensive care units at Duke University Hospital. The study was presented in New Orleans today (June 14, 2003) during the 63rd Scientific Session of the American Diabetes Association.
Use of the new protocol reduced cases of two types of common errors by about one-third, said the researchers. These errors in intravenous insulin administration include improper discontinuation of intravenous treatment and failure to reduce consistently high blood sugar levels, they said.
Intravenous insulin remains effective in the body for only about 10 minutes, said Susan Spratt, M.D., Duke associate in medicine and a study co-author. Insulin given by subcutaneous injection, however, remains in the body for four to six hours following administration. "That's why it is really important to give a dose of subcutaneous insulin approximately one hour before stopping the IV," said Spratt.
According to the researchers, failure to give a dose of subcutaneous insulin before discontinuing intravenous insulin could cause the blood sugar to once again rise to unacceptably high levels, requiring a return to treatment with intravenous insulin.
"While this protocol doesn't change the timing or dosage of the subcutaneous injection, it does provide extra reminders to nursing staff that the dose is necessary one hour before the IV is stopped," said Spratt. "By taking into account the rate at which a patient's blood sugar is falling, nurses are also able to anticipate when a patient will be removed from the intravenous insulin, so that they won't find themselves giving the subcutaneous dose too late."
"In the Duke Hospital units using the new protocol, our goal is to regulate blood sugars at between 100 and 175 milligrams per deciliter," said Mark Feinglos, M.D., professor of medicine and chief of the division of endocrinology, metabolism and nutrition at Duke. "That's a bit more aggressive than traditional approaches, which called for an upper limit of 200 milligrams per deciliter, but the new protocol allows us more control in the safe regulation of blood sugars at a lower level."
The new protocol also resulted in significantly fewer cases in which medical staff failed to increase the insulin dose for patients whose blood sugar levels remained high despite treatment. The new protocol instructs nurses to administer additional insulin if a patient's blood sugar fails to reduce or continues to rise.
"We're quite encouraged by the results of this study," said Feinglos, "While a great deal of calculation went into the development of this protocol, the underlying theory is quite simple. Factors other than the current blood sugar reading contribute to the patient's response rate, so they should be included in calculating the insulin dose."
"We will continue studying this protocol within Duke Hospital, and plan to share it with other hospitals that may wish to implement a similar program," said Lien.
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