Wednesday, August 23, 2017

Glucose Control in Intensive Care Unit: Where Innovation and Technology Will Help?

Vanessa De Azevedo, RN - PhD Student
College of Nursing
University of Utah



What is Stress Induced Hyperglycemia?

Stress Induced Hyperglycemia (SIH) is characterized by level of blood glucose of 140 mg/dl or higher in patients receiving treatment in Intensive Care Unit (ICU) from surgery, traumatic injury, and critical or acute medical illnesses. Regarding the reason for admission in ICU, the presence of hyperglycemia is associated with increased morbidity and mortality. Patients with or without previous diagnose of Diabetes are also susceptible to present hyperglycemia when involved in critical scenarios.

Excessive counter regulatory hormones (e.g. glucagon, growth hormone, catecholamine and endogenous or exogenous glucocorticoid), and high circulation or tissue levels of cytokine are the causes of SIH. Such a condition makes insulin incapable of combating hepatic gluconeogenesis (the formation of glycose by the liver) responsible for blood glucose levels, and also makes the absorption of glucose into skeletal muscles impaired. In addition, intravenous nutrition therapy commonly received in critical settings is also responsible for events of hyperglycemia.

It is well known in medicine that controlling SIH in critical patients is a challenge for health care providers. The ideal blood sugar target range is 70-110 mg/dl; however, the high risk of hypoglycemia is eminent when such a target is applied. Researchers are trying to find a safer ways to control patients’ glycemic level without producing adverse hypoglycemia events. Insulin protocols, randomized control trials (RCT), and revision of guidelines have been done to solve such an important issue.

        What happens if a patient presents hyper or hypoglycemia when in ICU?

        Hyperglycemia is characterized by blood sugar level higher or equal to 110 mg/dl in a healthy person. Considering critical patients, high levels of blood sugar (< 140 mg/dl) can result in mitochondrial damage, endothelial dysfunction, and immune suppression, leading to an increased risk of infection. Indeed, SIH can result in polyneuropathy which requires a longer use of mechanical ventilation and longer hospitalization in ICU.      
        
       Hypoglycemia is defined as blood glucose level below or equal to 70 mg/dl. Glucose is not a villain for our body, it is also a metabolic fuel for the brain. Lack of glucose in the human body can be the consequence of a tight glucose control in ICU, in other words, excessive amount of insulin administrated when restrictive insulin protocols are applied. Other causes of hypoglycemia are inadequate nutrition, and insufficient provision of glucose. If untreated, hypoglycemia can result in permanent brain damage and death.
        
       Both hyperglycemia and hypoglycemia if not properly treated can result in poor care outcomes and even death.

        What has been done to avoid SIH in ICU settings?

        After a detection of blood sugar elevated, physicians prescribe an insulin protocol which consists of an intravenous administration of regular insulin (fast acting) through a pump. The dose of insulin is calculated by the level of glucose measured at the moment of administration. Through a simple but reliable glucometer, the blood glucose level is measured. The blood sample can be collect through finger sticks, and venous or arterial line. Arterial blood is the most accurate source for accessing glycemic level. 

       The insulin protocol requires hourly glycemic assessments in order to manage the insulin dose administrated. Such approach causes a delay in treatment which might result in adverse events such as hypoglycemia. The American Diabetes Association (ADA), the American College of Critical Care Medicine (ACCM), and the American Association of Clinical Endocrinologists (AACE) recommend a target glucose range of 140-180mg/dl. They also recommend the use of paper-based or computerized protocols that allow for predefined adjustments in infusion rate based on glycemic fluctuations and insulin dose, and initiation of intravenous insulin protocol at 180 mg/dl. Furthermore, hypoglycemia protocols should be established for each patient. The goal of the guidelines above is to avoid hypoglycemia and hyperglycemia and to mitigate adverse outcomes.


What is the role of nurses taking care of patients with insulin protocol in ICU?

        Nurses play a crucial role in glycemic management. They assess glycemic level from the beginning to the end of the therapy, making critical decisions that will impact the evolution of the therapy, and patient care outcomes.
        
       Such responsibilities require time, attention, dedication, and application of scientific knowledge. Once insulin therapy is initiated, nursing workload will increase.

Why do we need a change?

        Hourly glycemic assessment is not enough when managing insulin protocols. The need for a more tight control is essential to avoid adverse events such as hyper or hypoglycemia.
        
        There is consensus among researchers that the more tight the glucose levels (70 -110 mg/dl) the more benefits patients will have. However, such a tight control is not recommended due to high incidence of hypoglycemia it may cause.
        
         Hourly measurement with glucometers and finger sticks will result in hematomas, and consequently poor quality of a blood sample. Indeed, such an approach will increase nursing workload which can drive nurses away from other critical care conditions that might require special attention.

Where innovation and technology can help?

        Currently in the market we have devices such as continuous glucose monitoring and bionic pancreas that are helping patients with Diabetes types 1 and 2 to self-manage their blood glucose. Even though, critically ill patients are not necessarily in the scope of diabetes, they will certainly be beneficiated with such technology in ICUs.

What is CGM? 

Illustration of a continuous glucose monitoring Dexcom G4, retrieved from: https://diatribe.org/issues/48/test-drive


Continuous Glucose Monitoring (CGM) is a device that was initially designed with the purpose of helping Diabetes Type 1 patients to self-manage their blood sugar. Such an equipment contains a glucose sensor, a transmitter, and a display. The sensor captures and measures in real-time glucose fluid in the subcutaneous tissue. Connected to a transmitter, glucose levels are send wirelessly via radio frequency to the monitor display device.

What is Bionic pancreas? 




Top figure represents a bionic pancreas monitor, retrived from: https://diatribe.org/introducing-beta-bionics-bringing-ilet-bionic-pancreas-market

Bottom figure respresents an ilustration of how artificial pancreas works. Retrieved from: http://discovermagazine.com/2016/may/13-priming-the-pump

Bionic pancreas is a device that aims at imitating the human pancreas delivering insulin and glucagon hormones based on a blood sugar result measured every five minutes. The system consists of a dual pump (one for insulin and one for glucagon) that receives information from a separate sensor –CGM- and automatically calculates the exact dose of hormone a patient needs.

What to expect using CGM and Bionic Pancreas in ICU?

In conclusion, the addition of the new technology in ICU settings will lead to a real-time management of glycemic levels, reduction of nursing workload, and more accurate and safe levels of glucose. CGM and bionic pancreas will help prevent/manage SIH by simulating an almost real and effective human pancreas resulting in reduction of incidence of infection, hospital length of stay, and better patient outcomes.



References and suggested links for further reading:






McCowen,K.C., Malhotra, A., Bistrian, B.R. (2001). Stress-Induced Hyperglycemia. Critical Care Clinics, 17(1), 107-124. Doi http://dx.doi.org/10.1016/S0749-0704(05)70154-8
Harp, J. B., Yancopoulos, G. D., & Gromada, J. (2016). Glucagon orchestrates stress-induced hyperglycaemia. Diabetes, Obesity and Metabolism, 18(7), 648-653. doi: 10.1111/dom.12668
Godinjak, A., Iglica, A., Burekovic, A., Jusufovic, S., Ajanovic, A., Tancica, I., & Kukuljac, A. (2015). Hyperglycemia in Critically Ill Patients: Management and Prognosis. Medical Archives, 69(3), 157-160. doi: 10.5455/medarh.2015.69.157-160
Lacherade, J.-C., Jacqueminet, S., & Preiser, J.-C. (2009). An Overview of Hypoglycemia in the Critically Ill. Journal of Diabetes Science and Technology, 3(6), 1242–1249.
Brunner, R., Kitzberger, R., Miehsler, W., Herkner, H., Madl, C., & Holzinger, U. (2011). Accuracy and reliability of a subcutaneous continuous glucose-monitoring system in critically ill patients. Critical Care Medicine, 39(4), 659-664. doi: 10.1097/CCM.0b013e318206bf2e
De Block, C., Manuel, Y. K. B., Van Gaal, L., & Rogiers, P. (2006). Intensive insulin therapy in the intensive care unit: assessment by continuous glucose monitoring. Diabetes Care, 29(8), 1750-1756.
Harris, D. L., Battin, M. R., Weston, P. J., & Harding, J. E. (2010). Continuous glucose monitoring in newborn babies at risk of hypoglycemia. Journal of Pediatrics, 157(2), 198-202.e191. doi: 10.1016/j.jpeds.2010.02.003








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