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C H A P T E R 3 8 Agents to control blood glucose levels

increase in type 2 diabetes in young people. The treat- ment of Type 2 diabetes usually begins with changes in diet and exercise. Dieting controls the amount and timing of glucose introduction into the body, and weight loss decreases the number of insulin receptor sites that need to be stimulated, as well as the intra-abdominal fat that blocks adiponectin release. Exercise increases the movement of glucose into the cells by sympathetic nervous system (SNS) activation and by the increased potassium in the blood that occurs directly after exercising. Potas- sium acts as part of a polarising system during exercise that pushes glucose into the cells. Clinical studies have shown that controlling serum glucose levels can decrease the risk of complications by up to 40% (ADA, 2008). When diet and exercise no longer work, other agents (discussed later) are used to stimulate the production of insulin in the pancreas, increase the sensitivity of the insulin receptor sites, or control the entry of glucose into the system. Injection of insulin may eventually be needed. This concept is often confusing for people who are learning about diabetes. Type 2 diabetes often evolves until insulin is needed. Timing of the injections of insulin is correlated with food intake and anticipated increases in blood glucose levels, as well as exercise levels and anticipated stress (ADA, 2008). See Box 38.4 Diabetes and blood glucose variations Certain ethnic groups tend to have a genetically predetermined variation in blood glucose levels, possibly caused by a variation in metabolism. In New Zealand, certain ethnic groups (particularly Ma– ori, Pacific Islanders and South Asians) are at a higher risk of developing diabetes and data suggests that the incidence of diabetes for Ma– ori and Pacific peoples are more than three times higher than the European rates and Ma– ori and Pacific peoples are more than five times as likely to die from type 2 diabetes. Similarly, it has been estimated that Indigenous Australians have a three times higher incidence of type 2 diabetes than the non-Indigenous population, and are twice as likely to die from a diabetes- related condition. People in these groups should be screened regularly for type 2 diabetes.They can also benefit from teaching about warning signs of diabetes. Beyond Australia and New Zealand, similar problems exist for many cultural groups including First Nation people in Canada, and African and Native Americans. The clinical importance of this relates to proper screening of individuals for hypoglycaemia and diabetes mellitus. Individuals in these groups who have fasting glucose tolerance tests need to have the standard readjusted before a diagnosis is made. Such people also require an understanding of potential differences in normal levels on home blood glucose monitoring units when they are regulating insulin at home. Sources: Dissanayake, A. (2008). About Diabetes. New Zealand Society for the Study of Diabetes (NZSSD). www.nzssd.org.nz/ education/diabetes.html; Australian Institute of Health andWelfare (AIHW). (2013). Diabetes. www.aihw.gov.au/diabetes. Cultural considerations BOX 38.3

The evidence

BOX 38.4

Managing glucose levels during stress The body has many compensatory mechanisms for ensuring that blood glucose levels stay within a safe range.The sympathetic stress reaction elevates blood glucose levels to provide ready energy for fight or flight (see Chapter 29).The stress reaction causes the breakdown of glycogen to release glucose and the breakdown of fat and proteins to release other energy. STRESS REACTIONS The stress reaction elevates the blood glucose concentration above the normal range. In severe stress situations—such as an acute myocardial infarction or a car crash—the blood glucose level can be very high (above 8.0 mmol/L).The body uses that energy to fight the insult or flee from the stressor. Nurses and midwives in acute care situations need to be aware of this reflex elevation in glucose when caring for people in acute stress, especially people in emergency situations whose medical history is unknown.The usual medical response to a blood glucose concentration of above 8.8 mmol/L would be the administration of insulin. In many situations, that is exactly what is done, especially if the person’s history is not known and the effects of such a high glucose level could cause severe systemic reactions. Insulin administration causes a drop in the blood glucose level as glucose enters cells to be either used for energy or converted to glycogen for storage. However, a problem may arise in the acute care setting, particularly in a non-diabetic person. Relieving the stress reaction can also drop glucose levels as the stimulus to increase these levels is lost and the glucose that was there is used for energy. A person in this situation who has been treated with insulin is at risk for development of potentially severe hypoglycaemia.The body’s response to low glucose levels is a sympathetic stress reaction, which again elevates the blood glucose concentration. If treated, the person potentially can enter a cycle of high and low glucose levels. BEST CARE PRACTICE Nurses and midwives are often the ones in closest contact with the highly stressed person—in the emergency room, the intensive care unit, the post- anaesthesia room—and should be constantly aware of the normal and reflex changes in blood glucose that accompany stress. Careful monitoring, with awareness of stress and the relief of stress, can prevent a prolonged treatment program to maintain blood glucose levels within the range of normal, a situation that is not “normal” during a stress reaction. Diabetic people who are in severe stress situations require changes in their insulin doses.They should be allowed some elevation of blood glucose, even though their inability to produce sufficient insulin will make it difficult for their cells to make effective use of the increased glucose levels. It is a clinical challenge to balance glucose levels with the needs of the person because so many factors can affect the glucose level. Source: American Diabetes Association (ADA). (2008). Standards of medical care for patients with diabetes mellitus. Diabetes Care, 38, S14–S36.