By Michael D. Smith
Your squad is responding as a first-tier basic life support unit to an ill patient with diabetes. You mention to your partner, “It seems like every patient we see has diabetes.”
Despite a wide variety of presenting complaints, diabetes is often a component of a patient’s medical history. Over time, diabetes affects every body systemheart, blood vessels, eyes, and kidneys. There is a very strong relationship between poor glucose control and blindness, cardiovascular disease, and amputations.
The American Diabetes Association estimates that more than 1.5 million new cases of diabetes will be diagnosed this year.1 Adding to the 14.6 million already diagnosed, 6.2 million undiagnosed, and some 54 million prediabetic patients, diabetes is one of the fastest growing health concerns Americans face.2 With obesity running rampant and a less active younger population, many public health experts warn of an impending diabetes epidemic. Our American youth tend to forsake the outdoors in favor of the indoors, playing video and computer games instead of running around playing tag, riding bikes, and getting exercise. Two million adolescents between the ages of 12 and 19 (which equates to one in six) are obese and are prediabetic. (1) Their diet also comes into play: Fast food and quick, overprocessed meals are implicated in the rapid rise in diabetes cases.3
TYPES OF DIABETES
Many prehospital providers have difficulty understanding diabetes. Perhaps changing classification terms used to describe diabetes has led to this confusion. Type 1 diabetes was previously known as juvenile onset or insulin-dependent diabetes mellitus. Without daily insulin injections, most Type 1 patients would quickly slip into a hyperglycemic state. For unknown reasons, the pancreas is able to make only very limited amounts to no insulin. As a consequence, such patients require exogenous (external) insulin injections. There are many theories as to why the pancreas stops making insulin. The most accepted of these is an autoimmune response in which the islet cells are destroyed as though they were foreign to the body.4 Type 1 diabetes accounts for only about five percent of all diagnosed diabetes cases in the United States. (1)
Type 2 diabetes, generally thought of as adult onset or noninsulin-dependent diabetes mellitus, is being diagnosed in more younger patients than ever before. Many Type 2 patients with diabetes use diet and exercise to maintain their blood glucose levels to as close to normal as possible. Since diabetes is a chronic progressive disease, most patients progress from diet and exercise to oral medications and then to insulin injections. While most Type 2 patients with diabetes don’t take insulin, some may require small amounts of a long-acting insulin to keep the diabetes in tight control. Noninsulin-dependent diabetes mellitus accounts for about 95 percent of all cases of diabetes. (1)
1. Insulin pump with luer lock. (Photos by author unless otherwise noted.)
Another type of diabetes is gestational diabetes, which affects only pregnant women and generally resolves post delivery. (1) Most of these patients are treated with diet and insulin. If blood glucose is not controlled, the fetus is at risk of being very large and having birth defects. There is a connection between large children born to mothers with gestational diabetes and obesity and the development of diabetes during adulthood.5 The mother is also at greater risk of developing Type 2 diabetes later in life.6
Every cell in the body uses glucose for energy. Brain cells require more glucose than any other cells. Insulin is needed to allow glucose to enter the cell; glucose is then used as fuel for the cell. Since the brain has no room to store glucose, the brain cells rely on the proper amount of glucose in the circulating blood. If that level drops too low, the brain starts to run a little lean, and other forms of less-efficient fuel are used for energy. A hypoglycemic patient will have difficulty thinking, will be confused, and may show signs of a cerebral event.
When there is not enough insulin to open the cell walls, glucose starts to accumulate in the blood. Once the patient becomes hyperglycemic, large glucose molecules thicken the blood, which forces the heart to work harder. The kidneys attempt to remove glucose by eliminating more fluid. This, in turn, causes dehydration, further concentrating the blood with excess quantities of large glucose molecules. Without enough insulin circulating in the blood, the body is unable to create energy in a normal fashion, and the cells switch to burning other forms of energy. Protein and fat can be used by most cells as a secondary fuel source; however, these do not burn as cleanly as glucose.7 The by-products of the inefficient combustion of these other fuels are pyruvic acid and excess ammonia, which causes a drop in blood pH (i.e., acidosis). Acidosis results from overproduction of acids, primarily ketones, which can lead to the characteristic odor of acetone on the breath of a patient with diabetic ketoacidosis.
As you approach the scene, your discussion switches to how you are going to get the assessment and blood glucose test done before the medics arrive. On-scene, you find a 68-year-old female complaining of vomiting and diarrhea for two days. Presently, she feels “really run down and weak.” Her blood pressure is 168/88, heart rate is 112 and regular, respirations 22, regular and clear bilaterally, and capillary refill is brisk. She has poor skin turgor, and her mucous membranes are dry. Her current prescribed medications are Amaryl®, 4 milligrams once daily; atenolol, 50 milligrams once daily; Humalog® insulin, 1 unit (subcutaneously) per 6 grams of carbohydrate with meals; and 25 units Lantus® insulin, at bedtime (which she has not taken since she became ill). As you continue to interview the patient, your partner prepares to check her blood glucose level.
Glucose testing is an important tool in the management of diabetes. With frequent testing, patients with diabetes are more capable of maintaining tight control of their disease. (6) The general public has used glucose monitors very successfully for glucose testing, so why aren’t EMT-Basics and EMT-Intermediates able to perform these tests in the field? We may not understand why this simple test is not in the scope of practice for the majority of EMTs in the United States. However, the current final draft of the National Scope of Practice endorses the use of blood glucose monitoring for EMT-Intermediate.8 Only a handful of states currently allow glucose monitoring by EMT-Basics. Many states that do not allow use of glucometers do allow EMTs to administer oral glucose to suspected hypoglycemic patients.
There are many different types and brands of glucose monitors. Not all work well in the prehospital setting. Many of the current monitors use capillary blood for testing and typically require capillary blood to report accurate results. Capillary blood carries enough oxygen so the blood sample will oxidize on the test strip. (8)9 A small electrical impulse surges through the blood sample and allows the software in the meter to report a glucose value in milligrams per deciliter (mg/dl).
2. If the patient is hypoglycemic, disconnect the pump at the luer lock. Here is the pump with the tubing disconnected.
Read the supporting material that accompanies your glucometer to ascertain if it requires capillary blood or if venous blood samples can be used. Several studies have demonstrated that glucose meters designed to test capillary blood are inaccurate when used with venous or arterial blood. These inaccuracies tend to be greater when results are outside normal ranges. This can be significant when relying on results for patient care and treatment. Use of capillary blood is also supported in an article regarding glucose testing in the geriatric population, “Capillary blood glucose testing in older people: reliable and accurate.”10
There are some commonsense points to keep in mind when performing this easy yet very important procedure. You will be using sharp implements to obtain a blood sample. Personal protective equipment is imperative. Have the patient hang his hand down to his side to facilitate blood pooling in the fingers. Use caution in your selection of the finger, as long-term patients with diabetes tend to have poor distal circulation. Coupled with long-term testing, scar tissue or calluses may have formed where frequent testing has occurred. The best results often come from poking the sides of the finger rather than the pad. The pads have many sensory nerves. Pads are more painful than the sides of the fingers, and the skin on the pads tends to be a little thicker.
Because of the possibility of poor circulation and the risk of potential infection, aseptic technique is important. Some glucometer documentation suggests not using the first drop of blood, as it might be contaminated with antiseptic, so wipe that drop with a clean, sterile dressing. One small study indicates that as long as you clean the site to eliminate any contaminants, any residual antiseptic is not a concern.11 Many patients and prehospital services typically use an antiseptic wipe (such as an alcohol pad) only when the sampling site is visibly dirty. Each glucometer comes with a procedure to perform a calibration or test to ensure the meter is working within its established parameters. All meters have high and low limits for displayed results. If the blood glucose is outside of one of these limits, the meter will register some indicator other than a number. Become familiar with your meter’s parameters and what the indicators are for the out-of-limit readings. Know what these out-of-range limits mean for patient treatment.
NEXT GENERATION OF INSULIN DELIVERY
The next generation of insulin delivery systems is revolutionizing diabetes care. Insulin pumps are quickly gaining popularity for tight control of glucose in patients with Type 1 diabetes. With small programmable external pumps (about the size of a pager or cell phone), the systems will fit almost any person with diabetes in need of tight insulin control. Current pumps allow programming basal insulin delivery rates to cover basic metabolic needs of the user. These can be further programmed by adjusting insulin doses to cover meals (i.e., the patient can program a specific insulin dose to cover a specific number of carbohydrates consumed). The insulin is delivered by the pump through a small-diameter infusion set to a subcutaneous catheter. The pump is refilled with short-acting insulin once every three to four days, at which time the catheter site and tubing are changed.
3. Stick the side of the patient’s finger instead of the pad, because it is less painful for the patient and provides a better blood sample
As more physicians and patients warm to the idea of carrying an insulin pump, EMS personnel will see them more frequently. Each manufacturer has proprietary delivery sets, which make it difficult for EMS providers to become familiar with all of the available sets. If you encounter a patient on an insulin pump and suspect hypoglycemia, you should disconnect the catheter (simple leur adapter) from the pump. This prevents inadvertent reprogramming of the pump. Treat the patient and, once he regains consciousness, he can reattach the pump and continue normal therapy. Since the catheter could be deployed in several different anatomical sites, I discourage searching for its location, since time is better served dealing with the patient’s needs.
Over the past two years, the Federal Food and Drug Administration has approved several continuous glucose monitors (CGMs). They use a glucose sensor placed just under the skin to provide a continuous reading of glucose levels. (11) These CGMs are often integrated with insulin pumps.12 Many new-generation pumps use CGM data to adjust basal insulin rates and make correction boluses to keep the glucose readings within a target range. These external insulin pumps are as close to an artificial pancreas as we have on the market today. The future may well see fully implantable pumps and sensors.
4. A typical glucose meter. (Photo courtesy of Roche Diagnostics.)
Any time a new skill set is introduced, it requires baseline education followed by ongoing education and skill competency verification. As with any skill, if you don’t use it, you will lose it. You lose not only the ability to perform the test but also the ability to identify the need to perform that skill.13,14 There must be a local policy regarding the procedure of how to perform the skill as well as how often the providers need to review and demonstrate competency of this skill.
On-scene with the patient you responded to, you are able to provide the advance life support unit with a quick report of your findings: a 68-year-old female with vomiting and diarrhea for two days who appears dehydrated and has a blood glucose higher than the meter will display, which you know to be 600 mg/dl. You also detect ketones on her breath. You are concerned that your patient is in diabetic ketoacidosis. The medics agree that the patient is probably developing this very serious diabetic complication. They thank you for your assessment, which has already decreased the time it will take for your patient to receive definitive care.
1. American Diabetes Association: www.diabetes.org/diabetes-statistics.jsp.
2. American Diabetes Association: www.diabetes.org/.
3. Astrup, A. “Super-sized and diabetic by frequent fast-food consumption?” Lancet, 2005; 365: 4-5.
4. Leslie, RD.; “Causes of insulin dependent diabetes”; British Medical Journal, 1983; 287: 5-6.
5. National Institutes of Health; National Institute of Child Health & Human Development; www.nichd.nih.gov/publications/pubs/gest_diabetes/sub2.cfm.
6. Kim, Catherine, MD, MPH; Katherine M. Newton, PHD; and Robert H. Knopp, MD: “Gestational Diabetes and the Incidence of Type 2 Diabetes: a systematic review”; Diabetes Care, 25:1862-1868, 2002.
7. Connelly, SA, WH Carpenter, “Fuel Utilization During Exercise, Aerobic and Anaerobic Metabolism, Control of Muscle Protein Metabolism/Anabolism”; Nutrition 101, UCLA Center for Human Nutrition.
8. National Association of EMS Educators; http://www.naemse.org/SoP_Final_Draft.pdf.
9. Rados, C., “Safety Alert on Blood Glucose Meters”; FDA Consumer; 2006.
10. Kabadi, U, MU Kabadi, “Capillary Blood Glucose Testing in Older People: Reliable and Accurate”; Journal of the American Geriatrics Society; Jan. 2003; 51: 1, 136.
11. Lewandrowski, K, Lee-Lewandrowski, E.; “Capillary Blood Glucose Testing at the Point of Care-Clinical Applications and the Evolution of Diagnostic Technologies”; Business Briefing: Global Healthcare; 3: 76-79.
13. Form W. “On the Degradation of Skills”; Annual Review of Sociology, 1987; 13: 29-47.
14. http://www.diabeteshealth.com/read/2007/09/18/5443.html, Diabetes Health, online.
MICHAEL D. SMITH, NREMT-P, CCEMT-P, is a firefighter/paramedic with the Grandview Heights (OH) Division of Fire, a flight paramedic for Medflight of Ohio, an Outreach critical care educator for Grant Medical Center’s LifeLink, and a paramedic instructor at Ohio University-Lancaster. He has been involved in EMS since 1986.