by Gary Scheiner
For anyone who uses an insulin pump, there are bound to be occasional problems.
For some, problems may be as rare as a Chicago Cubs’ World Series victory;
for others they may occur as often as a Hollywood scandal.
Insulin pumps, being mechanical devices, are subject to mishaps that can result in interruptions or irregularities in insulin delivery or action. When too little insulin is being infused into your body, high blood sugar will occur. When absorption is inconsistent, highs and lows can occur. And if no insulin is being delivered, diabetic ketoacidosis (DKA) can occur in just a few hours.
DKA is a serious condition that will make you very ill and can kill you. The primary cause of DKA is a lack of working insulin in the body, accompanied by dehydration. When you are using an insulin pump, there is no long-acting insulin present in your body. Any interruption in insulin delivery can result in a sharp rise in blood sugar and ketone production can start as soon as three hours after the last bit of insulin was infused.
The most important step in preventing ketoacidosis is early detection of the problem. You accomplish this by checking for ketones with any unusually high blood sugar levels. Everyone on a pump should be prepared to test for ketones and you can do this by way of a urine dipstick (ketostix or ketodiastix) or a fingerstick blood sample (Precion Xtra meter from Abbott).
Positive ketones are indicated by either of the following:
• Urine testing that indicates small, moderate or large levels of ketones (³15 mg/dl)
• Blood testing that indicates the presence of b-Hydroxybutyrate (³.6 mmol/l)
If your ketone test shows negative or trace amounts, your high blood sugar is probably due to insufficient insulin coverage for food you ate recently. Positive ketones indicate either an illness, infection or, more likely, a problem with the pump’s insulin delivery. Three steps should reverse the problem:
1. Give yourself an injection of insulin with a syringe (use your normal correction
formula to determine the dose).
2. Drink as much water as possible.
3. Change your pump’s cartridge, tubing and infusion set and use a fresh vial of insulin.
Remember, failure to correct the problem could result in ketoacidosis in just a few hours.
Insulin delivery problems can be caused by a variety of pump-related factors.
Tubing or infusion set clogs: tubing clogs are quite rare, but infusion set (specifically the cannula, or soft plastic tube below the skin) can become twisted and pinched off. To minimize the risk of a clog, change your infusion set every two or three days, and any time an occlusion/blockage detected/no-delivery alarm is triggered by your pump. If these alarms occur often, consider switching to a steel needle infusion set.
Leaks in the tubing or cartridge: Pump tubing can break if it is tugged, sliced, or chewed on by a pet. If you smell insulin, there may be a leak in the system. Change your tubing and cartridge immediately.
Air pockets in the tubing: One inch of air equals approximately ½ unit of insulin. Do your best to purge any air bubbles out of the cartridge before priming the tubing, and point the tubing up while priming. To help minimize the presence of foam, air pockets and large bubbles, be sure to: (1) lubricate the cartridge well before filling; (2) fill cartridges with insulin that is at room temperature; (3) pressurize the vial properly by injecting air into it first; (4) avoid twisting the plunger as you draw down; and (5) if necessary, push air and foam back into the vial several times while filling.
Dislodgement of the cannula from beneath the skin: Loose tape or a good tug on the tubing can pull the cannula out of the skin. Check your site visually or by feel a couple of times each day to ensure that your tape is fully in place. If it is peeling loose, remove the set and replace it.
Insufficient priming: If you fail to prime the tubing completely, you may end up with no insulin delivery for many hours. Prime until several drops come out the end of the tubing, and fill every new infusion set with an appropriate amount of insulin to take up the air space in the cannula.
Extended pump disconnection: If you disconnect from your pump for more than an hour it can result in a significant loss of basal insulin. If you need to do so, work with your health care team to come up with a plan for replacing the missed insulin. Some people reconnect hourly and bolus their missed basal amount; others bolus prior to their initial disconnection; others take injections of long-acting basal insulin prior to periods of disconnection.
Insulin spoilage: The insulin in your pump may be affected by extreme cold and heat. Cold is less of an issue, as long as the pump is worn near your body. However, heat can be a problem—especially during summer months. Exposing insulin to temperatures above 86°F for several hours can cause it to lose some of its effectiveness, and exposure to temperatures above 98°F for even short periods almost certainly will cause problems. And although humidity does not affect insulin, sunlight can. So keep your pump covered or shaded, and avoid prolonged exposure to hot temperatures. Use a cooling pack, such as the Frio pump pouch, when hot weather is unavoidable.
Hindered insulin absorption: This may be the single most common cause of erratic blood sugars for pump users. Poor absorption can result in highs (as boluses fail to kick in as expected) followed by lows (if or when the insulin finally kicks in later on). The best way to avoid absorption problems is to ROTATE, ROTATE, ROTATE! Those who use the same couple of infusion sites repeatedly tend to see diminished insulin absorption and action over time. A small amount of scar tissue remains after an infusion set is removed; hitting the same small area again too soon keeps the scarred area from healing properly. Use areas on both sides of your body, and utilize 10-15 different spots on each side. It is only necessary to move an inch or two each time you change your site.
Obviously, pumping insulin has its advantages as well as its drawbacks, but
when you depend on a mechanical device to deliver your insulin, you
must stay on top of your game. If insulin is not getting into your body or is not working properly, you could face serious health problems. If infusion set, cartridge or tubing changes are not immediately feasible, give yourself injections via syringe or pen. Don’t forget that old Boy Scout motto: Be
Gary Scheiner MS, CDE is a diabetes educator with a private practice (Integrated Diabetes Services) near Philadelphia, and author of Think Like A Pancreas: A Practical Guide to Managing Diabetes With Insulin. He has had Type-1 diabetes for 20 years, and offers diabetes education and management consultations via phone, fax, and Internet to patients throughout the world. Submit inquiries to [email protected], or call (877) SELF-MGT.