Insulin pumps deliver rapid- or short-acting insulin 24 hours a day through a catheter placed under the skin. Your insulin doses are separated into three doses: basal, bolus, and correction.
Basal insulin is delivered continuously over 24 hours, and keeps your blood glucose levels in range between meals and overnight. Often, you program different amounts of insulin at different times of the day and night.
When you eat, you use buttons on the insulin pump to give additional insulin called a bolus. You take a bolus to cover the carbohydrate in each meal or snack. If you eat more than you planned, you can simply program a larger bolus of insulin to cover it.
You also take a bolus to treat high blood glucose levels. If you have high blood glucose levels before you eat, you give a correction or supplemental bolus of insulin to bring it back to your target range.
(Source: American Diabetes Association)
A CGM is a small wearable device that tracks your glucose throughout the day and night, notifying you of highs and lows so you can take control of your blood sugar levels.
The continuous glucose monitor automatically checks your blood sugar every 5 minutes and displays your “numbers” on a screen. It also features a convenient application that is accessible to iPhone and Android users..
Please note that the Freestyle Libre sensor is a little bit different due to the fact that it will not alert you when you are high or low. You use the handheld reader to scan the sensor to check sugars.
The CGM consists of three parts:
wireless display device (or receiver) – has a screen where you can check your current glucose level, look at past data over a span of 24 hours, and get trends about whether glucose is likely to go up or down, and how fast.
transmitter – is the small piece that fits onto the sensor and sends glucose information data wirelessly to your display device.
sensor – is inserted just underneath the skin, is thinner than a needle and roughly half an inch long. The sensor remains in the skin for several days, detecting glucose information.
(Source: Beyond Type 1)