Insulin Pump


Insulin Pump, Medtronic Minimed, Tandem T, Insulet Omnipod

  • Epidemiology
  1. Insulin Pump used by more than half of Type I Diabetics
  • Background
  1. Device that delivers Insulin subcutaneously
    1. Most patients use a rapid-acting Bolus Insulin (e.g. Lispro or Humalog) in Insulin reservoir
    2. Device can deliver Insulin basal rates down to 0.01 units/h
  2. Costs
    1. Pumps typically cost $4000 to $6000 with a monthly cost of $300 to $500 for supplies (2022)
    2. Type II diabetics may have more out of pocket expenses (non-reimbursed costs) than type 1 diabetics
  • Indications
  1. Type I or Type II Diabetes Mellitus on multiple Insulin injections per day AND
  2. Capable and willing to manage the complexities of Insulin Pumps and related activities (e.g. carb counting)
  • Components
  1. Insulin Pump
    1. Insulin reservoir (disposable)
      1. Filled with U-100 (100 U/ml) Bolus Insulin (highly concentrated)
      2. Bolus Insulin used is typically InsulinLispro (Humalog) or InsulinAspart (Novolog)
      3. Bolus Insulin is infused at a slow basal rate plus meal time bolus doses
    2. Control pad
      1. Pager-sized hand-held computer with small screen
      2. Enter Insulin Infusion maintenance rate (basal rate)
      3. Enter bolus dose directly or calculated based on Carbohydrate intake
  2. Infusion set (disposable)
    1. Tubing
      1. Connects Insulin Pump to subcutaneous insertion site
      2. May be disconnected when showering, bathing, swimming
    2. Cannula to insert subcutaneously
      1. Introduced in similar fashion to IV start (except subcutaneous)
      2. Needle is used to introduce the catheter subcutaneously
      3. Needle is removed after insertion and catheter is left in place
    3. Variations
      1. Omnipod
        1. Wireless Insulin reservoir attached directly to body at subcutaneous insertion site
        2. No tubing is required
        3. Controlled by a wireless device
  3. Insertion site
    1. Subcutaneous cannula with adhesive to hold it in place
    2. Changed every 3 days (up to 5 days)
      1. Rotate infusion sites to avoid infection, Lipodystrophy
    3. In rare cases, site may become infected
  4. Additional functions
    1. Some pumps allow for Continuous Glucose Monitoring
    2. Some pumps are waterproof (others, such as Tandem, must be removed for bathing or swimming)
    3. Pumps function continuously (providing basal Insulin) and pausing pump (without detaching) is more complicated
  5. Other related, but separate components
    1. Continuous Glucose Monitor (CGM)
      1. Some CGMs integrate with Insulin Pump to function as a "Closed loop system"
      2. Alternatively, without a CGM, patients should check Blood Glucose at least four times daily
  • Protocol
  • Pump Malfunction
  1. Typically results in Hyperglycemia (not Hypoglycemia)
  2. Examples
    1. Pump failure
    2. Tube disconnected
    3. Infusion set leak
    4. "Insulin Bad"
    5. Subcutaneous insertion site problem (e.g. insertion at scarred tissue)
  3. Prevention
    1. Have emergency supply of backup Insulin and syringes in case of pump failure
    2. Patients should keep a copy of their current pump settings
  1. Attempt to use pump to deliver Insulin boluses
    1. Tests if the Insulin Pump (and infusion set) is functional
  2. Persistently high Blood Glucose values
    1. Subcutaneous Insulin injections can still be given in addition to pump
  3. Detach the pump in severe hyperglycemia Critical Illness or Diabetic Ketoacidosis
    1. Manage per Insulin Drip or Hourly Subcutaneous Insulin protocols
  1. See Hypoglycemia Management in Diabetes Mellitus
  2. Immediately detach pump in severe hypoglycemic episode
  3. Causes
    1. Patient error (too high of Insulin dose selected)
    2. Acute illness (e.g. Acute Kidney Injury, infection)
  • Procotol
  • Hospitalization
  1. Consult endocrinology as needed
  2. Leave Insulin Pump attached in most cases to provide Insulin basal rate in the hospital setting
    1. Risk of DKA while detached (patient has no sustained basal Insulin activity, e.g. Insulin Glargine)
  3. Detach the Insulin Pump during hospitalizations where Insulin will be managed by nursing and provider orders
    1. Initiate subcutaneous or intravenous Insulin within 30 minutes of discontinuing Insulin Pump
    2. Indications to detach Insulin Pump
      1. Insulin Pump malfunction (or supplies unavailable)
      2. Critical Illness
      3. Poor Glucose control
      4. Altered Mental Status
      5. MRI
  • Adverse Effects
  1. Lipodistrophy
  2. Cannula site pain
  • Safety
  1. Diabetic Ketoacidosis is NOT more common with Insulin Pumps (per T1D registry)
    1. Theoretic risk of unrecognized pump failure did not occur significantly in reality
  • References
  1. (2022) Presc Lett 29(5): 27-8
  2. Claudius and Pedigo (2021) EM:Rap 21(8): 10-12
  3. Smith (2018) Am Fam Physician 98(3): 154-62 [PubMed]