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Modernising management with insulin pump therapy

Peter Jennings
BSN BAPsychol
Diabetes Specialist Nurse
Jenny O'Neill Diabetes Unit
Derbyshire Royal Infirmary
Derby
E:Peter.Jennings@sdah-tr.trent. nhs.uk

Insulin pump therapy is a method of administering insulin using a pager-sized, battery-driven pump. A syringe reservoir filled with short-acting insulin fits inside the pump and connects to a catheter inserted into the subcutaneous tissue of the patient.
The pump automatically delivers a continuous infusion of short-acting insulin to stabilise the glucose. This basal rate, which is programmed by the patient, can be immediately adjusted depending on individual insulin requirements. For example, to reduce the risk of hypoglycaemia, a basal rate of 1 unit per hour could be reduced to 0.5 units per hour during exercise.
When eating, the patient programmes the pump to deliver a bolus of insulin. The number of units required relates to the amount of carbohydrate consumed. An apple at lunchtime may require just one unit of insulin, but a bag of chips at dinner might require 10 units. The bolus replaces the usual mealtime insulin pen injection.
Insulin is delivered to the patient via a small Teflon catheter placed in the subcutaneous tissue. Every three days the patient performs a set change that takes approximately five minutes. This involves filling a new syringe reservoir with insulin, priming the infusion tubing and inserting a new catheter. Insulin pump therapy requires fewer injections as patients only site the catheter once every three days instead of giving themselves four injections per day using a typical basal/bolus regimen. The pump-user should not feel any discomfort when the catheter is in situ as the metal guide needle is removed following insertion.
Pumps mimic the continuous insulin secretion of a healthy pancreas by accurately delivering small pulses of short-acting insulin. Continuous delivery into one area (such as the abdomen) leads to more reproducible insulin absorption, resulting in more stable glucose levels compared with injecting intermediate- and long-acting insulin around numerous regions (the abdomen, legs and buttocks).(1)
The ability to programme the pump allows insulin regimens to be tailored to the individual. Basal rates can be set to deliver more or less insulin at specified times. For a patient with history of nocturnal hypoglycaemia, the basal rate could be programmed to decrease at night and return to a higher rate during the day.
With the basal rate delivering a constant supply of insulin, a patient can sleep late, miss breakfast and still expect to have a normal glucose value. Patients with erratic lifestyles, such as shift workers, frequent travellers or busy mothers, benefit from the flexibility of choosing when to eat. Neither snacks nor set mealtimes are necessary, as patients programme a bolus of insulin when they choose to eat.
Insulin pumps do not require any daily maintenance. They are durable and can withstand being dropped or bumped. Pumps have safety alarms that sound if insulin delivery is interrupted due to a clogged infusion set, empty reservoir or low battery. If the pump stops working the patient must temporarily resort to insulin injections until the problem is resolved. Pump manufacturers offer 24-hour telephone support to assist with technical difficulties.
Many people wear the pump like a pager. Because the pump is small, it is easy to conceal completely. Some pumps also include a remote control to allow more discrete programming. At night, it can be connected to pyjamas or placed under a pillow. Patients can temporarily disconnect from the pump when bathing, swimming or exercising.
 
The history
Insulin pump therapy is not a new treatment for diabetes. Its use was first reported in 1978 by a team from Guy's Hospital in London.(2) However, shortly after being introduced, reports were published suggesting that insulin pump therapy was associated with a high incidence of diabetic ketoacidosis (DKA) and infected infusion sites.(3,4) As a result, pump therapy fell out of favour in the UK. Advances in pump technology and improved patient education led to wider usage outside the UK, where pumps became recognised as a safe and valuable treatment option. Currently, more than 100,000 patients in the USA, 30,000 patients in Germany and 20,000 patients in France are estimated to use pumps, compared with less than 1,000 patients in the UK.

Benefits
Recent studies have shown that pumps can reduce the incidence of severe hypoglycaemia and improve quality of life. The risk of DKA appears to be equal to that for injection therapy.(5,6) The Diabetes Control and Complications Trial showed that intensively managing diabetes resulted in lower blood glucose and prevented or delayed the onset of diabetic complications such as retinopathy by 76%, neuropathy by 60% and kidney disease by 54%. During the last year of this study, 42% of the intensively managed group were using pump therapy.(7)
Ideally, intensive management of diabetes first involves educating well-motivated patients to take control of their diabetes using multiple injections of insulin. Patients are taught how insulin, exercise and food affect blood glucose. Patients monitor blood glucose levels at least four times per day and have the knowledge to take action based on those readings.(8) Insulin pumps should be used as a component of intensive diabetes management programmes. The clinical effectiveness of pump therapy can be more accurately determined when comparing outcomes from intensively managed patients using injections to those using pumps.(6)
Normally, an experienced physician and diabetes specialist nurse initiate pump therapy at the outpatient diabetes clinic. Nurse educators employed by pump manufacturers can also provide training to healthcare teams or potential users. Individuals may initially spend 2-3 days wearing a pump with a saline infusion to become familiar with the device. This valuable experience answers many questions and provides an opportunity for the patient to practise programming and set changes without the anxiety of mistakenly overdosing insulin. When patients feel confident, the crossover to insulin is less threatening. Patients should be familiar with adjusting infusion rates, caring for infusion sites, treating hypoglycaemia and safely managing hyperglycaemia in order to prevent DKA. Pump manufacturers initially provide a trial period or money-back guarantee, in case a patient is dissatisfied with the therapy. Following the adjustment period, pump patients require similar ongoing support as those injecting insulin.

Current status
Insulin pump therapy is regaining momentum within the UK. This rapid growth is fuelled by a renewed interest from healthcare professionals and strong patient demand. Diabetes UK recognises insulin pumps as a beneficial therapy "in terms of overall control and quality of life", and believes that pumps should be available to patients according to their clinical need and not their ability to pay.(8) Insulin pumps cost 0„52000 and require an additional 0„51000 pounds per year to purchase infusion sets, reservoirs and batteries. Pump therapy is not routinely funded within the NHS; however, some health authorities will pay the costs.
The National Institute for Clinical Excellence (NICE) is conducting an appraisal of insulin pump therapy with the following objective: "To establish the clinical and cost effectiveness of insulin pump therapy in both type 1 and type 2 diabetes, to advise on the criteria for selecting patients for whom this treatment would be particularly appropriate and to provide guidance to the NHS in England and Wales."(9) Recommendations from NICE supporting the use of insulin pumps and NHS funding for the costs would result in more widespread use within the UK.
Inexperienced healthcare professionals may not feel confident caring for those patients using pumps. Pump Management for Professionals (PUMP) is a national professional group that can advise on the use of pump therapy. PUMP holds annual meetings and offers professional training courses (see Resources).

Conclusion
All healthcare providers should feel encouraged to learn about insulin pump therapy from the experts - the patients themselves. Many will be delighted to demonstrate how their pumps work, show infusion sets and share how their diabetes management has changed since switching to insulin pump therapy. No matter how experienced the pump user, practice nurses can reinforce the need for frequent blood glucose testing, rotation of infusion sites and ensure that patients can safely switch to insulin injections in case of an emergency. For suitable patients struggling to intensively manage their diabetes using insulin injections, practice nurses can raise awareness that pump therapy exists as a treatment option that may ease the burden of living with diabetes.

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References

  1. Lauritzen T, Pramming S, Deckert T, Binder C. Pharmacokinetics of continuous subcutaneous insulin infusion. Diabetelogia 1983;24:326-9.
  2. Pickup JC, Keen H, Parsons JA, Alberti KG. Continuous subcutaneous insulin infusion: an approach to achieving normoglycaemia. BMJ 1978;i:204-7.
  3. Mecklenurg RS, Benson EA, Benson JW Jr, Fredlund PN, Guinn T, Metz RJ. Acute complications associated with insulin infusion pump therapy. Report of experience with 161 patients. JAMA 1984;252:3265-9.
  4. Knight G, Jennings AM, Boulton AJ, Tomlinson S, Ward JD. Severe hyperkalaemia and ketoacidosis during routine treatment with an insulin pump. BMJ 1985;291:371-2.
  5. Bode BW, Steed RD, Davidson PC. Reduction in severe hypoglycemia with long-term continuous subcutaneous insulin infusion in type I diabetes. Diabetes Care 1996;19:324-7.
  6. Boland EA, Grey M, Oesterle A, Fredrickson L, Tamborlane WV. Continuous subcutaneous insulin infusion. A new way to lower risk of severe hypoglycemia, improve metabolic control, and enhance coping in adolescents with type 1 diabetes. Diabetes Care 1996;22:1779-84.
  7. The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:683-9.
  8. Diabetes UK. Pump therapy. Position statement. London: Diabetes UK; 2001. Available from URL:http://www.diabetes.org.uk/infocentre/state/pump.htm
  9. National Institute for Clinical Excellence. The clinical effectiveness and cost effectiveness of insulin pump therapy. Technology appraisal. London: NICE; 2002. Available from URL: http://www.nice.org.uk

Resources
Pump Management for Professionals (PUMP)
Professional organisation promoting pump education and research within the UK
E:joan.everett@virgin.net
or
E:diabetes.team@hhc-tr.northy. nhs.uk
INPUT
Patient-led support group for insulin pump users in the UK
W:www.geocities.
com/Vienna/Strasse/5726/input/home
Insulin
Pumpers UK
Website devoted to pump users
W:www.insulin-pumpers.org.uk
Diabetes UK
W:www.diabetes.org.uk
NICE
W:www.nice.org.uk

Further reading
Walsh J, Roberts R. Pumping insulin: everything you need for success with an insulin pump. San Diego: Torrey Pines Press; 2000