Applications

In these pages we aim to provide full information about the products and as much detail as we can about the various applications. There is a brief explanation of why pumps may be considered appropriate for certain types of drug administration.

WHY USE A PUMP?

The aim of any drug administration therapy is to alleviate symptoms of a condition, (e.g. We take Aspirin to get rid of a headache), or to eliminate the causes of an illness (e.g. We take antibiotics to treat a bacterial infection). To achieve this the person responsible for the administration will determine a dosage which will achieve the desired effect.

MORE INFORMATION

In general this means that an estimate will be made of the level of drug which will circulate in the bloodstream to achieve the desired effect. So we will decide to take one, two or three aspirin depending on the severity of the headache.

The level at which a drug becomes effective can be termed the therapeutic level, and the aim of any administration is to achieve this level for a specified period of time. This is difficult to determine precisely as the rate of absorption of the drug into the bloodstream is variable, and of course the drug will get metabolized in the body chemistry which will reduce this effect.

The diagram below shows how the blood level of a drug will vary with time as the result of a single injection, or oral dose of medicine.

The injection will not reach the therapeutic level in the blood until some time after the dose has been administered. In general, however, for the drug to be effective over a period of time the initial dosage will cause the blood levels to rise significantly above the desired therapeutic level. This is to ensure that the drug is not eliminated from the body so quickly that it cannot be effective.

In many cases, of course, this may not be particularly important. However, unfortunately, many of the drugs that we take can be toxic, or have unpleasant side effects, if the blood levels become too high. It then becomes a difficult exercise to get the appropriate balance between effectiveness and limitation of side effects.

Examples of drugs where this may be important are Insulin, Diamorphine for pain relief, and many Chemotherapy agents which can be highly toxic.

In effect pumps can be considered to be giving frequent small injections, and would provide a pattern as shown below.

A short while after the administration has started the drug will have achieved its therapeutic level. Then the frequent addition of small doses of the drug will maintain this level, without producing the excessive, and possibly toxic, levels provided by the more conventional route.

Pumps are widely used in the hospitals to give continuous infusion of a variety of medications. AMT, however, is concerned exclusively with those therapies which use portable pumps to allow individuals to receive the treatment away from the hospital environment.

PUMP THERAPY AND ASTHMA

AMT products are employed only in a specialised area of Asthma therapy. Asthma is a common condition frequently related to various allergies, and unfortunately with apparently increasing frequency.

In these pages we will only address those limited areas where we have a direct interest. However we have also researched the Internet resources in this field, and have provided a number of links which we hope will be found useful for those interested in this general topic.

We have also included the above section titles MORE INFORMATION explaining why Pumps, which provide a continuous infusion, may offer benefits over more conventional intermittent injections.

There are, at present, two pioneering centres in the UK who are using pumps to provide continuous subcutaneous infusion of Terbutaline (Bricanyl) as a means to control some extremely difficult cases of asthma. To provide a professional overview of this application we have had permission to reproduce a published article which discusses the control of Brittle Asthma and refers to the use of infusion pumps in this area.

Our infusion products are widely used in this area and there is a wide choice to suit individual patient requirements. Products of particular benefit in this therapy are Saflo™ and Saflo™ 90 needle safe infusion sets, the Medtronic Silhouette or Quick-Set Infusion Sets and the Neria™ Soft range of products.

The special feature of these sets is that they use soft teflon connections in place of conventional needles. These are much more comfortable for the individual, and significantly reduce the problems of allergic reaction at the infusion sites. This provides an opportunity for long term infusion to make this therapy effective.

The Crono and Crono 30 pumps are widely used in this application.

PRIMARY IMMUNODEFICIENCY (PID)

With the recent introduction of Immunoglobulin drugs licenced for subcutaneous infusion there has been created a need for a suitable device for the delivery of these drugs. The viscous nature of these drugs, and the fast infusion times currently required, are a challenge to current pump technology, and the Super PID pump has been specifically developed to meet this requirement.

Main Relevant Products: Crono Super PID, Crono S-PID 30, Crono S-PID 50, Crono Twin, Neria range of needle sets, Saflo™ 90.

ONCOLOGY

There is widespread use of portable infusion devices for the administration of therapeutic agents in Oncology. Continuous infusion of these drugs, as opposed to large bolus injections, enables them to be employed more effectively, whilst helping to minimise some of the extreme side effects that may occur.

Main Relevant Products: Crono SC 50.

PAIN RELIEF MEDICATION

The most common application in this area is the continuous administration of Diamorphine as a means to control pain, frequently associated with end stage cancer therapy. Most usually pumps like the McKinley T34 are employed in this area, but where portability is an important factor the CronoCrono 30 and the Crono SC 50 pumps can be of benefit.

HORMONE THERAPY

Pumps have been employed in the area of fertility control for some time but this appears to be diminishing now. The most frequent applications have been the use of GnHRH and LHRH infusions. A particular requirement for pumps in this area is for drugs to be administered as pulses at fixed intervals, typically 90 minutes, to mimic the normal Hormone release mechanisms.

The recent introduction of the Crono P pump, however, may well broaden the range of applications.

REHYDRATION

More recently we have become aware of the use of subcutaneous infusion to provide a route for medium volume rehydration. This has been developed to avoid the need to use the more conventional Intravenous route in areas where there may not be the appropriate clinical support, for example in Nursing Homes. This therapy is termed HYPODERMOCLYSIS.

Main Relevant Products: Saflo™ 90.

PARKINSONS DISEASE

The continuous subcutaneous infusion of Apomorphine is used in the treatment and support of this condition.

Main Relevant Products: Neria™, Saflo™ 90.

ADDISON'S DISEASE

Exciting new work on pulsatile cortisol for Addison’s Disease is being performed using the Crono P pulsatile infusion pump. The primary researchers working on it are Georgina Russell and Stafford Lightman in Bristol. The following links will provide more information on this.

Subcutaneous pulsatile glucocorticoid replacement therapy. More Information

Cardio-metabolic consequences of glucocorticoid replacement: relevance of ultradian signalling. More Information

Subcutaneous pulsatile glucocorticoid replacement therapy. More Information

Main Relevant Products: Crono P, Quick-Set Infusion Sets.

SITE DEVELOPMENT

These are areas of therapy where there is little information readily available. We would welcome any contributions which provide additional information on these topics, which we will publish and/or link to from these pages. Please email us or visit our contact page if you have something you would like to contribute.