Infusion technologies of the '90s.

Reviewing the capabilities available to long-term care today

Tecnologic innovations have led to the development of new delivery systems for medications and intravenous fluids. Internal and external infusion pumps are two examples that will certainly find their way into long-term care facilities in the near future. Such devices allow for administration of substances via previously inaccessible or difficult-to-enter sites such as epidural, subarachnoid, intrathecal, or intraventricular, as well as intravenous and subcutaneous spaces.

Nurses are called upon for initiation of therapy, education of the patient, assessment, recognition and management of side effects and evaluation of the efficacy of these techniques. It is paramount that nursing personnel have an understanding of these innovations to facilitate optimal patient care intended by such advances in knowledge (see also, "What It Takes To Start An Infusion Therapy Program," p. 32, this issue).

To briefly review the available technology, specific treatment modalities include total parenteral nutritional support, hydration fluid therapy, intermittent antibiotic therapy, cancer chemotherapy and patient-controlled analgesia. Computerized programmable infusion devices are available for individualization of therapy for a given patient. Some pumps are programed by entering the desired information by hand, while others utilize bar codes containing the necessary information. One such device can be programmed through the use of a telephone using a lap top computer and modem, allowing for a physician or pharmacist to make adjustments in patients' regimens without having to be physically present in the facility. Medications are administered either by a syringe or cassette containing the drug which is attached to the pump. Such syringes and cassettes are prepared by the pharmacy and dispensed to the nursing unit.

Total Parenteral Nutritional Support

and Hydration Therapy

Although the need for parenteral nutritional support and hydration therapy is not commonly encountered in the nursing home as yet, it will be in the future. As Americans are living longer, more and more of our geriatric population will eventually require the services of a long-term care facility. Some of these patients will have previously been placed on parenteral nutritional support due to a non-functioning gastrointestinal tract.

An advantage of programmable infussion devices for large-volume fluid administration in institutionalized patients is that tapering rates can be set to automatically begin, taper and end infusions without nursing personnel physically making these adjustments. Additionally, these pumps usually have alarm systems which alert facility staff to malfunctioning of the equipment. For example, a patient may receive intravenous fluid administration over a 12-hour period in the evening. If the patient rolls over on the infusion catheter and impedes flow or fluid, an alarm will sound warning personnel of the need to reposition the patient to assure completion of therapy.

Antimicrobial and Cancer

Chemotherapy

Parenteral antimicrobial therapy may also administered by these programmable infusion devices. Pumps are commercially available which may be programmed to administer intermittent doses of antibiotics from a single cassette. Once the initial attachment of the pump to the patient has been made, no further nursing intervention, other than routine needle site inspection, etc., is necessary until the cassette requires replacing.

Cancer chemotherapy can be administered similarly. Doses are generally given on a daily basis until the total prescribed dose has been administered. Interestingly, antiemetics for control of nausea and vomiting associated with these drugs are often administered in a similar fashion.

Other drugs which are chemically stable at room temperature in a syringe or cassette could possibly be administered by this means in the patient unable to tolerate oral medications. For example, a case can be made for administering dobutamine therapy in this way in patients with congestive heart failure unresponsive to oral medication.

Analgesic Therapy

Patient-controlled analgesia (PCA) is probably the most popular form of therapy utilizing the techniques described thus far. The infusion device is connected to an intravenous, subcutaneous, ventricular, epidural or subarachnoid catheter, and narcotic analgesics can be administered by the patient's activating a button attached to the pump. Such devices can be programmed to deliver a specified dose of medication on demand at predetermined time intervals (usually every 5 to 10 minutes). This latter feature prevents the patient from overdosing or abusing the analgesics.

Once satisfactory analgesia is achieved, patients generally require less analgesia than when it is administered by P.R.N. intramuscular dosing. Additionally, patient controlled analgesia can be accompanied by a continuous infusion of narcotic utilizing the same infusion device. Such therapy is especially effective in the management of chronic refractory pain associated with cancer.

The major advantage of PCA is in maintaining a minimum effective analgesic serum concentration without producing toxicity and/or recurrence of pain. These latter two problems are commonly encountered in patients receiving traditional P.R.N. intramuscular administration of analgesics.

Such patients, upon the onset of pain, request a dose of narcotic to be administered. At that time the nurse prepares the dosage form and administers the drug (this process has been shown to take as long as 30 minutes to one hour following the patient's initial request). At this point, the patient may be experiencing severe or excruciating pain. Absorption of narcotic from the muscle takes over 30 to 40 minutes before a peak analgesic effect is achieved. Unfortunately, this peak effect is often accompanied by toxicity (i.e., significant sedation, possible respiratory depression, etc.). As serum levels of narcotic begin to decline, analgesia will be maintained for three to eight hours (depending on the agent used) followed by a recurrence of pain, and the cycle repeats itself.

PCA breaks this cycle and allows the patient to administer a dose of analgesic at the onset of the pain sensation, resulting in immediate relief. Because the dose is small (.e.g, 0.5 to 1.0 mg morphine sulfate IV), toxicity does not occur.

Studies have demonstrated that PCA provides pain relief superior to the traditional intramuscular route of administration, with fewer side effects and complications from narcotics and reduced nursing time for dose administration. Contra indications to this form of therapy include an inability or unwillingness to understand the concept and/or a physical incapacity to press the button that administers the dose. Obese individuals suffering from obstructive sleep apnea or hypoventilation syndromes may be at higher risk for narcotic-induced respiratory compromise and should be more closely monitored. In fact, it has been suggested that continuous administration of narcotics should be avoided in these patients initially.

Implantable infusion devices are also utilized for narcotic analgesic administration. These pumps are surgically implanted in the subcutaneous tissues, usually in the abdominal area, and a catheter attached to the pump is placed intravenously or in the epidural or subarachnoid space. Programming is accomplished by utilizing a computerized device which regulates the rate of infusion of drug from the pump. Adjustments in the rate of administration can be made as the patient's analgesic needs change. These infusion devices contain a reservoir into which the drug is placed via an injection through the skin. Refilling of the reservoir may not be necessary for as long as eighteen to twenty-five days.

This method is an excellent means of managing intractable pain from malignancy as well as non-malignant pathology. Interestingly, cancer chemotherapy can also be administered by this modality.

Disposable infusion devices are also available for drug administration. Following completion of the infusion, the device is replaced by another. A major advantage of this method is cost savings, as programmable infusion devices are expensive. For short-term therapy, disposable infusion devices are more cost-effective, whereas in situations in which long-term infusions are needed, purchasing a programmable device will result in cost savings.

Conclusion

Advancing technology has revolutionized medication and intravenous fluid administration. Many of the infusion pumps developed will improve therapy in nursing home residents. It is of utmost importance that nursing personnel in these facilities have working knowledge of these devices so that optimal patient care can be provided as residents' medical needs evolve.

William E. Wade, Pharm.D., is Associate Professor at the University of Georgia College of Pharmacy, Athens, GA.