There had been many innovations for developing equipment that could deliver nutrients or even doses of medications inside a person’s body. One of these developed medical devices is the infusion pump. Infusion pumps are used to deliver nutrients and medications, such as antibiotics and pain killers. They can also be used to administer chemotherapy drugs which, if not administered properly, can be the difference between life and death for the patient (Brady).
Infusion devices are usually classified based on the power source used and could be either of two types: gravity controllers or infusion pumps. Gravity controllers, which utilize gravity, are usually used in applications with lower risks, such as in fluid replacement therapy. On the other hand, infusion pumps can be pneumatic, electrical or mechanically powered devices. Infusion pumps are further classified into different types, namely, syringe pumps, elastomeric pumps, patient-controlled analgesia (PCA) pumps, anesthesia pumps, ambulatory pumps and volumetric pumps (Infusion Pumps).
Volumetric infusion pumps are more commonly used for medium to high rates, as well as for enteral or large-volume intravenous infusions. Furthermore, this type of infusion pumps is most suited for the administration of therapies of categories B and C. Category B are therapies which involve the administration of drugs, more specifically those not with short half-life, and also diamorphine. Category C therapies involve fluid maintenance transfusion. But then, not all category C therapies require pumps for they can also be administered using gravity controllers (Infusion Pumps).
Plum A+: Principles and Procedure
A more specific type of a volumetric infusion pump is Plum A+. This type of pump is a multi-function cassette-based infusion pump with one line out and two lines in. The pump is usually used for countercurrent, standard or “Piggyback” delivery. Plum A+ infusion pump therapy modes include standard infusions, a multistep programming, a loading dose and lastly dose calculations. A Plum A+ infusion system includes a pumping module, which is specifically the pump, a set of assorted disposable IV’s, optional accessories and lastly an operating manual. It is actually used in a wide range of surgical or medical applications and also finds use in critical care. The Plum A+ can be applied, but not limited, to the following disciplines: hemodialysis, burn unit, pediatrics and neonatology (Abott Plum A+).
Since the administration of an infusion pump is very critical, user qualifications are defined. Plum A+ should only be used under the supervision of a licensed physician. Supervision may also be done by other healthcare professionals who have undergone training regarding the administration of enteral, parenteral and epidural fluids. Epidural administration of fluids can be used in providing analgesia or anesthesia. Training includes the prevention of IV-related complications and also precautions in preventing accidental air infusion (Abott Plum A+).
The Plum A+ infusion pump is, according to the Abbott Plum A+ operation manual, compatible with administration sets manufactured by LifeCare Plum series. All discussions regarding the use of the Plum A+ will be based on the Abott Plum A+ operating manual. Before preparing an administration set, the user has to be familiar with the components of the set. A diagram of an administration set can be found in the appendix as Figure 1. In preparing the administration set, a person has to apply aseptic technique for priming. Before proceeding, the regulator should be closed. The piercing pin should be inserted into the container outlet by a twisting motion. The drip chamber should be field to the score mark or until the chamber is half full. It should be noted that the chamber should not be completely filled.
Since the administration needs to be primed first, the first step that needs to be done is by inverting the cassette. Then the flow regulator should be tuned counter-clockwise until a drop of the fluid is visible inside the pumping chamber. The cassette would be turned upright and then the remainder of the set will be primed. Confirmation that there is no flow is done by closing the flow regulator. After priming the cassette, the next step is to load the cassette into the Plum A+ infusion set. To insert the cassette, the cassette door should be lifted by the handle and inserting it into the door guides. Then the cassette door should be closed and it should also be confirmed that there are no kinks in the tubing and that there is no flow. In case there is flow, the tubing clamps should be closed and the administration set should be replaced. Proper disposal of the replaced administration set should be carried out.
In a cassette, there are two lines namely line A and line B. Line A is the inlet line into the cassette situated at the top center portion of the cassette. Line B on the other hand is the inlet line situated at the top right portion of the cassette. The Plum A+ runs on either the Concurrent or the Piggyback delivery mode if two fluids are to be administered. A Piggyback delivery mode is when line B delivers fluid first then followed by line A. Meanwhile a Concurrent delivery mode is when two fluids are delivered simultaneously but the two fluids are running or being delivered at two independent flow rates.
The Plum A+ could use vials or syringes on second port. Even without re-priming the cassette, the secondary line could be prepared. Aseptic technique should be performed in preparing the secondary line. Then, the white cap should be loosened, removed, and properly discarded. The secondary syringe or tubing is then added. Before pressing start, the proximal clamps should all be opened. After this, the pump could be set-up following the operating instructions. If a vial or syringe is used, the container should be secured to the cassette door by using the container support arm which is optional. Furthermore, if a vial is used, the vial adapter should be attached to the secondary port. If necessary, the air present in the vial adapter should be back-primed into the vial.
If the fluid flow needs to be discontinued, the fluid flow should be stopped by pressing top on the keypad first. The door should be opened to remove the cassette. It should be known that to prevent free flow, the flow regulator will close automatically if the door is opened. Also, if the door is opened and the alarm sounds, the pump should be turned off. The gravity rate should be set by turning the flow regulator in a counter-clockwise direction noting that the cassette is maintained in an upright position.
Figure 2 of the appendix shows the Keypad and Front Panel Display Basic Layout of the pump. For safety, the Plum A+ needs to undergo self-tests before it could be used to administer fluids into patients. Thus, the Plum A+ must not be used if it fails these self-tests. These specific tests are always performed whenever the pump is to going to be used to evaluate the readiness of the equipment for operation. To perform these tests, upon turning the equipment on, a beep should be heard, and this will verify that the audio of the equipment is properly working. Then, the equipment will proceed with self-testing, and if successful, a cassette that is fully primed can then be installed.
Plum A+: Buttons, Indicators and Display
The keys on the keypad and front panel will now be discussed. Basically, the [ON/OFF] key’s basic function is to turn the equipment on or off. However, it should be noted that for the equipment to power off, fluid deliveries should be stopped first. An indication that the equipment has properly shut down is a ‘double beep’ sound. If this set of beeps is not heard, this means that the equipment will be turning back on and will run on the back-up power of the battery. Basically, the [START] key is used to begin fluid deliveries or infusions, and it is also used as indication that the programming has been confirmed. On the other hand, the [STOP] key is basically used to stop a fluid delivery as discussed previously. To stop the flow on both lines, the [STOP] key is used together with softkeys. If an alarm sets off and the alarm is being addressed, the [SILENT] key is used. To move the cursor on the programming field, the [SELECT] key is used. Also, from the figure, it could be observed that there are numerical keys. These keys are used whenever a field is requiring the input of a numerical data. If a data entry needs to be cleared, the [CLEAR] key is used while the [DECIMAL POINT] key is basically used whenever there is need to input values with decimal places.
The softkeys serve a variety of functions. These keys are usually located at the bottom part of the main display. Each key’s function is indicated by whatever is in display above that softkey.
There are three indicators that could be found on the display. These indicators are the Charge/Line indicator, the fluid drop symbols, and the battery capacity. The Charge/Line indicator basically indicates if the equipment’s battery is charging. It should be noted that if the equipment is plugged in while the battery is intact, and the indicator is not on or illuminated, the technical support should be contacted in order to diagnose the problem on the equipment. If there is an active infusion, the fluid drop symbols located on top of the display should be flashing. These fluid drop symbols indicate fluid flow for lines A and B. There is also battery capacity symbol or indicator found on the right portion of the message region.
The equipment also feature rear case controls located on the back of the equipment. There is an audio rotary knob that is used to adjust or change the audio levels of alarms. Below this knob is the toggle switch. If the toggle switch is in ‘up’ position, it means that the lockout function is activated. Meanwhile if it is on the ‘down’ position, it means that the front panel is disabled, except for the [STOP] key. Below the toggle switch is the Nurse Call Relay Connector which provides a notification to the nurse whenever needed. Also, there is an RS-232 DataPort used to connect to a computer host.
For simple deliveries or fluids or simple infusions, the delivery rate can be programmed by pressing the softkey which indicates ‘A’. Then, the delivery rate can be entered by using the numerical keys. As previously discussed, the [SELECT] key is used to toggle between the fields on the main display. After the delivery has been set, the VTBI amount is also entered using the number keys. Pressing the ‘down’ portion of the [SELECT] key makes the cursor go to the DURATION field. Then, the number keys can again be used to change the duration of the infusion in terms or hours. The duration could also be changed from hours to minutes. It should be noted that if any of these parameters are changed, the other parameters will be automatically recalculated. Before pressing [START] to initiate the infusion, all the parameters on the field should be verified first.
Simple deliveries can also be administered using the drug list. On the main delivery screen, either A or B is selected using the softkeys. The values for the rate of the fluid flow, VTBI and duration are entered. The softkey indicating [Program Options] is pressed, and a drug list screen appears by pressing the [Drug List] softkey. To highlight a specific drug name, the [SELECT] key is employed and the [Enter] soft key is pressed if a selection has been made. Then, the parameters are verified and the infusion can start.
For titration, the softkey indication A or B is presses. Then, the desired fluid flow rate is entered. Again, if the rate is changed, the duration of the delivery will be automatically calculated. This time, the current VTBI value will be used to recalculate for the new duration period. As previously stated, before pressing [START], all of the parameters on the main display screen should be verified first.
For a Piggyback delivery, the infusion will stop fluid delivery on line A and start infusing Line B until the VTBI is completed then Line A automatically restarts. With the infusion starting on line A, press the [B] softkey to program a Piggyback delivery. The mode can be changed using the [Change Mode] softkey. The fluid flow rate is then entered on the RATE field, the VTBI value is entered as well as the duration. The infusion is then initiated if all the parameters on the main screen display have been verified.
For Concurrent delivery, the two fluids are delivered simultaneously, but are being delivered at independent flow rates. In this type of delivery, an alarm could occur when one of the line stops while the other continues to deliver the fluid. Just like what was done on the Piggyback delivery, the mode is changed to Concurrent by using the [Change Mode] softkey. Then values for the rate, VTBI and duration are entered using the numerical keys and [SELECT] key to toggle between the fields. These entered values are again verified first before the infusion is started.
Back-priming is done in order to remove fluid or air in the cassette air trap and in the proximal line. However, it is necessary that the [Back Prime] softkey is applied with a long press until the fluid coming from Line A to B has pushed the air from the air trap to the secondary container. Note that the fluid flow in this set up is at its maximum possible rate. Upon releasing the [Back Prime] softkey, the cassette will be tested in order to confirm if the equipment is ready for pumping. After this, the [START] key is pressed to resume the previously programmed delivery.
Plum A+: Risks and Errors
It was previously stated that infusion pumps are used to effectively deliver nutrients and medicines to patients. But then, with any other medical procedure, malfunctions and faulty administrations cannot be overseen. One misplaced decimal point, for example, in the parameters needed for infusion, can cause life or death situation for the patient. This kind of incident defeats the purpose of having medical treatments which is for the patient to be treated. Through the years, a lot of incidents have been reported regarding the use of infusion pumps. It should be noted that this incidents are not for Plum A+ specifically but for all kinds of infusion pumps or infusion systems.
On 1987, the artist Andy Warhol died due to a cardiac arrhythmia which occurred during a gall-bladder surgery. But then, this subject was brought to court and the family argued that the cause of death of the artist was due to a misadministration of an infusion pump. The arrhythmia was, according to the lawsuit filed by the family, due to water intoxication during the infusion. With this argument, the family of Warhol won and the New York City Hospital paid millions due to this error (Brady).
Some infusion errors may include battery malfunctions, software errors, dosage calculations and opioid overdoses. Between 2005 and 2009, the United States Food and Drugs Administration of FDA received 56,000 incidents regarding infusion pumps with 710 deaths leading to 87 equipment recalls. Then, the FDA released a white paper regarding this issue. The initiative of the paper was ‘to support the benefits infusion pumps can provide while reducing associated risks’. From this, manufacturers of infusion pumps aimed to improve the design of each manufactured pump in order to eradicate, if not, minimize errors (Brady).
In April 30, 2010, the FDA obligated the Baxter Healthcare Corporation to recall and furthermore destroy all the manufactured models of Colleague Volumetric Infusion Pumps. In all United States, it was estimated that 200,000 of the units are of use during those times (Brady).
Since a lot of medical institutions are already employing infusion pumps, if not all of them, safety records of these technologies are still under monitoring in case incidents arise. Authorities are bound to release safety standards about the equipment, regulations about medical personnel handling the equipment, and also, standards for the interoperability of the devices (Brady).
“Abbott Plum A+: System Operating Manual”. Abbott Laboratories. N.p. 2001 May. Web. 22 Nov. 2014
Brady, Jody Lannen. “First, Do No Harm: Making Infusion Safer’. Advancing Safety in Medical Technology, 2010 Oct. Web. 22 Nov. 2014.
“Infusion Pumps”. Medicines and Healthcare Regulatory Agency. N.p., 2013. Web. 22 Nov. 2014.
Figure 1. Administration Set (Abbott Plum A+)
Figure 2. Keypad and Front Panel Display Basic Layout (Abbott Plum A+)