Invented by Mark Randal Simmons, Baxter Healthcare SA, Baxter International Inc
The Baxter Healthcare SA, Baxter International Inc invention works as follows
An infusion apparatus with a pain-controlled analgesic (PCA?) input device is disclosed. Infusion pump apparatus consists of a housing with a pump actuator attached to the housing and a PCA device. Infusion pump apparatus includes electronics that are configured to control pump actuators, deliver a voltage to PCA input devices, and detect an electrical signal when the pain controlled input device is pressed. The infusion apparatus also includes a controller that is electrically connected to the electronics, and is programmed to determine if the sensed electrical signals are discontinuous. If the sensed signal has been discontinued, the output will indicate the pain controlled input device is not functioning properly.Background for Infusion pump with pain-controlled analgesic (PCA) apparatus
The present disclosure is related to the delivery of medication and, in particular, to the delivery of a Pain Controlled Analgesic (PCA ?).
Infusion pumps are used for the administration of liquid drugs to patients. The liquid drug comes from the source and is delivered to the patient using a catheter, or another injection device. Infusion pumps control the way liquid drugs are infused into the patient. Pumps can be programmed to infuse liquid drugs using different modes. Infusion pumps can have different modes of operation. For example, they can deliver liquid drugs in a continuous or intermittent mode. The pump can be programmed to deliver a unique infusion rate at discrete time periods. (v) A pain controlled analgesic (?PCA?)
The PCA device has several benefits, including: (i), a faster delivery of analgesia when the patient needs it; (ii), a reduced workload for nursing staff (amounts of analgesics sufficient for multiple doses are pre-loaded in the infusion devices and delivered via PCA); (iii), a lower risk of medication errors (PCA is programmed according to physician’s orders for dosage); (iv), patients get medicine as soon as they need it instead of waiting for nursing staff
PCA drug delivery involves the intravenous or epidural administration of liquid opioids. Infusion pumps used for PCA give clinicians two parameters when prescribing drugs for patients: (i), a dose of drug or bolus administered every time the patient presses a key, and (ii), a lockout period which defines how long after the first bolus has been administered before a second can be administered if the patient presses that button again. The PCA pump will ignore a request from a patient who presses ‘button’ before the lockout period has expired. Pumps are programmed with the lockout and dose for each patient and drug combination. The clinician will determine the dose based on his or her assessment of the patient?s opioid or drug requirement, depending on their weight and habituation. Lockout intervals are generally determined by the time it takes for a drug to have a clinical effect. The lockout period is designed to prevent an overdose by a patient who gives themselves another dose before the first one has taken effect.
Sometimes, a third parameter can be programmed into the pump that delivers PCA. It is the flow of a continuous medication infusion that provides a background opioid to which PCA can be added. The continuous infusion can be adjusted to deliver the least amount of medication needed by the patient over time. The PCA component allows the patient administer additional (rescue) or “break-through” pain doses when needed. The continuous infusion technique, combined with PCA, reduces the need for patients to repeatedly push the button as the bolus wears out. This is especially useful at night, when the patient would otherwise have to wake up frequently.
The PCA is connected via a cord to the infusion pumps. The infusion pumps supplies analog voltage to the PCA button. Infusion pump electronics detects the patient closing the PCA button. This is done by detecting the change in voltage, which is not normally seen but is seen when the PCA button is pressed.
The analog cables are prone to errors. The frayed wires in the cord could prevent current from flowing or not enough current may flow to trigger electronics when the PCA button is pressed by the patient. This would cause the pump to be unable to deliver an analgesic bolus, or it might deliver one when not requested or needed. The wires may short-circuit, damaging electrical components or opening a fuses, which could require replacement and lead to an incorrect dosage of analgesic.
There is a need for a better PCA input device and method.
The present disclosure discloses a pain-controlled analgesic apparatus (?PCA?) The present disclosure provides a pain controlled analgesic (?PCA?)
In one embodiment an infusion device is provided which is connected to a PCA-input device with one or more buttons. The cord connects the device to the primary housing of the pump. The PCA input devices include a remote integrated circuit or microchip. The chip or integrated circuit communicates with the local chip or integrated circuit at the infusion pumps. The remote microchip (button), and the local microchip (pump), communicate digitally or through frequency matching. Inter-Integrated Circuits (?I2C?) Serial Peripheral Interface Bus (?SPI?) (two or three wire), Transistor-Transistor Logic Universal Asynchronous Receiver/Transmitter (?TTL UART? Transistor-Transistor Logic Universal Asynchronous Receiver/Transmitter, (?TTL UART? The remote microchip and the local microchip can be connected using either Standard RS232 Universal Asynchronous Receiver/Transmitter (?RS232 UART?) The number of wires within the cord will determine the type of protocol used. The cord may have a single fiber-optic cable, two or three wires that are configured to carry low voltage analog signals, such as 3 to 24VDC.
The remote microchip detects when one or more PCA buttons are pressed, and sends the corresponding signal to a local microchip. The local microchip is electrically connected to the pump’s memory and processing. This causes the motor to deliver an analgesic when the conditions are right, for example, if pressing the button hasn’t happened too soon after the previous press.
The digital protocol is configured for example to detect when a communication link has been broken. For instance, by detecting the absence of a response to a handshake request from the remote microchip to the local microchip. The local microchip could be programmed to send the handshake request after a certain time interval to the remote chip. The local microchip will inform the pump memory and processing if the PCA button is not working. Pump electronics can tell the local microchip to send a new handshake request, or it can be programmed by the microchip. Infusion pumps are configured to respond appropriately if a second handshake is not received (second request not necessary, or multiple requests could be made).
In one embodiment, the appropriate action is to provide an alarm or alert on the pump. This can be in the form an audible warning and a message displayed on the video screen of the pump saying, for example, “PCA disabled.” The pump can also be set up to deliver analgesics to the patient at a predetermined interval and dosage or at the last recorded dose and interval. If the alarm has not been cleared (e.g. no nurse responded, or the patient was asleep at home), and time passes after the pump would have been instructed to deliver an analgesic dose, the pump will continue to provide the prescribed dose at set intervals.
In one embodiment, the handshaking routine above is repeated often enough so that a frayed or broken cord can be detected before a patient presses the PCA button. The remote or local chip or pump electronics can both be programmed to detect other PCA input failures such as those with the PCA buttons or switches in the input device housing each button. In order to achieve this, one or more microchips as well as the pump electronics may have programmable memory and processing capabilities.
For instance, the button on the PCA input is momentary in one embodiment. The patient only needs to press the button for a few seconds to start the delivery of an analgesic. A spring is pushed by the patient when he releases the button. This breaks the electrical contact. The spring may not work properly, and the button remains depressed even after the patient releases it. The PCA system can detect a stuck button using a variety of methods.
In one sense, the remote integrated chip detects a constant input rather than a brief momentary input coming from the PCA. The remote integrated has a programmed memory and processing to determine the condition of a stuck button. It sends a “stuck button” message. The local integrated circuit relays this message to the pump?s processing and memory. This alarms, and takes other corrective actions.
The remote integrated circuit can also detect a constant input rather than a momentary one from the PCA and send the constant signal back to the local integrated. The local integrated has a programmed memory and processing to determine the condition of a stuck button. The local integrated sends a “stuck button” message. The pump’s memory and processing send a “stuck button” message.
The pump’s memory and processing are programmed to determine a stuck button condition and alarms and take other corrective action. The pump’s memory and processing has been programmed to detect a stuck button and alarms, and take other corrective actions.
In a second example, the PCA input button is a maintained one, and the patient only needs to press it for a few seconds in order to start the delivery of an analgesic. In this case, when the patient releases it, the button will remain depressed until a different action is taken, such as a timer expiring or the bolus being completed. The mechanism that holds the button depressed, such as a spring or other device, may not be able to maintain electrical contact. This causes the button, which is held in this state by the mechanism, to “chatter” or make intermittent contact. The PCA system disclosed here can also detect chattering PCA contacts in many ways. This is done by placing the processing and memory on the local integrated chip, remote integrated chip, or pump’s memory.
In another example, the PCA cord’s wires can short out, causing an incorrect request for a dose. The pump’s memory and processing can also be used to treat a continuous signal the same way as a stuck switch. The local integrated can also send a confirmation signal to the remote circuit when it receives the signal from the remote circuit. The remote integrated will either not send a confirm signal, or the shorted line will interfere with the signal.
The present disclosure is therefore advantageous in that it provides an improved infusion device.
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