Mechanical Patient Controlled Analgesia Device
Our group has designed and holds two patents for an inexpensive patient-controlled analgesia device (PCA) which allows emergency patients to titrate their own pain medications safely and with minimal supervision. Unlike standard electronic PCAs it is easy to set up, purely mechanical and designed to be disposable. The device consists of a syringe, spring, flow restriction, plunger, medication reservoir, and two one-way valves in a sealable box. The nurse or pharmacist fills the reservoir with medication and seals the box. The device is connected to the patient’s intravenous line. The patient pushes the plunger and injects a small dose of medication when they need pain relief. Then the spring and restriction slowly refill the syringe. The design ensures that the patient cannot give more medication than is prescribed or give it too fast.
Patients in emergency rooms and ambulances are often in severe pain from injuries or acute medical problems. They need pain medications given quickly and safely. But this is surprisingly difficult to do in moving ambulances or chaotic emergency departments. The problem is that all pain medications have serious side effects. Give too much or give them too fast and they can cause vomiting, over sedation or even death. The solution is to give small doses frequently until the pain is controlled and side effects are minimized. Unfortunately, this requires a lot of provider time. For example, a reasonable amount of morphine for a patient with severe pain might be 20 mg given in 2 mg doses with 3 minutes between injections. This would require a half hour of nursing time! It is not surprising then that most patients with broken bones or heart attacks do not get optimal relief. Doubling the dose would halve the nursing time but would increase the risk – some patients would get side effects or stop breathing.
There is a better way to administer pain medication to hospital inpatients. Patient-controlled analgesia devices (PCAs) are electronic pumps that patients can use to administer their own medications. PCAs are loaded with medications that are injected when the patient pushes a button. Electronic PCAs are expensive, fragile and take careful and time-consuming programming for each new patient and medication. In an emergency they are simply too complicated to use.
The potential market is any location in which patient controlled titration of medication is desirable, particularly during acute care visits. An estimate of market size is derived from the 130 million emergency room visits each year in the US, of which approximately 50 million are for painful conditions. Initial form and function review by a group of emergency nurses and doctors revealed essentially one hundred percent support. All of our reviewers said they would use the PCA if available.
PCAs are standard in the hospital for post-surgical patients. Patients can safely control their own medication dose which has been shown to provide better relief and fewer side effects. Patients on PCAs actually use less pain medication and there is evidence that early treatment reduces the risk of abuse. PCAs are actually cost effective because they save nursing time. In bulk our device has an estimated cost of about two dollars – far less than the cost of nursing time for the current method. Our device has all these advantages and could be used for any medication that can be titrated to effect and given intravenously.
1. Decrease drug use
2. Improve pain management
1. Saves physician and nursing time
2. Increases patient safety
3. Reduces the risk of drug diversion
4. Minimizes waste
It is better and less expensive – what is not to like?
US Utility Patent 8,920,381 B1
“A mechanical patient controlled analgesia device”
Issued December 2014
US Patent 9,592,349 B2
Issued Mar. 14, 2017
Mechanical Medical Infusion Pump
Many critical medications must be given by careful infusion into a vein. Examples include insulin (for diabetes), dopamine, epinephrine and norepinephrine (to treat shock) and oxytocin (to start and augment labor). Often the drug must be titrated to effect—in the case of oxytocin the dose is gradually increased until uterine contractions are adequate in strength. These drugs all have very narrow “therapeutic indices”: too little and they are ineffective, too much and they are toxic. Accurate electro-mechanical infusion pumps solve this problem but are expensive, fragile, complex and require a stable electricity source. They cannot be afforded in low income countries and are difficult to use during patient transports or in austere environments where the electric supply is unreliable and weight is limiting. Without an infusion pump a nurse must count the number of drops of medication that fall into the I.V. tubing per unit time—which is time consuming, inaccurate and unsafe. This means more caesarean sections and more deaths.
We are developing an inexpensive and potentially disposable, all mechanical infusion pump. It uses a weight and calibrated flow restriction (which may be variable) to control the rate of drug delivery. No electricity is needed.
Infusion pumps are needed to deliver oxytocin to safely augment labor in pregnant patients and infuse critical medications in intensive care units and emergency departments. Although computer driven pumps are available they are expensive, fragile and depend on a reliable supply of electricity. This makes all currently available devices inappropriate for disaster zones and many low income countries. Our design was selected a finalist in the 2016 “Saving Lives at Birth Grand Challenge” and we presented the device at “Development XChange” held in July 2016 in Washington DC. The Grand Challenge is sponsored by USAID, The Bill and Melinda Gates Foundation and the Governments of Norway, Canada, UK and Korea. DevX is the premier venue for low cost medical devices and technologies that may be applicable in the developing world.
U.S. Patent No.: 9,744,292 B2
Title: “Infusion Device”
Date of Patent: Aug, 29, 2017