Surgery – Means for introducing or removing material from body for... – Treating material introduced into or removed from body...
Reexamination Certificate
1999-07-14
2002-10-22
Hayes, Michael J (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Treating material introduced into or removed from body...
C604S411000, C604S905000
Reexamination Certificate
active
06468261
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application is related to commonly assigned, copending application, serial number unknown, filed Jul. 14, 1999 and entitled MEDICAL FLUID DELIVERY SYSTEM, naming Small et al. as inventors, which is hereby incorporated by reference herein in its entirety and commonly assigned, copending application, serial number unknown, filed Jul. 14, 1999 and entitled MEDICAL FLUID DELIVERY SYSTEM, naming Small et al. as inventors, which is hereby incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
The invention relates generally to a device and method for providing a specified volume of a medical fluid from a bulk source to a dose container.
BACKGROUND OF THE INVENTION
Medical fluids are often packaged in standard size containers which are intended for single-use administration only. Typical containers include bags, bottles, vials, ampules, blister packs, etc. Once the factory seal on a medical fluid container is compromised, the Food and Drug Administration (FDA) mandates that the contents must be either administered within a set time interval or discarded. The underlying rationale for this regulation is that a medical fluid in an opened container has potentially been contaminated by either environmental pathogens or, if the container holds a multipatient fluid supply, by fluids from other patients. In multipatient or bulk fluid containers, the FDA has determined that if a continuous fluid path exists from the fluid to the patient, there is a possibility that the bulk fluid may be contaminated by exposure to a patient's fluids. Even a separating unit that is inserted in the fluid path from a fluid source to a patient, for example, a drip chamber such as a conventional intravenous drip chamber, a mixing chamber, a filter, one or more check valves, a peristaltic pump, and/or other flow control devices, is considered insufficient as a barrier for purposes of sterility. A problem with these devices is that a continuous thin fluid film may exist across the valve seat and/or check mechanism, which provides a contamination pathway for blood and pathogens from the patient. Therefore, only a system having a physical separation between the fluid supply source and the patient will meet FDA standards. While the strictness of this requirement has increased costs to the hospital and patient because it limits the fluid in a bulk container to a single use, it has also desirably decreased the incidence of nosocomial infections in patients.
In current medical practice for fluid administration to a patient, medical personnel typically either use prefilled containers that hold a single patient (unipatient) supply of medical fluid, or they transfer a unipatient fluid supply to a container from a bulk source of the fluid. Use of prefilled containers adds to the cost of the fluid and/or the procedure in which the fluid is used, such as a contrast agent used to enhance an imaging procedure. Transfer of a unipatient supply of fluid to a container from a bulk source, while less expensive, adds an additional point of potential contamination. Typically, a clinician or technologist draws fluid into a unipatient container using a transfer tube or needle or, in some cases, pours the fluid into the container. Such transfers are best performed using aseptic techniques in an attempt to reduce exposure of the fluid to nonsterile air or other sources of contamination, although this is not always done in practice. These techniques reduce the likelihood of contamination, but sufficient risks still exist such that using any fluid remaining in the bulk supply source is not generally considered an acceptable medical practice. If anything less than the entire volume of fluid from the bulk supply source ;s transferred, the remaining fluid should be discarded, resulting in wasted material.
Many types of fluids are administered to patients, including diagnostic, therapeutic and physiologic fluids. These fluids are administered under a variety of circumstances and for a variety of reasons. For example, imaging procedures such as ultrasound, magnetic resonance imaging (MRI), angiography and computed tomography frequently require image enhancement by contrast agents. Contrast agents are fluids that are normally administered intravascularly to provide a better view of the organ or system to be imaged. The dose of contrast agent is determined to achieve optimal imaging without providing excess agent, since the agent may be expensive and/or difficult to be efficiently removed from the body. The maximum dose is based upon pharmacokinetic limits, specified as milligrams (mg) of active ingredient per kilogram (kg) of patient body weight, and the minimum dose is predicated on achieving clinically viable diagnostic information from the imaging procedure. The range between the minimum dose and maximum dose varies widely for any given imaging procedure and patient. The optimal dose is influenced by a number of parameters, such as the image equipment technology, diagnostic techniques, clinician experience, and patient-specific parameters such as age, presence of pathology, physical proportions and other physiological parameters. For a “typical” 70 kg male patient in good health, a volume of about 100 ml of contrast agent is normally administered.
Use of fluid from a bulk source would facilitate timely administration of such fluids. For example, in imaging procedures it is common for physicians to administer excess x-ray contrast agent. Since higher blood concentrations of contrast agent generally yield improved images, physicians often reason that the excess volume is justified because it decreases the probability that a repeated image will be needed. Accordingly, there are now standardized protocols in which the maximum volume of x-ray contrast agent is used. The maximum volume is often based upon the available standard packaging sizes and concentrations from the manufacturers of contrast agents, and the entire content of the package is typically utilized regardless of its clinical necessity. This practice results in over medication and commensurate safety concerns for the patient, since adequate diagnostic information may be obtained at a dose that is well below even the maximum physiological threshold for a particular patient. Administration of excess agent may have nominal to severe pharmacological consequences, depending upon the condition of the patient and the identity of the agent.
Administration of less than the optimal volume of contrast agent may also have consequences, determined by the particular circumstances. For example, an optimal volume of agent may be required to be administered within a predetermined period of time. If the time of administration exceeds the predetermined time, the result may suboptimal imaging. Administration of a suboptimal volume may require performing the entire procedure at a later time and/or administering a second dose of agent. Suboptimal dosing thus exposes the patient to the possibility of receiving two doses of the agent in a short period of time, potentially compromising patient health and well being, and is a time- and cost-inefficient process.
A system is thus needed to provide a desired volume of a medical fluid from a bulk source in a medically acceptable, cost- and time-efficient manner.
SUMMARY OF THE INVENTION
The invention is directed to a medical fluid delivery system. The system comprises a bulk container for containing a bulk or multipatient fluid supply, a connecting site for access to the fluid in the bulk container, and a dose container for receiving a unipatient supply of fluid from the bulk container at the connecting site. The system may have a device to maintain sterility of the connecting site. The dose container may also function as a delivery container with either inflexible walls, e.g., a syringe, or at least one flexible wall, e.g., a bag. The system may contain a detector for the presence of air and may be automated.
The invention is also directed to a method of delivering a medical fluid. A bulk container
Fago Frank M.
Small James R.
Smith Mitchell A.
Tyson Joseph B.
Wagner Gary S.
Hayes Michael J
Mallinckrodt Inc.
Wood Herron & Evans L.L.P.
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