Apparatus for providing a controlled flow of intravenous fluid to a patient

In combination for introducing fluid to a patient,

• a source of fluid,
• an input conduit extending from the source to a first position,
• pump means connected to the input conduit at the first position to pump fluid through the input conduit at a controlled rate,
• an output conduit extending from the pump means to a second position below the first position,
• means disposed in parallel with the pump between the input and output conduits, such parallel means including means for establishing a fluid-isolated relationship between the input and output conduits and for alleviating the pressure in the output line, and
• means operatively associated with the parallel means for detecting pressures of the fluid in the output conduit above the pressures produced in the fluid by the differences in height between the first and second positions to control the further operation of the pump means.

In combination for introducing fluid to a patient,

• a source of fluid,
• an input line extending from the source to a first position,
• an output line extending downwardly for connection to the patient,
• implementing means connected at the first position to the input and output lines to pump the fluid from the source to the patient at a particular rate,
• bypass means disposed between the input and output lines and operative to entrap air in the input line and prevent such air from passing to the output line, and
• the bypass means including means for providing a fluid-isolated relationship between the input and output lines and for alleviating the fluid pressure in the output line, and
• sensing means operatively associated with the bypass means to detect the pressure of the fluid in the output line and to interrupt the operation of the implementing means when the pressure of the fluid has risen to a value dependent upon the difference in height between the first position and the position of connection of the output line to the patient.

In combination for introducing fluid to a patient,

• a source of fluid,
• an input line extending from the source and disposed below the source to provide a particular pressure of the fluid from the source in accordance with the vertical distance of the input line below the source,
• an output line extending downwardly to the patient,
• implementing means connected to the input and output lines to pump fluid from the source to the patient at a particular rate,
• sensing means operatively associated with the output line to detect the pressure of the fluid in the output line and to interrupt the operation of the implementing means when the pressure of the fluid has risen to at least the particular pressure,
• switching means having open and closed states and operatively associated with the sensing means to become opened when the sensing means senses a pressure of the fluid in the output line at the particular level, the switching means being connected in a circuit with the implementing means to discontinue the operation of the implementing means,
• the implementing means constituting a pump,
• a bypass line connected across the implementing means and communicating with the input and output lines,
• resilient means disposed in the bypass line to isolate the input side of the bypass line against the flow of fluid to the output side of the bypass line and to alleviate the pressure of the fluid in the output line, and
• the sensing means being disposed at a particular position at the output side of the bypass line to sense the presence of fluid at this particular position in the bypass line and to provide for the opening of the switching means upon such a fluid pressure.

In combination for introducing fluid from a source to a patient,

• flow lines for providing a flow of fluid on a gravitational basis,
• means disposed in the flow lines and operative to implement a flow of fluid through the flow lines,
• means associated with the flow lines for sensing an obstruction in the flow lines or an improper operation of the implementing means in accordance with the pressure of the fluid in the flow lines, and
• means responsive to the sensing means for discontinuing the operation of the implementing means when the sensing means senses an obstruction in the flow lines or an improper operation of the implementing means,
• the flow lines being disposed to receive the fluid from the source and to pass the fluid to the patient and being disposed relative to the source to provide a build-up in pressure from the source and the sensing means being disposed relative to the flow lines to sense when the pressure of the fluid flowing to the patient increases to a value above the built-up pressure in the flow lines,
• the flow lines and the implementing means being connected in a series relationship and a bypass line being connected in a parallel relationship with the implementing means and means being included in the bypass line to inhibit the flow of fluid through the bypass line and the sensing means being disposed to sense the pressure of the fluid in the bypass line,
• hydrophilic membrane means being disposed between the flow lines and the bypass line to provide for a passage of liquid from the flow lines to the bypass line and to prevent a passage of air bubbles from the bypass line to the flow lines.

In combination for introducing fluid from a source to a patient,

• flow lines for providing a flow of fluid on a gravitational basis,
• means disposed in the flow lines and operative to implement a flow of fluid through the flow lines,
• means associated with the flow lines for sensing an obstruction in the flow lines or an improper operation of the implementing means in accordance with the pressure of the fluid in the flow lines, and
• means responsive to the sensing means for discontinuing the operation of the implementing means when the sensing means senses an obstruction in the flow lines or an improper operation of the implementing means,
• the flow lines being disposed to receive the fluid from the source and to pass the fluid to the patient and being disposed relative to the source to provide a build-up in pressure from the source and the sensing means being disposed relative to the flow lines to sense when the pressure of the fluid flowing to the patient increases to a value above the built-up pressure in the flow lines, the flow lines and the implementing means being connected in a series relationship and a bypass line being connected in a parallel relationship with the implementing means and means being included in the bypass line to inhibit the flow of fluid through the bypass line and the sensing means being disposed to sense the pressure of the fluid in the bypass line,
• first hydrophilic membrane means being disposed between the input conduit and the bypass line to provide for a passage of liquid from the input conduit to the bypass line and to prevent a passage of air bubbles from the bypass line to the input conduit, and
• second hydrophilic membrane means being disposed between the output conduit and the bypass line to provide for a passage of liquid from the output conduit to the bypass line and to prevent a passage of air bubbles from the bypass line to the output conduit.

In combination for introducing fluid to a patient,

• a source of fluid,
• an input line extending from the source and disposed below the source to provide a particular pressure of the fluid from the source in accordance with the vertical distance of the input line below the source,
• an output line extending downwardly to the patient,
• implementing means connected to the input and output lines to implement the flow of fluid from the source to the patient at a particular rate,
• sensing means operatively associated with the output line to detect the pressure of the fluid in the output line and to interrupt the operation of the implementing means when the pressure of the fluid has risen to at least the particular pressure,
• switching means having open and closed states and operatively associated with the sensing means to become opened when the sensing means senses a pressure of the fluid in the output line at the particular level, the switching means being connected in a circuit with the implementing means to discontinue the operation of the implementing means,
• the implementing means constituting a pump,
• a bypass line connected across the implementing means,
• means disposed in the bypass line to isolate the input side of the bypass line against the flow of fluid to the output side of the bypass line, and
• the sensing means being disposed at a particular position at the output side of the bypass line to sense the presence of the fluid at this particular position in the bypass line and to provide for the opening of the switching means upon such a fluid pressure,
• first means providing a hydrophilic action in providing for a passage of liquid from the input line to the bypass line and in preventing a passage of air bubbles from the bypass line to the input line, and
• second means providing a hydrophilic action in providing for a passage of liquid from the output line to the bypass line and in preventing a passage of air bubbles from the bypass line to the output line.

In combination for introducing fluid from a source to a patient,

• flow lines for providing a flow of fluid on a gravitational basis,
• implementing means disposed in the flow lines and operative to pump fluid through the flow lines,
• means associated with the flow lines for sensing an obstruction in the flow lines or an improper operation of the implementing means in accordance with the pressure of the fluid in the flow lines, and
• means responsive to the sensing means for discontinuing the operation of the implementing means when the sensing means senses an obstruction in the flow lines or an improper operation of the implementing means,
• the flow lines being disposed to receive the fluid from the source and to pass the fluid to the patient and being disposed relative to the flow lines to sense when the pressure of the fluid flowing to the patient increases to a value above the built-up pressure in the flow lines,
• the flow lines and the implementing means being connected in a series relationship and a bypass line being connected in a parallel relationship with the implementing means between the flow lines and being constructed to entrap air in the flow lines and means being included in the bypass line to prevent the flow of fluid through the bypass line and to alleviate the pressure of the fluid in the input line, the sensing means being disposed to sense the pressure of the fluid in the bypass line.

In combination for introducing fluid to a patient,

• a source of fluid,
• an input conduit extending from the source to a first position,
• a pump connected to the input conduit at the first position to pump fluid from the conduit to a controlled rate,
• an output conduit extending from the pump to a second position below the first position,
• means for detecting pressures of the fluid in the output conduit,
• means responsive to the detection of fluid pressures in the output conduit for interrupting the operation of the pump in introducing fluid to the output conduit when the pressure in the output conduit exceeds a pressure dependent upon the difference in height between the first and second positions,
• a bypass line extending between the input and output conduits in bypass relationship to the pump,
• a chamber disposed in the bypass line and a resilient diaphragm extended across the chamber to prevent the flow of fluid through the bypass line and to alleviate the fluid pressure in the output line, and
• the detecting means being disposed in operatively coupled relationship to the bypass line to detect the pressures of fluid in the output conduit.