Disposable blood metering device

Abstract

To provide a measurement system which can measure accurately and in real time the volume of blood drawn from a patient in order to monitor the amount of blood drawn from the patient.SOLUTION: A blood metering device comprises: an adapter unit comprising a housing that defines a blood flow pathway that is configured to be connected to a blood collection set, where the adapter unit has disposed therein a volume indicator that measures a volume of blood flowing through the blood flow pathway; and a sensor unit that is engaged with the adapter unit. The sensor unit comprises: i) a sensor that is configured to detect signals from the sensor in response to blood flowing through the blood flow pathway in the adapter unit; and ii) a processor that associates the sensor signals with a blood volume and controls the response of the sensor unit in response to a determination by the sensor unit that a predetermined volume of blood has passed through the adapter unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] [Related Applications] This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 62 / 883,294, filed August 6, 2019, which is incorporated herein by reference.

[0002] The device described herein is a measurement system that can be used at a patient's bedside to monitor the amount of blood withdrawn from the patient. The system uses disposable actuation and sensor electronics to measure and control the amount of blood withdrawn from the patient for analysis. [Background technology]

[0003] During blood collection for blood culture from patients in hospitals or other settings, it is important to provide a target blood volume in the blood culture bottle that ensures that neither too much nor too little volume is drawn, as inoculating blood cultures with samples that are too small or too large can adversely affect the accuracy of the blood culture analysis results. At this point, the only feedback to the medical personnel (typically) drawing blood from the patient is to visually monitor the fluid level in the blood culture bottle during collection and to discontinue collection when full volume is determined to have been reached.

[0004] Currently, medical personnel make this determination visually. Blood culture bottles have volumetric scale markings on the bottle or bottle label. Medical personnel are often required to mark the target fill volume of blood on the side of the bottle. In practice, this method is prone to error. When a medical professional draws blood into a blood culture bottle, the medical personnel may not hold the bottle in the correct vertical orientation, making it difficult or even impossible to determine the actual volume of blood drawn and increasing the likelihood that the target volume will not be obtained. Another issue that can affect the accuracy of the amount of blood drawn is the lack of uniform instructions on how to properly inoculate a blood culture bottle with the target volume of blood. Additionally, patient requests (which may present challenges during blood draw that may prevent medical personnel from accurately monitoring the blood draw) can adversely affect the accuracy of the amount of blood drawn by medical personnel.

[0005] The success of culturing and detecting bacteria infecting a patient depends heavily on the collection of bacteria in the blood sample taken from the patient. The probability of having bacteria in a blood sample increases with the volume of blood collected. Therefore, it is very important to accurately collect the desired target volume in a blood culture bottle (one example is the BACTEC™ culture bottle). Summary of the Invention [Problem to be solved by the invention]

[0006] As discussed above, currently, medical personnel drawing a blood sample must visually determine when the correct volume of blood has been drawn and collected into the culture bottle and accurately stop drawing at that point to avoid overfilling the blood culture bottle. Thus, there continues to be a need for blood collection methods and devices that can ensure that the correct target volume of blood is drawn. [Means for solving the problem]

[0007] The blood metering devices described herein measure the volume of blood flowing through the device and into a blood collection container. The blood metering device is mounted within the blood collection container. The blood collection container is any suitable container for receiving a blood sample. One example is a blood collection tube, such as a BD Vacutainer™ tube. BD Vacutainer is a registered trademark of Becton, Dickinson and Company. Another example is a blood culture bottle, such as the BACTEC bottle mentioned above. The blood metering device provides at least one of: 1) an indication when a target volume of blood has flowed through the device and into the blood culture bottle; or 2) an automatic shutoff when the target volume of blood has flowed through the device and into the blood culture bottle.

[0008] The blood meter is a standard blood collection set in fluid communication with a mechanical rotating paddle wheel that rotates in response to blood flow through the housing. The paddle wheel is rotatably mounted within the housing. The paddle wheel is positioned within the housing so that it rotates freely. In one embodiment, the axis of rotation of the paddle wheel is a pin fixed within the housing and defining the axis of rotation of the paddle wheel. The paddle wheel is in communication with a measurement sensor that can track the rotation of the paddle wheel. One example of such a sensor is a small magnet that rotates with the paddle wheel and a Hall effect sensor that is activated as the magnet passes by the sensor. Each activation is a number of rotations. The sensor converts the number of rotations into blood volume. In some embodiments, the rotational speed of the paddle wheel is also measured to calculate the volume of sample passing through the blood meter. Another example of a sensor is an optical sensor (e.g., an LED) that can cooperate with an optical fiducial located on the paddle wheel to count the number of paddle wheel rotations, the speed at which the paddle wheel rotates, or both.

[0009] The blood metering device has a controller. The controller can perform one or more of the following functions: i) correlating the volume of blood flowing through the device with the number of rotations; ii) correlating the speed at which the paddlewheel rotates with the volume of blood passing through the paddlewheel; iii) shutting off blood flow in response to determining that the target volume of blood has been reached; and iv) providing a signal to medical personnel regarding the volume of blood that has passed through the blood metering device. For example, the blood metering device can emit a green light when the volume of blood falls below a certain threshold. When the volume of blood passing through the device reaches the target volume, the green light can change to yellow. When the target volume of blood passes through the blood metering device and into the blood culture bottle, the sensor can change to yet another color (e.g., red) to indicate that the blood culture bottle has received the target volume. Blood does not flow through the sensor. In this regard, the blood metering device is an assembly of a sensor unit and a metering / culture bottle adapter unit.

[0010] In one example, the sensor is disposable. In this example, the sensor includes disposable electronics that measure the volume of blood flowing through the blood meter during a blood draw from a patient. The disposable system notifies the user based on a visual or audio signal whether a predetermined desired volume of blood has passed through the sensor.

[0011] The disposable sensor device includes a sensor capable of electronically measuring blood flow. The disposable sensor unit is integrated within a disposable housing as part of an overall blood collection set. The disposable sensor unit is removably attached to a culture bottle adapter unit. The culture bottle adapter unit is configured to receive a paddle wheel disposed within the housing and to form a blood flow path from the blood collection system to a collection container (e.g., blood collection tube, blood culture bottle, etc.).

[0012] In some embodiments, the sensor need not be disposable. In such embodiments, the sensor unit does not come into contact with blood, allowing the sensor unit to be reused or recycled.

[0013] The blood fill volume is measured and monitored by a microprocessor, which counts the rotation of the paddle wheel or the rotation speed of the paddle wheel with a sensor, which is a calibrated and accurate measurement system. The system interacts with the user with optical and / or acoustic and / or other sensory signals (e.g., vibrations) that indicate that the predetermined volume of blood has been delivered to the blood culture bottle or blood collection container.

[0014] Optionally, the blood measuring device includes an adapter unit, which is a housing defining a blood flow path and configured to connect to a blood collection set. A volume indicator is disposed within the adapter unit to measure the volume of blood flowing through the blood flow path. Optionally, the volume indicator is a paddle wheel flow detector. The volume indicator may be a hair sensor, an acoustic sensor, or an optical sensor. The sensor may be one of an axial rotor sensor, a peristaltic pump sensor, a magnetic field sensor, and a rotation sensor.

[0015] In such a detector, the volume of blood flowing through the sensor is calculated from the number of rotations of the paddle wheel. The blood measuring device also has a sensor unit engaged with the adapter unit. The sensor unit has i) a sensor configured to detect a signal from the sensor in response to blood flowing through the blood flow path in the adapter unit, and ii) a processor that correlates the sensor signal with the blood volume and controls the response of the sensor unit in response to the sensor unit determining that a predetermined volume of blood has passed through the adapter unit. The sensor unit is either detachably engaged with the adapter unit or monolithically integrated with the adapter unit.

[0016] The paddle wheel is disposed within the blood flow path but is freely rotatable within the housing, e.g., supported on a pin within the housing that provides an axis of rotation. The paddle wheel has an axis of rotation that is perpendicular to or aligned with the direction of blood flow in the blood flow path. The paddle wheel can carry a magnet, and a Hall effect sensor can be disposed on the housing that is activated when the magnet passes by the Hall effect sensor.

[0017] 12. The blood measuring device of claim 11, wherein the paddle wheel rotates freely within the housing on an integral pin supported by the housing.

[0018] Optionally, the processor correlates the rotation of the paddle wheel with the blood volume to determine a measured blood volume that has flowed through the blood measuring device, and controls a response of the sensor unit in response to the sensor unit determining that a predetermined volume of blood has passed through the paddle wheel located in the adapter unit.

[0019] The adapter unit is attachable to a collection container, which may be a blood culture bottle or a sample collection tube.

[0020] Optionally, the processor is configured to compare the measured blood volume with a predetermined blood volume, and when the measured blood volume equals the predetermined volume, the processor sends a signal to close a blood flow valve to block blood flow to the blood measuring device.

[0021] Optionally, the adapter unit includes an activation lever that activates the processor when the adapter unit is attached to a blood culture bottle. The sensor unit optionally includes a battery, which can be turned on by the activation lever to power the processor.

[0022] The sensor unit optionally includes a valve actuator that controls a valve in the adapter unit, the valve actuator being one of a moving magnet actuator, a microactuator, a solenoid, or a twin magnet actuator.

[0023] The blood measuring device optionally includes a flow meter that functions as a pump. One example of such a pump is a motor having a rotor. The housing forms a stator for the pump. The rotor can include one or more magnets. The motor can further include a Hall Effect sensor that measures the rotational speed of the rotor. The processor determines the amount of blood flowing through the pump based on the rotational speed of the motor. In operation, if the rotational speed of the motor falls below a predetermined rotational speed, the processor indicates venous collapse. The sensor unit can include an indicator light that indicates a predetermined amount of blood has passed through the adapter unit based on a signal from the processor, or can include an indicator light that indicates venous collapse has occurred based on a signal from the processor.

[0024] The blood meter is used by connecting the adapter unit to a blood collection set having a needle configured for venipuncture and tubing. In operation, when the rotational speed of the motor falls below a predetermined rotational speed, the processor indicates venous collapse.

[0025] Also described herein is a method for determining the amount of blood flowing from a patient to a collection bottle. In the method, an assembly of an adapter unit and a sensor unit is provided, the adapter unit having a housing defining a blood flow path configured to be connected to a blood collection set. Optionally, a paddle wheel is disposed within the adapter unit, the paddle wheel being disposed within the blood flow path but freely rotatable within the housing. The sensor unit is as described above and includes a sensor configured to detect a signal from the sensor in response to blood flowing through the blood flow path in the adapter unit. The sensor unit also includes a processor that correlates the sensor signal with the blood volume and controls the response of the sensor unit in response to the sensor unit determining that a predetermined amount of blood has passed through the adapter unit. The sensor unit also includes a valve actuator in signal communication with and controlled by the processor. In the method, the assembly is connected to a blood collection set, the blood collection set having a needle configured for venipuncture and tubing such that the blood collection set is in fluid communication with the blood flow path. The adapter unit is connected to a blood collection container such that the blood flow path in the adapter is in fluid communication with the blood collection container. The pressure within the blood collection container is typically below atmospheric pressure to draw a blood sample from the patient to the blood collection set. This causes blood to flow through a paddle wheel sensor, whose rotation is measured to determine the amount of blood flowing from the blood flow path to the blood collection container. The determined blood volume is compared to a predetermined blood volume. When the measured blood volume equals the predetermined blood volume, the processor sends a signal to a valve actuator to stop blood from flowing into the collection container. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 1 shows a blood collection assembly with a flow meter device coupled to a blood culture bottle. [Figure 2A] FIG. 2 illustrates the meter electronics portion of the flow meter assembly. [Figure 2B]FIG. 10 shows the flow meter adapter portion of the flow meter assembly attached to a blood collection bottle. [Figure 2C] 2C shows a blood flow path through the flow meter adapter portion shown in FIG. 2B. [Figure 3] Figure 3A illustrates a workflow for using the flow meter devices described herein in conjunction with blood culture bottles, and Figure 3B illustrates a workflow for using the flow meter devices described herein in conjunction with blood collection tubes. [Figure 4] FIG. 2C is an exploded view of the flow meter adapter portion shown in FIG. 2B. [Figure 5] FIG. 2B is an exploded view of the flow meter electronics portion shown in FIG. 2A. [Figure 6] 1 is a schematic diagram of a flow meter device illustrating the theory of operation. [Figure 7] FIG. 10 shows the paddle wheel components of the flow meter adapter portion. [Figure 8] FIG. 10 shows a housing that receives a paddle wheel coupled to a motor that drives the paddle wheel. [Figure 9] FIG. 1 illustrates one embodiment of a motor that drives a paddle wheel. [Figure 10] 10A-10C show an alternative assembly of a blood measuring device and blood culture bottle. [Figure 11] FIG. 11 is an exploded view of the assembly of FIG. [Figure 12] FIG. 11 shows the assembly of FIG. 10 integrated into a blood collection system. [Figure 13] FIG. 1 is a transparent perspective view of the blood measurement device when viewed from the front of a disposable sensor unit integrated with an adapter unit. [Figure 14] FIG. 2 is a see-through perspective view of the blood measurement device when viewed from the rear of the sensor unit. [Figure 15] 2A-2C illustrate an embodiment of a pinch valve used in the blood metering assembly of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0027] FIG. 1 shows a blood collection system including one embodiment of a blood measuring device in accordance with the present technology. As shown in FIG. 1, the blood collection system includes a needle 110, a tube 120, a blood measuring device 130, a sensor unit 140, an adapter unit 150, and a collection bottle 160. The adapter unit 150 includes a needle 152 (FIG. 2B). The collection bottle 160 includes a cap 163 (FIG. 3A). The needle 152 pierces the cap 163.

[0028] During the process of drawing a blood sample from a patient, needle 110 is used to puncture a patient's vein or artery. Blood from the patient is directed toward collection bottle 160 through tubing 120, driven by vacuum pressure created by collection bottle 160. Blood flows into collection bottle 160. Along the way, the blood passes through adapter unit 150 and needle 152. The sensor unit is also referred to herein as the electronics portion, as the sensor unit houses the device actuator and sensor electronics.

[0029] 2A, the sensor unit 140 includes a housing 180 within which are located a processor 182, an indicator 184, a battery 186, and a valve actuator 188 that controls a valve 189 on the housing inlet 164. The sensor unit houses the device actuator and sensor electronics. A printed circuit board 182 (carrying the processor and other electronics) responds to the blood volume sensed by the measuring device and may provide an indicator (shown as a colored light) to indicate when a predetermined target volume has passed through the measuring device, although audible or vibrational indications are also contemplated. The sensor may also provide signals for other indicators of system conditions, such as indications of other flow conditions (i.e., blood flow rates higher or lower than those specified by the system).

[0030] In one embodiment, valve actuator 188 controls the flow of blood drawn from a patient by maintaining valve 189 (FIGS. 2B and 4) closed when blood draw from the patient begins. After blood draw begins, valve actuator 188 receives a signal indicating blood flow has begun. In response to such a signal, valve actuator 188 gradually opens valve 189. Valve actuator 188 is programmed to open valve 189 to mitigate hemolysis of blood flowing through the adapter unit (FIG. 2B). In the illustrated embodiment, valve 189 is integrated with adapter unit 150 shown in FIG. 2B. However, valve 189 can also be integrated with valve actuator 188. In either embodiment, valve 189 is positioned in line with inlet 164 in the adapter unit, described below.

[0031] In an alternative embodiment, the sensor unit may be coupled (via wired or wireless communication) to a sensor 111 positioned near the needle 110. If such sensor 111 detects a flow condition indicative of venous collapse or imminent venous collapse (i.e., a decrease in blood flow above a predetermined threshold), the response of the valve actuator 188 is to close the valve 189 and then gradually reopen the valve 189.

[0032] Suitable valve actuators are known to those skilled in the art and will not be described in detail herein, and include moving magnet actuators, microactuators, solenoids, twin magnets, etc. that open and close valve 189 in response to a signal.

[0033] Valves suitable for use in the blood measuring devices disclosed herein will not be described in detail herein but are known to those skilled in the art. An example of a suitable valve is a shut-off valve, which advances a valve seat into a passageway to close the valve and retracts the valve seat from the passageway to open the valve. Another suitable valve is a pinch-tube valve 500. Such a valve is shown in FIG. 15. The pinch-tube valve 500 is opened and closed by a solenoid 510 that drives a valve body 520 between an open position and a closed position (and vice versa). As shown in FIG. 15, a tube 530 passes through the valve body 520. When the valve body 520 is open, blood flows through the tube 530. When in the open position, the valve body 520 does not pinch the tube 530. When in the closed position, the valve body 520 blocks the tube 530, preventing blood from flowing through the valve body 520. The solenoid 510 receives power through a conductor 540 positioned within a solenoid cap 570. Pinch tube valve 500 also has a panel 550 and a seal 560 that prevent the solenoid from coming into contact with blood. Pinch tube valve 500 is provided with a manual override button 580 in case the valve body fails to release properly. Other suitable valves include ball valves, membrane valves, slide valves, check valves, release valves, etc.

[0034] Referring to FIG. 2B, the adapter unit 150 has a small paddle wheel 154 that can rotate freely within the housing 156 on an integrated pin 158 within the housing 156. In the embodiment shown in FIGS. 2B and 4, the integrated pin 158 is part of a flow path 162 through the housing 156. The flow path exits the adapter unit 150 through an outlet 166. Blood flow is directed tangentially along the paddle wheel 154 through the inlet 164. The paddle wheel has a void in the wall of the housing 156 to allow it to rotate freely. No sealing interference fit is required. The adapter unit has an activation lever 190 that activates the electronics only after the adapter unit 150 is placed on the blood culture bottle 160 (FIG. 3A). This allows the device to be turned "off" when not in use, conserving battery power. When needle 152 of adapter unit 150 pierces the blood culture bottle, a reduction in the internal pressure of the blood culture bottle causes the patient's blood to be drawn through the device and into the blood culture bottle. Optionally, the metering device is configured so that blood flow is axial through the metering device instead of tangential.

[0035] Blood flow path 162 through adapter unit 150 is shown in Figure 2C. Blood enters adapter unit 150 through inlet 164. The blood flow travels through paddle wheel 154 and then moves upward through channel 169 in which valve 189 is located. When valve 189 is open, blood enters and passes through outlet channel 166 of the adapter unit.

[0036] Operation of the device is illustrated in Figures 3A and 3B. Referring to Figure 3A, blood metering device 130 is attached to culture bottle 160 by placing adapter unit 150 on the neck of culture bottle 160 so that needle 152 pierces cap 163. During blood collection, indicator light 184 is one color (e.g., red). Optionally, indicator light 184 flashes. Optionally, the flashing frequency correlates with blood flow. When a target blood draw volume is detected or a predetermined blood draw duration is reached, indicator light 184 changes to a second color (e.g., green). Optionally, the metering device sends a signal to valve actuator 188 to cause valve actuator 188 to close a valve that shuts off blood flow from the patient. Blood metering device 130 is then separated from culture bottle 160. In one embodiment, adapter unit 150 is spring-loaded, and the spring is biased to withdraw the adapter unit from engagement with culture bottle 160. In operation, the metering device is engaged with a culture bottle or other collection container by an operator or collection device. Once collection is complete, the force holding the adapter unit 150 into engagement with the collection container is released, and the spring-loaded biasing force 171 of the adapter unit pulls the adapter unit 150 out of engagement with the collection container.

[0037] 3B illustrates an alternative workflow using blood metering device 130 to collect blood 210 into blood collection tube 200 instead of culture bottle 160. Operation is as described above with respect to FIG. 3A. Septum cap 173 on blood collection tube 200 is slightly different than cap 163 on the blood culture bottle, but in operation, needle 152 pierces the septum of septum cap 173 when piercing the septum of cap 153.

[0038] Figure 4 is an exploded view of adapter unit 150 of Figure 2B. The adapter unit is itself an assembly of paddle wheel housing 156, which includes inlet 164, along with adapter 150. Valve 189 and paddle wheel 154 are disposed between paddle wheel housing 156 and adapter 150. The paddle wheel is rotatably mounted on pin 158. Blood flow path 162 through adapter 164 passes through the paddle wheel housing and exits needle 152. An actuating lever 190 is disposed on the housing and fits through a notch 187 in paddle wheel housing 156, allowing actuation of actuating lever 190 by placing sensor unit housing 180 on paddle wheel housing 156.

[0039] 5 is an exploded view of the sensor unit 140 shown in FIG. 2A. Disposed within housing 180 are processor 182, indicator 184, battery 186, and valve actuator 188, which controls valve 189, located adjacent paddle wheel housing 156. Sensor unit 140 houses the device actuator and sensor electronics. Printed circuit board 182 (which carries the processor and other electronics) is responsive to the blood volume sensed by the metering device and may indicate when a predetermined target volume has passed through the metering device via indicator 184 (shown as a colored light), although audible or vibrational indications are also contemplated.

[0040] Referring to FIG. 6, the inlet 164 to the housing 156 optionally has a small nozzle 167 that aims a focused jet of blood at the paddlewheel 154A. In the embodiment shown in FIG. 8, a small magnet 168 is integrated into the paddlewheel 154. A non-contact Hall-effect sensor (not shown but located within the sensor unit 140) can measure the rotation of the magnet 168 through the housing 156A in which the paddlewheel 154 is located (the flow path 164 through the housing 156A is linear). Other examples of sensors include axial rotor sensors, in which the turbine is perpendicular to the direction of blood flow. The turbine rotates the rotor in response to blood flowing through the turbine, and the rotor rotation is used to determine blood flow through the sensor. Other suitable sensors include peristaltic pump sensors, magnetic field sensors, and rotation sensors.

[0041] In one embodiment, blood meter 130 is programmed to provide several selectable different blood volume presets for the volume of blood passing through paddlewheel 154. The presets are more common blood volumes (e.g., 10 mL) that are drawn from patients.

[0042] Zhen, W. et al., "Computational study of the tangential type turbine flowmeter," Flow Measurement and Instrumentation, Vol. 19, pp. 233-239 (2008), which is incorporated herein by reference, describes the calibration of a tangential type turbine flowmeter. In FIG. 6, W1 is the inlet velocity, and r0 is the axis between the shaft and the jet outlet axis. As described in Zhen et al., the rotor drive torque (T r ) is calculated using the following formula: Tr=ρQ(V1r cos α1-V2r cos α2) (1) where ρ is the fluid density, Q is the volumetric flow rate, r is the rotor radius, α1 is the angle between V1 and U1, and α2 is the angle between V2 and U2. The absolute velocity V1 is given by: V1=Q / A (2) where A is the jet aperture, and the rotational speed (n) is calculated by: V2cos α2=u=2πr0n (3)

[0043] From the above, the rotor drive torque is calculated, and the meter performance is calculated from the following formula: T r -T rm -T rf -T re =0 (4) where T r is the rotor driving torque, and T rm is the journal bearing braking torque, and T rf is the rotor blade braking torque due to fluid drag, and T re is the braking torque due to the attractive force of the magnetic pickup. These values ​​are used to calculate turbine meter performance values, as further described in Zhen et al., which allow the volumetric flow rate to be determined from the rotor speed, paddlewheel meter dimensions, etc.

[0044] The dimensions of the paddle wheel 154 and housing 156 are largely a matter of design choice. A smaller paddle wheel 154 will rotate more per mL of blood passing through it compared to a larger paddle wheel. The width of the individual paddles 154A (FIG. 6) in the paddle wheel 156 should be slightly larger than the width of the blood jet (which is the same size as the opening in the nozzle portion 167 of the housing inlet 164). Other non-contact motion detection means for the paddle wheel may also be used, such as LEDs and photosensitive receivers. Such is shown as 170 in FIG. 6.

[0045] An alternative in-line housing 156A configuration is shown in Figures 7 and 8. In this configuration, the housing inlet 264 and outlet 266 are in line and the blood flow path is straight. Figure 2B shows a housing 156 in which the housing inlet 164 is perpendicular to the housing outlet 166.

[0046] The blood jet is ejected tangentially against the paddle wheel 154, which exerts a moment of force (torque) on the paddle wheel 154, causing it to rotate. This is caused by the kinetic energy of the blood jet. After the paddle wheel housing 156 initially fills with blood, air bubbles may form, impeding the motion of the paddle wheel 154.

[0047] As mentioned above, the relationship between the number of rotations of the paddlewheel and the actual volume of blood passing through is not linear. In addition to the driving jet of fluid against the paddlewheel, there is also the damping effect of the rotating paddle in this fluid. This causes "slip," which varies with pressure and viscosity differences. Optionally, the behavior of the paddlewheel can be monitored and modeled to predict slip based on flow conditions. Once slip is determined, the flow conditions can be provided to a processor, which can correct the volume calculated based on the number of rotations of the paddlewheel to account for the slip. This can result in large variations in the actual measured volume along with the measured volume.

[0048] Optionally, the device is calibrated to correlate the measured metered volume with the actual metered volume. This ensures that the blood metering devices described herein accurately draw the target blood volume (typically 8 mL to 10 mL of blood) at any time. The rate at which blood is drawn also affects the accuracy of the measured volume. It is contemplated that the metering devices described herein are calibrated so that the effect of flow rate on the measured volume is known. In one embodiment, the rotation of the paddle wheel is correlated to the volume of blood flowing through the paddle wheel. In an alternative embodiment, the rotation speed (i.e., the RPM of the paddle wheel) is used to determine the flow rate, which is then used to calculate the volume of blood passing through the paddle wheel. Once calibrated, the metering device measures the rate of blood flow and adjusts the measured volume to compensate for known inaccuracies in volume measurement at certain blood flow rates. Optionally, the blood metering device has a switch that powers on the system and resets the system each time a new blood culture bottle is presented for filling.

[0049] Although the embodiments herein describe paddle wheel flow meters, other measurement devices are contemplated, such as hair sensors, acoustic sensors, optical sensors, etc. Such sensors are known to those skilled in the art and will not be described in detail herein. In some embodiments where the sensor unit does not contact blood, the sensor unit may be reused.

[0050] As previously mentioned, the combined flow meter / pump blood metering devices described herein can be configured to detect venous collapse (by detecting reduced or inadequate blood flow) and re-expand the vein (by stopping blood flow through the metering device rather than removing the needle for drawing blood from the patient). As noted above, the blood metering devices described herein can be activated when the device determines that a target blood volume has been drawn, thereby stopping blood flow through the metering device.

[0051] To actively measure blood flow, a low-intensity commutating magnetic field can be induced by the controller to aid in rotor rotation at low flow rates. A disposable flow meter / pump 300 is shown in FIG. 9. As shown, the stator 310 (i.e., housing) and rotor 320 are completely separate and can be easily disassembled. The rotor 320 can be a single piece that is sintered and magnetized. A magnet 330 is mounted on the rotor 320. A Hall effect sensor 340 detects the movement of the magnet and determines the rotor RPM. From the resulting RPM, the blood flow rate into the culture bottle is determined. In the pump function, the rotor is driven by coils A and B 350. It is noted that for the device shown in FIG. 9, the flow meter and pump functions cannot be performed simultaneously. By measuring the back EMF from coil 350, the Hall sensor can be eliminated.

[0052] Magnets 330 on rotor 320 also function as paddles (such as paddle 154A in FIG. 6). Thus, motor 300 can function as a paddlewheel flow sensor or, when driven by coil 350, as a centrifugal pump. Housing 310 around rotor 320 is airtight / watertight and made from a non-conductive material so as not to interfere with the magnetic field required to drive the rotor. There are tangential inlets / outlets 360 to the housing and axial inlets / outlets (not shown in FIG. 9). Optionally, the two coils are positioned so that the coils and Hall sensors cover less than 180 degrees of the rotor's rotation. This greatly facilitates disassembly when compared to current stator designs, which cover a full 360 degrees.

[0053] The motor 300 is provided with a commutated, low-power rotating magnetic field to help drive paddle wheels within the device at low flow rates. The rotor 320 is optionally made from a single magnetizable material. The rotor 320 is optionally ring-shaped with protrusions 330 on the periphery and paddles that act as magnetic poles. The stator 310 has at least two turns, and therefore two coils 350 are shown. The coils 350 are positioned on the stator no more than 180 degrees apart. This ensures easy assembly and disassembly of the rotor / housing 320 and stator 310. The illustrated mounting 300 can be incorporated into devices that measure blood flow and / or pump blood, drugs, samples, reagents, etc., to a patient or a container such as a collection tube. The poles / magnets are radially oriented in this example, but may also be axially oriented. The motor is preferably synchronous, but may also be operated using asynchronous commutation.

[0054] 10 shows an alternative configuration of a blood measuring device and blood culture bottle. Blood measuring device 430 is attached to blood culture bottle 460. In this embodiment, sensor portion 440 is monolithically integrated with adapter portion 450 to form blood measuring device 430.

[0055] Figure 11 is an exploded view of the assembly of Figure 10. In this view, the monolithic blood measuring device 430 is removed from the blood culture bottle 460.

[0056] 12 shows a blood collection system. The blood collection system includes a needle 410, tubing 420, a blood measuring device 430, a sensor portion 440, an adapter portion 450, and a collection bottle 460. During the process of collecting a blood sample from a patient, the needle 410 is used to puncture a vein or artery of the patient. Blood from the patient is directed through the tubing 420 toward the collection bottle 460, driven by vacuum pressure created by the collection bottle 460. The blood is collected into the collection bottle 460.

[0057] 13 is a see-through perspective view of disposable blood meter 430, viewed from the front of sensor portion 440 integrated with adapter portion 450. Blood meter 430 includes a processor 482, which includes a small embedded memory and a disposable printed circuit board (PCB). Stored within the processor's embedded memory is information that controls the operation of the blood meter. Non-limiting examples of such information include the total volume of blood passing through the device (i.e., the predetermined fill volume), the maximum duration of blood draw (after which the device will cease further blood draw from the patient), and changes in blood flow rate from the patient that indicate venous collapse. LED indicator 484 provides an indication of the amount of fluid (e.g., blood) that has passed through blood meter 430. Other indicators (to both the user and the actuator) that the container has received the predetermined fill volume include a sensory alert, such as a vibration alert.

[0058] 14 is a see-through perspective view of blood meter 430 as viewed from the back of sensor portion 440 integrated with adapter portion 450. Blood meter 430 has a paddle wheel 454 mounted within a blood flow path 462 that enters top portion 431 of blood meter 430. Hall sensor 469 detects magnet 468 within the paddle wheel, and the number of revolutions detected by Hall sensor 468 is converted to volume by processor 482. Mechanical contact 490 detects contact of blood meter 430 with collection bottle 460 and initiates the collection of blood from the patient into collection bottle 460.

[0059] In this specification, the word "comprising" is understood in its "open" sense, i.e. in the sense of "including", and is therefore not limited to its "closed" sense, i.e. in the sense of "consisting only of". A corresponding meaning is ascribed to the corresponding words "comprise", "comprised" and "comprises" where they appear.

[0060] While specific embodiments of the present technology have been described, it will be apparent to those skilled in the art that the present technology may be embodied in other specific forms without departing from its essential characteristics. The present embodiments and examples are therefore considered in all respects to be illustrative and not restrictive. For example, although the present disclosure describes the collection of blood in a blood culture bottle, the same principles are applicable to the collection of other fluids in other containers.

[0061] It will be further understood that any reference to subject matter known in the art is not an admission that such subject matter is generally known to those skilled in the art to which the technology pertains, unless otherwise indicated.

Claims

1. an adaptor unit including a housing defining a blood flow path configured to be connected to a blood collection set, the adaptor unit having a volume indicator disposed therein for measuring the volume of blood flowing through the blood flow path; a sensor unit engaged with the adapter unit, the sensor unit comprising: i) the sensor configured to detect a signal from the sensor in response to blood flowing through the blood flow path in the adapter unit; and ii) a processor that correlates the sensor signal with a blood volume and controls a response of the sensor unit in response to the sensor unit determining that a predetermined blood volume has passed through the adapter unit; A blood measurement device comprising:

2. 10. The blood measurement device of claim 1, wherein the sensor unit is one of detachably engaged with the adapter unit and monolithically integrated with the adapter unit.

3. 10. The blood measuring device of claim 1, wherein the volume indicator is a paddle wheel disposed within the blood flow path but freely rotatable within the housing.

4. 4. The blood measurement device according to claim 3, wherein the paddle wheel has a rotation axis that is perpendicular to the direction of blood flow in the blood flow path.

5. The blood measurement device according to claim 3 , wherein the paddle wheel has a rotation axis that is aligned with the direction of blood flow in the blood flow path.

6. 6. The blood measuring device of claim 3, wherein the processor correlates rotation of the paddle wheel with blood volume to determine a measured blood volume flowing through the blood measuring device, and controls a response of the sensor unit in response to the sensor unit determining that a predetermined blood volume has passed through the paddle wheel disposed within the adapter unit.

7. 10. The blood measuring device of claim 1, wherein the adapter unit is attachable to a collection container, the collection container being selected from the group consisting of a blood culture bottle and a sample collection tube.

8. 7. The blood measuring device of claim 6, wherein the processor is configured to compare the measured blood volume to the predetermined blood volume, and when the measured blood volume equals the predetermined amount, the processor sends a signal to close a blood flow valve to shut off blood flow to the blood measuring device.

9. The blood measurement device of claim 1 , wherein the volume indicator is one of a hair sensor, an acoustic sensor, and an optical sensor.

10. The blood measurement device of any one of claims 3 to 5, wherein the sensor is one of an axial rotor sensor, a peristaltic pump sensor, a magnetic field sensor, and a rotation sensor.

11. 6. The blood measuring device of claim 3, wherein the paddle wheel carries a magnet, and the housing has a Hall effect sensor disposed thereon that is activated when the magnet passes by the Hall effect sensor.

12. 12. The blood measuring device of claim 11, wherein the paddle wheel rotates freely within the housing on an integral pin supported by the housing.

13. 10. The blood measuring device of claim 1, wherein the housing defines a blood flow path, the flow path exiting the adapter unit through an outlet.

14. 10. The blood measuring device of claim 1, wherein the adapter unit includes an activation lever that activates the processor when the adapter unit is attached to a blood culture bottle.

15. The blood measurement device of claim 1 , wherein the sensor unit includes a battery.

16. The blood measurement device of claim 1 , wherein the sensor unit comprises a valve actuator.

17. 17. The blood measurement device of claim 16, wherein the valve actuator is one of a moving magnet actuator, a microactuator, a solenoid, or a twin magnet actuator.

18. The blood measurement device of claim 1 , wherein the volume indicator is a combination flow meter and pump.

19. 20. The blood measurement device of claim 18, wherein the pump comprises a motor, the motor comprising a rotor, and the housing forms a stator for the pump.

20. 20. The blood measurement device of claim 19, wherein the rotor comprises one or more magnets.

21. 21. The blood measurement device of claim 20, further comprising a Hall effect sensor that measures the rotational speed of the rotor.

22. 22. The blood measuring device of claim 21, wherein the processor determines the volume of blood flowing through the pump based on the rotational speed of the motor.

23. 23. The blood measuring device of claim 22, wherein the blood collection set comprises a needle configured for venipuncture and tubing.

24. 24. The blood measuring device of claim 23, wherein, in operation, the processor indicates venous collapse when the rotational speed of the motor falls below a predetermined rotational speed.

25. 10. The blood measuring device of claim 1, wherein the sensor unit includes an indicator light that indicates when a predetermined volume of blood has passed through the adapter unit based on a signal from the processor.

26. 25. The blood measurement device of claim 24, wherein the sensor unit includes an indicator light that indicates when venous collapse occurs based on a signal from the processor.

27. an adapter unit including a housing defining a blood flow path configured to be connected to a blood collection set, the adapter unit having a paddle wheel disposed within the blood flow path but freely rotatable within the housing; a sensor unit engaged with the adapter unit, i) the sensor configured to detect a signal from the sensor in response to blood flowing through the blood flow path in the adapter unit; ii) a processor that correlates the sensor signal with blood volume and controls a response of the sensor unit in response to the sensor unit determining that a predetermined volume of blood has passed through the adapter unit; iii) a valve actuator in signal communication with and controlled by said processor; a sensor unit comprising: A blood measurement device comprising:

28. 28. The blood measuring device of claim 27, wherein the adapter unit includes an activation lever that activates the processor when the adapter unit is attached to a blood culture bottle.

29. 30. The blood measuring device of claim 28 or 29, wherein the processor correlates rotation of the paddle wheel with blood volume to determine a measured volume of blood flowing through the blood measuring device, and controls a response of the sensor unit in response to the sensor unit determining that a predetermined volume of blood has passed through the paddle wheel disposed within the adapter unit.

30. 1. A method for determining the amount of blood flowing from a patient to a collection bottle, comprising: providing an adapter unit and sensor unit assembly, the adapter unit including a housing defining a blood flow path configured to be connected to a blood collection set, the adapter unit having a paddle wheel disposed within the blood flow path but freely rotatable within the housing; The sensor unit is i) the sensor configured to detect a signal from the sensor in response to blood flowing through the blood flow path in the adapter unit; ii) a processor that correlates the sensor signal with blood volume and controls a response of the sensor unit in response to the sensor unit determining that a predetermined volume of blood has passed through the adapter unit; iii) a valve actuator in signal communication with and controlled by said processor; connecting the assembly to the blood collection set, the blood collection set including a needle configured for venipuncture and tubing, such that the blood collection set is in fluid communication with the blood flow path; connecting the adapter unit to a blood collection container such that the blood flow path in the adapter is in fluid communication with the blood collection container, wherein pressure within the blood collection container is less than atmospheric pressure; using the needle to obtain a blood sample from the patient by venipuncture of the patient, whereby blood flows through the blood flow path and into the blood collection container; flowing blood through a paddle wheel sensor; measuring rotation of the paddle wheel sensor; measuring the amount of blood flowing from the blood flow path to the blood collection container; comparing the determined blood volume with a predetermined blood volume; Including, When the measured blood volume equals the predetermined blood volume, the processor sends a signal to the valve actuator to stop blood from flowing into the collection container.

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