Abstract:
A method and apparatus for pneumatic control of a blood pressure determination are disclosed. The method and apparatus comprise an inflatable cuff for obtaining a blood pressure measurement from a patient, a hose configured to operate with a pressurizing apparatus for providing pressurization of the inflatable cuff, the hose including a patient end and a non-patient end. In addition the method and apparatus comprise a pneumatic switch coupled to the inflatable cuff near the patient end of the hose.

Description:
BACKGROUND OF THE INVENTION 
   The field of the invention is patient monitoring systems. More particularly, the invention relates to a method and apparatus for regulating a blood pressure determination from the patient end of a patient monitoring system. 
   The heart muscles of humans periodically contract to force blood through the arteries. As a result of this pumping action, pressure signals exist in these arteries and cause them to cyclically change volume. The baseline pressure for these signals is known as the diastolic pressure and the peak pressure for these signals is known as the systolic pressure. A further pressure value, known as the “mean arterial pressure” (MAP), represents a time-weighted average of the blood pressure. The systolic, MAP and diastolic values for a patient are useful in monitoring the cardiovascular state of the patient, in diagnosis of a wide variety of pathological conditions, and in treating disease. Therefore, it is a great advantage to a clinician to have an automatic blood pressure monitor which can accurately, quickly, and non-invasively estimate these blood pressure values. 
   In many instances, a clinician will use a long tube or hose connected to an automatic blood pressure monitor when measuring a patient&#39;s blood pressure. This is often necessary when the monitor is wall mounted or there is no room to locate the device next to the patient. In these types of situations, the clinician must apply the cuff to the patient and then move some distance away from the patient to activate the blood pressure determination process. This can be time consuming and inefficient since it is typically advantageous to remain near a patient to check other vital signs or offer more personal care for the patient. Thus, there exists a need for a method and apparatus for controlling a blood pressure determination from the patient end of the tube or hose, thereby allowing the clinician to remain next to the patient during the automated determination. 
   SUMMARY OF THE INVENTION 
   One embodiment of the present invention provides an apparatus for pneumatic control of a blood pressure determination, the apparatus including an inflatable cuff for obtaining a blood pressure measurement from a patient, a hose configured to operate with a pressurizing apparatus for providing pressurization of the inflatable cuff, the hose comprising a patient end and a non-patient end, and a pneumatic switch coupled to the inflatable cuff near the patient end of the hose. 
   Another embodiment of the present invention provides a system for pneumatically controlling a blood pressure determination, the system including means for acquiring a blood pressure measurement from a patient, means for pneumatically isolating a lumen and creating a pressure signal therein, means for sensing a pressure signal, and means for providing a signal based on the pressure signal to a microprocessor in order to control overall operation of the system. 
   Another embodiment of the present invention provides a method of pneumatically controlling a blood pressure determination, the method comprising pressurizing an inflatable cuff of a blood pressure measurement device in order to obtain a blood pressure determination. In addition, the method includes depressing a pneumatic switch coupling the inflatable cuff to at least one lumen near a patient end of the lumen, whereby depressing the controller switch pneumatically isolates the lumen and creates a pressure signal therein. Further, the method includes using a sensor to sense the pressure signal and signaling a microprocessor as a result of the pressure signal in order to control the blood pressure determination. 
   Another embodiment of the present invention provides a method of pneumatically controlling a transfer of medical data, the method including acquiring medical data from a patient using medical apparatus, controlling the acquisition of medical data by using a switch configured to pneumatically create a pressure change in the medical apparatus that may be sensed by a sensor. In addition, the method includes signaling a microprocessor of the change, wherein the microprocessor toggles the acquisition of the medical data based on preprogrammed logic. 
   Another embodiment of the present invention provides a computer program product for controlling a blood pressure determination based on a pneumatic controller switch, the computer program product comprising a means for acquiring a blood pressure measurement from a patient, a means for pneumatically isolating a lumen and creating a pressure signal therein, a means for sensing the pressure signal, and a means for providing a signal based on the pressure signal to a computer useable medium having computer logic for enabling at least one processor in a computer system to toggle control of the blood pressure determination. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a diagram of a non-invasive blood pressure monitoring system in accordance with an embodiment of the present invention. 
       FIG. 1B  is a diagram of a non-invasive blood pressure monitoring system in accordance with an embodiment of the present invention. 
       FIG. 2  is a diagram of a pneumatic non-invasive blood pressure regulating device according to an embodiment of the present invention. 
       FIG. 3  is a top plan view of the pneumatic non-invasive blood pressure regulating device of  FIG. 2  in greater detail. 
       FIG. 4  is a side plan view of a pneumatic non-invasive blood pressure regulating device of  FIG. 2  in greater detail. 
       FIG. 5  is a cross-sectional view of the pneumatic non-invasive blood pressure regulating device of  FIG. 2  in an extended position. 
       FIG. 6  is a cross-sectional view of the pneumatic non-invasive blood pressure regulating device of  FIG. 2  in a compressed position. 
       FIG. 7  is a diagram of a pneumatic non-invasive blood pressure regulating device in accordance with an alternative embodiment of the present invention. 
       FIG. 8  is a cross-sectional view of the pneumatic non-invasive blood pressure regulating device of  FIG. 7  in an extended position. 
       FIG. 9  is a cross-sectional view of the pneumatic non-invasive blood pressure regulating device of  FIG. 7  in a compressed position. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1A  shows a blood pressure determination system including the arm of a human subject wearing a flexible inflatable cuff  101  capable of occluding the brachial artery when fully inflated. As cuff  101  is deflated using deflate valve  102  having exhaust  103 , the arterial occlusion is gradually relieved. The deflation of cuff  101  via deflate valve  102  is controlled by microprocessor  107  via control line  116 . 
   Referring to  FIG. 1A , a pressure transducer  158  is coupled by a hose (e.g. tube, duct, etc.)  154  to the cuff  101  for sensing the pressure therein. Cuff pressure levels in the artery are sensed by changes in the counter-pressure of the cuff  101 , and these cuff pressure levels are converted into an electrical signal by transducer  158  and coupled over path  106  to microprocessor  107  for processing. Also, the deflate valve  102  is connected by hose  114  via a branch connection  115  with the hose  156  leading to cuff  101 . Cuff pressure levels are converted to an electrical signal by transducer  160  and coupled over path  120  to microprocessor  107  for processing. Switch  150 , which is described in greater detail below, may be included to control the overall operation of the blood pressure determination. 
     FIG. 1B  shows the arm of a human subject wearing a flexible inflatable cuff  301  capable of occluding the brachial artery when fully inflated according to an alternative embodiment. The system of  FIG. 1B  is similar to the system of  FIG. 1A  described above except for the additional lumen  370 . As such, the elements shown in  FIG. 1B  that correspond to like elements in  FIG. 1A  described above will be identified by the same reference numerals but increased by 200. As cuff  301  is deflated using deflate valve  302  having exhaust  303 , the arterial occlusion is gradually relieved. The deflation of cuff  301  via deflate valve  302  is controlled by microprocessor  307  via control line  316 . 
   A pressure transducer  358  is coupled by a hose (e.g. tube, duct, etc.)  354  to the cuff  301  for sensing the pressure therein. Cuff pressure levels in the artery are sensed by changes in the counter-pressure of the cuff  301 , and these cuff pressure levels are converted into an electrical signal by transducer  358  and coupled over path  306  to microprocessor  307  for processing. Also, the deflate valve  302  is connected by hose  314  via a branch connection  315  with the hose  356  leading to cuff  301 .  FIG. 1B  further shows hose  370  and transducer  372 . Cuff pressure levels within hose  370  are converted to an electrical signal by transducer  372  and coupled over path  334  to microprocessor  307  for processing. Switch  350 , which is described in greater detail below, may be included to control the overall operation of the system. 
     FIG. 2  shows an exemplary embodiment of a pneumatic non-invasive blood pressure regulating switch  150  that may be used with the monitoring system of FIG.  1 A. Referring to  FIG. 2 , switch  150  is shown for use with a dual-lumen hose  152  and cuff  101 . Hose  152  may include a first and second lumen  154 ,  156 . Pressure sensors  158 ,  160  are connected to lumens  154 ,  156 , respectively, for sensing the pressure therein. Typically, sensors  158 ,  160  may exist in a monitor for displaying blood pressure data. Cuff pressure levels are converted into electrical signals for display of blood pressure (or other medical) data of a patient. Cuff  101  includes lumens  162 ,  164  for providing a path of pressurized air through the system. Switch  150  couples cuff  101  by way of lumens  162 ,  164  to lumens  154 ,  156 . Preferably switch  150  is located near the patient end  175  of hose  152 . 
   Switch  150  may include a button  166  (e.g., knob, switch, plunger, etc.) for controlling the overall operation of the blood pressure system. According to this embodiment, button  166  is configured so that when depressed (e.g., activated), it creates a pressure signal in one lumen greater than the pressure in the other lumen, thereby causing at least one of pressure sensors  158 ,  160  to measure the change in pressure. This information may then be sent to microprocessor  107 . Microprocessor  107  may analyze this information in order to toggle (e.g., control, regulate, stop, restart, delay, etc.) operation of the blood pressure system. Since microprocessor  107  may be configured to identify a pressure differential between lumens  154 ,  156 , the orientation of the system (e.g., position and attachment of hoses, lumens, sensors, cuffs, etc.) can vary. Accordingly, pneumatic switch  150  allows a caregiver to remain near a patient during a blood pressure determination and still control the overall operation of the system. 
   Referring to  FIGS. 3 and 4 , pneumatic switch  150  is shown in greater detail. According to an exemplary embodiment, switch  150  includes cuff connectors  182 ,  184 . Cuff connectors  182 ,  184  are configured to attach lumen  162 ,  164  to switch  150 . Many different attachment methods are contemplated for connecting lumens  162 ,  164  to switch  150  by way of cuff connectors  182 ,  184 . For example,  FIG. 3  shows connectors  182 ,  184  as having externally threaded male portions  186 ,  188 . Threaded male portions  186 ,  188  may be threaded into internally threaded female portions  192 ,  194  located on lumens  162 ,  164  (as shown in FIG.  2 ). Switch  150  further includes hose barbs  196 ,  198 . Hose barbs  196 ,  198  are configured to connect switch  150  to lumens  154 ,  156 . For example, as shown in  FIGS. 3 and 4 , hose barbs  196 ,  198  may include ridges  200 ,  202  for lumens  154 ,  156  to slide over and grip during operation.  FIGS. 3 and 4  are provided as examples and are by no means intended to be limiting in any way. Thus, any number of other suitable attachment mechanisms could be used (e.g., fasteners, clamps, bolts, etc.) between switch  150  and lumens  162 ,  164  and barbs  196 ,  198 . 
     FIGS. 5 and 6  show detailed exemplary cross-sectional views of the interior of switch  150  from  FIGS. 2-4 . Specifically,  FIG. 5  shows switch  150  while button  166  is in an extended position and  FIG. 6  shows switch  150  while button  166  is in a compressed position. As shown in  FIGS. 5 and 6 , pressurized air may travel through switch  150  along two separate paths. First, air may travel between lumens  154  and  162  by way of path  202 . Second, air may travel between lumens  156  and  164  by way of path  204 . Each path is preferably pneumatically isolated from one another. Accordingly, a pressure signal from the activation of button  166  would only exist in one path. 
   Referring to  FIG. 5 , button  166  may be configured to move between an extended position and a compressed position through an aperture  232  located on an end cap  230 . Preferably, button  166  is configured to remain in an extended position when not depressed. For example, switch  150  may include a spring mechanism  215  for applying a biasing force against the bottom of button  166 . Spring mechanism  215  may be positioned within a cavity  220  formed in switch  150 . As spring mechanism  215  biases button  166  in an extended position, cavity  220  remains substantially unobstructed for pressurized air to flow between lumens  154 ,  156  and/or  162 ,  164  (not shown). Switch  150  further includes seals (rings)  222  and  224 . These seals are preferably o-ring seals configured to create seals between button  166  and switch  150 . Ring  222  may be attached to end cap  230  so that while button  166  is in the extended position, seal  222  creates a seal between button  166  and end cap  230 . In addition, seal  224  may be attached to button  166  to create a seal with the upper portion of cavity  220 . Each seal helps prevent pressurized air from exiting switch  150  around button  166  out through aperture  232  located on end cap  230 . 
   Referring to  FIG. 6 , button  166  may be depressed (activated) to move longitudinally through cavity  220 . As button  166  is activated, spring  215  is compressed thereby allowing button  166  to at least substantially fill cavity  220 . Upper ring  222  provides a seal between button  166  and end cap  230  during the movement of button  166 . Similarly, once button  166  moves a predetermined distance within cavity  220 , lower ring  224  makes contact with a lower portion of cavity wall  240 . As a result, pressurized air is blocked at points  242  and  244  by lower ring  224  and at points  246  and  248  by upper ring  222 . Accordingly, a pressure signal may be created in path  202  that may be detected by sensor  158  (not shown). Based on data received from sensor  158 , microprocessor  107  may thereby control operation of the system according to preprogrammed logic. Many monitors used in the art already utilize transducers that may detect the pressure signal created by switch  150 . 
   As described above, since each of paths  202 ,  204  are pneumatically isolated from one another, the pressure signal in path  202  will not directly affect the flow of pressurized air along path  204 . Thus, it is important to note that button  166  may be configured to work along either path. For example, even though button  166  has been described as working along path  202 , it may just as easily be situated in a similar fashion with respect to path  204  to create a pressure signal therein. In addition, switch  150  may be used with a single hose system utilizing a second dedicated lumen. For example, one hose could provide the a path of pressurized air through the system and a second hose could be used as a dedicated lumen attached to the switch. Thus, the blood pressure determination data could be obtained along the path of pressurized air while the pneumatically isolated second hose and switch could control the overall operation of the system. 
     FIG. 7  shows an alternative embodiment of a pneumatic non-invasive blood pressure regulating switch  350  that may be used with the monitoring system of FIG.  1 B. For example,  FIG. 7  shows switch  350  for use with a tri-lumen hose  352  and cuff  301 . Hose  352  may include a first, second, and third lumen  354 ,  356 , and  370 . Although this embodiment describes a single hose  352  comprising three lumens  354 ,  356  and  370 , alternative configurations are contemplated. For instance, lumens  354 ,  356  and  370  may exist outside of a single hose, may be integrally connected to one another, and/or may be detached from one another. Pressure sensors  358 ,  360  are connected to lumens  354 ,  356 , respectively, for sensing the pressure therein. Typically, sensors  358 ,  360  may exist in a monitor for displaying blood pressure data. Cuff pressure levels are converted into electrical signals for display of blood pressure (or other medical) data of a patient. Cuff  301  includes lumens  362 ,  364  for providing a path of pressurized air through the system. Switch  350  couples cuff  301  by way of lumens  362 ,  364  to lumens  354 ,  356 . Preferably, switch  350  is located near the patient end  375  of hose  352 . It is important to note that lumen  370  preferably exists as a separate, pneumatically self-contained lumen relative to lumens  354 ,  356 . 
   Switch  350  may include a button  366  (e.g., knob, switch, plunger, etc.) for controlling the overall operation of the blood pressure system. According to this embodiment, lumen  370  is configured to remain at a static pressure during normal operation of the system. However, once depressed, button  366  pneumatically creates a pressure signal in lumen  370 . Pressure sensor  372  then measures the pressure signal and/or change in pressure in lumen  370 . This information may then be sent to and processed by microprocessor  307  which toggles (e.g., stops, restarts, delays, etc.) operation of the blood pressure system. Since microprocessor  307  may be configured to identify a pressure change in lumen  370 , the orientation of the system (e.g., position and attachment of hoses, lumens, sensors, cuffs, etc.) can vary. Accordingly, pneumatic switch  350  allows a caregiver to remain near a patient during a blood pressure determination and still control the overall operation of the system. 
     FIGS. 8-9  show detailed exemplary cross-sectional views of the interior of switch  350  from FIG.  7 . Specifically,  FIG. 8  shows switch  350  while button  366  is in an extended position and  FIG. 9  shows switch  350  while button  366  is in a compressed position. As shown in  FIGS. 8 and 9 , pressurized air may travel through switch  350  along two separate paths. First, air may travel between lumens  354  and  362  by way of path  402 . Second, air may travel between lumens  356  and  364  by way of path  404 . In addition, air may be held at a substantially static pressure within lumen  370 . Lumen  370  is preferably pneumatically isolated from paths  402 ,  404  (e.g., lumen  370  exists as part of a closed system). Accordingly, a pressure signal from the activation of button  366  would only exist in lumen  370 . 
   Referring to  FIG. 8 , button  366  may be configured to move between an extended position and a compressed position through an aperture  332  located on an end cap  330 . Preferably, button  366  is configured to remain in an extended position when not depressed. For example, switch  350  may include a spring mechanism  415  for applying a biasing force against the bottom of button  366 . Spring mechanism  415  may be positioned within a cavity  420  formed in switch  350 . As spring mechanism  415  biases button  366  in an extended position, the air pressure in cavity  420  remains substantially static since lumen  370  and cavity  420  comprise a closed system. Switch  350  further includes seals (rings)  322  and  324 . These seals are preferably o-ring seals configured to create seals between button  366  and switch  350 . Ring  322  may be attached to end cap  330  so that while button  366  is in the extended position, seal  322  creates a seal between button  366  and end cap  330 . In addition, seal  324  may be attached to button  366  to create a seal with the upper portion of cavity  420 . Each seal helps prevent pressurized air from exiting switch  350  around button  366  out through aperture  332  located on end cap  330 . 
   Referring to  FIG. 9 , button  366  may be depressed (activated) to move longitudinally through cavity  420 . As button  366  is activated, spring  415  is compressed thereby allowing button  366  to at least substantially fill cavity  420 . Upper ring  322  provides a seal between button  366  and end cap  330  during the movement of button  366 . Further, lower ring  324  provides a seal between button  366  and cavity  420  during movement of button  366 . Thus, as button  366  moves longitudinally through cavity  420 , air in lumen  370  and cavity  420  is pressurized since lumen  370  and cavity  420  form a pneumatically isolated closed system. Accordingly, a pressure signal may be created within lumen  370  that may be detected by sensor  372  (not shown). Further, since lumen  370  is pneumatically isolated from paths  402 ,  404 , the pressure signal will not directly affect the flow of pressurized air along either of paths  402 ,  404 . Based on data received from sensor  372 , microprocessor  307  may thereby control operation of the system according to preprogrammed logic. Many monitors used in the art already utilize transducers that may detect the pressure signal created by switch  350 . 
   While the embodiments and application of the invention illustrated in the figures and described above are presently preferred, it should be understood that these embodiments are offered by way of example only. For example, although embodiments are described using dual and tri-lumen configurations, any number of lumens could be used (e.g., one, four, five, six, ten, etc.). In addition, the length of the hose may vary depending on the needs of the caregiver and patient. Further, the use a pneumatic controller switch is not intended to be limited to blood pressure devices or measurements. For instance, a pneumatic switch may be used in any medical situation where a caregiver desires to regulate the medical data transfer near the patient (e.g., ECG readings, blood oxygen level, body temperature, etc.). Furthermore, although the embodiments described herein relate to hand controlled switch devices, any number of variations may still be used. For example, switches controlled by a foot are also contemplated. Instead of having a switch with a button for a finger or hand to activate, a similar switch may be used that rests on the ground and may be depressed or activated by pushing it with a foot or the toes. Accordingly, the present invention is not limited to a particular embodiment, but extends to various modifications that nevertheless fall within the scope of this application.