Abstract:
The present invention relates to a device and method to control suction in a patient environment. The device comprises a body portion having an interior chamber adapted for coupling to a source of the vacuum; a valve comprising a shaft rotatably coupled to the body portion; and an actuator coupled to the shaft of the valve. In operation the valve is rotatable between i) a first position in which the vacuum is provided to the interior chamber via the valve at a first predetermined level and ii) a second position in which the vacuum is interrupted to the interior chamber. The actuator is adapted to move between a first position and a second position which increases the vacuum in the interior chamber to a second predetermined level for clearing occluded suction lines in the patient circuit.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to provisional application Ser. No. 60/527,695 filed on Dec. 8, 2003. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to medical vacuum devices. More specifically, the present invention relates to devices and methods for monitoring and maintaining constant flow in a patient vacuum circuit without the need to break any patient connections for evaluation or intervention. 
     BACKGROUND OF THE INVENTION 
     Suction is widely employed in a Hospital environment to assist health care providers in the care of patients. On its most basic level, suction is used to remove fluids and debris from body cavities and is employed in virtually any location where patient care is needed. 
     Bodily fluids drawn through these suction lines are not typically of homogenous viscosity and may even be a suspension of both solid and liquid components. Certain applications dictate that very low levels of vacuum (&lt;120 mm Hg) be used to remove these accumulated fluids. Such instances may be found when suctioning the airway and surrounds. 
     Low levels of vacuum are appropriate from a patient safety standpoint, but these low levels may not create adequate force to pull viscous fluids through the lines. Further, the suction lines are prone to blockage when very viscous fluids, congealed blood, or solid particles enter the vacuum circuit. Certain biological fluids may also congeal inside of the suction lines if the fluid is not constantly moving in the circuit. 
     The present standard of care for occluded suction lines begins with uncoupling the line downstream of the blockage. A conventional syringe is then used to draw any accumulated debris through the line. This syringe acts as a flow limited vacuum generating device. 
     Disadvantageously, uncoupling this line creates a vector for micro-organisms to enter the patient circuit. Uncoupling this line also exposes the health care provider and patient to cross contamination from each other or the environment. Each time a blockage occurs valuable time is dedicated to maintaining sterile technique. Further, additional disposable medical waste is also generated by these interventions. 
     SUMMARY OF THE INVENTION 
     In view of the shortcomings of conventional systems and methods, the present invention is an apparatus and method which allows health care providers to quickly evaluate if a suction line is occluded. 
     According to one aspect of the invention the device comprises a body portion having an interior chamber and adapted for coupling to a vacuum source; a valve comprising a shaft rotatably coupled to the body portion; and an actuator coupled to the shaft of the valve, wherein the valve is rotatable between i) a first position in which the vacuum is provided to the interior chamber via the valve at a first predetermined level and ii) a second position in which the vacuum is interrupted to the interior chamber, and the actuator is adapted to move between a first position and a second position which increases the vacuum in the interior chamber to a second predetermined level. 
     According to another aspect of the invention, the device further comprises a further valve rotatably coupled to the body portion, and an output port coupled to the interior chamber for receiving the first and second predetermined levels of vacuum. 
     According to a further aspect of the invention, an indicator is coupled to the body portion to display a level of vacuum provided to the output port to indicate a condition of the patient circuit. 
     According to still another aspect of the invention, the valve comprises a first vacuum circuit including a groove disposed partially around an outside portion of the shaft, such that the groove provides fluid communication between the interior chamber and the source of vacuum when the valve is in the first position; and a second vacuum circuit including a first orifice disposed along at least a portion of the shaft along the longitudinal axis, a second orifice disposed in the shaft oriented transverse to the longitudinal axis and in fluid communication with the first orifice, and a third orifice disposed in the shaft oriented transverse to the longitudinal axis and in fluid communication with the first orifice, such that the second vacuum circuit provides fluid communication between the interior chamber and the source of vacuum when the actuator is in the second. 
     According to yet another aspect of the invention, the actuator further comprises a shaft coaxially coupled to the shaft of the valve, a first orifice extending from an end of the shaft and at least partially along an interior of the shaft, a circumferential groove disposed along an outside potion of the shaft, a second orifice formed in the circumferential groove, transverse to the first orifice and in fluid communication with the first orifice, such that the actuator provides fluid communication between the interior chamber and the source of vacuum via i) the first orifice, ii) the circumferential groove and iii) the second orifice when the actuator is in the second position. 
     These and other aspects of the invention are set forth below with reference to the drawings and the description of exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in connection with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawing are not to scale. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. Included in the drawing are the following Figures: 
         FIG. 1  is perspective view of an exemplary embodiment of the present invention; 
         FIG. 2  is an exploded perspective view of the device of  FIG. 1 ; 
         FIG. 3  is a sectional perspective view of a portion of the embodiment of  FIG. 1 ; 
         FIG. 4  is a perspective sectioned view of an exemplary vacuum selection mechanism in a standard ‘ON’ position; 
         FIG. 5  is a perspective sectioned view of the vacuum selection mechanism of  FIG. 4  with the device activated to allow application of temporary increased vacuum; 
         FIG. 6  is an perspective sectioned view of the vacuum selection mechanism of  FIG. 4  in the “OFF” position; and 
         FIG. 7  is a perspective sectioned view of another exemplary vacuum selection mechanism in a standard ‘ON’ position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention relates to improvements in a mechanical or electromechanical control device and methods used to control suction in a patient environment. The invention provides improvements to the functional regulation characteristics allowing the use of a temporary increase in the level of suction to facilitate the removal of blockages from a suction line. Desirably, this increase in vacuum is both regulated and flow controlled to mitigate any potential harm to the patient. If the suction line is not occluded, operating the present invention will not effect level of vacuum in the patient circuit. 
     A trained health care provider can easily operate the exemplary device and visually evaluate if fluid flow in the suction line is occluded. If fluid flow is occluded, the health care provider can then operate the exemplary device to remove the blockage from the line. Because any potential blockage isolates the regulated vacuum source from the patient, the increased vacuum generated in the line is not experienced by the patient. Once the blockage is cleared, the flow and/or pressure restricted nature of the present invention will be overridden by the main regulating mechanism and an excessively high vacuum will not be applied to the patient. 
     Certain design characteristics have been identified as having unique qualities for a suction control used to maintain patient and flowing suction lines in a clinical environment. Among these characteristics are:
         1. The exemplary regulator comprises a simple momentary actuator, which will temporarily increase the applied vacuum when depressed. Once the actuator is released, there is no impact on the regulated vacuum setting.   2. The exemplary actuator allows a simple determination of whether or not a suction line is occluded, without breaking sterile technique.   3. The exemplary actuator allows the use of an existing vacuum gauge to determine if a suction line is flowing, without the need for an additional flow gauge.   4. The exemplary actuator allows the temporary application of increased vacuum that is regulated via the relative ratio of two orifices.   5. The exemplary actuator allows the temporary application of increased vacuum that is regulated via a second independent regulator internal to the device.       

     Referring now to  FIGS. 1 and 2 , an exemplary embodiment of the present invention is illustrated. As shown in  FIG. 1 , device  100  comprises a body portion  104  which is coupled to a source of vacuum, such as wall source  102 . Spool valve  101  is rotatably coupled to body portion  104  at a side thereof. Regulator  103  having an adjustment knob  105  is coupled to an end of body portion  104 . Connection port  106  is also coupled to body portion  104 . Additionally, gauge  113  is coupled to body portion  104  and in fluid tight communication with connection port  106  in order to indicate a level of pressure present in a patient vacuum circuit (not shown for simplicity). 
     In operation, the rotation of spool valve  101  alternatively connects vacuum provided from wall vacuum source  102  or atmospheric pressure from vents (not shown) to body portion  104 . In the ‘ON’ position, as best illustrated in  FIG. 3 , vacuum from vacuum source  102  is provided to regulation chamber  302  of regulator body  104  via partial circumferential groove  304  which is formed in a portion of shaft  306  of spool valve  101 . Regulation chamber  302  is in fluid tight communication with connection port  106  and thus provides vacuum to a patient vacuum circuit (not shown). 
     When spool valve  101  is in the ‘OFF’ position (best illustrated in  FIG. 6 ), vacuum from vacuum source  102  is interrupted by shaft  306  of spool valve  101  while a vent port (not shown) disposed in body portion  104  is permitted to communicate with regulation chamber  302  via transverse orifice  326  to thus vent regulation chamber  302  and the patient circuit to atmospheric pressure. In one exemplary embodiment, the vent port is disposed in the rear portion of body portion  104 , for example. 
     Adjustment knob  105  is rotated to regulate the level of vacuum provided from vacuum source  102  to the patient via connection port  106 . The amount of regulated vacuum is displayed by gauge  113  as a change in level as viewed though window  114 . In the exemplary embodiment shown in  FIG. 1 , gauge  113  is coupled to a central portion of regulator body  104  and adjacent spool valve  101 . Regulator orifice  107  penetrates from an outer surface of body portion  104  into a central portion thereof allowing regulator  103  to leak a controlled amount of atmosphere to maintain a substantially constant vacuum level and vent the patient circuit when the level of regulated vacuum is decreased. Additionally shown in  FIG. 1  is a momentary actuator disposed in spool valve  101 , depicted as a pushbutton  111  in this embodiment, that will facilitate the methods described herein. 
       FIG. 4  is a sectional perspective view of an exemplary embodiment of spool valve  101 , having been removed from body portion  104  ( FIG. 1 ) for clarity. Spool valve  101  comprises outer shaft  306 , having a longitudinal orifice  307  extending though at least a portion of the length of shaft  306 , a user accessible end  305  which allows the user to apply or interrupt vacuum applied to the patient circuit by rotating spool valve between an “ON” and an “OFF” position, an inner shaft  308  slidably disposed within longitudinal orifice  307 , and a actuator  111  coupled to a distal end of inner shaft  308 . A resilient member  312 , such as a spring, is disposed over inner shaft  308  and positioned between an inner portion of actuator  111  and a wall portion  321  of spool valve  101  to maintain inner shaft  308  in a normally extended position. Inner shaft  308  comprises a longitudinal orifice  316  extending though at least a portion of the length of inner shaft  308  and is in fluid communication with orifice  314  which extends from an outer portion of inner shaft  308 . Orifice  314  also communicates with circumferential groove  315  which extends about the outer portion of inner shaft  308 . By providing the combination of orifice  314  in fluid communication with circumferential groove  315 , orientation of orifice  314  within longitudinal orifice  307  is not a concern. 
     In the exemplary embodiment of  FIG. 4 , channel  304  is formed as circumferential groove disposed about a portion of outer shaft  306  and traversing about 180 degrees. An orifice  313  extends from on outer portion of channel  304  into longitudinal orifice  307 . Orifice  313  is oriented such that it is in fluid tight communication with vacuum source  102  when spool valve  101  is in the “ON” position. Another orifice  310  extends from an outer portion of shaft  306  into longitudinal orifice  307 . Orifice  310  is oriented such that it is in fluid tight communication with regulation chamber  302  when spool valve  101  is in the “ON” position. 
     Referring again to  FIG. 4 , spool valve  101  is shown in the ‘ON’ position. Regulated fluid flow is allowed to pass from regulation chamber  302  to vacuum source  102  (best shown in  FIG. 1 ) via channel  304 . Reduced pressure is provided into elongate interior chamber  307  of spool valve  101  via orifice  313 , but flow is absent because, in this position of shaft  306 , there is no fluid commutation to regulator chamber  302 . 
     As illustrated in  FIG. 4 , in the normally extended position of shaft  308 , vacuum is communicated into inner longitudinal orifice  316  of inner shaft  308  and to orifice  314  which extends from the outer surface of inner shaft  308  and communicates with inner longitudinal orifice  316 . In this case, however, the inner wall of elongate interior chamber  307  prevents further communication of vacuum. 
     Referring now to  FIG. 5 , actuator  111  is shown in a depressed position, thereby allowing longitudinal orifice  316 , circumferential groove  315 , orifice  314  and orifice  310  to communicate, in tight fluid relation, the decreased pressure in the interior of spool valve  101  with regulation chamber  302 . If there is already fluid flow passing from regulation chamber  302  to vacuum source  102  via the path provided by groove  304 , the flow restriction provided via orifice  313  have no impact on the regulated vacuum. 
     Depressing actuator  111  when there is already fluid flow between regulation chamber  302  and vacuum source  102  will have no impact on gauge  113  (best shown in  FIG. 1 ). The absence of movement in gauge  113  indicates that the system is flowing and is not occluded. 
     If the downstream patient port connection  106  ( FIG. 1 ) or patient circuit is occluded, however, pressing actuator  111  will increase the vacuum in regulator chamber  302  as discussed above with respect to  FIG. 5 . In this figure the absolute vacuum generated in vacuum chamber  302  will be determined by the relative ratio of effective areas of orifice  313  and regulator orifice  107  ( FIG. 1 ). The absolute fluid flow of the system is dictated by the size of the orifice  313  and the relative pressure differential across it. In one exemplary embodiment, the difference between a normal vacuum level (about 0.6 L/min), based on regulator orifice  107 , and the vacuum level applied upon pressing actuator  111  (about 6.0 L/min), based on orifice  313 , increases gradually over a predetermined period of time (between about 30 seconds to 1 minute) to generate a high vacuum signal of about greater than about 400 mmHg in the patient circuit. 
     Gauge  113  will also react to the increase in vacuum in regulator chamber  302 . The movement of the gauge indicates the patient circuit coupled to connection port  106  is occluded. 
       FIG. 7  illustrates a second exemplary embodiment of the present invention. As shown in  FIG. 7 , spool valve  701 , inner shaft  308 , and actuator  111  all function similarly as described in the first exemplary embodiment. The decreased pressure in the interior chamber  707  is no longer the same as the vacuum source  102 , but rather regulated to another level via an internal pressure regulation mechanism. 
     In this embodiment, an atmospheric leakage port  716  is formed along a longitudinal axis of outer shaft  706  such that it extends to an end  720  of shaft  706 . The end of shaft  706  is coupled to body portion  104  via securing member  722 , such as a screw for example (best shown on  FIG. 2 ). To provide a port to atmosphere, securing member  722  has an orifice (not shown) extending along its length. As such, atmosphere communicates through securing member  722  and atmospheric leakage port  716  with interior chamber  707 , via resilient member  712  (illustrated as a spring in this embodiment, for example), sealing member  714  (illustrated as a ball in this embodiment, for example), and seat member  717 . Pressure from resilient member  712  against sealing member  714 , forces sealing member  714  to close against seat member  717 , limiting the amount of air allowed in from atmospheric leakage port  716 . In this embodiment, the increased vacuum allowed to communicate from interior chamber  707  to regulator chamber  302  is determined by the amount of atmospheric pressure allowed to enter atmospheric leakage port  716 . 
     Similar to the first exemplary embodiment, when spool valve  701  is in the “ON” position and actuator  111  is depressed, longitudinal orifice  316 , circumferential groove  315 , orifice  314  and orifice  310  to communicate, in tight fluid relation, the decreased pressure in spool valve interior chamber  707  with regulation chamber  302 . 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.