Abstract:
A vent system for an infusion drip chamber is provided according to the invention. The vent system includes an automatic air eliminator communicating with an interior and an exterior of the infusion drip chamber. The automatic air eliminator is capable of automatically venting air from the infusion drip chamber in a substantially continuous manner. The vent system further includes a mechanical air eliminator communicating with the interior and the exterior of the infusion drip chamber. The manual air eliminator is capable of mechanically venting air from the infusion drip chamber at discrete time intervals.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 10/646,842, filed Aug. 25, 2003 now U.S. Pat. No. 6,972,000, which is a continuation of U.S. application Ser. No. 09/935,690, filed on Aug. 24, 2001 now abandoned, the disclosures of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the field of intravenous fluid delivery. 
     2. Description of the Background Art 
     Intraveneous fluid delivery systems are devices used to infuse a fluid into the circulatory system of a patient. This may be done as part of medical treatment. The infusion may include infusion of fluids such as whole blood or blood components, saline solution, medications, etc. The infused fluid is therefore injected into the patient&#39;s bloodstream, where it may be circulated. A popular infusion site is in an arm of a patient. 
     Infusion is generally accomplished by use of a needle and tubing. The needle is inserted into a patient&#39;s blood vessel, and an infusion fluid is introduced into the tubing. 
     A concern during infusion is the air that may be trapped in the tubing at the start of fluid delivery. The air in the needle and tubing is displaced by the supplied fluid, and if not vented it can be transported into the patient&#39;s circulatory system as air bubbles. These bubbles may be dangerous in the patient&#39;s circulatory system. Furthermore, air bubbles may interfere with the flow of the infusion fluid. Therefore, it is imperative that all air bubbles be removed from the infusion system. 
     In the prior art, air bubbles are commonly removed in a manual fashion by the person administrating the infusion fluid. This comprises venting the air bubbles by opening a port or tapping the tubing to move air bubbles up into a vent opening or drip chamber. 
     The manual air bubble removal of the prior art has several drawbacks. It is time-consuming on the part of the person administering the infusion fluid. In addition, it is another task to be remembered and performed. Furthermore, it is subject to error or an incomplete performance. 
     There remains a need in the art for an improved intraveous fluid delivery. 
     SUMMARY OF THE INVENTION 
     A vent system for an infusion drip chamber is provided according to one embodiment of the invention. The vent system comprises an automatic air eliminator communicating with an interior and an exterior of the infusion drip chamber. The automatic air eliminator is capable of automatically venting air from the infusion drip chamber in a substantially continuous manner. The vent system further comprises a mechanical air eliminator communicating with the interior and the exterior of the infusion drip chamber. The manual air eliminator is capable of mechanically venting air from the infusion drip chamber at discrete time intervals. 
     An air venting method for an infusion drip chamber is provided according to another embodiment of the invention. The method comprises the steps of providing an automatic air eliminator capable of substantially, automatically and continuously venting the air and providing a mechanical air eliminator capable of mechanically venting the air at discrete time intervals. 
     The above and other features and advantages of the present invention will be further understood from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional diagram of a manual/auto-prime air elimination system according to one embodiment of the invention; and 
         FIG. 2  is a cross-sectional diagram of a mechanical air eliminator according to another embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a cross-sectional diagram of a manual/auto-prime air elimination system  100  according to one embodiment of the invention. The manual/auto-prime air elimination system  100  includes a drip chamber  102 , an inlet  105 , an outlet  106 , an automatic air eliminator  120 , and a mechanical air eliminator  150 . The drip chamber  102  may contain fluid  110  and air  112 . The manual/auto-prime air elimination system  100  vents air  112  from the drip chamber  102 , as it is imperative that the air  112  not travel into the outlet  106 . 
     The automatic air eliminator  120  includes a body  122  having a body air passage  126  and a receptacle chamber  128 . A hydrophobic element  132  is placed in the receptacle chamber  128 . The hydrophobic element  132  may be a membrane or filter that allows air  112  to pass through but does not allow fluid  110  to pass. A cap  135  is placed on top of the hydrophobic element  132  and fits into the receptacle chamber  128 . The cap  135  is retained in the receptacle chamber  128  by a friction fit or a snap fit, for example. The cap  135  further includes a cap air passage  138 . 
     Air  112  may travel through the body air passage  126 , through the hydrophobic element  132 , and out the cap air passage  138 . The air  112  may travel through the automatic air eliminator  120  as a result of a positive air pressure inside the drip chamber  102  due to the introduction of the fluid  110 . In addition, air  112  may pass through the hydrophobic element  132  in the absence of a positive pressure. 
     The material of the hydrophobic element  132  may be any manner of oleophobic or hydrophobic material (referred to hereinafter only as hydrophobic for simplicity). The material of the hydrophobic element  132  may include MFLONO® PTFE membrane, VERSAPOR® R membrane, SUPOR® R membrane (all available from Pall Specialty Materials), etc. The hydrophobic material allows air to vent but is repellant to fluids. The hydrophobic material allows air to pass until the material becomes wetted. Wetting is a saturation of the pores of the hydrophobic material. If wetting occurs, further air cannot pass through the material. 
     The mechanical air eliminator  150  in the embodiment shown includes a deformable conduit  152  that fits into a port  172  in the drip chamber  102 . A deformable ball  166  is positioned in the conduit  152  and normally substantially blocks and seals the conduit  152 . 
     When the conduit  152  and the ball  166  are manually deformed or squeezed by a force F, air  112  is allowed to pass around the ball  166  and through the conduit  152 . When the deforming force F is removed, the ball  166  resumes its normal shape and the mechanical venting ceases. 
     The automatic air eliminator  120  and the mechanical air eliminator  150  may be attached to any three-port drip chamber, as shown. Alternatively, the mechanical air eliminator  150  and the automatic air eliminator  120  may be combined into a single device (not shown) sharing a common conduit and fitting into an available port of a two-port drip chamber. 
     In operation, air  112  may substantially, automatically and continuously vent through the automatic air eliminator  120  by passing through the hydrophobic element  132 . The automatic air eliminator  120  therefore substantially, automatically and continuously vents air, and does so without need of human intervention. In addition, the mechanical air eliminator  150  may operate at discrete time intervals to vent air. The mechanical air eliminator  150  or  250  may mechanically operate (open) in response to a predetermined positive air pressure in the drip chamber  102  (see  FIG. 2  and accompanying text), or may be manually operated by a technician. The manual mechanical air eliminator  150  may be manually operated at any time, although it likely will be used when the automatic air eliminator  120  is not adequately venting air. 
       FIG. 2  is a cross-sectional diagram of a mechanical air eliminator  250  according to another embodiment of the invention. The mechanical air eliminator  250  may be used in place of the previously shown and discussed manual mechanical air eliminator  150 . 
     The mechanical air eliminator  250  includes a conduit  204 , a plunger  215 , a plunger chamber  210 , a biasing device  222 , and at least one vent opening  228 . 
     The conduit  204  may fit into a port in the drip chamber  102 , as in the manual mechanical air eliminator  150 . The conduit  204  communicates air  112  from the drip chamber  102  into the plunger chamber  210 . The plunger  215  is normally held in a position blocking the conduit  204  by the biasing device  222 . The biasing device  222  may be any manner of spring, diaphragm, etc., that provides a biasing force to hold the plunger  215  in a normally closed position in an absence of a positive air pressure inside the drip chamber  102 . The biasing device  222  may be selected so that the plunger opens in response to a predetermined positive air pressure in the drip chamber  102 . Therefore, the plunger  215  may mechanically open at discrete time intervals in order to vent air. When the plunger  215  is displaced by a positive air pressure, the at least one vent opening  228  may be placed in communication with the conduit  204 , allowing air venting for the drip chamber  102 . 
     The combination of the automatic air eliminator  120  and the mechanical air eliminator  150  or  250  enables a complete air venting of the drip chamber  102 . In addition, the combination allows the air  112  to be automatically vented, and with the manual mechanical air eliminator  150  or  250  providing additional venting if the air  112  is not being adequately vented by the automatic air eliminator  120 . Furthermore, the mechanical air eliminator  150  or  250  may be used if the hydrophobic element  132  of the automatic air eliminator  120  becomes wetted or clogged and no longer allows air to pass. Moreover, the mechanical air eliminator  150  or  250  may be used in conjunction with the automatic air eliminator  120  in order to increase the venting rate. Therefore, the air  112  may be removed as desired, preventing air from passing through the outlet  106  and enabling a fluid prime of the outlet  106 . 
     While the invention has been described in detail above, the invention is not intended to be limited to the specific embodiments as described. It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific embodiments described herein without departing from the inventive concepts.