Patent Application
20070060844
1. Field of the Invention
This invention relates, in general, to medical devices, medical kits and associated methods, and, in particular, to caps for lancing devices, lancing kits and lancing methods.
2. Description of the Related Art
A variety of medical conditions, such as diabetes, call for the monitoring of an analyte concentration (e.g., glucose concentration) in a blood, interstitial fluid or other bodily fluid sample. Typically, such monitoring requires the extraction of a bodily fluid sample from a target site (e.g., a dermal tissue target site on a user's finger). The extraction (also referred to as “expression”) of a bodily fluid sample from the target site generally involves lancing the dermal tissue target site with a lancing device and applying pressure in the vicinity of the lanced site to express the bodily fluid sample.
Conventional lancing devices generally have a rigid housing and a lancet that can be armed and launched so as to protrude from one end of the lancing device. For example, conventional lancing devices can include a lancet that is mounted within a rigid housing such that the lancet is movable relative to the rigid housing along a longitudinal axis thereof. Typically, the lancet is spring loaded and launched, upon release of the spring, to penetrate (i.e., “lance”) a target site (e.g., a dermal tissue target site). A biological fluid sample (e.g., a whole blood sample or interstitial fluid (ISF) sample) can then be expressed from the penetrated target site for collection and analysis. Conventional lancing devices are described in, for example, U.S. Pat. No. 5,730,753 to Morita, U.S. Pat. No. 6,045,567 to Taylor et al. and U.S. Pat. No. 6,071,250 to Douglas et al., each of which is incorporated fully herein by reference.
Lancing devices often include a cap with a distal end that engages the target site during use. Such a cap usually has an aperture (i.e., opening), through which the lancet protrudes during use. When a cap is engaged (i.e., contacted) with a target site, pressure is usually applied to the target site prior to launch of the lancet. This pressure urges the cap against the target site with the intent of creating a target site bulge within the opening of the cap. The lancet is then launched to penetrate the target site bulge. A biological fluid sample, typically blood, is thereafter expressed from the lanced target site bulge. The expressed biological fluid sample can then, for example, be tested for an analyte (such as glucose, lactate, ketones and HbAlc) using an associated meter.
However, conventional caps may not serve to reliably produce an adequate volume of biological fluid sample due to insufficient contact between the cap and the target site and/or inadequate application of pressure on the target site by the cap. Furthermore, in order to obtain a sufficient volume of biological fluid sample, additional pressure (such as a pumping or milking action) usually must be applied either manually or mechanically to the target site following lancing. This additional pressure can serve to facilitate expression of an adequate volume of biological fluid sample. Examples of mechanical devices designed for such use are described in co-pending U.S. application Ser. No. 10/653,023 (published as US 2004/0249253 on Dec. 9, 2004), U.S. application Ser. No. 10/652,464 (published as US 2004/0253736 on Dec. 16, 2004) and U.S. Pat. No. 5,951,493, each of which is fully incorporated herein by reference.
A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
Once apprised of the present disclosure, one skilled in the art will recognize that a variety of conventional lancing devices can be readily modified for use with caps according to the embodiments of the present invention, including, for example, lancing devices described in U.S. Pat. Nos. 5,730,753, 6,045,567 and 6,071,250, each of which is hereby incorporated in full by reference. Moreover, embodiments of caps according to the present invention can be employed with lancing devices that utilize various techniques for expressing a biological fluid sample from a dermal tissue target site including, but not limited to, techniques that employ lancets, hollow needles, solid needles, micro-needles, ultrasonic extraction devices, or thermal extraction devices. Furthermore, caps according to embodiments of the present invention can be employed with a combined lancing device and integrated meter for testing an analyte (e.g., a meter for testing blood glucose). In addition, such caps can be configured for urging against a dermal tissue target site of a user's finger.
Referring to
Cap body 102 is depicted as primarily cylindrical in overall form. However, once apprised of the present disclosure, one skilled in the art will recognize that cap bodies employed in embodiments of the present invention can take any suitable form including, but not limited to, forms that include contoured contact surfaces and a contact surface in the form of saddle-shaped compression surface as described in U.S. patent application Ser. No. 11/045,542. Moreover, any suitable compression surface known to those of skill in the art can be employed as a contact surface in embodiments of caps for lancing devices according to the present invention, including those described in U.S. patent application Ser. No. 10/706,166, which is fully incorporated herein by reference.
Cap body 102 can be formed of any suitable material including, for example, a rigid material such as acrylonitrile butadiene styrene plastic, injection moldable plastic, polystyrene and metallic materials or a relatively resiliently deformable material, including, but not limited, to elastomeric materials, polymeric materials, polyurethane materials, latex materials, silicone materials and any combinations thereof.
Cap body 102 has an opening (i.e., aperture) 110 therethrough that extends from proximal end 106 to distal end 104. Cap 100 further includes a sensor consisting of electrical contact pads 112 and 114 and electrical signal wire 116. One skilled in the art will recognize that the entire length of electrical signal wire is not depicted in
Target site contact surface 108 of distal end 104 includes a surface portion 108a (also referred to as a “moveable” surface portion) that is moveable between a first position (depicted in
Cap 100 further includes a spring 120 with a predetermined spring constant. Spring 120 is disposed between moveable cap body portion 102a and the remainder of cap body 102 within guide recess 118. Spring 120 is configured and adapted such that the force of spring 120 must be overcome to move moveable cap body portion 102a (and surface portion 108a) from the fist position of
Prior to use of cap 100, moveable surface portion 108a and moveable cap body portion 102a protrude beyond the remainder of target site contact surface 108 (see FIG. 2 in particular). Therefore, in use, moveable cap body portion 102a will make initial contact with the target site when cap 100 urged toward the target site. Such initial contact is depicted in
During use of cap 100, target site contact surface 108, including moveable surface portion 108a, is urged against a target site (e.g., a dermal tissue target site of a user's finger) such that cap body 102 engages (i.e., contacts) the dermal tissue target site and a target-site bulge TB is created within opening 110 (see
When such urging is done with sufficient force, spring 120 is compressed. The spring constant of spring 120, thus, determines the force required to move moveable cap body portion 102a from the first position to the second position and the force constant can be predetermined such that adequate pressure is applied to the target site to engender a successful expression of bodily fluid sample upon lancing of the target site.
When moveable cap body portion 102a is in the second position (see
The lancing device can, for example, employ the electrical signal to immediately initiate lancing of a target site or to trigger a timer within the lancing device that serves to delay initiation of lancing. Such a delayed initiation can occur after a time interval (i.e., a delay) in the range of, for example, 0.5 seconds to 5.0 seconds. If desired, the time interval can be varied from use-to-use such that a user does not become accustomed to the time interval and prematurely withdraw the target site from the cap prior to lancing. Moreover, if cap 100 is withdrawn from the target site such that electrical contacts pads 112 and 114 no longer touch, then the timer can be reset and lancing delayed until, and if, electrical contact pads 112 and 114 again touch and the timer again triggered.
Further characteristics of caps according to embodiments of the present invention are evident from the sequence of
As dermal tissue target site TS is further urged against cap 100, spring 120 becomes partially compressed (see
Referring now to
Cap 100 has several beneficial characteristics. For example, a user of a lancing device that incorporates cap 100 is not required to press a button or a switch to initiate lancing. Also, lancing is only initiated when a predetermined pressure has been applied to target site contact surface 108 (including moveable surface portion 108a) such that moveable cap body portion 102a has moved from the first position to the second position. The predetermined pressure can be predetermined such that it serves to express an adequate bodily fluid sample (for example, by the creation of a target site bulge with an opening of the cap body). In addition, if an optional timer is employed in the lancing device, lancing can be delayed as needed to optimize bodily fluid expression. Furthermore, caps according embodiments of the present invention include a sensor that is responsive to force (pressure) applied directly to a contact surface of the cap and, therefore, there is a minimal risk of erroneously sensing forces applied to components of the lancing device or to other surfaces of the cap.
A further benefit of caps according to embodiments of the present invention is a reduction in apparent pain associated with lancing. Initiating lancing upon sensing of adequate applied pressure is expected to increase the likelihood of lancet penetration to a proper penetration depth. A user is therefore less likely to have to re-lance due to improper penetration depth.
Referring to
Distal end 204 includes a target site contact surface 208a on cap body portion 202a and moveable contact surface 208b on moveable cap body portion 202b. Proximal end 206 can be configured for attachment to a lancing device (for example, to a housing of a lancing device) by a snap fit, frictional fit or other suitable attachment technique.
Cap body 202 has an opening (i.e., aperture) 210 therethrough that extends from proximal end 206 to distal end 204. Cap 200 further includes a sensor consisting of electrical contact pads 212 and 214 and electrical signal wire 216. One skilled in the art will recognize that the entire length of electrical signal wire 216 is not depicted in
Moveable contact surface 208b is moveable between a first position (depicted in
Cap 200 further includes a spring 220 with a predetermined spring constant. Spring 220 is disposed between moveable cap body portion 202b and the remainder of cap body 202 within guide recess 218. Spring 220 is configured and adapted such that the force of spring 220 must be overcome to move moveable cap body portion 202b (and moveable contact surface 208b) from the first position of
During use of cap 200, target site contact surface 208a and moveable contact surface 208b are urged against a target site (e.g., a dermal tissue target site TS of a user's finger F) such that cap body 202 engages (i.e., contacts) the dermal tissue target site and a target site bulge TB is created within opening 210 (see
When such urging is done with sufficient force, spring 220 is compressed. The spring constant of spring 220, thus, determines the force required for movement to occur between the first position and the second position. Therefore, the spring constant can be predetermined such that adequate pressure is applied to the target site to result in a successful expression of bodily fluid sample upon lancing of the target site.
When moveable cap body portion 202b is in the second position (see
Cap body 202 is configured, therefore, to sense when a predetermined pressure is being applied to a target site (i.e., a predetermined applied pressure) and signal a lancing device accordingly. The lancing device can, for example, employ the electrical signal to immediately initiate lancing of a target site or to trigger a timer within the lancing device that serves to delay initiation of lancing.
Moveable cap body portion 202b of cap body 202 has a beneficially low risk of being accidentally depressed due to the relatively small size of moveable cap body portion 202b and its disposition on the distal end 204 of cap body 202. This reduces a likelihood of launching a lancet within the lancing device by accidental depression of moveable cap body portion 202b.
It should be noted that caps according to the present invention can employ multiple sensors and multiple moving cap body portions in order to determine whether or not a predetermined applied pressure is being applied at multiple locations on a distal end contact surface. In other words, the sensors can be sensors uniformly distributed about the cap body. For example, the embodiment of
Once apprised of the present disclosure and the embodiments of
A kit according to embodiments of the present invention includes a lancing device (as described herein) and a cap for the lancing device. Moreover, such a cap includes a cap body and at least one sensor. In addition, the cap body includes a distal end with a target site contact surface, a proximal end for attachment to a lancing device and a opening through the cap body from the distal end to the proximal end. Furthermore, at least a portion of the target site contact surface is moveable between a first position and a second position upon application of a predetermined pressure to the portion of the distal end contact surface, and the sensor is configured to detect movement of the portion of the distal end contact surface into the second position and communicate such detection to the lancing device.
If desired, the lancing device can include a timer and the sensor can communicate such detection to the timer. The cap can be any cap as described herein. Moreover, although particular sensor embodiments have been described, the sensor of caps and kits according to embodiments of the present invention can be any suitable sensor, including mechanical sensors, electrical sensors, optical sensors and combinations thereof. In addition, the lancing device can be adapted to employ artificial learning to determine and utilize an optimal time interval between receiving a communication from the sensor and initiating lancing of the target site. Such adaptation can be accomplished, for example, by incorporating a suitably programmed microprocessor into the lancing device.
Method 300 includes contacting at least a portion of a contact surface of a distal end of a cap body of a cap for a lancing device with a target site, as set forth in step 310. In step 310, the cap body has a distal end with a target site contact surface, a proximal end for attachment to a lancing device and an opening through the cap body from the distal end to the proximal end of thereof. In addition, the cap has at least one sensor.
Moreover, in method 300 at least a portion of the target site contact surface is moveable between a first position and a second position upon application of a predetermined pressure (force) to the portion of the distal end contact surface, and the sensor is configured to detect movement of the portion of the distal end contact surface into the second position and communicate such detection to the lancing device.
Subsequently, at step 320, the cap body is urged towards the target site such that the portion of the contact surface moves from a first position to a second position under the predetermined force and a target site bulge is created within the opening of the cap body. The sensor is then employed to detect that the portion of the contact surface is in the second position (see step 330) and signals the lancing device upon such detection (see step 340). The target site bulge is thereafter lanced with the lancing device.
It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.
