Patent Application
20110196219
Not Applicable
Not Applicable
1. Field of Invention
The present invention relates generally to a medical diagnostic testing device. More particularly, the invention is directed toward a diagnostic testing device in which a liquid collector is combined with a sharp edge or point for piercing skin to draw blood and test the pH of the blood.
2. Description of the Related Art
Fetal hypoxia-ischemia is believed to be a leading cause of cerebral palsy. Studies have indicated a strong correlation between hypoxia and acidosis. Measuring the pH of the scalp in utero can provide early detection of acidosis and likely hypoxia. The preferred detection method involves sampling fetal scalp blood and measuring the pH of that blood sample. General practice for the procedure involves inserting a plastic cone into the vagina after the expecting mother's cervix is dilated at 3 cm or more. The fetus's scalp is cleaned with a cotton swab, a small laceration is made in the scalp, and blood droplets are collected in a capillary tube. The blood sample is then tested with a blood gas analyzer—usually in the hospital laboratory, but sometimes in the delivery room itself. This traditional method requires that the expecting mother's cervix is dilated at 3 cm or more. The traditional method also involves a delay, often of several minutes, between the laceration and reporting a blood pH result to medical personnel.
Other devices have been developed to address these and other problems. Typical of the art are those devices disclosed in the following U.S. patents: U.S. Pat. No. 4,320,764, issued Mar. 23, 1982 to Hon; U.S. Pat. No. 4,360,016, issued Nov. 23, 1982 to Sarrine; U.S. Pat. No. 4,441,510, issued Apr. 10, 1984 to Worley, deceased et al.; U.S. Pat. No. 4,658,825, issued Apr. 21, 1987 to Hochberg et al.; U.S. Pat. No. 4,660,570, issued Apr. 28, 1987 to Dombrowski; U.S. Pat. No. 5,551,424, issued Sep. 3, 2996 to Morrison et al.; U.S. Pat. No. 6,058,321, issued May 2, 2002 to Swayze et al.; and U.S. Pat. No. 6,423,011, issued Jul. 23, 2002 to Arulkulmaran et al. Also typical of the art is the device disclosed in U.S. Patent Publication No. 2004/0092843 A1, published on May 12, 2004, by Kreiser et al.
A hand-held analyzer for collecting a sample of blood from the scalp of a fetus and measuring the pH of the blood sample is disclosed. The analyzer includes a probe with a blunt proximal end that facilitates a firm and positive placement of the probe against the scalp. The probe includes a capillary tube for collecting blood and an extensible lancet which at rest is positioned within the capillary tube. During use of the analyzer, the lancet is extended to make an incision in the scalp. The lancet then retreats, and blood flows into the capillary tube. Sensors for measuring pH are in liquid communication with the interior of the capillary tube. A display on or near the hand-held analyzer shows the fetal blood pH.
The above-mentioned features of the invention will become more clearly understood from the following detailed description of the invention read together with the drawings in which:
The present invention provides a fetal scalp blood analyzer that combines the functions of lancing the scalp, collecting a blood sample, and analyzing the blood sample to measure the pH of the fetal scalp blood. The analyzer includes a probe with a capillary tube and an extensible lancet positioned within the capillary tube. The analyzer further includes at least one pH sensor in liquid communication with the interior of the capillary tube, a controller adapted to receive information from the sensor and measure blood pH, and a display adapted to report the blood pH.
During use, an operator inserts the probe 20 into the birth canal until the proximal end 20a of the probe 20 has made contact with the scalp of the fetus. Next, the operator uses the trigger 40 to signal the actuator 45 to extend the lancet 23. The lancet 23 makes a small incision in the scalp sufficient to produce blood. The lancet 23 then retreats within the capillary tube 22. Blood flows into the capillary tube 22, where the sensor 24 measures the pH of the blood. The sensor 24 communicates its information to the controller 25, which in turn communicates with the display 50 to show the operator the pH of the drawn blood.
During use, an operator inserts the probe 201 into the birth canal until the proximal end 210a of the probe tube 210 has made contact with the scalp of the fetus. In some embodiments of the invention, the proximal end 210a of the probe tube 210 has a blunt, rounded surface, as shown in
The present invention provides a simplified apparatus for sampling fetal scalp blood by integrating lancing, blood sample collection, and blood analysis in one device. The blunt proximal end and clear probe tube facilitate quick and successful sample collection. Because the sensor is in close proximity to and in liquid communication with the capillary tube within which the blood sample is collected, the present invention also reduces the time between the beginning of the procedure and the delivery of blood pH analysis results. Because the lancet is positioned within the capillary tube, the probe tube has a smaller profile than other devices, allowing for its use on patients with smaller cervix dilation than required for other methods of fetal scalp blood analysis.
In some embodiments, the probe comprises a detachable unit that is disposed after one use. In some embodiments, the analyzer is adapted for use on adults to take real-time measurements of blood pH, as in emergency situations or in remote locations. In some embodiments, the analyzer described herein is modified, by changing sensors, to analyze other properties or characteristics of fetal scalp blood, such as lactose levels or a platelet count.
While the present invention has been illustrated by description of some embodiments, and while the illustrative embodiments have been described in detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of applicant's general inventive concept.
