Method for positioning a fluid withdrawing means by detecting local temperature

Claim 3

An amniocentesis procedure comprising the steps of: (a) inserting a cannula means through the abdomen of a living mammal at least until the distal end of said cannula means is in contact with the wall of the uterus of said mammal; (b) measuring the temperature of the portion of myometrium tissue of the wall of said uterus which surrounds the distal end of the cannula means by means of a temperature-sensing probe inserted into said cannula means; (c) penetrating into said uterus with the distal end of said cannula means while retaining said temperature-sensing probe in its inserted position within said cannula means and continuing to measure the temperature of said uterus with said temperature-sensing probe; (d) stopping penetration with said cannula when the temperature measurement obtained according to said step (c) increases by at least about 0.1° C.; (e) removing the temperature-sensing probe from said cannula means; and (f) withdrawing a sample of amniotic fluid from said uterus through said cannula means.

Claim 4

An amniocentesis procedure comprising the steps of: (a) inserting a cannula means through the abdomen of a living mammal at least until the distal end of said cannula means is in contact with the wall of the uterus of said mammal; (b) measuring the temperature of the portion of myometrium tissue of the wall of said uterus which surrounds the distal end of the cannula means by means of a temperature-sensing probe inserted into said cannula means; (c) penetrating into said uterus with the distal end of said cannula means while retaining said temperature-sensing probe in its inserted position within said cannula means and continuing to measure the temperature of said uterus with said temperature-sensing probe; (d) stopping penetration with said cannula when the temperature measurement obtained according to said step (c) increases by at least about 0.1° C.; (e) removing the temperature-sensing probe from said cannula means; and (f) withdrawing a sample of amniotic fluid from said uterus through said cannula means.

Claim 5

An amniocentesis procedure comprising the steps of: (a) inserting a temperature-sensing probe having a temperature-sensing element at its distal end into a cannula through the proximal end of said cannula, whereby said temperature-sensing element becomes located adjacent to the distal end of said cannula and a cannula/temperature-sensing probe combination is obtained; (b) inserting said cannula/temperature-sensing probe combination until it contacts the wall of the uterus and measuring the temperature of said wall; (c) further inserting said cannula/temperature-sensing probe combination a distance of at least about one centimeter until a measurement of the temperature of the myometrium of the uterus can be obtained; (d) continuing to insert said cannula/temperature-sensing probe combination until the temperature measured adjacent to the distal end of said cannula increases, in less than 5 seconds, by about 0.2° C. to about 0.8° C. above the previously measured temperature of the myometrium; (e) ceasing insertion of said cannula/temperature-sensing probe combination and retaining the position of said cannula means fixed while removing said probe and attaching a fluid-aspirating device to the proximal end of said cannula means; and (f) aspirating amniotic fluid from said uterus with said fluid-aspirating device.

Claim 6

An amniocentesis procedure comprising the steps of: (a) inserting a temperature-sensing probe having a temperature-sensing element at its distal end into a cannula through the proximal end of said cannula, whereby said temperature-sensing element becomes located adjacent to the distal end of said cannula and a cannula/temperature-sensing probe combination is obtained; (b) inserting said cannula/temperature-sensing probe combination until it contacts the wall of the uterus and measuring the temperature of said wall; (c) further inserting said cannula/temperature-sensing probe combination a distance of at least about one centimeter until a measurement of the temperature of the myometrium of the uterus can be obtained; (d) continuing to insert said cannula/temperature-sensing probe combination until the temperature measured adjacent to the distal end of said cannula increases, in less than 5 seconds, by about 0.2° C. to about 0.8° C. above the previously measured temperature of the myometrium; (e) ceasing insertion of said cannula/temperature-sensing probe combination and retaining the position of said cannula means fixed while removing said probe and attaching a fluid-aspirating device to the proximal end of said cannula means; and (f) aspirating amniotic fluid from said uterus with said fluid-aspirating device.

Claim 7

Amniocentesis procedure according to claim 3 wherein the distal end of said cannula means is blunt, and the distal end of said temperature-sensing probe has a sharp point for penetrating tissue.

Claim 8

Amniocentesis procedure according to claim 4 wherein said distal end of said temperature-sensing probe includes a thermistor means.

Claim 9

Amniocentesis procedure according to claim 4 wherein said sharp point of said probe extends beyond said distal end of said cannula means during said steps (a) through (d).