2007年4月15日 星期日
be alert to posterior labor
It is my experience that with appropriate diagnosis and minimal intervention this condition can be corrected by assisting the baby to rotate as soon as it is diagnosed. Many times the position is not diagnosed until labor is advanced and progress arrested. At the onset of labor, it is important for the midwife to assess the position. It is relatively simple to assist the rotation of the baby when the mother is in early labor and very difficult once labor becomes advanced.
訂閱：
張貼留言 (Atom)
2 則留言:
Diagnosis of Posterior in Labor
....
Assuming that the mother's cervix is soft and a little dilated, insert a finger through the cervical opening in order to accurately determine the direction of the suture lines and to find the anterior fontanel. If the head is in a posterior position, you will readily find it between 12 o'clock and three o'clock on the fetal skull. Have courage! This exam may not be pleasant for either you or the mother. Your task will be easier if you keep in mind that you may be saving her endless hours of an extremely painful labor, with no guaranteed outcome. If you are not able to find the anterior fontanel, the baby is probably in the correct position; when the head is LOA or ROA, the anterior fontanel usually cannot be felt unless the head is assuming a military position. (That, of course, is another story....)
Assisting Anterior Rotation during Labor
... the first thing I do is have the mother assume and maintain a knee-chest position for approximately 45 minutes.....
Make every effort to avoid rupturing the membranes, as the "pillow" offered by the forewaters gives a cushion on which the baby's head may spin more easily. Furthermore, if the waters break before the baby has rotated to the anterior, sudden descent of the fetal skull may possibly result in a deep transverse arrest.
If labor is more advanced when the posterior is identified, say 4 to 5 centimeters, the attendant may help by placing her hand in the mother's vagina, gently lifting and somewhat disengaging the head thus allowing it to turn to anterior, while the mother is in the knee-chest position.
If the posterior has not been discovered until complete dilation, or if the other methods have not been applied in early labor, the baby's head can still be turned to make delivery more likely. With the mother in a knee-chest position, knees slightly apart, the midwife inserts her hand into the woman's vagina. She should attempt to lift the head by grasping it firmly, waiting for a contraction, then turning the baby into an anterior position. As soon as the head is correctly positioned, hold on tightly. When the uterus contracts again, urge the mother to push very hard. If the amniotic sac has not yet ruptured, rupture it now. This will assure that the position remains fixed and the baby usually will be born very rapidly. While this procedure is both safe and sane, it will take some physical strength to turn this recalcitrant little head against the force of a good contraction.
KEY TERMS RELATED TO FETAL POSITIONS
a. "Lie" of an Infant. Lie refers to the position of the spinal column of the fetus in relation to the spinal column of the mother. There are two types of lie, longitudinal and transverse. Longitudinal indicates that the baby is lying lengthwise in the uterus, with its head or buttocks down. Transverse indicates that the baby is lying crosswise in the uterus.
Use Leopold's Maneuvers to determine the presentation and lie of the fetus
b. Presentation/Presenting Part. Presentation refers to that part of the fetus that is coming through (or attempting to come through) the pelvis first.
(1) Types of presentations (see figure 10-1). The vertex or cephalic (head), breech, and shoulder are the three types of presentations. In vertex or cephalic, the head comes down first. In breech, the feet or buttocks comes down first, and last--in shoulder, the arm or shoulder comes down first. This is usually referred to as a transverse lie.
2) Percentages of presentations.
(a) Head first is the most common-96 percent.
(b) Breech is the next most common-3.5 percent.
(c) Shoulder or arm is the least common-5 percent.
(3) Specific presentation may be evaluated by several ways.
(a) Abdominal palpation-this is not always accurate.
(b) Vaginal exam--this may give a good indication but not infallible.
(c) Ultrasound--this confirms assumptions made by previous methods.
(d) X-ray--this confirms the presentation, but is used only as a last resort due to possible harm to the fetus as a result of exposure to radiation.
c. Attitude. This is the degree of flexion of the fetus body parts (body, head, and extremities) to each other. Flexion is resistance to the descent of the fetus down the birth canal, which causes the head to flex or bend so that the chin approaches the chest.
(1) Types of attitude
a) Complete flexion. This is normal attitude in cephalic presentation. With cephalic, there is complete flexion at the head when the fetus "chin is on his chest." This allows the smallest cephalic diameter to enter the pelvis, which gives the fewest mechanical problems with descent and delivery.
(b) Moderate flexion or military attitude. In cephalic presentation, the fetus head is only partially flexed or not flexed. It gives the appearance of a military person at attention. A larger diameter of the head would be coming through the passageway.
(c) Poor flexion or marked extension. In reference to the fetus head, it is extended or bent backwards. This would be called a brow presentation. It is difficult to deliver because the widest diameter of the head enters the pelvis first. This type of cephalic presentation may require a C/Section if the attitude cannot be changed.
(d) Hyperextended. In reference to the cephalic position, the fetus head is extended all the way back. This allows a face or chin to present first in the pelvis. If there is adequate room in the pelvis, the fetus may be delivered vaginally.
(2) Areas to look at for flexion.
(a) Head-discussed in previous paragraph;
(b) Thighs-flexed on the abdomen.
(c) Knees-flexed at the knee joints.
(d) Arches of the feet-rested on the anterior surface of the legs.
(e) Arms-crossed over the thorax.
(3) Attitude of general flexion. This is when all of the above areas are flexed appropriately as described.
d. Station. This refers to the depth that the presenting part has descended into the pelvis in relation to the ischial spines of the mother's pelvis. Measurement of the station is as follows:
(1) The degree of advancement of the presenting part through the pelvis is measured in centimeters.
(2) The ischial spines is the dividing line between plus and minus stations.
(3) Above the ischial spines is referred to as -1 to -5, the numbers going higher as the presenting part gets higher in the pelvis (see figure10-3).
(4) The ischial spines is zero (0) station.
(5) Below the ischial spines is referred to +1 to +5, indicating the lower the presenting part advances.
e. Engagement. This refers to the entrance of the presenting part of the fetus into the true pelvis or the largest diameter of the presenting part into the true pelvis. In relation to the head, the fetus is said to be engaged when it reaches the midpelvis or at a zero (0) station. Once the fetus is engaged, it (fetus) does not go back up. Prior to engagement occurring, the fetus is said to be "floating" or ballottable.
source from : http://www.brooksidepress.org/Products/Obstetric_and_Newborn_Care_1/lesson_10_Section_1.htm
張貼留言