Peridural anesthesia (PDA) is an anesthesia of the abdominal and pelvic area, which is used on request at birth, especially in severe birth pain. The anesthesia, in contrast to the spinal anesthesia, the motor function is not completely switched off, that is, the patient can still move the legs mostly, albeit restricted. In the case of PDA, the anesthetic is injected into the peridural space, the space between the vertebral bodies and the hard spinal cord, and thus not directly into the spinal cord or spinal fluid.
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The PDA is usually set at the request of the expectant mother. The decision can in most cases be made spontaneously if the pain of labor is felt unbearable for the patient. It makes sense, however, to perform at least the education of the doctor about risks and course even before the onset of labor or at the beginning of labor activity, if a PDA is eligible. Thus, the information can be explained in a more relaxed environment and questions are clarified and the anesthesia can be set quickly in an emergency.
Prerequisite for setting the PDA is that the patient, despite labor, can stand still for several minutes. The entire procedure of the PDA takes on average 10 minutes. A breather is used to set the catheter to ensure that the patient is relaxed and does not move. Since the effect occurs after a few minutes and reaches its maximum after about 15 minutes, the PDA can in theory be set at any time before birth, as long as the actual birth process (expulsion phase) has not yet begun.
Like any narcotic that the patient takes during pregnancy and childbirth, the anesthetic of the PDA also enters the bloodstream of the child through the umbilical cord and placenta. This can make the child sleepier after birth than children born without PDA. As a rule, however, the PDA is well-tolerated for the newborn and has fewer side effects than, for example, general anesthesia.
However, because births under the PDA last on average a little longer, the birth can be more stressful even for the child. In addition, a PDA makes it difficult for some children to get into the correct position of birth, so that so-called "star gazers" are born more often, children born face-up rather than under-born.
This birth position can lead to bruising in the child and the birth must be supported more often than normal position by means of suction cup or forceps. This can also lead to bruising and swelling, especially in the head area of the child, but in most cases disappear after a few days.
The most common side effect with the patient is a drop in blood pressure. This comes about by dilation of the vessels in the anesthetized area. To prevent this, an infusion can be attached and the blood pressure is checked regularly. Patients with pre-existing heart conditions may therefore be at risk of PDA, but the personal risk should always be discussed with the doctor.
In addition, headaches can occasionally occur. This is caused by too far advancement of the needle and thus injury of the hard spinal cord skin ( dura mater ) and leakage of cerebrospinal fluid. If the injury is not noticed and the anesthetic is injected into the spinal area, spinal anesthesia may occur inadvertently, turning off the entire motor system of the abdominal and leg muscles.
In rare cases, a spinal cord or nerve injury may occur. However, as the obstetric PDA is set very low, below the end of the spinal cord, this complication is unlikely.
In addition, bruising may occur at the injection site. If a vein is hit in the peridural space during the procedure, it can also cause hemorrhages in the peridural space. The resulting pressure can damage the spinal cord.
The birth under a PDA can take place without pain. The required doses of narcotic but usually also greatly restrict the mobility of the legs, so that the patient can not walk around independently. In addition, with complete absence of pain, the contractions are no longer noticeable.
This leads to the fact that the woman does not feel the natural urge to squeeze during the ejection phase and thus an active cooperation is difficult. For these reasons, the narcotic is usually dosed a little lower in a PDA, so that the birth is not completely painless.
The goal, however, is to reduce the pain to such an extent that it remains on a tolerable level for the patient and that she can rest better during the opening phase.
Common side effects with PDA are mild hypotension, especially in the first half hour after the PDA has been established. This can lead to dizziness and nausea. About 23% of women get a fever from the PDA. It can also lead to a slowed pulse. Therefore, the patient is monitored by a doctor, especially in the initial phase.
In addition, it may cause difficulty urinating, as well as the area of the bladder is stunned. It may therefore be necessary for the bladder emptying that a bladder catheter must be placed. This can lead to infections especially of the bladder.
Also numbness and tingling in the legs occur relatively frequently.
If the hard spinal cord skin is injured by the needle and CSF comes out, it can cause severe headaches that last several days.
A difference to births without narcosis and narcotics is that the birth process takes more time on birth with PDA on average. This is primarily due to the fact that the contracting and pressing rhythm is no longer exactly perceived by the expectant mother and the opportune time to squeeze and thereby promote the birth is not used.
In addition, it is more common for the child to not turn into the correct birth position and face-up instead of face-down. On the one hand this can lead to bruising in the head area of the child and on the other hand it is a situation that has to be supported more frequently with the forceps or the suction cup. This obstetric device can lead to vaginal trauma in the woman and often has to be assisted by an episiotomy.
The risk of having a Caesarean section is not increased by a PDA. However, if a caesarean section is necessary, it is often possible to dispense with general anesthesia and to dose the PDA higher, so that the mother can consciously experience the birth and then take the child on her arm.
Back pain after birth with PDA does not occur more frequently than after birth with other pain-relieving medicines. However, mild pain may cause bruising at the injection site after setting the PDA, but it will subside after a few days.
The preparation of the PDA and the setting of the pain catheter usually take 10 minutes with good cooperation of the patient. However, since the actual puncture in most cases is waiting for a break in labor, so that the woman can keep still, the setting can also take a few minutes longer.
The painkilling effect of the anesthetic begins after a few minutes, reaching its maximum after about 15 minutes. The effect usually lasts for 2-3 hours, the anesthesia sounds at the latest after 4 hours completely off. In order to ensure a longer effect during labor, which often last longer, therefore, usually a catheter is set, can be injected at any time on demand analgesics, without performing a renewed procedure. Thus, the duration and also the strength of the anesthesia can be individually adapted to the needs of the patient.
The PDA is put on sitting or in a side position. The skin is disinfected and the puncture site locally anesthetized, so that the puncture itself is barely noticeable. The patient is asked to curve her back and relax her shoulders.
In the lower part of the spinal column, the point between two spinous processes is palpated and there inserted a hollow needle, which is connected to a syringe filled with liquid.
If this fluid can be injected without resistance, the ligaments were passed between the vertebral bodies and the syringe is located in the peridural space, ie between vertebrae and hard spinal cord skin. Thereafter, a small tube, the catheter, is introduced via the hollow needle, via which the analgesic can be administered at any time. The needle is removed and a bandage applied. The procedure is usually not painful and usually only a pressure in the back area is felt when inserting the needle. The first dose of pain medication is usually a test dose, a small amount of painkillers to test the effect on the patient. Attention is also paid to the response of the blood pressure and the effects on mobility. If everything is within the normal range, a larger amount of anesthetic can be given.