Labor Continued
Analgesia and Anesthesia
Medications
Analgesic
Any drug or agent that will reduce or relieve pain.
Considerations
The administration of analgesics or anesthetics in labor should take into consideration the following factors:
- The preparation, training and practice prior to labor of the pregnant woman and her coach. This includes the woman’s understanding of the normal processes of labor and of her ability to utilize coping strategies.
- The woman’s support network prior to and during labor.
- The pregnant woman’s level of pain tolerance or threshold. This includes the individual woman’s response to the length of labor and to the strength of her contractions.
Systemic Medications
Tranquilizers
In labor, these medications are most commonly given in combination with analgesics to potentiate (increase) the effect of the narcotics.
Form
Usually IM injection or IV push.
Examples
Largon, Vistaril, Phenergan, Valium, Librium, Compazine.
Time
Onset in 15-20 minutes. Lasts 3-4 hours in the mother. Fetal cord blood levels are 95-100% for most of these drugs.
Benefits/Purposes
- To reduce tension and anxiety and promote relaxation.
- May raise maternal pain threshold by altering attitude towards pain.
- May reduce nausea and vomiting due to antiemetic effects.
- Potentiates effect of narcotics.
Risks/Disadvantages
May cause drowsiness, confusion, dizziness, blurred vision, dry mouth, heart rate and blood pressure changes, or urinary retention in the laboring woman.
Possible fetal risks include variations in fetal heart tones, lowered body temperature, poor muscle tone, increased jaundice, restlessness, decreased attentiveness, poor sucking ability and slow adaptation to feeding.
Anesthesia
Partial or complete absence of sensation with or without loss of consciousness.
- Certain phases or stages of labor may contraindicate the use of particular pain relief methods (e.g., narcotics are usually withheld in late transition labor due to their possible fetal depressant effect).
- The condition of certain infants may cause them to be more sensitive to the effects of medications (e.g, preterm or small-for-gestational-age infants).
- The administration and use of certain medications requires special equipment and/or personnel to be present and available in the labor and delivery unit at all times.
- Certain procedures (e.g., forceps or Cesarean deliveries) require anesthesia for the mother’s comfort.
Narcotic Analgesics
These medications may be administered during active labor and may be combined with tranquilizers to potentiate (increase) their action.
Form
IM injection or IV.
Examples
Demerol, Morphine, Stadol, Nubain, Codeine, Dilaudid, Talwin, Sublimaze, Fentanyl.
Time
Onset in 5-20 minutes. Lasts 1-4 hours in the mother. Fetal cord blood levels for Demerol is 80-130%; for Talwin it is 40-70%.
Benefits/Purposes
- Narcotics help to reduce, abolish, or alter the maternal perception of pain without loss of consciousness.
- In labor they may promote relaxation between contractions and increase the feelings of comfort and control during contractions.
- They may be administered during a Cesarean delivery or post-partum.
Risks/Disadvantages
- If given too early in the labor, narcotics may slow labor progress.
- Maternal side effects include dizziness, dry mouth, euphoria, nausea, slowed respiratory rate, lowered blood pressure, difficulty with concentration and the ability to focus on breathing patterns.
- Analgesics may depress the infant’s respirations and may alter the newborn’s behavioral responses for several days or weeks.
Narcotic Antagonists
These drugs are given when there is a need to reverse the effects of a narcotic analgesic.
Form
IM injection or IV push to the mother. IM injection into the umbilical vein of the baby.
Examples
Narcan, Nalline, Lorfan.
Time
Within 2-5 minutes
Benefits/Purposes
To reverse respiratory depression or other side effects caused by narcotic analgesics.
Risks/Disadvantages
There do not appear to be side effects to the mother. Little is known about the long term effects to the newborn.
Regional Anesthesia
Spinal Block/Saddle Block
A spinal/saddle block provides anesthesia during second stage labor for a vaginal delivery (as with forceps) or for a Cesarean delivery. An anesthetic agent is injected directly into the spinal fluid in the spinal canal. A spinal/saddle block is administered with the mother either lying curled on her side or sitting up in a curled knee-chest position.
Takes Effect In
3-5 minutes.
Examples
Pontocaine, Pentothal.
Area Affected
Spinal Block: From the breast level to the toes.
Saddle Block: The inner thighs, perineum and buttocks.
May Be Given At
Second stage labor.
Effects May Last For
1.5-2 hours.
Benefits/Purposes
- Spinal anesthesia is used to achieve anesthesia for a Cesarean delivery.
- Saddle block may be chosen to provide anesthesia for a forceps delivery.
- Nearly 100% receive good anesthesia.
Risks/Disadvantages
- Possible drop in maternal blood pressure (greater than with epidural anesthesia).
- Loss of urge to push.
- May have difficulty in urinating afterwards necessitating catheterization.
- Possible “spinal headache” afterwards. Patients are required to lie flat for 12 hours after administration of a spinal or saddle block to reduce incidence of “spinal headaches”. If a “spinal headache” occurs-which is thought to be due to leakage of spinal fluid-it may be treated with a blood patch procedure whereby 10cc of maternal blood is injected into the epidural space. The ensuing blood clot applies pressure and seals the leak. Success of this treatment ranges from 91-100%.
Epidural Block
- An anesthetic agent is introduced between the 4th and 5th lumbar vertebrae and into the epidural space. The epidural space is between two membranes which are outside the spinal canal. The epidural medication does not mix with the spinal fluid.
- The epidural block may be given as a single injection or a small plastic catheter may be left in the epidural space to allow for additional single doses or a continuous infusion of the anesthetic agent.
Takes Effect In
3-20 minutes
Examples
Bupivacaine, Marcaine, Lidocaine, Fentanyl and/or Sufenta.
Area affected
Waist to knees, or below the ribs to the toes.
May Be Given At
During active labor-after 3 to4 centimeters-and through delivery. During second stage labor only. Prior to and during Cesarean delivery.
Effects May Last For
1.5-2 hours.
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Benefits/Purposes
- Usually gives good pain relief for uterine contractions, birth and repair.
- Little medication reaches the baby.
- Does not make the woman drowsy.
- May be anesthesia of choice for an instrument (forceps) delivery.
Risks/Disadvantages
- May slow down or prolong labor if given too early in labor. The woman’s inability to move around and/or ambulate and to make use of gravity may also slow down labor progress.
- May require use of Pitocin augmentation to stimulate a sluggish labor.
- Woman must remain in bed as she cannot walk about or use the bathroom.
- Will probably require intermittent or continuous urinary catheterization during labor, and for a short time after delivery and termination of the epidural.
- Must have continuous intravenous fluids and electronic fetal monitoring.
- May cause a drop in the maternal blood pressure affecting circulation and oxygenation to the placenta and fetus.
- Must have frequent blood pressure readings taken to assure stability of maternal blood pressure.
- Diminishes urge to push and bearing-down reflex which may prolong 2nd stage labor. This may also increase the use of fundal-pressure, vacuum extractor or forceps to accomplish delivery.
- Woman is totally dependent upon her coach and support personnel for her basic physical needs.
- Requires an anesthesiologist to administer who must also remain in the labor and delivery unit as long as a patient has an epidural.
- Not cheap.
Pudendal Block
Inside the vaginal vault an anesthetic agent is injected via the pudendal nerve trunks near the ischial spines. The pundendal nerve supply the perineal muscles, the perianal region, the urethral sphincter, and the vulvar region.
Takes Effect In
2-3 minutes.
Examples
Xylocaine/Lidocaine, Nesacaine.
Area Affected
Vaginal and Perineum
May Be Given At
Second stage labor.
Effects May Last For
One hour.
Benefits/Purposes
- Anesthetizes the vulva, birth canal, and perineum and is used for vaginal delivery, episiotomy and repair.
- Effective anesthesia for low forceps delivery.
Risks/Disadvantages
- Maternal relief is achieved for a perineal distention but not from uterine contractions.
- May eliminate the urge to bear down during second stage labor but the woman may still be able to push effectively with appropriate coaching.
- Possible fetal depression with large doses administered too far in advance of delivery.
Local Anesthesia
An injection is given into the tissues of the perineum just prior to delivery of the infant, or after the birth, for repair of the episiotomy.
Takes Effect In
2-5 minutes.
Examples
Xylocaine/Lidocaine, Nesacaine.
Area Affected
The perineum eliminating the sensation of “burning and stretching” with the crowning of the infant’s head at the vaginal opening.
Local Anesthesia
May Be Given At
Second or third stage labor.
Effect May Last For
20 minutes
Benefits/Purposes
- Numbs perineum fir episiotomy repair (suturing). (Note: The “local” is not required for episiotomy pain relief as the stretching of the perineal tissues and pressure from the fetal head on the perineal nerves create a temporary, natural anesthesia).
Risks/Disadvantages
- Woman may feel stinging upon administration of medication.
- Infant may have decreased muscle tone if medication is administered too long prior to delivery.
General Anesthesia
General anesthesia induces an unconscious state which eliminates awareness of pain and the delivery experience. General anesthesia is used only for delivery. Its use is indicated when certain complications arise and rapid anesthesia is desirable such as for a true emergency Cesarean delivery or when there is a threat of unusual maternal hemorrhage.
Method of Administration
By introduction of IV medications such as Brevital or Pentothal, and inhalation anesthetics such as Nitrous Oxide, Penthrane or Fluothane.
Time Of Effect and Recovery
General anesthesia is used only when delivery is imminent as the medications cross the placenta rapidly and have the same effects on the fetus as on the mother. Recovery time varies with the type of medication and quantity used.
Benefits/Purposes
- Gives complete body anesthesia during the operative procedure.
Risks/Disadvantages
- Nausea and vomiting with the possibility of lung aspiration.
- Cardiac and/or respiratory depression.
- Postpartum uterine atony (lack of tone) increasing the possibility of postpartum hemorrhage.
- Newborn infant depression directly proportional to the depth and duration of anesthesia.
- Delayed maternal-infant bonding.
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