As a matter of fact, today we can only use three local anesthetics for epidural analgesia of labor: ropiva kain (best of all), bupivacaine (if there is no ropivacaine), lidocaine (if there is nothing else). Consideration of the others is only of historical interest — in the event of a temptation to try them.
Novocain for epidural anesthesia has long been not used because of its weak and short action.
Mepivacaine (Mepivacaine, Meaverin, Polocaine) is not used in obstetrics, due to its significant penetration through the placenta and slow metabolism in the fetus. Described cases of depression born after epidural anesthesia with mepivacaine in the mother.
Prilocaine (Prilocaine) penetrates the fetal blood faster than any other anesthetic. At the same time, its concentration in the fetal blood can be even higher than that of the mother [ P.Brownridge, SECohen, 1988]. It causes methemoglobinemia in both the mother and the fetus, sometimes (especially after repeated injections) more than 10% of the baby’s hemoglobin is converted to methemoglobin, which leads to marked cyanosis. For this reason, prilocaine is considered contraindicated for use in obstetrics.
Etidocaine (Etidocaine, Duranest, Duranest), due to its rapid onset, long duration, good muscle relaxation and very little penetration through the placenta, was successfully used for epidural anesthesia (1% solution) for caesarean section . However, due to the long and deep motor block even at low concentrations, it was not used for anesthesia of vaginal genera.
Chloroprocaine (Chloroprocaine, 2-chloroprocaine, Nesacaine) is an ester-based local anesthetic of rapid onset and short-acting, almost never accumulates in the blood, as it is rapidly destroyed by plasma cholinesterase. Therefore, it has been widely used for a long time in obstetric anesthesiology in the West. But, due to neurological complications with inadvertent subarachnoid administration, he lost popularity. The reason for these neurological complications is considered to be the antioxidant bi-sulfite, which was previously added to its preparations. Later, when it was started to be produced without bisulfite, it could be used for the anesthesia of childbirth, but due to the short action, repeated doses were required to be administered quite often. A concentration of 2% is usually quite sufficient for the first period of labor, and to deepen analgesia in the second period, and for cesarean section, 3 % was used.
Lidocaine (Lidocaine, Lignocaine, Xylocaine, Xycaine), a local anesthetic of rapid onset and medium duration of action, is used for both pains of the first stage of labor (if there is nothing else) at a concentration of 1%; 1.5-2% for caesarean section -2% . The advantage of lidocaine is the rapid onset of action, the lack of anesthesia for the genes is significant motor block and arterial hypotension, especially at high concentrations.
Bupivacaine
Among the anesthetic of the amide group to the fetus to a lesser extent do drugs that are more associated with proteins. Bupivacaine has the highest protein association among common local anesthetics.
Bupivacaine (Bupivacaine, Bucain, Markami, Sensorcaine, Anecain), a local anesthetic of slow onset and long-acting, is especially good for anesthesia of labor due to its inherent differential block. Before the advent of ropivacaine, he was the local anesthetic of choice for epidural analgesia of labor. Concentration of 0.25 % or less {see tab. 37), used during the first period, provides sufficient analgesia without a motor block of the abdominal press (interfering with attempts) and legs (frightening a woman). Due to less sympathetic blockade, hemodynamics are more stable than with other local anesthetics (except ropivacaine). Due to the long-term effect of bupi vakain, its repeated doses are less frequent — this is more convenient and the risk of intoxication is less. Main a lack of bupivacaine is a more severe course of intoxication caused by it in case of overdose or intravascular administration. Another drawback is the slow onset of action, therefore, if necessary, a rapid deepening of analgesia for the second stage of labor or emergency caesarean section, often switch to lidocaine. However, with our speed of unfolding the operating rooms and gathering all members of the obstetric team, for those 10-15 minutes that will be spent on this, and bupivacaine will have time to act.
In order not to miss the moment of cessation of the effect of the administered epidural bupivacaine, it is necessary either to regularly evaluate the level of the block or to apply its continuous infusion into the epidural space.
Ropivacaine ( N Aropin) 0.2% (2mg / ml) —the drug of choice for epidural anesthesia of childbirth, due to its inherent differential block — sufficient analgesia with virtually no motor block and arterial hypotension. Even a single administration can relieve childbirth for 2–2.5 hours with practically no side effects. Thanks to the person who wrote the Ukrainian instructions, 0.1-0.2% of Naropin allowed the addition of fentanyl (at a concentration of 1-10 µg / ml), sufentanil (at a concentration of 0.4-4.0 µg / ml), morphine (at a concentration of 20–100 µg / ml) and clopheline (at a concentration of 5–50 µg / ml), which was approved by the Ministry of Health of . However, the reader should not forget about the side effects and dangers from these adjuvants, especially from morphine. Forms of release (convenient for obstetrics): ampoules of 20 ml 0,2% (2 mg / ml) – for epidural anesthesia of labor and 10 ml of 0.75% (7.5 mg / ml) – for epidural anesthesia of cesarean section.
Levobupivacaine (Hirokain) – laevorotatory isomer bupivacaine (which is a racemic mixture) and less cardiotoxic than Ratseev nomic bupivacaine, similar to it on the top and duration of effect, but with less motor block. Its special advantages for the treatment of childbirth are not identified.