Anesthesia during childbirth

All women entering the maternity ward are potential candidates for planned or emergency anesthesia during childbirth. In this regard, the anesthetist should know about each pregnant woman in the department, the following minimum: the age, the number of pregnancies and births, the period of the present pregnancy, concomitant diseases and complicating factors.

A list of laboratory-instrumental examinations to be sought for in gestosis, including HELLP-syndrome (H-hemolysis-hemolysis; EL-elevated liver function tests-elevation of liver enzymes; LP-low platelet count-thrombocytopenia):

• a general blood test, including platelets, VSC, hematocrit;
• general urine analysis (assessment of proteinuria);
• hemostasiogram, including paracoagulation tests;
• total protein and its fractions, bilirubin, urea, creatinine, blood plasma glucose;
• electrolytes: sodium, potassium, chlorine, calcium, magnesium;
• ALT, ACT, APF, LDH, KFK;
• osmolality and CODpl. Blood;
• indicators of CBS and blood gases;
• determination of the presence of free hemoglobin in the blood plasma;
• ECG;
• control of the CVP according to the indications.

With eclampsia - consultation of the ophthalmologist and neurologist, according to indications and if possible: lumbar puncture, magnetic resonance imaging of the brain and transcranial dopplerometry of the brain vessels.

[1], [2], [3], [4]

Premedication:

Diphenhydramine IV infusion before induction 0.14 mg / kg, once
+
Atropine IV 0.01 mg / kg, once on the operating table or iodide iodide 0.01 mg / kg, once on the operating table
+
Ketoprofen in / in 100 mg, once or Ketorolac IV at 0.5 mg / kg, once.

What methods does anesthesia use during childbirth?

There are non-pharmacological and medicinal methods of anesthesia during childbirth.

Postulates during analgesia and anesthesia during labor:

• if the effect of drugs is unpredictable and / or the incidence of side effects is high, it is not used;
• The anesthesiologist uses that method of anesthesia (analgesia, puncture, etc.), which he best knows.

Anesthesiologic manual in obstetrics conditionally includes 5 sections.

The first section - anesthesia in childbirth, including pregnant women with pelvic presentation and multiple pregnancies:

• in a healthy pregnant woman with a physiological pregnancy;
• in a pregnant woman with extragenital pathology;
• in pregnancy with gestosis;
• at a pregnant woman with a gestosis on a background of extragenital pathology.

It should be noted that the probability of development of abnormalities of labor (ARD) increases from the first to the last group, i.e. The number of physiological births decreases, in connection with which the following section is formed.

The second section is anesthesia during childbirth through the natural birth canal in pregnant women of the above groups with ARD to be treated, with pelvic presentation and multiple pregnancies.

Sometimes, with weakness of the RD and / or intrauterine hypoxia of the fetus in the second period, when the possibility of caesarean section is missed, the imposition of obstetric forceps is shown, which requires anesthesia.

ARD most often develop in pregnant women with a burdened obstetric-gynecological anamnesis (OASA), extragenital pathology, gestosis, but can also be a consequence of incorrect tactics of labor. Repeated unsystematic use of uterotonics (oxytocin) may be one of the reasons for discoordination of the contractile function of the uterus. Overdose of these drugs can lead to hypoxia and even fetal death. It should be remembered that when discoordination of labor (DRD) and AH is contraindicated the use of ganglion blockers that cause hypotension of the uterus and contribute to the development of ischemic damage to neurons of the brain in the fetus.

The ARD includes:

• weakness of the taxiway:
• primary;
• secondary;
• weakness in attempts;
• excessively strong taxiway;
• discoordination of RD;
• discoordination;
• hypertension of the lower segment of the uterus;
• convulsive contractions (tetany of the uterus);
• cervical dystocia.

In the presence of OASA, extragenital pathology, gestosis, chronic fetal hypoxia, treatment of discoordination of PD is not indicated, it is advisable to deliver by caesarean section. This is due to the fact that all of the above factors are dangerous for the life of the pregnant and fetus with conservative management of labor. Discoordination of the RD has such complications as rupture of the uterus, embolism with amniotic fluid and placental abruption, which are accompanied by hypotonic and / or coagulopathic hemorrhage. Gestosis in the form of pre-eclampsia, eclampsia and HELLP-syndrome, prolapse of the umbilical cord at the pelvic and abnormal positions of the fetus is an indication for abdominal delivery.

Consequently, the third section of anesthesia in obstetrics will be the anesthesia of a caesarean section in pregnant women of the above-mentioned groups with ARD, which are not amenable to or can not be treated, the pelvic and abnormal positions of the fetus, multiple pregnancies.

Such situations as manual examination of the uterine cavity, manual separation / removal of the afterbirth, restoration of the perineum, scraping of the uterine cavity after a late miscarriage and abortion (fruit-destroying operations) unites that, with their anesthetic support, the task of eliminating the harmful effect of drugs on the fetus - this is the fourth section of anesthesia in obstetrics: anesthesia for small obstetrical operations in pregnant women (puerperas) of the above groups.

Pregnant women may require surgery for diseases other than pregnancy; therefore, the fifth section of anesthesia in obstetrics will be the anesthesia of surgical interventions not related to pregnancy in pregnant women of the above groups.

The need for such a gradation of initial and developing functional disorders during / as a result of pregnancy is due to the fact that they can significantly reduce the adaptive capacity of the organism of the pregnant woman and the fetus, and therefore change their reaction to pharmacological effects. The uniqueness of a physiologically occurring pregnancy consists in the fact that it combines the adaptation syndromes, because is a physiological process, and disadaptation, because proceeds on a high level of reaction of vital organs and systems that is not characteristic of a healthy adult person. Consequently, the higher the degree of functional disorders in a pregnant woman, the greater the risk of complications of pregnancy, labor (spontaneous and operational) and their anesthesia due to the predominance of the process of maladaptation.

Indications for anesthesia during childbirth is severe pain in the background of established RD (regular fights) when the cervix is opened for 2-4 cm and there are no contraindications (the obstetrician determines, but the anesthesia chooses the type of anesthesia during labor).

An objective criterion for assessing the individual threshold of the pain sensitivity of the pregnant woman and the tactics of anesthesia during labor is the relationship between contractions and labor pain, on the basis of which the algorithm of analgesia was built:

• at a very high pain threshold, pain during labor is almost not felt and anesthesia during labor is not required;
• at a high pain threshold, the pain is felt for 20 seconds at the height of the contraction. In the first period, the use of analgesics is shown, in the second period - intermittent inhalation with dinitrogen oxide with O2 in a ratio of 1: 1;
• at the normal pain threshold, the first 15 sec of the pain there is no pain, then the pain appears and lasts 30 seconds. In the first period, the use of analgesics is also shown, in the second period - constant inhalation with dinitrogen oxide with O2 in a ratio of 1: 1;
• at a low pain threshold, the pain is felt throughout the entire bout (50 seconds); shows EA or an alternative option - intravenous analgesics and tranquilizers in the first period and constant inhalation with dinitrogen oxide with O2 in a ratio of 2: 1 (control is needed because of the risk of fetal hypoxia) - in the second.

Anesthesia during childbirth with dinitrogen oxide in our country for various reasons was not widely used, technical capabilities and attitude to regional methods of analgesia and anesthesia were unstable, which did not allow to assess their advantages and disadvantages in a timely manner in practice. The attitude towards the use of anxiolytics (tranquilizers) during childbirth was mentioned above. In this regard, from the above algorithm, we can take only the first part: the determination of the individual threshold of pain sensitivity by the relationship between contraction and labor pain.

The second part of the algorithm - the tactics of anesthesia during childbirth requires a serious improvement, based on the results of recent studies evaluating pregnancy from the SSRI perspective and the placental ischemia / reperfusion syndrome. For a long time, for the purpose of anesthesia during labor, narcotic (trimeperidine, fentanyl) and non-narcotic (metamizol sodium and other NSAIDs) analgesics administered intravenously or intravenously were used. Recently, the issue of total withdrawal from the / m introduction of opioids has been widely discussed. From the point of view of pharmacokinetics and pharmacodynamics, this route of administration is considered impractical due to uncontrollability. The most common opioid used in our country for anesthesia during childbirth is trimiperidine. It is administered intravenously with a steady RD and the opening of the cervix at least 2-4 cm. The use of narcotic analgesics during latent or at the beginning of the active phase of labor can weaken the uterus contraction. At the same time, anesthesia during childbirth with trimeperidine with an established RD contributes to the elimination of its discoordination due to a decrease in adrenaline release. The administration of trimepiperidine should be discontinued 3-4 hours before delivery. The possibility of its use for 1-3 hours before delivery (in the absence of an alternative) should be coordinated with the neonatologist, tk. T1 / 2 trimepiperidine in the fetus is 16 hours, which increases the risk of depression of the central nervous system and respiratory distress in a newborn. It should be noted that agonists-opiate receptor antagonists and tramadol do not have advantages over agonists, t. Are also capable of inhibiting respiration and the function of the central nervous system, but due to the specific mechanism of action and the state of the intrauterine fetus, the extent of their inhibition is unpredictable.

In connection with this, EA is currently the most popular method of anesthesia in childbirth, as it effectively removes pain without affecting the consciousness of the mother and the possibility of cooperation with it. In addition, it provides a reduction in metabolic acidosis and hyperventilation, ejection of catecholamines and other stress hormones, which improves placental blood flow and fetal status.

In order to systematize indications for the use of different drugs and methods of their use for anesthesia during labor, it is necessary to build a new algorithm based not only on the evaluation of pregnancy from the SSRI position, but also on the detection of dysfunction of nonspecific mechanisms for the formation of a common adaptation syndrome in a pregnant woman and a fetus / newborn in the process pregnancy / childbirth. It is known that more than 70% of the patients undergoing surgery are sympathotons (dysfunction of CAS - non-specific starting link in the formation of the general adaptation syndrome). Consequently, the initial state of ANS in women before the onset of pregnancy is more often characterized by sympathicotonia.

In this regard, even a physiologically occurring pregnancy is accompanied by a tendency to vagotonia (the rate of pregnancy), and sympathicotonia. The presence of extragenital pathology (more often from the cardiovascular system) and / or gestosis contributes to the progression of sympathicotonia in 80% of this category of pregnant women. Pain syndrome at birth, especially pronounced, closes the vicious circle of the negative impact of sympathicotonia (dysfunction of the ANS) on the formation of a compensated metabolic reaction of the maternity and fetus (the general adaptation syndrome) to the process of delivery, transferring it to decompensated (complications).

In particular, excessive release of catecholamines (adrenaline) through stimulation of beta2-adrenoreceptors can reduce the frequency and force of contractions, slowing the process of childbirth. An increase in OPSS due to hypercatecholamineemia significantly reduces uteroplacental blood flow, which, due to hypoxia, leads to an increase in transplacental permeability and the progression of endothelial damage. Consequently, as sympathicotonia increases, indications for use for anesthesia during the birth of regional analgesia / anesthesia and drugs with non-opiate analgesic activity, realized through exposure to the vegetative component of pain (central alpha-adrenomimetics) increase.

At the same time, it should be remembered that gestosis is a CBP, which, being non-specific, is accompanied by a nonspecific ischemia / reperfusion syndrome, in this case - the placenta. The causes of placental ischemia are violations of trophoblast formation, endothelin synthesis in the first trimester of pregnancy, defects in the development of spiral arteries, placenta hypertrophy, vascular diseases, and immune disorders. The good results of the use of calcium antagonists in gestosis, apparently, are associated not so much with the action of drugs on the smooth muscle of blood vessels, as with the prevention of calcium damage to cells (elimination of secondary messenger-calcium dysfunction) and a decrease in phagocyte activity. The role of the calcium mechanism of cell damage is confirmed by studies showing an increase in intracellular calcium concentration in the endothelium of pregnant women with gestosis in comparison with healthy pregnant women and nonpregnant women. The concentration of calcium ions in the endothelium correlated with the level of ICAM-1. Therefore, in addition to sympathicotonia, the degree of severity of the placental ischemia syndrome also determines the nature of the metabolic reaction of the mother and fetus / newborn to the birth process. Thus, endothelial insufficiency of the woman in childbirth and vascular insufficiency of the placenta dictate the need to use drugs for the purpose of anesthesia during childbirth with non-opiate analgesic activity, realized through increasing the resistance of tissues to hypoxia. These drugs include calcium antagonists (nifedipine, nimodipine, verapamil, etc.) and to a certain extent beta-adrenoblockers (propranolol, etc.).

In case of severe gestosis (SSSR - nonspecific reaction of the organism), in addition to the dysregulation of cytokine synthesis, the mediators of pain and inflammation, activated by Hageman (hemostasis, kinin-kallikrein, complement and arachidonic cascade) mediators play a significant role in the pathogenesis of this drug, drugs with non-opiate analgesic activity due to inhibition of synthesis and inactivation of these mediators. These drugs include protease inhibitors, including their synthetic analogue of tranexamic acid, and NSAIDs that inhibit the synthesis of algogenic PG. These drugs are especially effective for the prevention of clinical manifestations of the second "mediator wave" of SSRM in response to tissue damage (caesarean section, extensive tissue trauma in childbirth).

Thus, the algorithm for anesthesia during childbirth is as follows.

Anesthesia with spontaneous childbirth

[5], [6], [7], [8]

Intravenous analgesia

Most often, anesthesia during labor in healthy pregnant women with a physiological pregnancy is carried out using a combination of drugs of several pharmacological groups administered intravenously (Scheme 1):

Trimeperidin IV 0.26 mg / kg (20-40 mg), the periodicity of administration is determined by clinical expediency
+
Difenhydramine iv 0.13-0.26 mg / kg (up to 10-20 mg), the periodicity of administration is determined by the clinical feasibility
+
Atropine i / in 0,006-0,01 mg / kg, once or iodide iodide iv at 0,006-0,01 mg / kg, once.

The use of opioids in 50% of cases can be accompanied by nausea and vomiting, caused by stimulation of the chemoreceptor trigger zone of the vomiting center. Narcotic analgesics inhibit the motility of the gastrointestinal tract, which increases the risk of regurgitation and aspiration of gastric contents into the trachea during general anesthesia. Combination of drugs of the above groups can prevent the development of these complications.

In the presence of contraindications to the administration of trimeperidine, the presence of the initial sympathicotonia, the following scheme of anesthesia during labor (Scheme 2) is shown:

Clonidine IV / 1.5-3 μg / kg, once
+
Ketorolac IV 0.4 mg / kg, once
+
Diphenhydramine IV 0.14 mg / kg, based
+
Atropine IV 0.01 mg / kg, once. In case of insufficient analgesic effect, clonidine is added after 30-40 min: clonidine iv 0.5-1 μg / kg (but not more than 2.5-3.5 μg / kg), once.

Pregnant with the initial sympathicotonia, extragenital pathology, gestosis, pelvic presentation and multiple pregnancy (often with diseases and complications of pregnancy, accompanied by dysfunction of ANS - sympathicotonia), in addition to the above, the following scheme is shown (Scheme 3):

Trimeperidine IV 0.13-0.26 mg / kg (up to 20 mg), the periodicity of administration is determined by clinical expediency
+
Diphenhydramine iv at 0.13-0.26 mg / kg (up to 10-20 mg), periodicity of administration is determined by clinical expediency
+
Atropine IV / 0.01 mg / kg, once or iodide iodide at 0.01 mg / kg, once
+
Clonidine IV 1.5-2.5 μg / kg (up to 0.15 -0.2 mg), the periodicity of administration is determined by clinical expediency. With a rigid neck of the uterus, pregnant women of all the above groups are additionally administered sodium oxybate. Our long experience of using this drug has shown that the danger of its administration in pregnant women with AH of any genesis (including gestosis) is incredibly exaggerated:

Sodium oxybate iv 15-30 mg / kg (up to 1-2 g), the frequency of administration is determined by clinical feasibility. The question may arise: what is the need to distinguish the last three groups, if the above schemes apply to all? The fact is that the severity and clinical significance of CNS depression and respiration in a newborn depend on the pharmacological characteristics and doses of drugs used, the maturity and the pH of fetal blood. Prematurity, hypoxia and acidosis significantly increase the sensitivity to drugs, depressing the central nervous system. The degree of severity of these disorders in the fetus depends on the presence and severity of manifestations of gestosis and extragenital pathology. In addition, 10-30% of patients are not sensitive or weakly sensitive to narcotic analgesics, which do not affect the vegetative component of pain. In this regard, the choice of drugs (narcotic and / or non-narcotic analgesics), dose, speed and time (before delivery) of their administration in pregnant women of these groups should be optimal (minimal but different in groups, which is determined by the skill and experience of the doctor). Therefore, in pregnant women with a high and normal pain threshold, the use of a combination of analgesics with a non-opiate mechanism of action in combination (according to indications) with opioids (dose reduction) and / or EA is more appropriate in the last three groups than tranperidin (opioid) anesthesia.

Adequate anesthesia during childbirth, accompanied by an abnormality of labor (ARD), can speed up the opening of the cervix in 1,5-3 times, i.е. Eliminate ARD due to a decrease in the release of catecholamines and normalization of uterine blood flow. In this regard, the principles (methods) of anesthesia during childbirth (with emphasis on epidural anesthesia), outlined above, remain relevant for this category of pregnant women.

Depending on the severity of sympathicotonia and placental insufficiency (gestosis), preference is given to techniques that include clonidine, beta-blockers and calcium antagonists. It is impossible to draw a clear line between anesthesia during childbirth and ARD therapy in this category of pregnant women. The management tasks do not include the description of ARD treatment methods (this is an obstetric problem, which in obstetrical institutions with a high level of pharmacorationality is decided by the development of a comprehensive obstetric-anesthesiologic-neonatal manual).

Anesthesia in childbirth and calcium antagonists

It is known that calcium antagonists possess anti-ischemic, tocolytic, moderate analgesic, sedative and weak myoplegic properties.

Indications for the appointment of calcium antagonists:

• premature delivery;
• excessively strong labor activity - with the purpose of reduction of a hypertonus of a myometrium;
• hypertonic form of mild labor - to normalize the increased basal tone of the uterus;
• DRD (contractions of irregular shape, violation of their rhythm) - to normalize the tone of the uterus;
• intrauterine fetal hypoxia due to ARD, intrauterine resuscitation;
• preparation for childbirth in the absence of biological readiness and a pathological preliminar period.

Contraindications to the appointment of calcium antagonists:

• for all calcium antagonists - arterial hypotension;
• for verapamil and diltiazem - syndrome of weakness of the sinus node, AV blockade of II and III degrees, severe LV dysfunction, WPW syndrome with antegrade impulse conduction along additional pathways;
• for dihydropyridine derivatives - severe aortic stenosis and obstructive form of hypertrophic cardiomyopathy.

Care must be taken when using these medicines against the background of treatment with prazosin, euphyllin, magnesium sulfate, beta-adrenoblockers, especially with their intravenous administration. Inclusion in the above schemes in healthy pregnant women, pregnant women with gestosis, with hypokinetic type of hemodynamics of nifedipine or rhiodipine, in addition to increased analgesia is accompanied by an increase in the shock index, SI and a decrease in OPSS (in the absence of hypovolemia), favorable changes in cardiothoracic parameters of the fetus, which allows us to evaluate the use of drugs as intranatal its protection from hypoxia: Nifedipine sublingual, transbukalno or inside up to 30-40 mg per birth, the frequency of administration is determined by the clinical goal oviformity or Riodipine inside 30-40 mg per birth, the frequency of administration is determined by clinical feasibility.

Pregnant with hyper- and eukinetic types of hemodynamics shows the use of verapamil or propranolol depending on the type of ARD.

Verapamil is applied intravenously intravenously or via the infusomat, depending on the purpose and the result (after the attainment of tocolysis, the administration is usually stopped):

Verapamil IV droplet 2.5-10 mg or through the infusomat with a speed of 2.5-5 mg / h, the duration of therapy is determined by clinical feasibility.

Calcium ions in the cytoplasm of cells are the initiators of the processes leading to damage to the fetal brain during reoxygenation after hypoxia due to activation of the release of glutamate and aspartate, proteases, phospholipase and lipoxygenase. In this regard, pharmacological prophylaxis of posthypoxic brain damage in a fetus, the development of which occurs in conditions of placental insufficiency, should include the use of calcium antagonists.

[9], [10], [11], [12], [13], [14],

Anesthesia during childbirth and beta-blockers

Propranolol (beta-adrenoblocker) potentiates the action of narcotic and non-narcotic analgesics, anesthetics, eliminates feelings of fear, stress, antistress and rhodoactivating effects, and increases the degree of neurovegetative inhibition (NVT) in anesthesia. The rhodoactivating effect of propranolol is due to blockade of the uterine beta-adrenoreceptors and an increase in the sensitivity of alpha-adrenoreceptors to mediators (norepinephrine) and uterotonics. Drugs are prescribed under the tongue (it is necessary to warn about local-anesthetic action of drugs) after intravenous administration of atropine, diphenhydramine and ketorolac (schemes 1 and 2, with severe pain syndrome, in combination with trimiperidin - not more than 2/3 of this dose) in combination with calcium chloride, if the task is to treat DRD:

Propranolol sublingually 20-40 mg (0.4-0.6 mg / kg)
+
Calcium chloride, 10% rr, in / in 2-6 mg.

If necessary, this dose of propranolol can be repeated twice at an interval of one hour, if the obstetrician sees an insufficient effect of treatment for DDD.

Contraindications to the appointment of beta-blockers - bronchial asthma, COPD, circulatory failure of II-III degree, bradycardia in the fetus, excessively strong labor activity, hypertension of the lower segment and tetany of the uterus.

With the duration of labor for 18 hours or more, the energy resources of the uterus and the body of the pregnant woman are exhausted. If during these 18 hours there is a picture of primary weakness of labor activity and the possibility of the completion of labor in the next 2-3 hours is completely excluded (the obstetrician determines), the provision of a medical mother with a sleep-rest is indicated. An anesthetic manual is provided for one of the above schemes, but with the mandatory use of sodium oxybate:

Sodium oxybate IV 30-40 mg / kg (2-3 g).

In the presence of absolute contraindications to its use use Droperidol: Droperidol IV 2.5-5 mg.

With secondary weakness of labor activity, the anesthesiologist's tactics are similar, but drug-induced sleep-rest should be less prolonged. In this regard, the dose of sodium oxybate is reduced.

Sodium oxybate IV 20-30 mg / kg I (1-2 g).

In case of need of superimposition of obstetric forceps can be used: intravenous anesthesia based on ketamine or hexobarbital; Intravenous anesthesia in childbirth based on ketamine or hexobarbital

[15], [16], [17], [18], [19]

Induction and maintenance of anesthesia during labor:

Ketamine i / in 1 mg / kg, once or Hexobarbital iv in 4-5 mg / kg, once
±
Clonidine IV 1.5-2.5 mg / kg, once.

Ketamine is administered after a premedication at a rate of 1 mg / kg, if necessary in combination with clonidine (the analgesic effect of clonidine develops 5-10 minutes after intravenous administration).

With IV anesthesia during childbirth, short-term relaxation of the uterus can also be achieved by the administration of nitroglycerin (IV, sublingually or intranasally), provided that hypovolemia is eliminated.

Inhalational anesthesia during childbirth

In parturient women with gestosis, ketamine is replaced with hexenal or mask anesthesia (halothane or better analogues - briefly for uterine relaxation, dinitrogen oxide, oxygen):

Dinitrogen oxide with oxygen inhalation (2: 1,1: 1)
+
Halothane inhalation up to 1.5 MAK.

Retinal anesthesia during childbirth

If epidural anesthesia is performed during childbirth, there are no problems for applying obstetric forceps.

The method of choice is also the CA, covering the segments T10-S5:

Bupivacaine, 0.75% rr (hyperbaric rr), subarachnoid 5-7.5 mg, single or lidocaine, 5% rp (hyperbaric rp), subarachnoid 25-50 mg, once.

Benefits:

• ease of implementation and control - the emergence of CSF;
• rapid development of the effect;
• low risk of toxic effect of anesthetic on CCC and CNS;
• does not exert a depressing effect on the contractile activity of the uterus and the fetal condition (while maintaining stable hemodynamics);
• Spinal analgesia is cheaper than epidural and general anesthesia.

Disadvantages:

• arterial hypotension (it is stopped by rapid infusion and / in the administration of ephedrine);
• limited duration (the presence of special thin catheters solves the problem);
• post-puncture headache (using smaller diameter needles significantly reduced the incidence of this complication).

It is necessary:

• monitoring the adequacy of spontaneous breathing and hemodynamics,
• full readiness for transferring the patient to mechanical ventilation and conducting corrective therapy.