The first experiments on the use of spinal anesthesia date back to 1898, but this method of pain relief was widely used much later. To use this method, the doctor must have certain knowledge in the field of anatomy of the spinal cord and its membranes.
Epidural and spinal anesthesia
These methods of pain management are regional. During their conduct, the anesthetic is injected into a special area located near the spinal cord. Due to this, the lower half of the body "freezes". Many do not know if there is a difference between spinal and epidural anesthesia.
The procedure for preparing and conducting anesthesia with these methods is similar. Indeed, in both cases, an injection is made in the back. The fundamental difference is that spinal anesthesia is called a single injection, and epidural (epidural) is the installation of a special thin tube through which anesthetic is administered over a period of time.
But the technique of performance is not the only difference between the two methods of pain relief. Spinal anesthesia is used in cases where it is necessary to achieve a short-term effect. Depending on the type of drugs used, the duration of anesthesia can vary from 1 to 4 hours. Epidural anesthesia is not limited in time. Anesthesia will continue until anesthetic is delivered to the body through an established catheter. Often this method is used to relieve the patient of pain, not only during surgery, but also in the postoperative period.
Operating principle
Epidural and epidural anesthesia are regional anesthesia in which drugs are injected into the epidural space of the spine. The principle of its action is based on the fact that the drugs used through dural couplings enter the subarachnoid space. As a result, impulses passing through the radicular nerves in the spinal cord are blocked.
After all, the drug is administered in the immediate vicinity of the trunk with nerve cells. Namely, they are responsible for the appearance of pain in various parts of the body and conducting them to the brain.
Depending on the place of administration of the drug, it is possible to disable motor activity and sensitivity in certain parts of the body. Most often, epidural anesthesia is used to “disconnect” the lower half of the body. For this, it is necessary to introduce an anesthetic into the intervertebral space between T10-T11. To anesthetize the chest area, the drug is injected into the area between T2 and T3, the upper half of the abdomen can be anesthetized by injection into the area of the T7-T8 vertebrae. The area of the pelvic organs "turns off" after the introduction of the anesthetic into the space between L1-L4, the lower limbs - L3-L4.
Indications for the use of regional anesthesia
Epidural and spinal anesthesia can be used both separately and in combination with general. The latter option is used in cases where it is planned to conduct thoracic surgery (on the chest) or prolonged surgical interventions in the abdominal region. Their combination and use of anesthetics minimizes the need for patients for opioids.
Separately, epidural anesthesia can be used in such situations:
- anesthesia after surgery;
- local anesthesia during childbirth;
- the need for operations on the legs and other parts of the lower half of the body;
- carrying out cesarean section.
In some cases, only epidural anesthesia is used. It is used when necessary operations:
- on the pelvis, thigh, ankle, tibia ;
- for the replacement of the hip or knee joints;
- with a fracture of the femoral neck ;
- for the removal of hernias.
Spinal anesthesia can be used as one of the methods of treating back pain. Often it is done after surgery. It is also used in vascular surgery in cases where it is necessary to carry out an intervention in the lower extremities.
Anesthesia for childbirth
More and more women use epidural or spinal anesthesia in order not to feel painful contractions. With the introduction of an anesthetic, pain disappears, but at the same time, consciousness remains in full.
Epidural anesthesia during labor is often used in developed countries. According to statistics, it is used by about 70% of women giving birth. This type of anesthesia allows you to anesthetize the entire process of childbirth. However, this does not affect the fetus.
Despite the fact that childbirth is a natural physiological process that does not require external intervention, more and more women insist on having anesthesia. Although during childbirth, the body produces a shock dose of endorphins. They contribute to natural anesthesia, because these hormones can provide an emotional boost, suppress a sense of fear and pain.
True, the mechanism of endorphin production depends on the condition and mood of the woman. For example, prolonged childbirth with severe pain negatively affects both the woman in labor and the unborn baby. In addition, a woman may experience increased pressure, a breakdown, and a malfunction of the main muscle, the heart, may occur. In such cases, analgesia is necessary.
But only in a planned manner can epidural anesthesia be performed. Contraindications to its implementation are quite common. But in emergency cases it is not used also because its action does not occur instantly. Half an hour may elapse from the moment the anesthetics are started and until complete pain relief.
The nuances of preparation
If possible, the patient is preliminarily prepared for anesthesia. If epidural (epidural), cerebrospinal anesthesia is planned, then in the evening the patient is given up to 0.15 g of Phenobarbital. If necessary, a tranquilizer can be prescribed. As a rule, doctors use Diazepam or Chlozepide. In addition, about an hour before the introduction of anesthesia, intramuscular injections of Diazepam or Diprazin are indicated, and Morphine and Atropine or Fentalin can also be prescribed.
Also a mandatory step is the preparation of sterile styling. For its implementation, wipes (both large and small), sterile rubber gloves, gauze balls, needles, syringes, catheters, two tweezers and two glasses for solutions of anesthetics are needed. It is also important to prepare everything necessary in order to be able to eliminate possible complications. With such anesthesia, it is impossible to exclude the possibility of severe malfunctions in the work of the blood supply and respiration system.
Pre-prepared 2 syringes, one of which should be a volume of 5 ml, and the second - 10 ml. Also, the medical staff prepares 4 needles, 2 of which are necessary for anesthesia of the skin area where the main injection will be made. Another one is needed in order to inject an anesthetic and a catheter, and the last one is for taking anesthetic medication into a syringe.
Anesthesia
Spinal and epidural anesthesia is given to a patient who sits or lies on his side. As a rule, the latter position is used much more often. In this case, the patient should bend the back as much as possible, pull the hips to the stomach, and press the head to the chest.
The skin in the injection area is carefully treated and wrapped with sterile wipes. This is done in the same way as before the operation. At the planned puncture site, the skin is anesthetized. In addition, to facilitate the passage of the needle through the skin, it is recommended to make a small puncture with a narrow scalpel.
Specialists distinguish two methods of how access to the epidural spinal space can be made: median and paramedial. At the first, the needle is inserted in the gap between the spinal processes. After the passage of the skin and fatty tissue, it first abuts against the supraspinatus, and then into the interspinous ligament. In elderly patients, they can be calcined, which significantly complicates the introduction of the needle.
The lateral, or paramedial method provides that the injection is done in the area of the border located between the vertebrae. It is carried out from a point located 1.5 or 2 cm from the spinous processes. But this method is used when it is not possible to puncture the channel in the middle way. It is recommended in patients with obesity and with sclerotic ligaments.
Features of the "epidural"
Before the planned operations, patients with an anesthetist decide which anesthesia will be used. But many patients themselves want to understand what is epidural and epidural anesthesia. What is the difference between these methods, it will not be possible to find out. After all, these are two names of the same method of analgesia, in which the anesthetic is fed into the body gradually through a catheter.
The doctor should know the nuances of a puncture. For example, for epidural anesthesia, the needle must pass through the yellow ligament. To do this, the mandrin is removed and a syringe is attached, in which there is a solution of sodium chloride, so that an air bubble remains. As soon as the needle enters the bundle, the air bubble will look constricted. But he straightens out immediately, as the point goes into the epidural region.
The anesthetist should also be mindful of other methods of checking whether the needle is positioned correctly. The fact that everything is normal is evidenced by the absence of cerebrospinal fluid in the needle after its patency was checked by mandrin. It is also ensured that the injected small amount of saline does not flow back through the needle after the syringe is disconnected. But this is not a complete list of verification methods. The doctor must carry out a comprehensive diagnosis in order to make sure the needle is positioned correctly.
Epidural anesthesia requires the use of a catheter. Its introduction, as a rule, does not present any difficulties. After selecting and checking for patency, it is advanced through the needle into the epidural space. After this, the needle is gradually removed, and the catheter is fixed, covering the place of its exit with a bactericidal patch or a sterile dressing.
Medicines used
In order to minimize possible complications during epidural anesthesia, it is important to choose the right dose of anesthetic and correctly carry out the puncture procedure itself. For pain relief, purified solutions of anesthetics that do not contain preservatives are used.
In some cases, lidocaine is used for epidural anesthesia. But they also use drugs such as Ropivacaine, Bupivacaine. Under the supervision of a highly qualified experienced doctor and, if indicated, medications related to opiates can be added to them. It can be such medicines as "Morphine", "Promedol". But the dosage of these funds is minimal. It can not even be compared with that used in general anesthesia.
With the introduction of anesthetic into the epidural region, the latter spreads along it in various directions. It passes up, down and into the paravertebral tissue through the intervertebral side openings. At the same time, finding out what the concentration of “Dicain” should be for epidural anesthesia, it must be remembered that the anesthesia zone will depend on the amount of solution, the intensity of administration and dosage. In addition to the above, Xicain, Trimecain, and Markain can also be used. For complete anesthesia, about 25-30 ml of solutions of these anesthetics can be used. But this amount is considered the maximum.
Necessary restrictions
Despite the fact that one of the safest is considered to be epidural anesthesia, it still has contraindications. These include:
- tuberculous spondylitis;
- pustules on the back;
- traumatic shock;
- organic lesions of the central nervous system;
- complex deformities of the spine, its diseases and pathological injuries;
- intestinal obstruction;
- cardiovascular collapse arising from peritonitis;
- general serious condition of the patient;
- decompensation of the heart;
- childhood;
- Hypersensitivity to the components of the anesthetic;
- exhaustion of the body.
Possible problems
But do not forget that epidural anesthesia is not always painless and without consequences. Contraindications, complications that occur, must be clarified before going to the operating table.
It must be understood that the technique for performing such anesthesia is complex, so the qualification of a doctor is crucial. The most dangerous is the occurrence of deep collapse after spinal or epidural analgesia. Most often, this condition occurs when the dura mater is damaged. Because of this, a blockade of sympathetic innervation sets in, as a result, vascular tone decreases, and severe hypotension develops. However, this condition can also develop with proper anesthesia when a large proportion of the anesthetic is administered, counting on the anesthesia of a wide area.
But problems can develop in the postoperative period. These include:
- the beginning of an inflammatory purulent process in the canal of the spinal cord (the cause, as a rule, is a violation of the rules of antiseptics);
- headache and discomfort in the back;
- paresis of the lower extremities, pelvic organs (can develop due to damage to the roots of the spinal cord with a needle).
If patients are anesthetized using Morphine, then they should be monitored more closely. Indeed, sometimes such an epidural anesthesia leads to respiratory depression. Contraindications for using this method are not distinguished separately. But it is worth remembering that the risk of respiratory depression is increased with increasing doses of morphine.
Features of spinal anesthesia
Despite the similarities, there are significant differences between epidural and spinal anesthesia. For example, the position of the needle after a puncture of the
yellow ligament is not so important. As soon as the needle passes the dura mater, the doctor feels a sense of failure of the needle. A catheter with this type of anesthesia is not installed.
When making a puncture, it is necessary to ensure that the needle does not go too far and does not damage the roots of the spinal cord. It is possible to confirm the fact that the tip has already entered the subarachnoid space if the mandrin is removed. In this case, cerebrospinal fluid begins to be released from the needle . If it arrives intermittently or in an insufficient quantity, then it is necessary to slightly change its position by rotation. After proper installation of the needle proceed with the introduction of analgesic agents. Their dosage is less than with epidural anesthesia.