IV. Table of contents of teaching

Local anesthesia – it is the reverse loss of pain sensitiveness of tissues in the limited areas of body, caused by the action of different chemical substances, physical or mechanical factors on nervous fibers or segments of nerves.

Local anesthetics are regularly used in clinical practice. Today 55% – 60% of surgical operations are executed under local anesthesia. Above all other situations, it is used in ambulatory-policlinic work during anaesthetizing of small operations. This is related to simplicity of its use, relative safety, absence of necessity of sophisticated equipment and special preparation of medical personnel. The main methods of anaesthetizing were attributed to O.V. Vishnevsky and his followers.

Indications: in all cases of contra-indications for general anesthesia; cardiovascular and pulmonary insufficiency, at the persons of declining and geriatric years, in ambulatory-policlinic practice.

Contra-indications: children younger than 12 – 14 years, elderly patients and those sensitive to anesthetics, violation of psyche, presence of inflammatory processes in tissues, outright refusal of the patient.

In the present day in surgical practice the following local anesthetics are used:

• Novocain in concentrations from 0,25 – 0,5% to 10 – 20%,

• Lidokaine in concentrations 0,25 – 0,5%, 1 – 2 – 10%,

• Trimekain in concentrations 0,25 – 1 – 2%,

• Dikain in concentrations from 0,25 – 0,5% to 1 – 2%,

• Sovkain in concentrations 0,5 – 1% and others.

The mechanism of action of local anesthetics is acquired by blocking the transmission of excitation to nervous fibers, as a result there is anaesthetizing of the area that is innervated by that nerve and its ending. They cause a polarizing block, retaining membranes in the polarized state.

Classification.

The following types of local anesthesia are distinguished: superficial infiltration and regional. Regional anesthesia is further subdivided into: a) exploratory, b) spinal epidural, in) intravascular (intra-arterial and intravenous), g) intraosseus, d) anesthesia of nervous interlacements, e) trunk anesthesia and others.

Most widespread in clinical practice: superficial (terminal), infiltration and different types of regional anesthesia. We seldom use intraosseus, intravascular methods and anesthesia by cooling.

Superficial anesthesia – type of anesthesia which is achieved by irrigation or lubrication of mucus membranes by 1% – by a 2% solution of Dikain, 5% solution of Ksikain, 0,25 – 2% Anestezine and some other anesthetics, which are able to be absorbed through mucous membranes. Such method is used in ophthalmology, otolaryngology, surgery, endoscopic researches, before intubation of trachea and others like that.

Infiltrative anesthesia. Preparation for operation under infiltration anesthesia is the same as general anesthesia. Incredibly important is the preparation of the psyche of the patient. During the operation the role of "psychical narcotization" can executed by one of the students. Anesthesia is begun with infiltration of the expected place of dissection of skin by creating a so-called "lemon crust". For this purpose local anesthetic is injected intracutaneously through a thin needle. Layer infiltration of tissues is further conducted according to the proper depth and width, depending on the type of operation.

For infiltration anesthesia a 0,25–0,5% solution of Trimecain or Lidocain is mainly used. A possible dose for one surgery for an adult using 0,5% solutions of Novocain – 500 ml, 0,25% - 750 ml., and on it that solution is outpoured during the operation during the incision of tissues, the dose can multiply up to 1000 – 1500 ml. In one hour of an operation it is permissible to enter 2,0 g of Novocain; the dosage of Trimecain suitable for one case must not exceed 20 mg/kg, and Lidocain – 15 mg/kg.

Infiltration anesthesia according to O.V. Vishnevsky’s method joins the positive qualities of infiltrative and exploratory anesthesia. The method is based on the anatomic features of structure of fascial formations-sheaths A solution of 0,25% Novocain is injected into the sheaths with a 5-10 ml syringe; the anesthetic spreads in them and penetrates to the nerves and their ending. O.V. Vishnevsky named this method "tight creeping infiltrate". It follows to underline the value and prevalence of this method in clinical practice.

Spinal anesthesia belongs to the group of regional anesthesia. It is used for anaesthetizing of a definite part of body or topographical area. In this type of anaesthetizing a 5% solution of Novocain, a 0,5-1% solution of Sovkane or Ksilokaine (up to 70 mg.) is injected into the subarachnoidal space by the puncture of hard spinal-tunic by a special needle named the Bira needle. Anesthetic quickly contacts with the sensory roots and anesthesia of all part of body below the place of puncture is produced. Most often the place for spinal puncture is between ІІІ–ІV or ІІ –ІІІ lumbar vertebrae. Duration of such anesthesia lasts from 1,5 to 3 hours. Introduction of an anesthetic into the subarachnoidal space higher than the level of the ХІІ pectoral vertebra can result in violation of activity of respiratory and vasomotor centers. At present, spinal anesthesia is used mainly in the case of operations on organs situated lower than the diaphragm and the lower extremities.

Complications of spinal anesthesia can show up in the decrease of bloody pressure, disorders of breathing and in the paralysis of the medullary vasomotor center. For the prophylaxis of complications it is recommend to simultaneously, with the anesthetic, to inject a 1,0–2,0% solution of caffeine, or 1,0 – a 5,0% solution of ephedrine.

If the patient stops breathing or there is a violation of cardiac activity it necessary to immediately intubate the trachea and employ artificial ventilation and/or perform a closed massage of heart. With a considerable fall of arterial pressure, blood transfusion and blood substitutes are used.

Epidural anesthesia – is a type of exploratory anesthesia. It is used in cases of operation on the lower departments of the abdominal region, urology, proctologic operations and operations on lower extremities. It is the method of choice in elderly patients those of geriatric age; in patients with cardiovascular pathology and those with functional violations of the kidney, liver, and in obstetric practice. Epidural anesthesia is widely applied for the removal of postoperative pain, rapid renewal of peristalsis of bowels after an operation, in complex medical treatment of peritonitis, impassability of bowels, sharp pancreatitis and others cases like this.

Epidural anesthesia is executed with the patient in a sitting position, or lying on a side with his legs drawn against the abdomen. An anesthetic effect is achieved due to the blockade of roots of the spinal cord when the anesthetic enters in the peridural space located between two sheets of hard brain-tunic which has the appearance of a narrow crack, filled with fatty tissue, lymphatic vessels, and vein interlacement. The front and back roots of the spinal nerves pass through this space, and since it does not communicate with either the brain or spinal brain, the anesthetic does not effect them.

Punction of the epidural space can be executed on any part of the spine, depending on the level of anesthesia. First the skin is anaesthetized. A thin needle without a syringe is entered between vertebrae, expressly on a back middle line on a depth 2–2,5 cm before the contacting with a yellow roll (resistance is felt). Then to the needle a syringe is tacked with isotonic solution of chloride of sodium and bubble of air in it. Subsequent advancement of needle is controlled by the change of form of bubble of air at pressure on the piston of syringe. As soon as the needle gets in epidural space the resistance diminishes and the solution is easily outpoured into the tissue. If the anesthesiologist disconnects the syringe and needle, from its opening a liquid must not flow out. Then 2–3 ml. is injected to move away the hard brain-tunic and prevent its perforation. In a needle a thin catheter through which anesthetic is injected during the operation and in the post operative period. Initially a test-dose of anesthetic (1/3 from set) and after 3–5 min. – the rest of the dose. More frequent a 2% solution of Lidocain (in a dose 5–10 mg/kg.), 2% solution of Trimekaine are used (5 mg/kg.). Anesthesia begins in 15–30 minutes and continues for 1,5–2 hour.

Complications meet rarely. Hypotension, disorders of breathing, nausea, vomiting, cramps, head pain is possible, traumatic radiculitis in the punction area.

Other types of the modern anaesthetizing:

Neuoleptanalgesia (NLA) – one of types of the combined anaesthetizing. An anesthetic effect is achieved by combination of neuroleptic (Droperidol) and narcotic analgetic (Fentanil). A result shows up the decline of psychical and motive activity, state of indifference, by thermoanesthesia while retaining consciousness. It is used in combination with local anesthesia or inhalation anesthesia and it stabilizes work of heart and vessels during implementation of traumatic stages of operation.

Electro-medicinal anesthesia (electro-anesthesia, Lemon, 1902) one of types of the common anaesthetizing by means the action of electric current of definite frequency, tension and force on a cerebrum.

It is used in combination with anesthetics, antispasmolitics and sedative medications. Anaesthetizing is characterized by the shutdown of consciousness, stability of hemodynamics, by dilation of pupils. For conducting elektroanalgesia there are the following instruments: "Elektronarkon-1-1", "Lenar-1-1", "Electro-sleep-4Т", "EA-30-1-30-1". This method is used in obstetrics, in heavy toxemia, burns, in patients with an allergy, poisoning, diseases of the cardiovascular system.

Complication of electro-anesthesia: possible burns in the places of appendix of electrodes, cramps, head pain, hypertension.

Acupunctural analgesia – anaesthetizing by means acupunctures. For this purpose special needles from stainless steel with a diameter of about 0,4 is used. The needle is placed either into the "classic points" or the so-called meridians in the distance from the place of implementation of operative actions, or under a skin on both sides from the operating field. The decline of pain sensitiveness (hypoanalgesia) is achieved thanks to the irritation of the nervous ending. However in this method of complete anesthesia does not occur. Acupunctural analgesia is used as a component of combined anaesthetizing in the post operative period, for the removal of pain syndrome, reduction of the use of narcotic analgesics, and others like that. Possibilities of wide application of such method for anaesthetizing of operations are studied.