MORPHOLOGICAL CHANGES IN THE SMALL INTESTINE AFTER LOCAL ANESTHESIA IN EXPERIMENTAL MECHANICAL TRAUMA

Аннотация

This literature review presents the pharmacokinetic properties of local anesthetics responsible for the effectiveness of regional anesthesia methods, and also examines in detail the gastrointestinal effects of local anesthetics, allowing a broader look at the possibilities of their use in intensive care. Keywords: local anesthetics, gastrointestinal tract, local anesthetics. Аннотация В данном литературном обзоре изложены фармакокинетические свойства местных анестетиков, ответственных за эффективность методов регионарной анестезии, а также подробно рассмотрены желудочно-кишечные эффекты местных анестетиков, позволяющие более широко посмотреть на возможности их применения в интенсивной терапии. Ключевые слова: местные анестетики, желудочно-кишечный тракт, местные анестетики Relevance. Today, several modern types of analgesics and drugs have been developed. It is very useful for performing invasive procedures in surgery, dentistry and traumatology. The methods used in anesthesia and the effects of drugs on all organs have been studied by scientists for many years, but the morphological changes of anesthetics in the intestine have not been fully studied. The effect of local anesthetics on the rate of gastrointestinal paresis resolution as a manifestation of systemic anti-inflammatory action. The pathophysiology of postoperative intestinal paresis is complex. Factors such as surgical stress response, sympathetic hyperactivity, intestinal manipulations, visceral pain stimulate nociceptive afferent and sympathetic efferent nerve fibers. The stress response is accompanied by increased release of endogenous opioids, which inhibit the propulsive activity of the gastrointestinal tract. The use of opioid analgesics in the postoperative period also prevents the restoration of normal gastrointestinal function due to the effect on opiate receptors of the small intestine. Increased formation of inflammatory mediators during tissue damage sensitizes peripheral nociceptors. Persistent activation of C-fibers contributes to central sensitization with expansion of receptor fields. Morphine and other opioid analgesics suppress the release of acetylcholine from 75 МЕЖДУНАРОДНАЯ КОНФЕРЕНЦИЯ АКАДЕМИЧЕСКИХ НАУК the mesenteric plexus, which increases the tone of intestinal smooth muscles and reduces the propulsive activity of the intestinal tract. Intravenous infusion of MA, in particular lidocaine, seems very promising in light of the recent trends of reducing the length of patients' stay in the clinic, as well as increasing their satisfaction with the quality of treatment in general. The severity of postoperative paresis depends on: a) the intensity of the inflammatory process, b) increased sympathetic tone, c) the total dose of prescribed opioids. It is believed that the positive effect of MA on this process mainly depends on their systemic anti-inflammatory effect [8], although one cannot ignore the decrease in the doses of opioid analgesics noted in a number of studies [9, 10]. Intravenous administration of lidocaine can also have a certain effect on sympathetic tone, although limited by its low concentration in plasma. Harvey K. et al. (2019) believe that systemic administration of MA has both peripheral and central mechanisms of action [11]. At the peripheral level, MA limit the synthesis of inflammatory mediators, at the central level, they modulate neuronal responses at the level of the posterior horns of the spinal cord. MA have a direct stimulating effect on intestinal smooth muscles, which is possibly the result of blockade of inhibitory reflexes originating from the mesenteric plexus. In addition, spinal reflexes, as well as peripheral reflexes conducted through the prevertebral ganglia, have an inhibitory effect on gastrointestinal motility. Intravenous infusion of lidocaine can limit the duration of postoperative intestinal paresis by reducing postoperative irritation of the peritoneum, as well as inhibition of inhibitory gastrointestinal reflexes. Some authors believe that amide MA, in addition to a powerful anti- inflammatory effect, are also capable of significantly reducing sympathetic activity, which, in particular, is manifested by a decrease in the concentration of catecholamines in the urine for 48 hours after surgery [12, 13]. Some studies have shown that intravenous prolonged administration of lidocaine allows not only to shorten the period of inpatient treatment, but also reduces the intensity of postoperative pain syndrome [9, 14]. The reduction in the length of stay in the hospital is mainly due to faster recovery of gastrointestinal functions. Three independent studies [8, 9, 14] showed that patients (open and endoscopic colorectal surgery, as well as radical prostatectomy) who underwent intravenous lidocaine infusion were discharged from the clinic 24 hours earlier than the control group, which is associated with faster recovery of gas passage and independent stool. The end of the infusion time varied f