Significant oxygen imbalance

Significant disturbances in the oxygen balance, especially at the beginning of the operation, were also detected when barbiturates were used for induction anesthesia (6–10 mg / kg thiopental sodium), which is associated with direct depressant effects of these drugs on the heart and vasoplegia. After 20 — min after the start of the operation, the normal or hyperdynamic regime of blood circulation is restored, but the stroke volume of the heart remains low, the arterio-venous difference in oxygen tension increases,

metabolic acidosis develops. In our opinion, these changes reflect the secondary nociceptive activation of stress-realizing systems due to insufficient analgesia, hypodynamia of the blood circulation and lack of oxygen transport, i.e. inadequate anesthesia. Considering that barbiturates do not possess analgesic activity (moreover, by activating oxidative processes in the liver, barbiturates reduce the effectiveness of other analgesics) and are able, due to the long-lasting effect, to potentiate respiratory depression, they are contraindicated during lung resections.

To improve the adequacy of anesthesia during lung surgery, you can use sodium oxybutyrate. Being a close chemical structure analogue of the mediator of the endogenous GABA-ergic system, sodium oxybutyrate has a powerful anti-stress effect and the ability to significantly reduce the degree of damage to organs and tissues during acute hypoxia. The combined use of this drug and ketamine (Babenko VI, 1989; Usenko L.V., 1990, 1993), called intravenous programmed anesthesia, provides, according to the authors, the minimum level of operational stress. The main disadvantage of this method is the poorly managed duration of action, so it is advisable to use it only in cases when, due to the patient’s low compensatory reserves or the expected features of the operation, there is a high risk of massive blood loss,deep hypoxia or other life-threatening conditions — prolonged mechanical ventilation is planned.

However, more often a quick and full recovery of consciousness is required. This problem, without using inhalation anesthetics, can Solve using propofol. In thoracic surgery, propofol is rarely used because of its high cost, but in some cases, such as anesthesia in patients with severe cerebral atherosclerosis, when using other drugs is accompanied by prolonged residual postoperative sedation, propofol can be considered the drug of choice. Of course, this shows the minimum anesthetic dose to maintain anesthesia — 4– mg / kg * hour, which does not cause hypotension and bradycardia. At this infusion rate, propofol does not reduce the blood flow rate and oxygen delivery to the tissues, but potentiates the effects of local anesthetics and fentanyl, enhancing the overall anti-stress effect of anesthesia.

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