Index of drugs

Introduction and maintenance of general anesthesia in combination with other anesthetics, inhalation or intravenous. In a mixture with oxygen used to achieve the analgesic effect induced by shallow anesthesia without losing consciousness (eg change of dressings, diagnostic tests, perinatal autoanalgesia).

The steel cylinder contains 7 kg or 28 kg of 100% nitrous oxide (liquefied gas, at a pressure of approx. 50 bar, at 15 ° C).

Medical gas. It has direct and indirect impact on numerous neurotransmission systems in the brain and spinal cord. Interaction with endogenous opioid receptor systems in the CNS may be one of many central mechanisms of action. Nitrous oxide causes the release of norepinephrine at the level of the posterior spinal cord, exerting some of the anti-anxiolytic effects by inhibiting the spinal cord. Although the effects of nitrous oxide are not fully explained, there is more and more reliable evidence showing its interaction with numerous pathways of neurotransmission. Nitrous oxide has a pronounced effect on perception and cognitive functions depending on the dose, which occurs from a concentration of 15% vol. In the mixture. Concentrations above 60-70% vol. they cause a lack of response to verbal commands. The preparation has dose-dependent analgesic properties that are visible at end-breath concentrations of about 20% by volume. The uptake of nitrous oxide after inhalation depends on the pressure gradient between inhaled air and the blood flowing through ventilated lung vesicles. The low solubility of the preparation in the blood and other compartments leads to a rapid leveling of the inspired and final respiratory concentration. Nitrous oxide is a fast-saturating agent. It achieves a state of balance in the patient's body much faster than other inhaled anesthetics. It is not metabolized, but gradually excreted in the alveoli and then exhaled. Due to low solubility in the blood and other tissues, both "saturation" and "rinsing" proceed quickly, relatively faster than with other inhaled anesthetics.

Hypersensitivity to nitrous oxide. Patients with symptoms of pneumothorax, air embolism or after diving (with the risk of decompression sickness); when performing pneumoencephalography when a circulatory-respiratory "by-pass" is used, operated with the help of a lung-heart or a severe head injury, when spaces filled with gas or air bubbles can be enlarged after administration of nitrous oxide. Patients after intraocular gas injections (e.g., SF₆, CF₈) due to the risk of a gas bubble expanding which may lead to blindness. Patients with symptoms of intestinal obstruction due to the risk of increased gas filling. Patients with heart failure or severe myocardial dysfunction (eg after cardiac surgery) when the weaker cardiodepressive effects of the preparation may cause further worsening of cardiac dysfunction. Patients with symptoms of chronic confusion, cognitive impairment or other symptoms that may be associated with increased intracranial pressure, because nitrous oxide can increase them. Patients with consciousness disorders or non-cooperating when nitrous oxide is used in analgesia, because of the risk of weakening of reflexes. Do not give nitrous oxide without the addition of oxygen and in a breathing mixture containing less than 30% by volume of oxygen. The time of administration in a mixture with oxygen should not exceed 12 hours.

Medical nitrous oxide should be used with caution in patients after intraocular injections only after obtaining certainty that sufficient time has passed since the injection, due to the increased risk of visual impairment and even permanent damage to the eyesight. Medical nitrous oxide at high concentrations (> 50%) can lead to loss of the laryngeal reflex and disturbance of consciousness. At concentrations above 60-70% it often causes loss of consciousness, which increases the risk of laryngeal reflex disorder.Nitrous oxide should not be used during surgical procedures performed on the airways, using laser techniques, due to the relatively high risk of explosion. After general anesthesia performed using high concentration of nitrous oxide, the risk of hypoxaemia (generalized hypoxemia) which depends not only on the composition of follicular gas, but also a weakened reaction to hypoxia, hypercapnia and decreased ventilation is a well-documented clinical problem. In this situation, supplemental oxygen saturation with monitoring of blood oxygenation with pulse oximetry is recommended until the patient shows signs of recovery. Nitrous oxide may cause an increase in pressure in the middle ear. There have been reports that prolonged exposure to trace levels of nitrous oxide causes health risks. It is currently not possible to identify a causal relationship between long-term exposure to low concentrations of nitrous oxide and overall health. However, it is not possible to completely reject the hypothesis that long-term exposure to nitrous oxide in lower concentrations may contribute to the development of cancer or other chronic diseases, reduced fertility, spontaneous abortion or congenital malformations. Today, an absolutely safe limit of long-term exposure to nitrous oxide can not be established, guaranteeing complete elimination of health risks. One should strive to maintain the lowest possible concentration of the preparation in the work environment, in accordance with applicable regulations. Operating theaters with air-conditioning and anesthetic devices, connected to extraction systems and the removal of residual gas from the respiratory system, are obvious, generally used methods to achieve an optimal, pollution-free working environment.

Do not use during pregnancy (especially in the first and second trimesters), if it is not absolutely necessary. Nitrous oxide penetrates through the placenta. It is not known to what extent gas passes into breast milk.

The following may occur: drowsiness, dizziness, nausea and post-operative vomiting. Medical nitrous oxide can easily penetrate into gas-filled body cavities, where it can increase their volume or pressure (middle ear, paranasal sinuses, flatulent intestinal loops, pneumothorax). After intraocular gas injections (e.g., SF₆, C₃F₈)_, this effect may cause damage to the eyesight due to increased pressure in the eyeball and impaired blood supply to the retina. Medical nitrous oxide can lead to megaloblastic anemia, leukopenia, thromboclenopenia and symptoms of myelopathy, described in the literature after prolonged administration of nitrous oxide. In all patients presenting symptoms of vitamin B deficiency₁₂ after the use of nitrous oxide, the possibility of using alternative anesthetic agents should be considered.

Persons using medical nitrous oxide should have adequate knowledge and training in the use of this medicinal gas. Medical nitrous oxide should be administered using appropriate equipment to ensure the passage of gases through the respiratory tract and allowing, if necessary, immediate resuscitation of the patient.Method of administration. Inhalant, using spontaneous or controlled ventilation. Nitrous oxide should be administered in a mixture with oxygen using a device designed for this purpose, supplying a mixture of nitrous oxide and medical oxygen. The device should have a monitoring and alarm system that prevents the oxygen concentration in the mixture below 21% by volume. The feeding time should not exceed 12 hours. Nitrous oxide can only be used in rooms with adequate ventilation, preventing excessive accumulation of gas in the air, in accordance with applicable regulations. Nitrous oxide is most often used in a mixture with oxygen in a volume ratio of 70% nitrous oxide and 30% oxygen to maintain anesthesia or in the proportion of 50% nitrous oxide and 50% oxygen to induce short-term analgesia. Nitrous oxide, when used alone, is usually not sufficient to induce a proper sleep state and should therefore be used in conjunction with appropriate doses of other anesthetics (inhalation or intravenous). Most with anesthetic agents, nitrous oxide has additive interactions.The potency of nitrous oxide does not depend significantly on the age of the patient, but the interaction with other anesthetics proceeds differently at different ages, thus acting relatively more strongly in elderly patients. Nitrous oxide should not be used in concentrations greater than 70 vol.%, Ensuring a safe concentration of oxygen in the mixture. In patients with impaired tissue oxygenation, a safe oxygen concentration should be maintained in the mixture. Nitrous oxide at concentrations up to 50-60% of the inhaled air volume results in analgesia or anesthesia, usually without affecting the state of consciousness and reactions to verbal commands. At these concentrations, breathing, circulation and defense reflexes are usually kept within a safe range.