Nitrous oxide - a means for inhalation anesthesia.
Release form and composition
Nitrous oxide is a compressed, colorless gas.
Available in metal bottles.
The active substance is dinitrogen oxide.
Indications for use
Nitrous oxide is applied:
- For inhalation anesthesia in combination with narcotic analgesics or other means of anesthesia;
- For general anesthesia in cases where deep anesthesia and muscle relaxation are not required (used in general surgery, operative gynecology, in dentistry, as well as for anesthesia of childbirth);
- For the relief of pain due to myocardial infarction, acute coronary insufficiency or acute pancreatitis;
- For the prevention of traumatic shock;
- To enhance the analgesic effect and enhance the anesthetic effect of other anesthetics, including for therapeutic anesthetic anesthesia in the postoperative period;
- For anesthesia during medical manipulations and procedures that require disabling the patient’s consciousness.
The use of nitrous oxide is contraindicated:
- With hypoxia;
- With alcohol intoxication and chronic alcoholism;
- Breastfeeding women;
- With increased sensitivity to the remedy;
- In diseases of the nervous system.
It is possible to use the product, but with extreme caution:
- With intracranial tumors;
- Patients with head injuries;
- Patients with increased intracranial pressure, including a history.
Nitrous oxide can be used during pregnancy only for the purpose of labor pain relief, only briefly and in low concentrations (2-3 breaths), since long-term use may adversely affect the condition of the child.
Dosing and Administration
Nitrous oxide is a gas used inhalation with the help of special equipment intended for gas anesthesia. It is used with oxygen or other means for inhalation anesthesia.
The most commonly used mixture containing 20-30% oxygen and 70-80% oxide dinitrogen.
For induction anesthesia (when a certain depth of anesthesia is needed quickly), a mixture containing about 75% of the dinitrogen oxide is used. 40-50% is usually enough to maintain general anesthesia. If necessary, a more powerful narcotic can be added to such a composition (for example, halothane, ether or barbiturates). To avoid diffuse hypoxia, oxygen is continued to be supplied for at least 4 minutes after stopping the supply of Nitrous Oxide.
For the purpose of pain relief during medical procedures, 25-50% mixture with oxygen can be applied.
Depending on its severity, a mixture with a dinitrogen oxide concentration of from 40 to 75% can be assigned to relieve pain syndrome.
When labor anesthesia, 40-70% mixture with oxygen is used. In this case, the method of intermittent autoanalgesia is applied: as soon as the precursors of the contraction appear, the woman begins to inhale anesthesia and finishes inhaling at the height of the contraction or closer to its end.
The dose of nitrous oxide during anesthesia for children is selected individually. The concentration of dinitrogen oxide should not exceed 70%, respectively, the oxygen concentration is not less than 30%. For the prevention of hypoxia, the supply of oxygen is continued for another 5 minutes after stopping the inhalation of anesthesia.
To prevent nausea and vomiting, reduce the patient's emotional arousal, and also to enhance the effect of Nitrous Oxide, sometimes patients are given premedication - intravenous administration of a 0.5% solution of diazepam (1-2 ml), a solution of 0.25% droperidol (2-3 ml ).
During the introduction of the patient into anesthesia there is a risk of developing supraventricular arrhythmias, bradycardia, circulatory failure.
After recovery from anesthesia in some cases, arise:
- Nausea and / or vomiting;
- Diffuse hypoxia;
- Post-anxiety delirium (manifested by nervousness, motor agitation, anxiety, confusion, agitation and / or hallucinations).
When using Nitrous Oxide for more than 2 consecutive days, there may be:
- Leukopenia, pancytopenia;
- Respiratory depression;
- Hyperthermal crisis;
- Postoperative chills.
An overdose of dinitrogen oxide is manifested by a pronounced decrease in blood pressure or hyperthermic crisis, delirium, acute hypoxia, respiratory depression, bradycardia, arrhythmia, and circulatory failure.
Bradycardia is usually eliminated by administering 0.3-0.6 mg of atropine. In case of arrhythmia, correction of the content of gases in the blood is shown. If respiratory depression occurs, a decrease in the anesthetic dose, the provision of airway and sometimes artificial ventilation of the lungs is necessary. In case of circulatory failure and hypotension, plasma or plasma substituting agent is administered, the depth of anesthesia is reduced, and in some cases it may be necessary to stop general anesthesia. In case of a hyperthermic crisis, inhalation is immediately stopped, oxygen supply is increased, then an antipyretic is administered, water-salt balance and metabolic acidosis are adjusted. For the prevention of recurrence of the crisis for 1-3 days after surgery, the patient is prescribed dantrolene (inside or intravenously at a dose of 4-8 mg / kg, divided into 4 applications).
With the development of delirium after the patient leaves the anesthesia, a small dose of a narcotic analgesic is administered.
Nitrous oxide is used exclusively in medical institutions.
During the patient's stay under anesthesia, the heart rate, heart rate and blood pressure are carefully monitored, and the body temperature, gas exchange and respiration are monitored.
The effect of nitrous oxide is enhanced by antihistamines, antipsychotics and anxiolytics, as well as narcotic analgesics and inhalation anesthesia agents.
Nitrous oxide enhances the effect of anticoagulants, antihypertensive drugs (especially diuretics, ganglioblokatora, diazoxide and chlorpromazine), as well as drugs that depress the respiratory center and central nervous system.
Simultaneous use of amiodarone increases the risk of arterial hypotension and bradycardia not relieved by atropine. Xanthines can cause arrhythmias.
Fentanyl and its derivatives enhance the effect of Nitrous Oxide on the cardiovascular system, in particular, on the minute volume of blood circulation and heart rate.
To the group of general anesthetics are means:
- Sodium oxybutyrate;
- Sodium oxybate.
Terms and conditions of storage
Nitrous oxide is not sold in the pharmacy chain, it is supplied only at the request of medical institutions. Gas cylinders are stored at temperatures up to 25 ºС. The shelf life of the product is 5 years.