From the Guidelines
Nitrous oxide is a commonly used anesthetic gas for sedation and analgesia. For adult patients, a typical starting dose is 30-50% nitrous oxide mixed with oxygen, titrated to effect, as supported by studies such as 1 and 2. The maximum recommended concentration is 70% nitrous oxide. For pediatric patients, a starting dose of 20-30% nitrous oxide is often used, as recommended by guidelines such as 3 and 4.
Key Considerations
- The gas should be administered via a scavenging system to minimize exposure to healthcare workers.
- Monitoring of oxygen saturation and vital signs is essential during administration, as emphasized by 5 and 6.
- Nitrous oxide is contraindicated in patients with pneumothorax, bowel obstruction, or increased intracranial pressure.
- It should be used with caution in patients with vitamin B12 deficiency or those taking certain medications, such as methotrexate or bleomycin.
Administration and Safety
- The typical duration of administration is 30 minutes to several hours, depending on the procedure and patient response.
- Studies have shown that nitrous oxide has a rapid onset and recovery, with an excellent safety profile, as reported by 1 and 2.
- However, potential side effects include hypoxia, hypertension, arrhythmias, nausea, vomiting, and headache, as noted by 1 and 2.
Clinical Applications
- Nitrous oxide can be used for various procedures, including colonoscopy, as demonstrated by studies such as 1 and 2.
- It is also useful for anxiolysis and pain control in pediatric patients, as discussed by 5 and 6.
From the Research
Role of Nitrous Oxide in Anesthesia
- Nitrous oxide (N2O) is a commonly used inhalational anesthetic agent in pediatric patients, providing good quality analgesia, decreased awareness, and accelerated induction and recovery from anesthesia 7.
- N2O has been shown to be effective for minor surgical procedures such as venipuncture, intravenous cannula placement, lumbar puncture, and minor dermatologic procedures, with a more rapid onset and shorter recovery time compared to other agents 8.
- The use of N2O has been questioned due to its potential adverse systemic, hematological, immune, and neurologic effects, but recent data have negated concerns over increased cardiovascular complications and mortality 7.
Physiological Effects of Nitrous Oxide
- N2O can alter intracerebral dynamics, cerebral blood flow, and intracranial pressure, particularly in patients with altered intracranial compliance 8.
- It can cause a dose-related depression of ventilatory function and control of upper airway patency, as well as a mild direct depressant effect on myocardial function 8.
- N2O may also inactivate the enzyme methionine synthetase, potentially affecting neurologic and hematologic function 8.
Safety and Efficacy of Nitrous Oxide
- N2O is considered a safe and effective method for achieving analgesia and sedation during minor, painful procedures in pediatric patients, with serious adverse events occurring in less than 0.5% of cases 9.
- Minor adverse events, such as dysphoria and vomiting, are more common, occurring in 4-8% of patients 9.
- The use of N2O is generally well-tolerated, but its utility may be limited in severely painful procedures, and combination with other agents may be necessary 8.