Indoor air contamination with N2O

Indoor air contamination with N2O

In today's guide, we look at the issue of room air contamination during nitrous oxide sedation. In addition to the efficient effect of nitrous oxide, safe use of the sedative must be ensured for the patient and also for the medical (auxiliary) staff.

As nitrous oxide sedation is an open procedure, the patient is not exposed to any Nitrous oxide unavoidably into the room air. But to what extent does this represent a burden for medical staff?

Technical rules for the application of Nitrous oxide on the job

Technical rules for the use of nitrous oxide in the workplace

The nitrous oxide emissions from the patient's mouth and through the leakage of the nasal mask are seen as particularly relevant to exposure. Exhalation and speaking by the patient through the mouth significantly increases the amount of nitrous oxide in the room air. The attending physician and also the assisting staff are unavoidably exposed to this room air contamination during the treatment of the patient. Therefore, possible negative health effects due to exposure to nitrous oxide must be considered in any case and avoided if possible.

For this reason, the TRGS (Technical Rules for Hazardous Substances), as well as the current occupational safety rules, provide for a limit value for the nitrous oxide concentration in the ambient air at the workplace. For the resorptive hazardous substance of category II, it is 180 mg/m3 (equivalent to 100 ppm), based on 8 hours. Up to four short-term exceedances (each max. 15 min) per shift with values up to 360 mg/m3 (exceedance factor 2) are permitted.

These values are laid down in the Technical Rules for Hazardous Substances TRGS 900 of the Federal Institute for Occupational Safety and Health. These are legally binding and must be observed. Nitrous oxide is also classified and labelled as a chemical-physical hazardous substance in the EU Regulation on the Globally Harmonised System (GHS). If the above-mentioned occupational exposure limits (OELs) are complied with, it can be assumed, based on current knowledge, that no negative health effects will occur.

From the point of view of occupational health and safety, it must be taken into account that nitrous oxide in this type of Sedation is inevitably released via breathing masks.

It enters the breathing zone of the patient through leaks at the interface between the fresh gas supply and the patient and through the patient himself. For this reason, proper handling of nitrous oxide sedation systems and uncontrolled leakage of nitrous oxide must be ensured.

Measures to reduce indoor air contamination

Even when all possible occupational safety measures are exhausted, it is not possible to achieve absolute freedom from emissions. Apart from leakages at the interface between the gas supply and the person being treated, the potential exhalation of nitrous oxide through the mouth into the breathing zone of the staff is mainly responsible for this. The resulting room air contamination is almost unavoidable. Against this background, proper use of the technical equipment seems all the more important.

On the one hand, it must be regularly checked for leaks, thus preventing uncontrolled escape of nitrous oxide, including at the gas containers themselves. In addition, room air contamination can be reduced by using the innovative Baldus disposable double-nose mask. The optimal fit of the masks and the high-quality material not only provide a comfortable feeling for the patient, but also prevent uncontrolled escape of nitrous oxide through leakage at the mask.

Single-nose masks are considered outdated, are no longer technically adequate and must be replaced by double-nose masks. Room air contamination increases immensely with this type of mask and can be greatly improved by switching to a modern hose system. In addition, sufficient efficiency of the extraction system must be ensured. When using a Baldus scavenger system, the required negative pressure can be adjusted to the mask size and the exhalation of the person being treated. The negative pressure enables the exhaled nitrous oxide to be transported away from the breathing zone of the person being treated. It takes place either via a special transport system for anaesthetic gases or a modified stool suction.

Recommendations and protective measures for dental laughing gas sedation

  • Staff trained and certified in the use of laughing gas sedation?
  • Before use, check the system for correct assembly and functionality
  • Leakage test (visual inspection) on the relevant components
  • Use of nitrous oxide extraction
  • Room ventilation
  • Use of well-fitting Baldus disposable double-nose mask
  • Nitrous oxide proportion according to the needs of the patient
  • Note the size of the breathing bag
  • Keep conversation with the patient to a minimum
  • Pay attention to the patient's nasal breathing

Different mask systems

Different mask systems

Nitrous oxide systems with single and double nasal masks are available on the market. Studies by the Employer's Liability Insurance Association explicitly recommend the use of double-nose masks. In one study, the mean exposure with double-nose masks was approx. 30 % below the mean exposure with single-nose masks. This result corresponds to the findings published in the literature. Single-nose masks exceeded the permissible short-term value in 31 of 47 measured values (66 %), whereas double-nose masks exceeded the permissible short-term value in 13 of 22 measured values (59 %). Double-nose masks reduced nitrous oxide concentrations as expected, but not sufficiently below the limit. Discover now the Baldus mask systems.

Ensure patient compliance

The medical literature points out that patients must have a certain basic compliance, i.e. in this case a willingness to cooperate with nitrous oxide sedation and the doctor's recommendations. Compliance is to be assessed subjectively by the doctor and cannot be influenced technically. In order not to endanger the treating staff, to cooperate optimally in the treatment and not to negatively influence the process of the laughing gas sedation, the patient should feel a positive and open-minded attitude towards the laughing gas sedation and accept the instructions of the doctor and the cooperating staff.

Baldus recommendation

Essentially, the following general conditions must be fulfilled in order to use sedation below
of the legal limit values:

  1. Before the start of each treatment, check the mask for tightness and optimal fit.
  2. The persons to be treated should show the necessary adherence during the treatment. The
    Medical staff are required to pay careful attention to the fact that the persons being treated are
    move as little as possible and do not speak.
  3. The suction (Baldus scavenger system) is to be connected to the chair suction and adjusted to the optimal
    Adjust the negative pressure.

If the above-mentioned framework conditions are observed, we know that the strict workplace limits can be met or undercut with a high degree of certainty. A risk to the personnel due to trace concentrations of N2O According to today's
effectively prevent the state of knowledge.


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