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Pollution with nitrous oxide using laryngeal mask or face mask
Author(s) -
Jenstrup M.,
Fruergaard K. O.,
Mortensen C. R.
Publication year - 1999
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.1999.430612.x
Subject(s) - nitrous oxide , medicine , laryngeal mask airway , anesthesia , ventilation (architecture) , airway , mechanical engineering , engineering
Background: As environmental pollution by nitrous oxide may influence the health of the personnel working in operating theatres, the incidence and magnitude of nitrous oxide (N 2 O) leakage, when using a face mask or a laryngeal mask airway (LMA) for controlled ventilation, were studied in 34 patients scheduled for elective cystoscopy. Methods: A semi‐closed gas delivery ventilation system with active scavenging was used. The N 2 O concentrations were measured every 8 s at a position 30 cm above the patient's mouth with a N 2 O gas monitor (GD 200, Simrad Optronics). Results: When using a face mask, the leakage of N 2 O resulted in a N 2 O concentration of 157 (85–332) p.p.m. (parts per million) (median concentration and 25% and 75% percentiles). With the LMA, a lower median concentration of N 2 O of 60 (28–126) p.p.m. was found ( P =0.04). With the face mask, a concentration above 100 p.p.m. was found during 51% of the exposure time compared to 24% of the time in the LMA group. Conclusion: Environmental pollution was less with the LMA than the face mask, but under the conditions of the study both modes of airway management were associated with levels of N 2 O peak concentrations in the breathing zone of anaesthetists that are deemed to be excessively high by the Danish National Institute for Occupational Safety.