Workplace NO and NO2 during combined treatment of infants with nasal CPAP and NO.
OBJECTIVE
To determine the workplace concentrations of NO and NO(2) in and around a paediatric incubator during inhaled NO (iNO) treatment and during an accidental emptying of NO cylinders into room air.


METHODS
We simulated iNO-nasal CPAP treatment in order to assess the impact on the occupational environment. Furthermore, two full NO cylinders for therapy, 1,000 ppm, 20 litres, 150 bar and 400 ppm, 10 litres, 150 bar, were emptied as rapidly as possible into an intensive care unit (ICU) room.


METHODS
University hospital ICU.


RESULTS
To correctly gauge the contribution from iNO-CPAP we constructed a system measuring breathing zone and room ventilation inlet-outlet values during a 10-ppm iNO treatment of a simulated infant. Maximal breathing zone values were 17.9 +/- 7.0 (mean +/- 95% CI) ppb for NO and 25.2 +/- 4.8 ppb for NO(2). If room inlet values were subtracted, the contributions to breathing zone values emanating from iNO-CPAP were 14.8 +/- 4.6 ppb for NO and 14.6 +/- 4.6 ppb for NO(2). At the ventilation outlet the maximal contributions were 4.2 +/- 2.9 ppb NO and 9.6 +/- 4.3 ppb NO(2). During rapid total release of a gas cylinder in the ICU room, simulating an accident, we found transient NO levels comparable to the high therapeutic dosing range, but only low NO(2) levels.


CONCLUSIONS
Neither 8-h time-weighted average (TWA) nor 15 min short-term exposure limits (STEL) were exceeded during normal operation or during a simulated accident. The contribution of nitrogen oxides from treatment to workplace air were minor compared to those from ambient air.
Lindwall
Robert
R
Karolinska Institutet, Department of Clinical Sciences, Division of Anaesthesia and Intensive Care, Danderyd University Hospital, Stockholm, Sweden. robert.lindwall@ds.se
Svensson
Mats E
ME
Frostell
Claes G
CG
Eksborg
Staffan
S
Gustafsson
Lars E
LE
D000280:Administration, Inhalation; D000395:Air Pollutants, Occupational / Q000032:analysis*; D001993:Bronchodilator Agents / Q000032:analysis* / Q000627:therapeutic use; D045422:Continuous Positive Airway Pressure; D006801:Humans; D007231:Infant, Newborn; D007363:Intensive Care Units, Neonatal; D009569:Nitric Oxide / Q000032:analysis / Q000627:therapeutic use; D009585:Nitrogen Dioxide / Q000032:analysis*; D016273:Occupational Exposure; D010083:Oxidants, Photochemical / Q000032:analysis*; D012127:Respiratory Distress Syndrome, Newborn / Q000188:drug therapy / Q000628:therapy
D000395:Air Pollutants, Occupational; D001993:Bronchodilator Agents; D010083:Oxidants, Photochemical; D009569:Nitric Oxide; D009585:Nitrogen Dioxide