Nitrous Oxide Biohazards PDF 2020

Nitrous Oxide Biohazards for Health Personnel Chronic Exposure ▪ 1967 Vaisman report reproductive problems in both male and female anesthesiologists in Russia ▪ 1980 study/survey of dentists and dental assistants, long term exposure could be associated with an increase in general health and reproduc...

Nitrous Oxide Biohazards for Health Personnel Chronic Exposure ▪ 1967 Vaisman report reproductive problems in both male and female anesthesiologists in Russia ▪ 1980 study/survey of dentists and dental assistants, long term exposure could be associated with an increase in general health and reproductive problems Chronic Exposure ▪ 1977 NIOSH reviewed scavenging potential of nitrous oxide: OR 25 ppm, Dental setting 50 ppm. Chronic Exposure ▪ Goal is to minimize trace gases Nitrous Oxide ▪ Oxides the cobalt form of cobalamin (Vit B12) ▪ Prevents the B12 acting as a coenzyme for methionine synthase ▪ Methionine synthase involved with DNA production and subsequent cellular reproduction Nitrous Oxide ▪ Concern with fetal development ▪ Pregnant rats at 60% for 24hrs resulted in miscarriage and other fetal abnormalities ▪ Significant demand for folic acid during organogenesis (first trimester), postponement of nitrous oxide sedation is recommended ▪ Staff: important to know levels, use scavenger systems, make decision if needs to avoid office setting in the first trimester Deoxyuridine Suppression Test ▪ Accurately determines the 1st signs of biologic effect associated with chronic exposure ▪ Shows early signs of inactivation of methionine synthase: Nunn et al found that no alterations of this enzyme occurred in anesthetists exposed to between 150 and 400 ppm Sweeney ▪ First signs of biologic effect with the deoxyuridine suppression test was at a chronic exposure level of 1800 ppm ▪ Suppression of methionine synthase activity has been shown to occur in some humans within 1 to 2 hrs following administration of 70% nitrous oxide ▪ B12 deficient individuals, nutritional disorder, malabsorption issues may be at risk ▪ Elderly, alcoholics, modified diets, GI problems/surgery, and those with pernicious anemia ▪ Need medical consultation Neurologic ▪ Disorders associated with chronic nitrous oxide exposure appear as myeloneuropathy ▪ B12 deficiency ▪ Nitrous oxide abusers ▪ Sensory and proprioception impairment: may be permanent, but are usually temporary with slow recovery Scavenging Trace Nitrous Oxide Gas Scavenging Nitrous Oxide ▪ Articles published in the 1990’s ▪ Minimize the trace amounts of gas before, during and after use ▪ It identifies all methods for the comprehensive removal of trace nitrous oxide Scavenging Mask System ▪ Standard on all product lines in the US ▪ Practicing without it is practicing below the standard of care ▪ Expired air through the nose and a vacuum suctioned into the central suction to the outside atmosphere ▪ Evacuation flow rate: 45L/min ▪ Improved mask design Detection and Monitoring of N2O in Ambient Air ▪ Infrared (IR) Spectrophotometry ▪ Uses electromagnetic energy to detect ▪ Can detect levels lower than 1 ppm ▪ Can detect levels of gas immediately in the ambient air ▪ These can be rented, or company hired (check with the hospital) ▪ May want to start with baseline, then have periodic evaluation Detection and Monitoring of N2O in Ambient Air ▪ Time-Weighted Average (TWA) Dosimetry ▪ Determines the amount of exposure of an individual over time ▪ Worn for a set time period, then return to company for analysis ▪ Material in the badge absorbs and is read by IR spectrophotometer in ppm ▪ Inexpensive Detection and Monitoring of N2O in Ambient Air ▪ Hand-Held Monitoring Device ▪ Small portable gas monitor that gives a continuous measure of nitrous oxide in the ambient air ▪ Has both ppm and TWA measurement capabilities ▪ Can store 1000 readings ▪ Needs to be recharged after 8 hrs ▪ Has audible alarms ▪ Can detect leaks around equipment Recommendation and Preventative Measures for Minimizing Waste Nitrous Oxide Gas Sources of Leakage From the Patient: ▪ Patient talking ▪ Poor fitting mask ▪ Displacement of the mask during patient ▪ ▪ ▪ ▪ movement Stuck flutter valve Mouth breathing Presence of facial hair preventing a tight seal Use rubber dam and/or high speed evacuation suction during operative procedures Sources of Leakage Other Than the Patient: ▪ Any place of connection on the equipment: includes the manifold and wall-mounted connections and any hoses associated with each ▪ Conducting tubing and reservoir bag due to breakdown/wear ▪ Soap and water method to determine leaks, or using IR spectrophotometry ▪ Door seals and any place where reentry of contaminated air can occur is a potential problem Vacuum System ▪ 45 L/min ▪ Adjustment of this rate is critical for effective sedation ▪ Important to periodically check during the sedation Adequate Ventilation Under investigation Best Practices ▪ Monitor the Environment for Nitrous Oxide Concentrations ▪ Baseline values, and monitoring HCW ▪ Prevent Leakage From the Delivery System ▪ Proper maintenance and periodic inspections ▪ Control Waste Nitrous Oxide ▪ Evacuation system ▪ Assess the Adequacy of Room Ventilation and Air Exchange