Eeditorial the atmosphere. 15 They can account for 50% of surgical procedure life cycle GHG emissions, 16, 17 and 5% of a health care facility’s carbon footprint. The National Health Service in England estimated that 2.5% of its GHG emissions stem from inhaled anesthetics alone. 18 Nitrous oxide is additionally concerning due to its ozone depleting potential. 19 Scavenging systems were designed to protect occupational health against indoor exposure, yet they simply vent WAG off of hospital rooftops to the outdoor atmosphere virtually unmetabolized and unchanged. When accounting for the entire life cycle (natural resource extraction, manufacturing, transportation, usage, and disposal), the global warming potentials of inhaled anesthetics are 4 orders of magnitude greater than a monitored anesthesia care-equivalent quantity of propofol (even accounting for plastic syringes and tubing and energy to run drug delivery pumps). 20 From the climate change perspective, TIVA is preferable to inhaled anesthetics20 (especially desflurane and nitrous oxide). 16, 18, 20 What about water and soil pollution? Propofol can find its way into the environment through spillage, improper disposal into municipal solid waste bin, and also unfortunately through direct dumping into the sewage system by those facilities that elect to classify it as a controlled substance. Propofol is detectable in hospital waste water. 21 Glucuronidation is the major metabolic pathway of propofol, and it is unknown if metabolites are cleaved back into their active form after sewage disposal. Propofol is not classified as hazardous to the environment according to the Materials Safety Data Sheet, 9 or under the dated US Resource Conservation and Recovery Act of 1976 that regulates pharmaceutical waste management on the US federal level. However, European regulations utilize the persistence, bioaccumulation, and toxicity (PBT) index to rank environmental risk of drugs. Propofol is not biodegradable in water, nor under anaerobic conditions. It has high potential for bioaccumulation. It is very toxic to aquatic organisms and may cause long-term adverse effects. Propofol was scored a PBT index of 6 out of possible 9 (the worst). 22 Of note, the PBT index does not reflect concentration of drug in the environment. With the exception of controlled substances, most operating room drugs are incinerated, consistent with manufacturer recommendations for the treatment of propofol waste. Resource-poor settings tend to burn medical waste, however, in a largely uncontrolled fashion.

How does one begin to compare concern for anthropogenic GHG emissions to that of air, water, and soil pollution overall? Multi-attribute decision analysis23 can aid decision-making tradeoffs of life cycle environmental and human health impact categories. When weighing both impact and time horizons, air pollution was ranked as the number 1 concern in the short term (0–10 years). However, for the medium term (10–100 years) and long term (100+ years), global warming dominated all the impact categories (Figure).