The contribution of anaesthesia & surgery to global warming - a carbon foot printing study of operating theatres of 3 different surgical specialities - A Prospective observational study

Climate change is a major global public health priority. The delivery of health-care services generates considerable greenhouse gas emissions. Operating theatres are a resource-intensive subsector of health care, with high energy demands, consumable load, and waste volumes. The carbon hotspots are single use plastics, inhalational volatile gases , intravenous drugs , air warmer and air conditioning. These activities are generally accepted as necessary for the provision of quality care, but their environmental impacts have not been examined in detail so far. In this study, we estimate the carbon footprint of 3 operating theatres of different surgical specialties where surgeries of different surgical specialties are conducted in our hospital. This study is the need of the era to obtain data and later adopt measures to reduce the greenhouse gas emissions from healthcare services.

The Greenhouse Gas Protocol defines three scopes of emissions for accounting and reporting. Scope 1 includes direct emissions from within the organisational boundary, scope 2 represents indirect emissions due to electricity consumption, and scope 3 includes all other indirect emissions occurring as a consequence of the ORs.

SCOPE – 1

Weekly volumes of volatile anaesthetic agents (isoflurane and sevoflurane) used in the respective OTs will be determined by the volume of agent used. As volatile anaesthetics undergo minimal in-vivo metabolism, the administered volume approximates the waste anaesthetic gas volume with the exception of sevoflurane for which a 5% correction will applied. Nitrous oxide and carbon dioxide used will be calculated by the total volume of gas used.  Emissions in CO2 equivalents (kg CO2e) will be calculated using Global Warming Potential (GWP100) values from the work of Sulbaek Andersen and colleagues, which is a measure of the contribution of a greenhouse gas to climate change over a 100-year time horizon. SCOPE – 2

Heating, ventilation, and air conditioning (HVAC) system thermal energy requirements will be calculated according to the specific system employed. Total electricity consumed will be calculated  by the power of all the electrical appliance used in the OR(airconditioning, cautery, lights, monitors, workstations,and suction apparatus) multiplied by the  time for which the equipment has been used.This will be measured in KWH.Greenhouse gas emissions due to electricity used will be calculated using grid intensities (emissions produced per kilowatt hr of electricity used) provided by local electrical utilities.A separate electrical meter in each OR will measure the total electricity consumption in each OR.

SCOPE – 3

Waste audits will be done in which all waste generated within the study boundary will be weighed and catalogued according to waste segregation practices on daily basis. We will measure total weight of various categories of waste produced in the individual ORs. This will be done on a weekly basis for 8 weeks. Production emissions factors will be used to account for emissions involved in the manufacture of surgical consumables, based on the material composition. Waste being sent to waste management company (Maridi eco industries) and the corresponding emission factors will be obtained from their records.

We will calculate the total CO2 emission equivalents of each OR individually in order to arrive at a conclusion as to the contributors to the carbon footprint.