USE LESS, a Comparative Cohort Study of Climate Change Impact From Orthopedic Surgery

Climate change impact

Mean carbon dioxide equivalent (CO₂e) emissions expressed in kgs per functional unit defined as one performed surgery. All single-use materials consumed during an operation will be registrered, categorized, weighted and converted into CO₂e using exsisting LCAs or databases. Energy comsuption for machines in the OR, heating and ventilation of the OR and for sterilization of reusable materials will be converted into CO2e using existing databases. Water usage for sterilization will be calculated and converted into CO₂e using databases.

Readmission

Readmission to hospital within 90 days of the procedure. Admission cause must be related the surgical proceure, e.g. surgical site infection demanding iv antibiotics.

Combustible waste

Weight of waste generated after each surgery measured in kgs. Staff in the OR will collect all waste in one or two plastic bags and weigh them using a hade scale INF model KBE-BHC025-11 D hand scale. The weight is recorded in kilograms in the study protocol in the OR.

Costs

Difference in costs for material and staff. Costs for all singe-use items will be collected from the purcahse department and recorded in SEK intitiallt before conversion to € at the time or data analysis. Costs for reuseable items will be collected and a value calculated for each usage will be obtained. Energy usage will be calculated in kWh and water consumtion will be measured in cubic meters and a converted into SEK/€ using price lists obtained from the Hospital. A mean value for costs for each staff category (e.g. doctor, nurse) per hour will be obtained from the hospital and mutiplied by the OR time.

Infections

Surgical site infection following the procedure. Patients charts will be examined after 90 days and if any antibiotics covering skin pathogens (e.g. Flukloxacillin, Clindamycin) has been perscribed by any caregiver during the period it will be assumed to be a positive value.

Hotspot analysis

Identification of major contributors to emissions by categorizing all activity data that contributes to emissions and calculated as a percentage of the primary endpoint; CO₂e expressed i kgs per fuctional unit (one surgery). Categories will include but not be restricted to; single-use items, manufacturing and usage of reusable items, egergy comsuption by machines in the OR, energy comsuption for heating and ventilation and energy and water consumption for sterilization of resuable items.