Carbon footprint of total intravenous and inhalational anesthesia in the transcatheter aortic valve replacement procedure

Objective We aimed to quantify and compare the emissions for deep sedation with TIVA and general anesthesia with inhaled agents during the transcatheter aortic valve replacement procedure. Design a retrospective study. Setting at a tertiary hospital in Boston. Participants The anesthesia records of 604 consecutive patients who underwent the TAVR procedure between January 1, 2018 and March 31, 2022 were reviewed and analyzed. Interventions Data were examined and compared in the following two groups: general anesthesia with inhaled agents and deep sedation with TIVA. Measurements & Main Results The gases, drugs, airway management devices, and anesthesia machine electricity were collected and converted into CO2e. The carbon emissions of intravenous medications were converted with the CO2e data for anesthetic pharmaceuticals from Parvatker et al. study. For inhaled agents, inhaled anesthetics and oxygen/air flow rate were collected at 15-minute intervals and calculated using the anesthetic gases calculator provided by the Association of Anesthetists. The airway management devices were converted based on life-cycle assessments. The electricity consumed by the anesthesia machine during general anesthesia was estimated from the manufacturer's data (Drager, GE, USA) and local Energy Information Administration data. The data were analyzed in the Chi-squared test or Wilcoxon rank-sum test. There were no significant differences in the patient's demographic characteristics, such as age, gender, weight, height, and BMI. The patients who received general anesthesia with inhaled agents had statistically higher total CO2e per case than deep sedation with TIVA (16.188 vs. 1.518 kg CO2e, P < 0.001), primarily due to the inhaled agents and secondarily to airway management devices. For deep sedation with TIVA, the major contributors were intravenous medications (71.02%) and airway management devices (16.58%). A subgroup study of patients who received sevoflurane only showed the same trend with less variation. Conclusions We found that the patients who received volatile anesthesia had a higher CO2e per case. This difference remained after a subgroup analysis evaluating those patients only receiving sevoflurane and after accounting for the differences in the duration of anesthesia. Data from this study and others should be collectively considered as a health care profession aims to provide the best care possible for our patients while limiting the harm we cause to the environment.