Operating in a Climate Crisis: A State-of-the-Science Review of Life Cycle Assessment within Surgical and Anesthetic Care

Abstract

Background: Both human health and the health systems we depend on are increasingly threatened by a range of environmental crises, including climate change. Paradoxically, health care provision is a significant driver of environmental pollution, with surgical and anesthetic services among the most resource-intensive components of the health system.

Objectives: This analysis aimed to summarize the state of life cycle assessment (LCA) practice as applied to surgical and anesthetic care via review of extant literature assessing environmental impacts of related services, procedures, equipment, and pharmaceuticals.

Methods: A state-of-the-science review was undertaken following a registered protocol and a standardized, LCA-specific reporting framework. Three bibliographic databases (Scopus®, PubMed, and Embase®) and the gray literature were searched. Inclusion criteria were applied, eligible entries critically appraised, and key methodological data and results extracted.

Results: From 1,316 identified records, 44 studies were eligible for inclusion. The annual climate impact of operating surgical suites ranged between 3,200,000 and $\mathrm{5,200,000}{\mathrm{kg}\mathrm{CO}}_{2}e$. The climate impact of individual surgical procedures varied considerably, with estimates ranging from $6\text{to}\mathrm{1,007}{\mathrm{kg}\mathrm{CO}}_{2}e$. Anesthetic gases; single-use equipment; and heating, ventilation, and air conditioning system operation were the main emissions hot spots identified among operating room- and procedure-specific analyses. Single-use equipment used in surgical settings was generally more harmful than equivalent reusable items across a range of environmental parameters. Life cycle inventories have been assembled and associated climate impacts calculated for three anesthetic gases ($2-85{\mathrm{kg}\mathrm{CO}}_{2}e/\text{MAC-h}$) and 20 injectable anesthetic drugs ($0.01-3.0{\mathrm{kg}\mathrm{CO}}_{2}e/\text{gAPI}$).

Discussion: Despite the recent proliferation of surgical and anesthesiology-related LCAs, extant studies address a miniscule fraction of the numerous services, procedures, and products available today. Methodological heterogeneity, external validity, and a lack of background life cycle inventory data related to many essential surgical and anesthetic inputs are key limitations of the current evidence base. This review provides an indication of the spectrum of environmental impacts associated with surgical and anesthetic care at various scales. https://doi.org/10.1289/EHP8666.

Figure 1.

Flow diagram summarizing search results.

Figure 2.

Life cycle greenhouse gas emissions reported for 21 surgical procedures with impact contributions disaggregated by life cycle stage and considerable methodological variability among underlying references in terms of a) boundary of analysis, b) life cycle stages assessed, and c) overall completeness. Note: Direct comparison between case studies from different underlying sources is not advisable due to the heterogenous nature of the current evidence base. Substantial methodological differences exist among included references, especially with respect to system boundary, life cycle stages analyzed, and overall completeness (refer to Table 1 for details). This heterogeneity is evidenced by the highly variable per-procedure impact estimates ($6–\mathrm{1,007}{\mathrm{kg}\mathrm{CO}}_2\mathrm{e}$) and inconsistent primary hot spot patterns depicted within Figure 2. Critical appraisal scores provide an indication of study quality. Each included reference was appraised using a predetermined point-based scoring system based on existing guidelines for critical review of life cycle assessment studies. Assigned points were tallied, and a percentage score was calculated to summarize results (see Excel Table S1 for details). Numerical data underlying Figure 2 are available in Excel Table S3. The disposal category in MacNeill et al. (2017) and the reuse category in both Campion et al. (2012) and Thiel et al. (2017) include production-related impacts due to disaggregated results not being reported. For case studies in Campion et al. (2012) and Tan and Lim (2021), absolute impact values and relative contributions were made available via the corresponding author. Absolute impact values for case studies in Thiel et al. (2015) were calculated based on information in the main text, whereas relative contributions for case studies in Thiel et al. (2015, 2018) were estimated from figures. With respect to MacNeill et al. (2017), impact estimates represent an average surgical procedure performed at each case study hospital (derived by dividing the global warming potential of annual surgical suite operation at the case study hospital by its annual surgical caseload). The dashed gray line partitions right and left axes. HVAC, heating, ventilation, and air conditioning; JRH, John Radcliffe Hospital; ${\mathrm{kg}\mathrm{CO}}_2\mathrm{e}$, kilograms of carbon dioxide equivalents; UK, United Kingdom; UMMC, University of Minnesota Medical Center; USA, United States of America; VGH, Vancouver General Hospital.

Figure 3.

Comparing life cycle greenhouse gas emissions of single-use and functionally equivalent reusable equipment used in surgical settings with results reported relative to the most impactful case study within each reference and disaggregated by life cycle stage. Note: Underlying data sources vary in terms of the breadth of life cycle stages assessed (refer to Table 2 for details regarding which stages were considered within each reference). Critical appraisal scores provide an indication of study quality. Each included reference was appraised using a predetermined point-based scoring system based on existing guidelines for critical review of life cycle assessment studies. Assigned points were tallied and a percentage score was calculated to summarize results (see Excel Table S1 for further details). Numerical data underlying Figure 3 are available in Excel Table S4. “Production” includes raw material acquisition due to difficulty disaggregating these stages among included studies. For select studies, relative global warming potentials and life cycle stage contributions were estimated from figures (see Excel Table S4 for details). HG, Horton General NHS Trust, United Kingdom; JRH, John Radcliffe Hospital, United Kingdom. References: (1) McGain et al. 2010; (2) McGain et al. 2017; (3) McGain et al. 2012; (4) Allison et al. 2020; (5) Lee et al. 2021; (6) Schmutz et al. 2020; (7) Davis et al. 2018; (8) Liang 2019; (9) Eckelman et al. 2012; (10) Sherman et al. 2018; (11) Leiden et al. 2020; (12) Grimmond and Reiner 2012; (13) McPherson et al. 2019; (14) Donahue et al. 2020; (15) Ison and Miller 2000; (16) Vozzola et al. 2018; (17) Vozzola et al. 2020; (18) Carre 2008; (19) Van den Berghe and Zimmer 2011; (20) Rizan et al. 2021; (21) Ibbotson et al. 2013; (22) Mikusinska 2012.

Figure 4.

Life cycle contributions to 7 impact categories arising from the provision and use of single-use equipment used in surgical settings relative to functionally equivalent reusable equipment with results from 22 studies covering a range of different items. Note: Each data point represents an individual study’s estimate of the impact of using an item of disposable surgical equipment relative to a functionally equivalent reusable item (multiplier). Environmental impact categories represent equivalent impact. Each box represents the interquartile range. The thick horizontal line within each box represents the median estimate; whiskers (vertical lines) represent the range of estimates. Horizontal deviation of data points along each whisker prevents them from overlapping and being obscured (i.e., it does not represent a hidden variable). Numerical data underlying Figure 4 are available in Excel Table S5.