Methods and evaluation metrics for reducing material waste in the operating room: a scoping review

Abstract

Background:

Operating rooms contribute up to 70% of total hospital waste. Although multiple studies have demonstrated reduced waste through targeted interventions, few examine processes. This scoping review highlights methods of study design, outcome assessment, and sustainability practices of operating room waste reduction strategies employed by surgeons.

Methods:

Embase, PubMed, and Web of Science were screened for operating room-specific waste-reduction interventions. Waste was defined as hazardous and non-hazardous disposable material and energy consumption. Study-specific elements were tabulated by study design, evaluation metrics, strengths, limitations, and barriers to implementation in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines.

Results:

A total of 38 articles were analyzed. Among them, 74% of studies had pre- versus post-intervention designs, and 21% used quality improvement instruments. No studies used an implementation framework. The vast majority (92%) of studies measured cost as an outcome, whereas others included disposable waste by weight, hospital energy consumption, and stakeholder perspectives. The most common intervention was instrument tray optimization. Common barriers to implementation included lack of stakeholder buy-in, knowledge gaps, data capture, additional staff time, need for hospital or federal policies, and funding. Intervention sustainability was discussed in few studies (23%) and included regular waste audits, hospital policy change, and educational initiatives. Common methodologic limitations included limited outcome evaluation, narrow scope of intervention, and inability to capture indirect costs.

Conclusion:

Appraisal of quality improvement and implementation methods are critical for developing sustainable interventions for reducing operating room waste. Universal evaluation metrics and methodologies may aid in both quantifying the impact of waste reduction initiatives and understanding their implementation in clinical practice.

Introduction

The United States spends $750 billion annually on medical waste, accounting for nearly one-quarter of total health care expenditures.¹ Estimates of operating room (OR) contributions to this waste vary widely, ranging from 20% to 70%, with a quantifiable impact on greenhouse gas emissions.^2–4

Waste can be defined using multiple perspectives. Previous reviews have categorized health care system waste into 6 domains: failure of care delivery, failure of care coordination, overtreatment or low-value care, pricing failure, fraud and abuse, and administrative complexity.^1,5 Others have focused on the environmental impact, defining waste in terms of carbon footprints, energy consumption, and disposable hazardous and non-hazardous material waste.^2–4,6–8 Herein, we define waste broadly, though we focus on wastes directly impacted by surgical decisions.

The scale and pervasiveness of OR waste related to surgical procedures have led to new interest in quantifying and reducing its extent, even prompting surgical societies to publish checklists for greening the OR.⁹ Although there has been a steady increase in the number of studies describing single-center experiences with surgical team interventions, most focus on the outcomes of their intervention rather than the methods for implementing them.^{3,6–8,10,11} Characterizing the extent of the problem and acknowledging the success of these interventions are important first steps; however, there is a paucity of data evaluating methods employed by institutions to obtain more sustainable practices. Evaluation of these methods has the potential for more wide-reaching impact and generalizability.

This scoping review highlights the methods and evaluation metrics of interventionsdincluding recruitment of stakeholders, study design, outcome assessment, and sustainability practices—made in the operating room by surgeons, surgical technicians, circulators, and sterile processing teams to decrease material waste, cost, time, and energy consumption in the OR.

Methods

Screening and eligibility

Embase, PubMed, and Web of Science were searched from their inception to November 1, 2022, using terms noted in Supplementary Appendix. Studies were limited to full-text articles published in the English language. Titles and abstracts were screened to include prospective interventions related to surgery-specific supplies and techniques limited to the operating room, performed at single hospitals or within individual health systems, and with outcomes related to practical methods of cost and material waste containment. For this reason, we excluded anesthesia-related interventions, interventions without aggregate evaluations of cost or environmental assessments, interventions related to glaucoma and cataracts, and studies limited to waste audits, life-cycle assessments, or surveys alone without real-world interventions. Finally, given the existence of several systematic reviews for improving turnover time, we excluded these studies and focused on material waste.^8,12–17 This review is intended to be hypothesis-generating for the implementation of similar quality improvement and implementation work at our institution and others.

Our study was performed in accordance with the 22-item Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines shown in Supplementary Table 1. Covidence software was used for article management and quantification of inter-rater consistency (Covidence, Melbourne, Australia).

Article selection

Titles and abstracts were screened by 4 investigators (J.B., J.C., J.K., W.M.), full-text articles were further reviewed by 3 authors (J.B., J.K., W.M.), and disagreements were adjudicated by a fourth party (A.F.). All authors were involved in the summary and interpretation of included articles. Data were compiled into a single table with variables tracking surgical specialty, study type, the intervention target, intervention performed, outcome type, summary of key findings, obstacles to implementation, study limitations, and study quality. Study type was defined as either case-series, pre- and/or postintervention, or controlled intervention. Primary targets of waste-reduction intervention were categorized into asepsis and surgical textiles, hospital utilities (water and electricity), operative approach and/or technique (office- or OR-based), time reduction, new technology, and instrument trays. Studies measured waste reduction in terms of costs, the weight of supplies, time, provider and patient perspectives, hospital utilities, and surgical complications. Critical appraisal of quality was performed using a study design-specific assessment tool with a focus on the generalizability of the intervention (https://www.nhlbi.nih.gov/health-topics/study-quality-assessment-tools). In addition to complying with National Institutes of Health Study Quality Assessment Tools, studies labeled as “good” also identified barriers to implementation and sustainability at their institutions. Similarities and differences in data elements were compiled in tabular format with Microsoft Excel version 16.6 (Microsoft, Corp, Redmond, WA).

Results

A total of 198 titles and abstracts were screened. Of those, 63 full-text studies were assessed for eligibility, 36 of which were excluded for reasons listed in Figure 1, leaving 27 studies. Cohen kappa statistic ranged from 0.84 to 1.00 between reviewers for full-text articles, implying strong agreement.¹⁸ An additional 11 studies were identified based on citations within the original articles during the review process. In all, 28% of the studies were classified as good, 68% as fair, and 21% as poor, per the National Institutes of Health Study Quality Assessment Tool.

Figure 1.

Screening and exclusion criteria.

Characteristics of the studies are shown in Supplemental Table S1 and Figure 2, A to D. Most studies were limited to a single specialty (97%), with 21% of those studies limited to 1 or 2 surgeons within that service. Orthopedic (34%) and general surgery (29%) were the most represented specialties initiating waste-control intervention, followed by neurosurgery (10%), otolaryngology (8%), urology (8%), gynecology (3%), and plastic surgery (3%).

Figure 2.

(A) proportion of studies performed by surgical specialty, (B) evaluation metrics for waste reduction strategies, (C) commonly cited barriers to practice implementation, (D) commonly cited limitations to gathering evaluation metrics.

Using extracted characteristics, we created a process map of identified practices and provided recommendations divided into Team Building, Study Design, Outcome Assessments, and Sustainability Practices. These are displayed in Figure 3.

Figure 3.

Process chart of key concepts identified within the scoping review alongside recommendations for best practice methods and evaluation metrics. CFIR, Expert Recommendation for Implementing Change; ERIC, Consolidated Framework for Implementation Research.

Team building

More than half (51%) of studies specified the involvement of multi-disciplinary teams of operating personnel or the creation of an OR-waste committee. Team members included surgeons, surgical technologists, circulators, anesthesia providers, sterile processing coordinators, and hospital finance and supply teams. Two studies involved multiple departments.^19,20

Study design

Of the studies we reviewed, 74% were pre- and/or post-design, with 15% using a randomized controlled study design^21–25, and 10% of studies were observational case series.^26–29 Several studies followed well-validated designs for quality improvement, including Plan, Do, Study, Act,³⁰ Six Sigma,³¹ Standards for Quality Improvement Reporting Excellence guidelines,³² and Lean process improvement.^10,33–36 No study reported using an implementation framework. One study employed a micro-costing design in which each direct and indirect input are separately measured, valued, and tabulated.³⁷

Outcome assessment

Study outcomes included cost (92%)^10,19–51, disposable waste by weight or the number of instruments (57%),^{10,21,23,26,29,31,33,35,36,40,45–47,49–52} time (26%),^{24,25,33–35,37,41,42,45,53} hospital water and energy consumption (7%),^19–21 stakeholder perspectives (5%),^29,32 and surgical complications (5%).^22,24

Most studies measured ≥2 outcomes simultaneously, though the cost was the only measured outcome in 5 studies^{27,28,30,38,43} and the primary outcome in an additional 12.^{22,26,31–34,37,39,42,44,46,50}Cost data were derived from local hospital billing practices, national estimates, supplier estimates, previously published studies,⁵⁴ or were not stated. Data collected included the purchase price of the materials, instrument sterilization and/or processing, and instrument depreciation cost. Hourly wages of the hospital staff were included in ten studies.^{24,25,33–35,37,41,42,45,53} Four studies included transportation costs.^19–21,41 Charges and costs were separated in 1 study,⁵¹ though discussion involving cost perspective (patient-, hospital-, or societal-level) was otherwise absent. Variability in billing, hospital charges, and costs were commonly identified as a study limitation.

Twenty-one studies investigated alternative primary and co-primary measurements. Weight in kilograms of the instrument tray or disposable waste were frequently measured before and after interventions. Time was recorded as set-up, operative, sterile processing, or turnover time.^{24,25,33–35,37,41,42,45,53} Perspectives from stakeholders, including patients and health care workers, were elicited through qualitative interviews regarding acceptance of the new practice in three studies.^32,52 Hospital utilities included estimates for water and electricity bills. No correlation was found between OR waste reduction interventions and rates of surgical complications.

Intervention

The most common intervention was instrument tray optimization (67%).^{10,21,29–37,40–51,53,55} Overall, studies describing instrument tray optimization were limited to 4 or fewer surgeons within a single specialty, but the studies followed a similar methodology of identifying a surgeon champion, incorporating multi-disciplinary buy-in, and estimating outcomes. Instruments were removed based on several principles, either through consensus among surgeons and surgical technologists,^{10,21,29,31,32,34,36,40–46,50,51} objective instrument use counts through a rules-based process (ie, <20% usage),^{30,32,33,35,41,49,55} through heat mapping,⁴⁸ score cards,⁴⁷ or proprietary technology, and outside consulting services.^34,45 Time was recorded in terms of set up time,^{10,31,32,34,35,40,41,43,45,46,53,55} sterilization time,^21,33,44 and OR time,^10,21,31,41 which was often intended to capture instances in which the circulating nurse needed to leave the room to procure additional instruments.

Other primary targets for intervention included waste separation (13%),^{19,20,38,39,56} aseptic technique and surgical textiles (10%),^23–25,52 surgical technique (8%),^22,26,28 and a new device (3%).²⁷ Aseptic technique and textiles referred to the efficient use of surgical gowns, gloves, and drapes,^23,24,52 along with hand washing and patient preparation.²⁵ Waste separation involves educating and facilitating the appropriate disposal of surgical waste, whether landfill, recycling center, autoclave, reprocessing facility, or incinerator. For surgical technique, 2 studies focused on transferring small hand procedures from the OR to the clinic.^26,28

Sustainability

Sustainability practices were discussed in 23% of studies. These included plans for expansion to other services and/or departments,^10,30,38,39 hospital policy changes with the elimination of certain instruments and regular audits,^34,41 dedicated operative sustainability committees with regularly scheduled meetings,^20,31,46 and surgical educational fellowships in sustainability.¹⁹ All studies that measured cost demonstrated cost savings with their proposed interventions.

Study Barriers and Limitations

Several common barriers to implementation were identified. Stakeholder buy-in and attitudes were the most commonly identified theme, with 39% of studies discussing the need for physician recruitment and continued support from physicians, nurses, staff, and administration.^{19,20,31–34,36,38,41,44,46,48,49,51,53,56} Other barriers mentioned included concern for additional operative time, for example requiring the circulating nurse to find an instrument not included in the reduced tray or increased processing time of reusable materials.^{10,30,34,36,39,53,56} As a barrier, knowledge gaps included a lack of understanding of the cost associated with instruments or waste disposal, environmental impact, or life cycle of operative materials.^34,38,46,51 Several studies cited a need for more hierarchical interventions in the form of hospital or governmental policies before widespread implementation.^25,34 Often, the lack of a “champion” impeded progress.^20,33,36,53 Some studies expressed concern for patient safety with reduced instrument trays or office-based hand surgeries, though no correlation was found between waste reduction and complication rates.^26,29,44 Others cited a need for improved data capture before wide-scale implementation efforts.^10,31,46,48 Finally, monetary concerns were cited as a barrier in 4 studies, including the cost of transition to reusable materials, replacement costs for new instruments, and funding for staff time and training; however, all studies noted their interventions resulted in cost savings.^19,39,46,49 Finally 37% of studies did not discuss barriers.

Common methodologic limitations included analysis restricted to a single outcome (25%), studies restricted to ≤2 surgeons (30%), cost estimates derived from published studies rather than local data (21%), inability to capture indirect costs (84%), and no reference to post-project sustainability (77%).

Discussion

There have been multiple reviews of greening measures and their relative efficacy, though few of these have examined methods in detail.^3,7,12,14,57 Given the strong evidence that these measures can reduce waste and lower costs without patient harm, this scoping review highlights the strategies used to implement and assess these changes. We found that most studies were of pre versus postintervention design, were limited to a single surgical service, focused on strategies for instrument tray reduction, used cost as the primary metric, and identified common barriers to implementation. These studies highlight avenues for universal methods and evaluation metrics, which we propose below and in Figure 3.

First, team building requires diverse stakeholder buy-in. In addition to those discussed above, collaboration with local environmental science departments may aid in capturing the full lifecycle cost of surgical waste.⁵⁸ Furthermore, buy-in is strongly related to internal motivation and institutional culture: knowledge of, and concern for, excessive waste can come from environmental, economic, and workflow perspectives, and reduction efforts must adapt the message to the local context. It is also valuable to have interventions invited, or “pulled,” by leaders, as they are more successful than those “pushed” onto the system by the quality improvement or investigator team.⁵⁹ Finally, although these efforts are multidisciplinary and require large teams, a single “champion” is often necessary to drive change.⁶⁰

Second, regarding study design, this scoping review touches on the distinct but similar fields of quality improvement and implementation science. Both are ultimately directed toward improvement in patient care; however, quality improvement generally involves a continuous cycle of testing and measuring outcomes related to a specific intervention, and implementation science focuses on how teams adopt and sustain known best practices.^6,61–64 A systematic review of validated quality improvement methodologies in surgery identified 34 studies targeting reductions in complications, temporal delays, antibiotic usage, and pain prescriptions, though only 2 studies from the 1990s measured cost.¹³ More recent studies found that although 88% of quality improvement initiatives demonstrated improvements, they were hampered by imprecise data collection, poor communication across hospital departments, the Hawthorne effect, and unreliable estimates of costs.^12,65 Assessment of material waste was not included in these reviews.

Conversely, there are very few published studies deploying implementation science frameworks in perioperative care, with most focusing on Enhanced Recovery After Surgery protocols.^64–67 Implementation outcomes of interest include acceptability, adoption, feasibility, costs, and sustainability, among others.^66,68 Two commonly used frameworks, the Expert Recommendation for Implementing Change and the Consolidated Framework for Implementation Research, facilitate the design and evaluation of implementation efforts by targeting specific domains.^69,70 The Expert Recommendation for Implementing Change offers discrete implementation strategies separated into 9 domains, whereas the Consolidated Framework for Implementation Research divides its components into 5. Implementation science employs mixed methods approaches, incorporating qualitative focus groups, formal interviews, and a quantitative collection of relevant outcomes to address each domain. These studies often employ a hybrid approach, where implementation and quality improvement are measured side-by-side. None of the studies reviewed herein acknowledged using an implementation framework, though they did incorporate elements of engaging stakeholder support, provider training, and demonstrating an understanding of institutional contexts. They are not alone in this regard, as we could not identify any study in health care generally employing an implementation framework for waste reduction. Implementation science remains a relatively novel method in the field of health care, and we encourage further incorporation of these frameworks into future efforts.

Third, what gets measured gets improved, and data capture is critical to demonstrating the success or failure of an intervention. We recommend collecting a breadth of qualitative and quantitative variables listed in Figure 3. Cost data are difficult to collect as there are several ways to measure them, ranging from general expenditure-based costing to more precise measurements of time-driven activity-based costing and micro-costing.^71,72 These methods must be determined before starting an intervention. Similarly, time can be subdivided by task, and investigators should clearly define the intervention stages and alternative scenarios. Although we did not incorporate turnover time into this review, multiple other studies have used task mapping to identify delays and improve flowthrough with strategies such as early intravenous line placement, separate rooms for induction, and machine learning strategies to predict postanesthesia care unit length of stay.^12,13,16,17

Finally, few studies discussed the sustainability of their practice or plans for scaling to other surgeons or departments. This can present a significant problem in an era of frequent staff turnover and disruptive supply chains. Sustainability practices, whether through the creation of sustainability committees, education programs, biannual waste audits, or changes to institutional policy and purchasing practices, are required to ensure that best practices are maintained.

Although these steps may be challenging to implement in their entirety, this review demonstrates ways to make waste-reduction efforts approachable, scalable, and sustainable. Ultimately, efforts to reduce waste would benefit from universal methods and evaluation metrics to best quantify the impact and provide proof of value.

Study limitations

We have identified several best practices for minimizing OR waste, though our search criteria may not have captured all relevant articles, especially considering the 11 articles added upon review of bibliographies. Nevertheless, we captured a broad section of the literature for OR waste reduction initiatives. Second, initiatives aimed at reducing turnover time were outside the scope of this review but have a definite impact on OR waste. Third, although we followed a modified version of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines for critical appraisal, our methods are ultimately subjective, consistent with the qualitative nature of many included studies. As expected for a scoping review, heterogeneity in study design precluded the performance of a meta-analysis of results, instead systematically mapping what is known and unknown on the topic. Finally, this study does not touch on the foundational contributions made by our colleagues in anesthesia, who have been driving both OR and hospital sustainability practices. There are several excellent reviews on judicious medication selection, reducing and recycling material waste, scavenging of anesthetic gas, and responsible sourcing of materials.^73–75 We continue to work closely with all involved parties through our university’s Sustainability Committee.

Conclusions

This review highlights methods used by surgeons to reduce waste in the OR. We found several common targets, including instrument trays, material waste separation, and surgical textiles. Outcomes were measured in cost, time, and volume of material waste. Barriers to implementation included the need for multidisciplinary buy-in, increased time requirements, knowledge gaps, and the need for leadership and funding. Studies were limited by imprecise measurements of cost and material life-cycle analysis as well as a lack of methods for sustainability and project expansion. We recommend using quality improvement and implementation science strategies to develop reproducible and sustainable interventions.

Supplementary Material

Supplementary materials associated with this article can be found in the online version, at [https://doi.org/10.1016/j.surg.2023.04.051].