We write with questions about Schouten and colleagues’ paper, “Operating room performance optimization metrics: a systematic review” [1]. The paper seems not to meet fully the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. Such research includes all studies meeting prespecified eligibility criteria, thereby reducing bias. The review by Schouten probably missed many scientific studies on the topic, potentially affecting conclusions. Our concern is based on the authors’ published search strings. We focus on PubMed because that database is available publicly, without charge. However, our critique applies to the Scopus and Web of Science databases, following source-specific changes to the search field tags.

The authors’ Fig. 1 gives their protocol, which included the string:

(1) “operating room” optimization.

The authors do not specify the date of their search. With their paper received 22 June 2022, we searched through 2021. We limited to English-language publications to match the authors’ criteria:

(2) “operating room” optimization English[LA] 1960:2021[DP].

We executed the author’s [1] search (2) on 7 February 2023, which returned 1792 articles. The authors’ criteria for inclusion were that the study had to “discuss ways to optimize the OR as a system” and involve healthcare or medicine. In their Table 3, they list four aspects: (1) Patient safety; (2) Quality of care; (3) Cost-effectiveness; (4) Well-being [of] healthcare professionals. In their Fig. 1, they state that 110 articles met eligibility criteria. However, the authors do not include a flow diagram or supplemental content listing reasons why 1682 papers were excluded. For example, included in the 1792 articles from search (2) was a paper published in 2020 titled “Perioperative COVID-19 defense: an evidence-based approach for optimization of infection control and operating room management” [2]. The abstract includes two changes in operating room workflow, overlapping with the authors’ paper’s Fig. 1 [1]. The category is to improve “quality of care & patient safety,” quoting from the authors’ Table 3 [1]. We ask that the authors explain why this paper [2] was excluded and, more precisely, what were the criteria they applied to select the 110 papers they included? As a second example, included in the 1792 articles from the authors’ [1] search (2) was a paper published in 2002 titled “Statistical power analysis to estimate how many months of data are required to identify operating room staffing solutions to reduce labor costs and increase productivity” [3]. The category seems absent from the authors’ Table 3 [1], that being statistical properties of a hospital’s own data. Both the anesthesia department and nurses work jointly, as a system, for performing and implementing the calculations. The abstract of the missing article [3] includes both the words “optimization” and “optimal.” Therefore, we ask the authors why this paper was not included, again as part of our broader question of how precisely did the authors select 110 articles from PubMed’s 1792 articles?

Our other questions are about tenses and British (Australian) versus North American English. After performing the authors’ [1] search (2) in PubMed, we selected Advanced Search and Details to see what was obtained. Because the authors’ search (2) included “operating room” in quotation marks, PubMed used the singular form. That could have introduced bias, because the restriction to the singular excluded papers with titles or abstracts where only the plural term, “operating rooms,” was used. Adding the PubMed wildcard increased the articles returned from 1792 to 2050:

(3) “operating room*” optimization English[LA] 1960:2021[DP].

We continued by adding some synonyms to the term “operating room” used in different countries and clinical specialties:

(4) (“operating room*” OR “surgical suite*” OR “operating theatre*” OR “surgical theatre*”) optimization English[LA] 1960:2021[DP].

That search (4) returned 2193 articles. Again, the authors’ [1] restriction of their search to “operating room” could have created bias by excluding studies from countries where alternative terms are in common use (e.g., “theatre” in the United Kingdom). Finally, the authors [1] relied on PubMed to broaden the word “optimization” by not including quotation marks. Using Advanced Search Details, PubMed broadened using North American English, not British. The following search returned 2307 articles:

(5) (“operating room*” OR “surgical suite*” OR “operating theatre*” OR “surgical theatre*”) (optimization OR optimisation) English[LA] 1960:2021[DP].

Our question to the authors was whether there was a scientific rationale for their systematic review of operating room optimization to be limited to singular “operating room” and to exclude British English? We also ask whether the restriction could have created bias in their systematic review and affected the results and conclusions of their study?