Download PDFPDF

Operating room relay strategy for turnover time improvement: a quality improvement project
Compose Response

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Author Information
First or given name, e.g. 'Peter'.
Your last, or family, name, e.g. 'MacMoody'.
Your email address, e.g.
Your role and/or occupation, e.g. 'Orthopedic Surgeon'.
Your organization or institution (if applicable), e.g. 'Royal Free Hospital'.
Statement of Competing Interests


  • A rapid response is a moderated but not peer reviewed online response to a published article in a BMJ journal; it will not receive a DOI and will not be indexed unless it is also republished as a Letter, Correspondence or as other content. Find out more about rapid responses.
  • We intend to post all responses which are approved by the Editor, within 14 days (BMJ Journals) or 24 hours (The BMJ), however timeframes cannot be guaranteed. Responses must comply with our requirements and should contribute substantially to the topic, but it is at our absolute discretion whether we publish a response, and we reserve the right to edit or remove responses before and after publication and also republish some or all in other BMJ publications, including third party local editions in other countries and languages
  • Our requirements are stated in our rapid response terms and conditions and must be read. These include ensuring that: i) you do not include any illustrative content including tables and graphs, ii) you do not include any information that includes specifics about any patients,iii) you do not include any original data, unless it has already been published in a peer reviewed journal and you have included a reference, iv) your response is lawful, not defamatory, original and accurate, v) you declare any competing interests, vi) you understand that your name and other personal details set out in our rapid response terms and conditions will be published with any responses we publish and vii) you understand that once a response is published, we may continue to publish your response and/or edit or remove it in the future.
  • By submitting this rapid response you are agreeing to our terms and conditions for rapid responses and understand that your personal data will be processed in accordance with those terms and our privacy notice.
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.

Vertical Tabs

Other responses

Jump to comment:

  • Published on:
    Turnover times on the same day are not statistically independent

    Riveros Perez et al. analysed 636 turnover times from a surgical suite with 16 theatres before and after intervention, a dedicated nurse anaesthetist for each of four theatres [1]. Their “overall” statistical analysis, reported in their abstract, seems to treat all turnovers as statistically independent events (i.e., treated the sample size as 16 x # analysed days). That probably was incorrect because the 636 turnover times likely were correlated among theatres on the same day [2]. The authors’ Wilcoxon-Mann-Whitney overall P-value (0.0121) likely is an underestimate of the correct result [2].

    To understand, consider that the authors’ intervention was one extra nurse anaesthetist for four theatres. If there were more than one turnover among the four theatres simultaneously, the nurse anaesthetist’s efforts would be diluted. That is precisely what happens routinely (e.g., for housekeeping staff [3,4]). Earlier, we showed validity and reliability of choosing the optimal number of shared personnel (e.g., nurse anaesthetist) by analysing those simultaneous turnovers [3].

    The authors state in their paper that the turnover times were skewed. Analysis methods tested by Monte-Carlo simulation for accurate P-values and confidence intervals are to take the mean of the turnovers among the 16 theatres, for each day, although the median could be used [2]. There then is one number per day as a summary measure. By central limit theorem (and in practice [2,5]), those means g...

    Show More
    Conflict of Interest:
    None declared.