The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial

Maria B. Altendorf; Martin Möckel; Liane Schenk; Antje Fischer-Rosinsky; Johann Frick; Lukas Helbig; Dirk Horenkamp-Sonntag; Dörte Huscher; Luisa Lichtenberg; Thomas Reinhold; Daniel Schindel; Britta Stier; Hanna Sydow; Yves-Noel Wu; Grit Zimmermann; Anna Slagman

doi:10.1371/journal.pone.0273115

Peer Review History

Original SubmissionJanuary 31, 2022
3 May 2022 Decision Letter - Steven Eric Wolf, Editor PONE-D-21-38548The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial.PLOS ONE Dear Dr. Altendorf, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Jun 17 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. 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I look forward to seeing the revision, which I will send back to the same referees for further comment and decision. Please understand that this is not a guarantee of future publication, as the revision must stand on its own merit. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions? The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses? The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory. Reviewer #1: Yes Reviewer #2: Partly ****** 3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable? Descriptions of methods and materials in the protocol should be reported in sufficient detail for another researcher to reproduce all experiments and analyses. The protocol should describe the appropriate controls, sample size calculations, and replication needed to ensure that the data are robust and reproducible. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Have the authors described where all data underlying the findings will be made available when the study is complete? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics. You may also provide optional suggestions and comments to authors that they might find helpful in planning their study. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The paper references a possibility of ‘over-diagnosis’ and over-exposure to radiation. When subjective information is protocolized, there is lots of variation and misdiagnosis. Guidelines are molded in the vein of being a clinician and coming to a diagnosis. The general pathway of medicine is history and physical exam then laboratory data/imaging to confirm the diagnosis. A guideline then provides treatment modalities based on the diagnosis and patient condition. The fear of creating a standardized protocol for the emergency department may lead to less clinical judgement and more reliance on following a standardized practice that does not individualize the patient. It would be good to see a protocol that could help triage the severity of the diagnosis and how not to delay consultant involvement. Severe pancreatitis was referenced in the paper, and it can be a very deadly disease. To diagnosis the diseases you need two of the following 1) Typical pain presentation 2) Elevated lipase greater than 3 times the upper limit of normal 3) imaging (CT or US) finding of pancreatic inflammation. Epigastric pain that radiates to the back may present in these patients, but is also found in ruptured aortic aneurysms (which is acutely more lethal). Would this protocol recognize this difference in severity? Early recognition of a diagnosis and resuscitation is what reduces mortality. This is done initially with a thorough history and physical. Imaging and labs only confirm diagnosis and should not be the leading factor in initial management of critical patients. Reviewer #2: the authors have embarked on a worthwhile albeit difficult journey. i am concerned that time in the ED is the primary endpoint. Time in the ed is dependent on so many variables, often not related directly to improved patient care or outcome. i would suggest the authors focus on a more patient centered outcome that is indicative of improved care, rather than a process measure. additionally there is little mention of how pain will be measured and controlled. Please describe ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review?** For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0273115.r001
Revision 1
18 May 2022 Author Response Response to review on manuscript “The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial.” (PONE-D-21-28548) We would like to thank the reviewer for his/her thorough review of our manuscript and the constructive, relevant remarks and suggestions. In the following, we will try to explain how we solved remarks indicated by the reviewer. The remarks of the reviewer are depicted first, followed by our responses in italics. Reviewer's comments: Reviewer #1: The fear of creating a standardized protocol for the emergency department may lead to less clinical judgement and more reliance on following a standardized practice that does not individualize the patient. It would be good to see a protocol that could help triage the severity of the diagnosis and how not to delay consultant involvement. We thank the reviewer for his/her critical thoughts on the tested standardized APU-process and we agree that a standardized treatment process may have its benefits and limitations. The reviewer fears that a standardized treatment process, such as the APU-process could potentially lead to less clinical judgement and more reliance on the process. We argue that treatment guidelines or standardized processes do not lead to potential delay in consultation and/or treatment. Other standardized treatment processes, such as the chest pain unit (1, 2), show very promising indications that such processes can improve processes and patient-centered outcomes are also standardized processes within the clinical setting. Moreover, physicians follow clinical guidelines for certain diagnoses, which differ between hospital(s wards). Also, as mentioned in the manuscript on page 4 & 5, line 89 ff.: “[…] no standardized care pathway for patients with atraumatic abdominal pain exists, why finding a diagnosis for those patients depends on […] each physician’s qualifications and experience (3).” As described in our manuscript (page 5, line 96 f.), the APU-process was developed by a multidisciplinary team of experts in a Delphi process (4) and therefore, seems very promising in increasing patient safety, patient satisfaction with the care provided and subsequently reducing mortality. It is important to note that there are no mandatory automatisms in the APU treatment process. The goal of the APU-process is to give guidance to physicians in a very complex field of emergency medicine. All final decisions in the treatment of atraumatic abdominal pain – even within the APU-process - are made by the physician. The APU-app guides-process can be seen as a checklist, which only supports physicians to not miss crucial aspects in treatment and diagnosis while being focused on clinical judgement. Severe pancreatitis was referenced in the paper, and it can be a very deadly disease. To diagnosis the diseases you need two of the following 1) Typical pain presentation 2) Elevated lipase greater than 3 times the upper limit of normal 3) imaging (CT or US) finding of pancreatic inflammation. Epigastric pain that radiates to the back may present in these patients, but is also found in ruptured aortic aneurysms (which is acutely more lethal). Would this protocol recognize this difference in severity? Early recognition of a diagnosis and resuscitation is what reduces mortality. This is done initially with a thorough history and physical. Imaging and labs only confirm diagnosis and should not be the leading factor in initial management of critical patients. We thank the reviewer for the attentive question whether the APU treatment process, may recognize the difference in severity, as for instance, between a ruptured aortic aneurism and a pancreatic inflammation. The APU treatment process is specifically designed to not miss crucial, time-critical diagnoses. This is ensured by various checks within the treatment process. The first step in the APU-process ensures that the attending physician recognizes signs of clinical instability, shock or sepsis based on vital parameters (like blood pressure, vigilance, heart rate) and clinical appearance. At the beginning of the APU-process, every patient receives an ECG to warrant that no ST-Elevation myocardial infarction is overlooked, which may present as upper abdominal pain. In a next and second step of the APU-process, a thorough history and physical examination, as well as pain management and abdominal lab will be executed. Then, as a result of the second step, a clinical evaluation of the patient’s condition will be done and again vital parameters will be checked. These steps have been designed to ensure that crucial diagnoses will be recognized as early as possible. As essential part of the APU-process, at many time points, physicians are reminded to watch out for “red flags” to guarantee, that they do not miss time-critical diagnoses, such as ruptured abdominal aortic aneurysm, incarcerated hernia, testicular torsion, hollow organ perforation, ileus, mesenteric ischemia, splenic rupture and myocardial infarction. Opposed to the reviewer’s remark that imaging and labs might be leading factors in the initial management of critical patients, in the APU-process these two tools are only used to confirm or reject certain diagnoses. Reviewer #2: The authors have embarked on a worthwhile albeit difficult journey. i am concerned that time in the ED is the primary endpoint. Time in the ed is dependent on so many variables, often not related directly to improved patient care or outcome. i would suggest the authors focus on a more patient centred outcome that is indicative of improved care, rather than a process measure. We thank the reviewer for this careful observation about potential concerns regarding the measurement and interpretation of the parameter time in the ED (i.e. we defined this parameter as “duration of treatment in the ED”). We agree with the reviewer that the parameter “duration of treatment in the ED” depends on various parameters, such as the triage level, chief complaint, and mode of arrival (5), and might therefore only partially illustrate improved care. However, a shortened duration of treatment can directly benefit patients regarding shorter waiting times for diagnostics and treatments. This is, because medical personal might be readily available and not engaged with other patients. However, as suggested by the reviewer, we also do focus on patient-centered outcomes (see page 5, line 98 ff.), to have a primary, aggregated aim of our study (consisting of three hypotheses): “1) Leading to a shorter duration of treatment in the ED while improving patient-reported outcomes (assessed as acute pain score or/and patient satisfaction) at discharge from the ED; or 2) Improving patient-reported outcomes (assessed as acute pain score or/and patient satisfaction) at discharge from the ED while measuring a constant duration of treatment in the ED; or 3) Leading to a shorter duration of treatment in the ED and unchanged patient-reported outcomes (assessed as acute pain score and patient satisfaction) at discharge from the ED.” Thus, we can highlight that we also measure patient-centered outcomes as main/primary endpoints. Namely: Patient-reported outcomes: patient satisfaction and acute pain score. Moreover, it is to be mentioned that by combining three different outcomes, it is possible that lower assesses pain score and higher patient satisfaction alone can be interpreted as an improvement of patient’s care, while the duration of treatment in the ED stays constant. Additionally there is little mention of how pain will be measured and controlled. Please describe With regards to the reviewer’s remark on the measurement of pain, we have now added a description of the measurement of pain with the NRS below Table 1 (page 8, line165 ff.): “NRS = Numeric rating scale; subjective measure for rating the pain on an eleven-point numeric scale from 0 (no pain at all) to 10 (worst imaginable pain).” References 1. Breuckmann F, Rassaf T, Hochadel M, Giannitsis E, Munzel T, Senges J. German chest pain unit registry: data review after the first decade of certification. Herz. 2021;46(Suppl 1):24-32. 2. Keller T, Post F, Tzikas S, Schneider A, Arnolds S, Scheiba O, et al. Improved outcome in acute coronary syndrome by establishing a chest pain unit. Clin Res Cardiol. 2010;99(3):149-55. 3. Berner L, Dormann H. Unclear abdominal pain in central emergency admissions. An algorithm. Med Klin Intensivmed Notfmed. 2013;108(1):33-40. 4. Helbig L, Stier B, Romer C, Kilian M, Slagman A, Behrens A, et al. [The abdominal pain unit as a treatment pathway : Structured care of patients with atraumatic abdominal pain in the emergency department]. Med Klin Intensivmed Notfmed. 2021. 5. Ding R, McCarthy ML, Desmond JS, Lee JS, Aronsky D, Zeger SL. Characterizing waiting room time, treatment time, and boarding time in the emergency department using quantile regression. Acad Emerg Med. 2010;17(8):813-23. Attachments Attachment Submitted filename: Response to Reviewers_final.docx https://doi.org/10.1371/journal.pone.0273115.r002
1 Jul 2022 Decision Letter - Steven Eric Wolf, Editor PONE-D-21-38548R1The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial.PLOS ONE Dear Dr. Altendorf, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Aug 15 2022 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Steven Eric Wolf, MD Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Does the manuscript provide a valid rationale for the proposed study, with clearly identified and justified research questions? The research question outlined is expected to address a valid academic problem or topic and contribute to the base of knowledge in the field. Reviewer #1: Yes Reviewer #2: Yes ******** 2. Is the protocol technically sound and planned in a manner that will lead to a meaningful outcome and allow testing the stated hypotheses? The manuscript should describe the methods in sufficient detail to prevent undisclosed flexibility in the experimental procedure or analysis pipeline, including sufficient outcome-neutral conditions (e.g. necessary controls, absence of floor or ceiling effects) to test the proposed hypotheses and a statistical power analysis where applicable. As there may be aspects of the methodology and analysis which can only be refined once the work is undertaken, authors should outline potential assumptions and explicitly describe what aspects of the proposed analyses, if any, are exploratory. Reviewer #1: Yes Reviewer #2: Yes ****** 3. Is the methodology feasible and described in sufficient detail to allow the work to be replicable? Descriptions of methods and materials in the protocol should be reported in sufficient detail for another researcher to reproduce all experiments and analyses. The protocol should describe the appropriate controls, sample size calculations, and replication needed to ensure that the data are robust and reproducible. Reviewer #1: Yes Reviewer #2: Yes ****** 4. Have the authors described where all data underlying the findings will be made available when the study is complete? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception, at the time of publication. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above and, if applicable, provide comments about issues authors must address before this protocol can be accepted for publication. You may also include additional comments for the author, including concerns about research or publication ethics. You may also provide optional suggestions and comments to authors that they might find helpful in planning their study. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: No further suggestions. Having a this protocol can be very helpful in the emergency setting. Reviewer #2: A minor comment,... The authors focussed on pain control, patient satisfaction and time in the ED. However, how will this insure that improving these outcomes also will improve standard quality of care outcomes? Please address this in the paper. ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: No ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0273115.r003
Revision 2
13 Jul 2022 Author Response We would like to thank the reviewer for his/her thorough review of our manuscript and the constructive, relevant remarks and suggestions. In the following, we will try to explain how we solved remarks indicated by the reviewer. The remarks of the reviewer are depicted first, followed by our responses in italics. Reviewer's comments: Reviewer #2: A minor comment,... The authors focussed on pain control, patient satisfaction and time in the ED. However, how will this insure that improving these outcomes also will improve standard quality of care outcomes? Please address this in the paper. We thank the reviewer for his/her critical thoughts on the outcomes of the APU study and the improvement of quality of care standards. The APU process is no standardized care process, but the project aims to implement a standardized process to quickly diagnose atraumatic abdominal pain in a symptom-based manner. Due to the very heterogeneous nature of the symptoms of abdominal pain, yet no standardized quality of care outcomes/ key indicators exist. For this reason, we aim to mirror an improvement of care with the three primary outcomes (i.e. acute pain, duration of treatment in the ED, and patient satisfaction). Moreover, we also assess quality of care / patient safety and process quality outcomes (e.g. mortality, course of treatment, ICU stay, process times) in the APU study, as mentioned in the manuscript in Table 1 ‘secondary outcomes’ (see yellow highlighted text, page 8 in revised manuscript). We hope that we adequately addressed all concerns and we would like to thank the editor and the reviewer once again for the helpful comments and suggestions. We would, however, be happy to consider further specific suggestions you might have. Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0273115.r004
3 Aug 2022 Decision Letter - Steven Eric Wolf, Editor The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial. PONE-D-21-38548R2 Dear Dr. Altendorf, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Steven Eric Wolf, MD Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0273115.r005
Formally Accepted
11 Aug 2022 Acceptance Letter - Steven Eric Wolf, Editor PONE-D-21-38548R2 The Abdominal Pain Unit (APU). Study protocol of a standardized and structured care pathway for patients with atraumatic abdominal pain in the emergency department: A stepped wedged cluster randomized controlled trial. Dear Dr. Altendorf: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Steven Eric Wolf Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0273115.r006

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