Share this article on:

Readability, Content, and Quality Assessment of Web-Based Patient Education Materials Addressing Neuraxial Labor Analgesia

Patel, Samir K. MD*; Gordon, Elisa J. PhD, MPH; Wong, Cynthia A. MD*; Grobman, William A. MD, MBA; Goucher, Haley MD*; Toledo, Paloma MD, MPH*†

doi: 10.1213/ANE.0000000000000888
Obstetric Anesthesiology: Research Report

BACKGROUND: Studies in a variety of disciplines have shown that the readability of Web-based patient education materials is above that of the sixth grade reading level recommended by the U.S. Department of Health and Human Services. The aim of this study was to evaluate the readability, content, and quality of English- and Spanish-language patient education materials addressing neuraxial labor analgesia.

METHODS: The websites of 122 U.S. academic medical centers with obstetric anesthesia divisions were searched for English- and Spanish-language patient education materials. Readability of English-language patient education materials was assessed with 3 validated indices: Flesch-Kincaid Grade Level, Simple Measure of Gobbledygook, and Gunning Frequency of Gobbledygook. Readability of Spanish-language patient education materials was assessed using the Spanish Lexile Measure. A 1-sample t test was used to evaluate the mean readability level against the recommended sixth grade reading level. A scoring matrix was developed to evaluate the content of patient education materials. Website quality was assessed using the Patient Education Materials Assessment Tool for Print.

RESULTS: We identified 72 English-language and 29 Spanish-language patient education materials. The mean readability levels of all patient education materials were higher than the recommended sixth grade reading level using all indices (Flesch-Kincaid Grade Level: 9.1 ± 1.9, Simple Measure of Gobbledygook: 8.6 ± 1.4, Gunning Frequency of Gobbledygook: 11.8 ± 2.1; P < 0.001 for all). All patient education materials discussed the benefits of neuraxial analgesia. However, only 14% (upper 95% confidence interval: 24%) discussed contraindications to neuraxial anesthesia. Postdural puncture headache and hypotension were the most commonly addressed complications (92%). All other complications were addressed by less than half of patient education materials. Patient Education Materials Assessment Tool for Print scores were consistent with poor website understandability (median score, 64%; interquartile range, 64–73).

CONCLUSIONS: The mean readability of Web-based patient education materials addressing neuraxial labor analgesia was above the recommended sixth grade reading level. Although most patient education materials explained the benefits of neuraxial analgesia, possible contraindications and complications were not consistently presented. The content, readability, and quality of patient education materials are poor and should be improved to help patients make more informed decisions about analgesic options during labor and delivery.

Published ahead of print August 6, 2015

From the *Department of Anesthesiology, Center for Healthcare Studies, and Department of Obstetrics and Gynecology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois.

Accepted for publication April 29, 2015.

Published ahead of print August 6, 2015

Funding: Dr. Toledo was supported by a grant from the Robert Wood Johnson Foundation, Harold Amos Medical Faculty Development program (award 69779). The content is solely the responsibility of the authors and does not necessarily represent the official views of the Robert Wood Johnson Foundation.

The authors declare no conflicts of interest.

This report was previously presented, in part, at the Society for Obstetric Anesthesia and Perinatology Annual Meeting, Toronto, Canada, May 2014.

Reprints will not be available from the authors.

Address correspondence to Samir K. Patel, MD, Department of Anesthesiology, Northwestern University Feinberg School of Medicine, 251 East Huron St., F5-704, Chicago, IL 60611. Address e-mail to samir.patel@northwestern.edu.

Neuraxial analgesia is the most effective method for relieving pain during labor.1 The use of this method during labor has been increasing in the United States.2 Despite this trend, many parturients forego neuraxial analgesia because of a lack of knowledge about their analgesic options or because of apprehensions about the risks of the procedure.3 Factors such as low socioeconomic and educational levels have been associated with decreased use of neuraxial analgesia during labor.4 Among the ethnic groups studied, Hispanics seem to be the least likely to use neuraxial labor analgesia.3,5,6 Such decisions may be driven by inordinate fear of rare complications such as paralysis and chronic back pain.7,8

The Internet is playing an increasing role in patient education. In 2011, the Pew Internet and American Life Project reported that 78% of adults in the United States have Internet access and 83% of Internet users search for health information online.a However, many studies show that much of the health information available online, including materials from hospital and university-affiliated websites, is written at a level that is above the average reading comprehension level for adults.9–11

The 2003 National Assessment of Adult Literacy defines health literacy as “the degree to which individuals have the capacity to obtain, process, and understand basic health information and services needed to make appropriate health decisions.”12 According to recommendations by the U.S. Department of Health and Human Services (DHHS) and the National Institutes of Health (NIH), the readability of patient education materials should be less than or equal to the sixth grade level.b–d Little is known about the readability of educational materials on the Internet that address neuraxial labor analgesia.

The purpose of this study was to evaluate the readability, content, and quality of patient education materials that address neuraxial labor analgesia on the websites of U.S. academic medical centers with obstetric anesthesia divisions. We hypothesized that the readability of these Web-based patient education materials would be higher than the recommended sixth grade reading level. Our secondary aim was to examine the presence, readability, content, and quality of Spanish-language patient education materials on these websites.

Back to Top | Article Outline

METHODS

We obtained the names of U.S. academic obstetric anesthesia divisions from a list used for a previous study (n = 122).13 Using the Google search engine, we searched for Web-based patient education materials using the names of the institutions along with the key words: obstetric anesthesia, labor pain relief, labor analgesia, labor epidural, spinal anesthesia, and health information. Patient education materials were excluded from readability, content, and quality analysis if they were written in languages other than English or Spanish, they contained fewer than 30 sentences, or information was presented only in graphic, pictorial, video, or tabular formats. Links to patient education materials from external nonacademic websites were also excluded.

Text from patient education materials was copied and saved as separate Microsoft Word and plain text documents for analysis. Text unrelated to the educational topic (e.g., author information, website URLs, addresses, hyperlinks, disclaimers, copyright information, and webpage navigation) was deleted to avoid influencing readability scores. Follow-up editing of the text was then performed as recommended,14 involving removal of colons and semicolons from sentences to avoid causing an overestimation of reading difficulty. The use of images or videos designed to facilitate the patient’s understanding of the material was noted, but the content of these visual aids was not analyzed.

The readability of English-language patient education materials was measured using 3 validated indices that produce scores reflecting the grade level required to comprehend a given text15: (1) Flesch-Kincaid Grade Level (FKGL),e which is directly proportional to the mean number of words per sentence and mean number of syllables per word14; (2) Simple Measure of Gobbledygook (SMOG),f which is directly proportional to the total number of polysyllabic words and inversely proportional to the total number of sentences16; and (3) Gunning Frequency of Gobbledygook (Gunning FOG),g which is directly proportional to the average number of words per sentence, as well as to the ratio of polysyllabic words to total number of words.17 Readability scores for English-language patient education materials were generated using the website www.readability-score.com, and scores for the Spanish-language patient education materials were generated using the online Spanish Lexile Analyzer available from MetaMetrics.h

A scoring matrix was developed by the authors to evaluate the content of patient education materials. The following items were evaluated: description of epidural and spinal analgesia, explanation of how the procedures are performed, effect of the neuraxial analgesia on labor progress, risks and benefits of the procedure, contraindications, and alternative analgesic modalities. Specific risks and adverse effects that were assessed included postdural puncture headache, hypotension, dizziness, nausea/vomiting, back pain/soreness, bleeding, infection, pruritus (itching), shivering, analgesia failure, epidural fever, drug toxicity, nerve damage, and paralysis. In total, 22 items were evaluated, and 1 point was assigned for each item addressed.

Website quality was evaluated using the Patient Education Materials Assessment Tool for Print (PEMAT-P), a validated instrument for evaluating the quality of patient education materials.18 The PEMAT-P evaluates 2 components: understandability and actionability. Understandability evaluates several domains, including content of the materials, word choice and style, the use of numbers, organization, layout and design, and the use of visual aids. Actionability evaluates the ability to identify actions that should be taken based on the information presented. Individual understandability and actionability items are scored 0 (disagree), 1 (agree), or N/A (not applicable). The points for each component (understandability and actionability) are summed and then divided by the total number of scored items for each component. This value is multiplied by 100; thus, the scores can range from 0% to 100%. A score <70% is considered to reflect material that is poorly understandable or poorly actionable.18 The PEMAT-P scoring tool and a link to the user’s guide are included in Appendix 1.

An example of patient education material with good actionability might include the following instructions: “You will need to remain very still during epidural placement. You will position yourself with your back arched outwards, and you will curve around your baby.” Including a visual aid showing the proper positioning would further increase the actionability of this material. Conversely, patient education material addressing the same topic but with poor actionability might include the following statement without visual aids: “Body positioning is important for successful epidural placement.”

Two of the investigators evaluated website content and quality. Intercoder reliability for website content was α = 95% and for website quality was α = 98%. Differences were reviewed and resolved through consensus with a third reviewer.

Descriptive statistics were used to describe the sample and website content. A one-sample t test was used to evaluate the mean readability level of English-language patient education materials compared with the recommended U.S. DHHS and NIH standard (sixth grade reading level). As 24 of 72 institutions had identical patient education materials from the same online health encyclopedia, a post hoc analysis was performed to evaluate readability scores excluding these materials. Probability distributions for counseling content items were obtained using the binomial distribution. P < 0.05 was considered significant. All data were analyzed using Stata SE (version 12, College Station, TX).

Back to Top | Article Outline

RESULTS

Seventy-two of the 122 (59%) U.S. academic medical centers with obstetric anesthesia divisions had Web-based English-language patient education materials that met the inclusion criteria. In addition, 29 of the academic medical centers offered patients Spanish-language patient education materials.

Fifty-one patient education materials (71%) contained instructional images. Of these, most had only 1 image (n = 28), 9 included 6 images, and 1 included 12 images. Four patient education materials contained educational videos. One institution’s website did not have any written materials but provided 2 images and a video.

Back to Top | Article Outline

Readability

The mean readability was above the sixth grade reading level, regardless of whether FKGL, SMOG, or Gunning FOG (Table 1) was used for assessment. Fewer than 15% of websites had materials that scored at or below the sixth grade reading level using any scale (FKGL: 11 patient education materials; SMOG: 10 patient education materials; Gunning FOG: 0 patient education materials). After excluding the data from the 24 institutions that used the same online health encyclopedia, the mean readability of English-language patient education materials remained above the sixth grade level using all 3 indices (data not shown). For the purpose of comparison, the readability of this article’s introduction section was assessed using all 3 indices, and these scores are reported in the legend of Table 1.

Table 1

Table 1

All Spanish-language patient education materials were direct translations of the English-language versions available on the same websites. The mean Spanish Lexile score was 1088 with a SD of 67. According to the score conversion table provided by the Lexile website,i this score translates to a seventh to tenth grade reading level. Two of the 29 Spanish-language patient education materials (7%) were written at or below the sixth grade reading level.

Back to Top | Article Outline

Content

Web-based patient education materials were analyzed for the inclusion of 22 different content items (Table 2). All 72 English-language patient education materials included information describing epidural analgesia, how it is performed, and the benefits of the procedure.

Table 2

Table 2

The most commonly addressed complications were postdural puncture headache and hypotension (92% of patient education materials). All other risks or complications were addressed by fewer than half of patient education materials. The least addressed complication was possible epidural analgesia failure (8%). Fourteen percentage of patient education materials discussed contraindications to epidural analgesia, whereas 68% discussed alternative analgesic modalities. The mean number of items addressed was 11, and the maximum was 16.

Back to Top | Article Outline

Quality

The PEMAT-P scores were below the 70% threshold for understandability and actionability. The median understandability score was 64% (interquartile range, 64–73), and the median actionability was 20% (interquartile range, 20–40).

Back to Top | Article Outline

DISCUSSION

The important finding of this study was that the mean readability of patient education materials addressing neuraxial labor analgesia on the websites of academic institutions was above the sixth grade reading level recommended by the U.S. DHHS and the NIH. Spanish-language patient education materials were available on the websites of 24% of the academic institutions, and only 2 were written at or below the sixth grade reading level. Our findings are consistent with those of readability studies of patient education materials in other medical disciplines.9–11,19,20

There are numerous strategies for improving readability, including limiting sentence size to 8 to 10 words,21 replacing long, polysyllabic words with shorter, more commonly used synonyms, and replacing medical jargon with simpler lay terms whenever possible.15 Other recommended ways to improve readability include using active rather than passive voice, breaking up text using headings and subheadings, and organizing content in bulleted format with short sentences rather than narrative format with lengthy sentences and paragraphs.j–l

Additional recommendations for improving patient education materials do not target the readability of the text, but rather focus on enhancing patient understanding in other ways. We found that the evaluated websites demonstrated poor understandability as measured using the PEMAT-P. Approaches for improving understandability include the use of strategic text formatting (color, font, and size variation),22,23 and integration of instructional images and videos. Past studies have shown that patients with low literacy skills develop a better understanding of health information when visual aids are used in combination with text.24,25 The present study found that most academic institutions incorporate very few images and videos into patient education materials that address neuraxial labor analgesia.

The decision of whether to use neuraxial labor analgesia has important maternal and fetal implications. Despite this being a consequential decision for the parturient, studies have shown that many patients’ decisions may be driven by a lack of knowledge or by misinformation.3 Thus, in addition to improving readability, the content of patient education materials is important.26 Most patient education materials included in this study described neuraxial procedures and explained their benefits. Most did not reliably present information regarding risks, adverse effects, and contraindications. Studies evaluating the content of patient education materials in other medical disciplines have shown a similar inconsistency in the presentation of information.27,28

Our study has several limitations. First, although many readability indices have been validated in the literature, there is no consensus on which index is best for assessing patient education materials. Each readability index uses a different formula to calculate readability. Scores by different indices may vary substantially. Nevertheless, in this study, the mean readability of patient education materials remained above the sixth grade reading level, regardless of which index was used. Furthermore, while there was variability in the content of the websites, there is likely similar variability in the discussion of risks and benefits performed routinely during the face-to-face informed consent discussion. Work in other fields has demonstrated both variability in the content of in-person counseling29 and deficits in patient knowledge following informed consent.29–31 It is not clear to what extent provider in-person counseling content reflects web-based content. Finally, the extent to which patients use academic department websites, as opposed to lay websites for information on neuraxial labor analgesia is unknown. In our experience, patient education materials on academic websites were relatively difficult to find compared with education materials provided by other online resources. A survey conducted by the Pew Research Center found that 77% of Internet users who were seeking information online began their search with a search engine such as Google, Yahoo, or Bing.m These search engines are likely to direct users to lay websites. The readability, content, and quality of these websites have yet to be studied.

In conclusion, we suggest that readability, content, and quality of Web-based English- and Spanish-language patient education materials addressing neuraxial labor analgesia should be improved to help patients make more informed decisions during labor and delivery. Future studies should examine patient understanding of Web-based materials and evaluate whether more readable patient education materials lead to better comprehension.

Back to Top | Article Outline

Appendix 1. Components of Patient Education Materials Assessment Tool for Printable Materials (PEMAT-P)

Table

Table

Back to Top | Article Outline

DISCLOSURES

Name: Samir K. Patel, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Samir K. Patel has seen the original study data, reviewed the analysis of the data, approved the final manuscript, and is the author responsible for archiving the study files.

Name: Elisa J. Gordon, PhD, MPH.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Elisa J. Gordon has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Cynthia A. Wong, MD.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Cynthia A. Wong has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: William A. Grobman, MD, MBA.

Contribution: This author helped analyze the data and write the manuscript.

Attestation: William A. Grobman has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Haley Goucher, MD.

Contribution: This author helped collect the data, reviewed the analysis of the data, and approved the final manuscript.

Attestation: Haley Goucher has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

Name: Paloma Toledo, MD, MPH.

Contribution: This author helped design the study, conduct the study, analyze the data, and write the manuscript.

Attestation: Paloma Toledo has seen the original study data, reviewed the analysis of the data, and approved the final manuscript.

RECUSE NOTEDr. Cynthia Wong is the Section Editor for Obstetric Anesthesiology for the Journal. This manuscript was handled by Dr. Steven L. Shafer, Editor-in-Chief, and Dr. Wong was not involved in any way with the editorial process or decision.

Back to Top | Article Outline

FOOTNOTES

a Digital differences. Available at: http://www.pewinternet.org/Reports/2012/Digital-differences/Main-Report/Internet-adoption-over-time.aspx. Accessed October 18, 2013.
Cited Here...

b Health literacy online: a guide to writing and designing easy-to-use health Web sites. Available at: http://www.health.gov/healthliteracyonline. Accessed June 20, 2014.
Cited Here...

c Toolkit for Making Written Material Clear and Effective. Available at: http://www.cms.gov/Outreach-and-Education/Outreach/WrittenMaterialsToolkit/Downloads/ToolkitPart01.pdf. Accessed June 20, 2014.
Cited Here...

d How to Write Easy-to-Read Health Materials. Available at: http://www.nlm.nih.gov/medlineplus/etr.html. Accessed June 20, 2014.
Cited Here...

e FKGL score formula: (0.39 × average number of words per sentence) + (11.8 × average number of syllables per word) − 15.59.
Cited Here...

f SMOG score formula: 3.1291 + 1.043 × square root (total number of polysyllabic words × [30/total number of sentences]).
Cited Here...

g Gunning Frequency of Gobbledygook formula: 0.4 × (average number of words per sentence + 100 [number of polysyllabic words/total number of words]).
Cited Here...

h MetaMetrics Inc. Lexile: The Lexile Framework for Reading Analyzer. Available at: http://www.lexile.com. Accessed June 20, 2014.
Cited Here...

i MetaMetrics Inc. Lexile: The Lexile Framework for Reading Analyzer. Available at: http://www.lexile.com. Accessed June 20, 2014.
Cited Here...

j Health literacy online: a guide to writing and designing easy-to-use health Web sites. Available at: http://www.health.gov/healthliteracyonline. Accessed June 20, 2014.
Cited Here...

k Toolkit for Making Written Material Clear and Effective. Available at: http://www.cms.gov/Outreach-and-Education/Outreach/WrittenMaterialsToolkit/Downloads/ToolkitPart01.pdf. Accessed June 20, 2014.
Cited Here...

l How to Write Easy-to-Read Health Materials. Available at: http://www.nlm.nih.gov/medlineplus/etr.html. Accessed June 20, 2014.
Cited Here...

m Information Triage. Available at: http://www.pewinternet.org/2013/01/15/information-triage/. Accessed March 5, 2015.
Cited Here...

Back to Top | Article Outline

REFERENCES

1. Anim-Somuah M, Smyth R, Howell C. Epidural versus non-epidural or no analgesia in labour. Cochrane Database Syst Rev. 2005:CD000331
2. Osterman MJ, Martin JA. Epidural and spinal anesthesia use during labor: 27-state reporting area, 2008. Natl Vital Stat Rep. 2011;59:1–13
3. Toledo P, Sun J, Peralta F, Grobman WA, Wong CA, Hasnain-Wynia R. A qualitative analysis of parturients’ perspectives on neuraxial labor analgesia. Int J Obstet Anesth. 2013;22:119–23
4. Liu N, Wen SW, Manual DG, Katherine W, Bottomley J, Walker MC. Social disparity and the use of intrapartum epidural analgesia in a publicly funded health care system. Am J Obstet Gynecol. 2010;202:273.e1–8
5. Glance LG, Wissler R, Glantz C, Osler TM, Mukamel DB, Dick AW. Racial differences in the use of epidural analgesia for labor. Anesthesiology. 2007;106:19–25
6. Toledo P, Sun J, Grobman WA, Wong CA, Feinglass J, Hasnain-Wynia R. Racial and ethnic disparities in neuraxial labor analgesia. Anesth Analg. 2012;114:172–8
7. Macarthur AJ, Macarthur C, Weeks SK. Is epidural anesthesia in labor associated with chronic low back pain? A prospective cohort study. Anesth Analg. 1997;85:1066–70
8. Loughnan BA, Carli F, Romney M, Doré CJ, Gordon H. Epidural analgesia and backache: a randomized controlled comparison with intramuscular meperidine for analgesia during labour. Br J Anaesth. 2002;89:466–72
9. Cherla DV, Sanghvi S, Choudhry OJ, Liu JK, Eloy JA. Readability assessment of Internet-based patient education materials related to endoscopic sinus surgery. Laryngoscope. 2012;122:1649–54
10. Sanghvi S, Cherla DV, Shukla PA, Eloy JA. Readability assessment of internet-based patient education materials related to facial fractures. Laryngoscope. 2012;122:1943–8
11. Gordon EJ, Rodde J, Gil S, Caicedo JC. Quality of Internet education about living kidney donation for Hispanics. Prog Transplant. 2012;22:294–303
12. Kutner M, Greenberg E, Jin Y, Paulsen C The Health Literacy of America’s Adults: Results from the 2003 National Assessment of Adult Literacy. 2006 Washington, DC National Center for Education Statistics, US Department of Education
13. Toledo P, Nixon HC, Mhyre JM, Wong CA, Weinberg G. Brief report: availability of lipid emulsion in United States obstetric units. Anesth Analg. 2013;116:406–8
14. Flesch R. A new readability yardstick. J Appl Psychol. 1948;32:221–33
15. Walsh TM, Volsko TA. Readability assessment of internet-based consumer health information. Respir Care. 2008;53:1310–5
16. McLaughlin G. SMOG grading: a new readability formula. J Reading. 1969;12:639–46
17. Gunning R The Technique of Clear Writing. 1952 New York McGraw-Hill
18. Shoemaker SJ, Wolf MS, Brach C. Development of the Patient Education Materials Assessment Tool (PEMAT): a new measure of understandability and actionability for print and audiovisual patient information. Patient Educ Couns. 2014;96:395–403
19. Colaco M, Svider PF, Agarwal N, Eloy JA, Jackson IM. Readability assessment of online urology patient education materials. J Urol. 2013;189:1048–52
20. Misra P, Kasabwala K, Agarwal N, Eloy JA, Liu JK. Readability analysis of internet-based patient information regarding skull base tumors. J Neurooncol. 2012;109:573–80
    21. Jackson RH, Davis TC, Bairnsfather LE, George RB, Crouch MA, Gault H. Patient reading ability: an overlooked problem in health care. South Med J. 1991;84:1172–5
    22. Albright J, de Guzman C, Acebo P, Paiva D, Faulkner M, Swanson J. Readability of patient education materials: implications for clinical practice. Appl Nurs Res. 1996;9:139–43
    23. Hoffmann T, McKenna K. Analysis of stroke patients’ and carers’ reading ability and the content and design of written materials: recommendations for improving written stroke information. Patient Educ Couns. 2006;60:286–93
    24. Michielutte R, Bahnson J, Dignan MB, Schroeder EM. The use of illustrations and narrative text style to improve readability of a health education brochure. J Cancer Educ. 1992;7:251–60
    25. Houts PS, Doak CC, Doak LG, Loscalzo MJ. The role of pictures in improving health communication: a review of research on attention, comprehension, recall, and adherence. Patient Educ Couns. 2006;61:173–90
    26. Doak C, Doak LG, Root J Teaching Patients with Low Literacy Skills. 19962nd ed. Philadelphia, PA J.B. Lippincott Company
    27. Strachan PH, de Laat S, Carroll SL, Schwartz L, Vaandering K, Toor GK, Arthur HM. Readability and content of patient education material related to implantable cardioverter defibrillators. J Cardiovasc Nurs. 2012;27:495–504
    28. Fagerlin A, Rovner D, Stableford S, Jentoft C, Wei JT, Holmes-Rovner M. Patient education materials about the treatment of early-stage prostate cancer: a critical review. Ann Intern Med. 2004;140:721–8
    29. Friedman M, Arja W, Batra R, Daniel S, Hoehn D, Paniz AM, Selegean S, Slova D, Srivastava S, Vergara N. Informed consent for blood transfusion: what do medicine residents tell? What do patients understand? Am J Clin Pathol. 2012;138:559–65
    30. Joffe S, Cook EF, Cleary PD, Clark JW, Weeks JC. Quality of informed consent in cancer clinical trials: a cross-sectional survey. Lancet. 2001;358:1772–7
    31. Lynöe N, Sandlund M, Dahlqvist G, Jacobsson L. Informed consent: study of quality of information given to participants in a clinical trial. BMJ. 1991;303:610–3
    © 2015 International Anesthesia Research Society