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Volitional Delay of Self-Reported Outcomes: Insights from a Case of Intraoperative Awareness with Explicit Recall

Villafranca, Alexander J. MSc*; Arenson, Benjamin G. BSc*; Avidan, Michael S. MBBCh, FCASA; Glick, David MD, MBA; Mashour, George A. MD, PhD§; Jacobsohn, Eric MB, ChB, FRCPC*

doi: 10.1213/ANE.0b013e3182771d3b
Patient Safety: Case Report
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Intraoperative awareness with explicit recall (AWR) is a self-reported outcome of interest in clinical practice, quality assurance initiatives, and clinical trials. Combining structured postoperative interviews with a preoperative description of AWR is assumed to ensure prompt patient disclosure. We describe a volitionally delayed reporting of AWR because of the perceived unimportance of nondistressing awareness experiences, despite preoperative education and 2 postoperative interviews. This delay had implications for a major randomized controlled trial on AWR. Volitionally delayed self-reported outcomes may affect statistical comparisons in clinical trials and quality assurance initiatives, and delay the treatment of subsequent sequelae in clinical practice. This limitation should be considered, even when using structured outcome assessment and preoperative education.

From the *Department of Anesthesia and Perioperative Medicine, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Anesthesiology, Washington University, St. Louis, Missouri; Department of Anesthesia and Critical Care, University of Chicago, Chicago, Illinois; and §Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan.

Accepted for publication, September 17, 2012.

Supported by funds from the Winnipeg Regional Health Authority and University of Manitoba Department of Anesthesia and Perioperative Medicine (EJ).

The authors declare no conflicts of interest.

Reprints will not be available from the authors.

Address correspondence to Eric Jacobsohn, MB, ChB, FRCPC, Department of Anesthesia and Perioperative Medicine, University of Manitoba, AE200 2nd Floor Harry Medovy House, 671 William Ave., R3E 0Z2. Address e-mail to ejacobsohn@exchange.hsc.mb.ca.

Intraoperative awareness with explicit recall (AWR) is an outcome of interest in clinical practice, quality assurance initiatives, and clinical trials. Delayed reporting by patients may influence the accuracy and precision of initiatives and clinical trials evaluating AWR. It may also prevent patients who experience psychological sequelae due to AWR from being identified and treated in a timely manner. Delayed reporting of AWR can be unintentional (due to delayed memory formation)1 or volitional (purposeful nondisclosure). Volitionally delayed reporting occurs in clinical practice with patients who have not received routine postoperative interviews.2,3 However, combining structured interviews with a preoperative explanation of AWR is assumed to ensure patient disclosure. Herein, we describe a volitionally delayed reporting of AWR, after preoperative education and 2 negative structured postoperative interviews. The patient has provided consent to publish this report. The lack of (or delay in) disclosure draws attention to a limitation of research involving patient-reported outcomes.

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CASE DESCRIPTION

A 75-year-old man with no psychiatric or neurologic history underwent on-pump 3-vessel coronary artery bypass grafting and aortic valve replacement. He had several suspected risk factors for AWR, including aortic stenosis, ASA physical status IV, cardiac ejection fraction of <40%, and pulmonary hypertension. He enrolled in the BAG-RECALL clinical trial4 (NCT00682825; clinicaltrails.gov), which evaluated whether a Bispectral Index (BIS)-based protocol was superior to an end-tidal anesthetic concentration–based protocol in preventing AWR in high-risk patients. The patient underwent a consent process explaining the definition, possible manifestations, and potential psychological sequelae of AWR.

For anesthesia induction, the patient received propofol (0.9 mg/kg), rocuronium (70 mg), sufentanil (35 μg), and midazolam (1 mg). Key points during the surgery are identified in Figure 1. Chest incision (Fig. 1, arrow A) occurred 32 minutes after anesthesia induction (45 minutes after the start of data collection). Five minutes after chest incision, the BIS increased to 70 (Fig. 1, arrow B). In response, an additional 50 mg of propofol was administered. After this, the BIS value fluctuated between 47 and 68, until reaching a second peak of 71, which was treated with an increase in sevoflurane concentration (Fig. 1, arrow C). Tracheal extubation occurred 6 hours after skin closure.

Figure 1

Figure 1

Clinical trial protocol5 required 3 blinded follow-up interviews (modified Brice interviews at 24 hours and 1 month postoperatively, and a mortality/satisfaction follow-up at 1 year postoperatively). The patient did not report awareness at either Brice interview. However, during the 1-year follow-up, he spontaneously reported an intraoperative awareness event in response to the satisfaction query. A standardized follow-up interview for patients who reported awareness was then administered.5 The patient reported a sequence of intraoperative recollections (Table 1).

Table 1

Table 1

The patient reported the awareness to his family upon awaking. He was not, however, motivated to disclose the AWR event to hospital staff, because he had not experienced pain or distress and felt that the experience was insignificant compared with other postoperative stresses. The patient’s wife disclosed that she and the immediate family had expressed skepticism regarding the AWR, which she believed may have influenced the patient’s decision to delay the reporting.

Three independent experts who had reviewed cases for the BAG-RECALL trial and were blinded to group assignment (i.e., BIS-guided group) unanimously classified the case as “definite, Class 2 AWR (tactile and auditory perceptions) without distress,” based on the Michigan Awareness Classification Instrument.6 The patient declined counseling referral and provided written consent for this case report.

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DISCUSSION

This case is an unexpected instance of delayed AWR reporting after 2 negative modified Brice interviews and an informed consent process related to a clinical trial investigating AWR. Both unintentionally1 and volitionally2,3 delayed reporting occur in clinical practice with patients who have not received routine postoperative Brice interviews. This case report demonstrates that a patient can have lucid memories of the surgery, but choose not to disclose them despite standardized assessment and preoperative education. This patient initially chose not to disclose AWR based not on the perceived validity of the experience, but on its perceived lack of importance. This finding has implications for research and quality assurance initiatives assessing patient-reported medical events. Because outcomes reported in a volitionally delayed manner may not be detected using standard assessment procedures (as in this case), their inclusion as detected cases in subsequent analyses may be inappropriate. The possibility of self-selecting bias in outcome reporting within such studies is demonstrated. Such bias has potential impact on studies comparing treatments/preventative measures, and on quality assurance initiatives aiming to prevent rare self-reported outcomes. In both cases, a single reported case could alter the statistical significance of the comparisons, especially if the outcome of interest occurs with low frequency.

This patient was randomized to the BIS-guided protocol in the BAG-RECALL trial. This case technically did not meet criteria for inclusion in the original trial (AWR detected via Brice interview at 24 hours or 1 month). Post hoc inclusion of this case would have supported the original trial conclusion that a BIS-guided protocol is not superior to an end-tidal anesthetic concentration–guided protocol at preventing AWR in high-risk patients.4 However, it would have altered both the point estimate for the difference in definite AWR, and its 95% confidence interval (Table 2). In fact, the smallest number needed to treat to benefit with the BIS-guided protocol would have increased from 33334 to 10,000. This illustrates the sensitivity of the number needed to treat to benefit and other point estimates to the addition of a single missed case of AWR.

Table 2

Table 2

Delayed reporting of AWR could also affect estimations of the incidence of AWR, leading to uncertainty regarding the magnitude of this complication. Lower incidence has been observed in retrospective studies of AWR using institutional databases7. However, this is likely attributable in part to insufficient preoperative education/instructions and a lack of well-timed postoperative Brice interviews.

Cases of delayed self-reported outcomes also have implications in the context of clinical practice. Patients who experience AWR may later experience symptoms of posttraumatic stress disorder related to the episode.1 Those who promptly report AWR are typically offered counseling8 and are provided information that could help them recognize such symptoms.9 It is possible that those who delay reporting may not receive this early intervention and may experience comparatively more psychological sequelae. The role of preoperative education in this case of delayed reporting is unclear. It is possible that patient education had the unintended effect of making the patient feel confident that he could decide whether the awareness episode was worthy of report. Thus, additional preoperative education may not prevent this situation. Although policy changes on the basis of a case report are not advisable, explicitly instructing patients to report all suspected AWR cases promptly, regardless of their perceived importance, should be explored as a means of decreasing cases of nonreported outcomes.

Volitionally delayed self-reported outcomes may affect statistical comparisons in clinical trials and quality assurance initiatives, and delay the identification and treatment of subsequent sequelae in clinical practice. This limitation of self-reported outcomes should be considered in research and clinical practice, even when using structured outcome assessment and preoperative education.

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DISCLOSURES

Name: Alexander J. Villafranca, MSc.

Contribution: This author helped write the manuscript, helped create the tables and plot (data analysis), and conducted 1-year follow-up interview with the patient featured in the case report.

Name: Benjamin G. Arenson, BSc.

Contribution: This author helped write and edit the manuscript, conducted awareness follow-up with the patient featured in the case report, helped create the tables and plot (data analysis), and contributed to the interpretation of the case.

Name: Michael S. Avidan, MBBCh, FCASA.

Contribution: This author helped write and edit the manuscript and contributed to the interpretation of the case.

Name: David Glick, MD, MBA.

Contribution: This author helped write and edit the manuscript and contributed to the interpretation of the case.

Name: George A. Mashour, MD, PhD.

Contribution: This author helped write and edit the manuscript and contributed to the interpretation of the case.

Name: Eric Jacobsohn, MB, ChB, FRCPC.

Contribution: This author helped write and edit the manuscript, contributed to the interpretation of the case, oversaw the project, and acted as the local primary investigator of the BAG-RECALL trial.

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RECUSE NOTE

Dr. George Mashour is the Cover Editor for the Journal. This manuscript was handled by Dr. Sorin J. Brull, Section Editor for Patient Safety for the Journal, and Dr. Mashour was not involved in any way with the editorial process or decision.

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REFERENCES

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