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Author Notes:

Correspondence: Darren F. Hight; darren.hight@insel.ch

PG and JS designed and oversaw the study.

DH and JW completed recordings. DH, JS, JW, AR and AG analyzed data and wrote the manuscript.

All authors interpreted data and made critical revisions to the final manuscript.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The authors gratefully acknowledge helpful discussions from ACCESS research conferences (Anesthesiologists focused on Cognition, Emergence, Sleep and Sedation)2.


Research Funding:

PG research efforts are supported in part by a Career Development Award #BX00167 (PI: PG) from the United States Department of Veteran Affairs, Biomedical Laboratory Research and Development Service and the James S. McDonnell Foundation Grant #220023046 (PI: PG).


  • disordered thinking
  • general anesthesia
  • inattention
  • post anesthetic care unit (PACU)
  • post-operative delirium
  • sedation

Inattentive delirium vs. Disorganized thinking: A new axis to subcategorize PACU delirium


Journal Title:

Frontiers in Systems Neuroscience


Volume 12


, Pages 22-22

Type of Work:

Article | Final Publisher PDF


Background: Assessment of patients for delirium in the Post Anesthesia Care Unit (PACU) is confounded by the residual effects of the varied anesthetic and analgesic regimens employed during surgery and by the physiological consequences of surgery such as pain. Nevertheless, delirium diagnosed at this early stage has been associated with adverse clinical outcomes. The last decade has seen the emergence of the confusion assessment method-intensive care unit (CAM-ICU) score as a quick practical method of detecting delirium in clinical situations. Nonetheless, this tool has not been specifically designed for use in this immediate postoperative setting. Methods: Patients enrolled in a larger observational study were administered the CAM-ICU delirium screening tool 15 min after the latter of return of responsiveness to command or arrival in the post-anesthesia care unit. Numerical pain rating scores were also recorded. In addition, we reviewed additional behavioral observations suggestive of disordered thinking, such as hallucinations, a non-reactive eyes-open state, or an inability to state a pain score. Results: Two-hundred and twenty-nine patients underwent CAM-ICU testing in PACU. 33 patients (14%) were diagnosed with delirium according to CAM-ICU criteria; 25 of these were inattentive with low arousal, seven were inattentive with high arousal, and one was inattentive and calm and with disordered thinking. Using our extended criteria an additional eleven patients showed signs of disordered thinking. CAM-ICU delirium was associated with increased length of operation (p = 0.028), but a positive CAM-PACU designation was associated with both increased operation length and age (p = 0.003 and 0.010 respectively). Two of the CAM-ICU positive patients with inattention and high arousal reported high pain scores and were not classified as CAM-PACU positive. Conclusion: Disordered thinking is correlated with older patients and longer operations. The sensitivity of the existing CAM-ICU score in diagnosing delirium or disordered thinking in PACU patients is improved by the inclusion of a few extra criteria, namely: patients having perceptual hallucinations, in an unreactive eyes-open state, or who cannot state a pain score. We present this alternative screening tool for use in the post-anesthetic period, which we have named CAM-PACU.

Copyright information:

© 2018 Hight, Sleigh, Winders, Voss, Gaskell, Rodriguez and García.

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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