Managing Intraoperative Awareness

Educational Objectives

The goal of this program is to improve the prevention and management of intraoperative awareness. After hearing and assimilating this program, the clinician will be better able to:

1. Identify procedural factors that contribute to the risk for intraoperative awareness.

2. Mitigate the psychological impact of intraoperative awareness on patients and providers.

3. Implement guidelines that minimize the risk for intraoperative awareness.

Summary

Intraoperative awareness: experience of consciousness combined with explicit memory of events during surgery

Case example: patient described 40 min of thoracotomy performed with no anesthetic; patient received infusion of cisatracurium; cardiothoracic attending physician switched from desflurane to sevoflurane without realizing sevoflurane vaporizer empty; speaker spent 10 hr with patient over succeeding days and discussed factors that contributed to error

Incidence of intraoperative awareness: Sandin et al (2000) — between 1:1000 and 2:1000; incidence doubled with use of paralytic agents; Pandit et al (2013) — found reported incidence of 1:15,000 among anesthetists in United Kingdom

Types of memory: explicit vs implicit — motor memory one example of implicit memory; explicit memories include facts accessible to conscious state; episodic vs semantic — semantic includes general memories based on collective of experiences; episodic memory includes specific memories of personal events associated with specific places and contexts; studies of intraoperative awareness concerned with explicit and episodic memory

Brice questionnaire: originally published in 1970; attempts to distinguish between awareness and dreaming, and to isolate single worst part of experience of intraoperative awareness

Mashour et al (2010): developed Michigan Awareness Classification Instrument that includes scale from 0 (no awareness) to 5 (paralysis and pain); additional designation of “D” included for reports of distress

Predisposing factors: factors of technique include underdosing of anesthesia; worst cases tend to arise from error or failure in delivery of anesthetic; administering sufficient dosages often unsafe in obstetric patients, patients with cardiac conditions, elderly patients, or those hemodynamically compromised by trauma; failure of delivery often catastrophic and traceable to correctable event; use of total intravenous anesthesia associated with greatest risk for awareness because gas analysis cannot be used to verify delivery of anesthetic

Psychological sequelae: include posttraumatic stress disorder, nightmares, depression, and avoidance of further care

Preoperative expectations: provider should discuss expectations of anesthetic effect with patient, particularly differences between general anesthesia and sedation; vast majority of patients expect unconsciousness

General anesthesia vs sedation: rates of psychological sequelae in cases of intraoperative awareness after planned general anesthetic 60% to 70%; rates of psychological sequelae in patients receiving regional anesthesia or sedation 25% to 40%; significant consequences possible if patient fails to understand anesthetic plan

Bispectral index (BIS) monitor: initially, good evidence supported use; use peaked 5 to 10 yr ago; Avidan et al (2011) demonstrated no benefit with use of BIS monitor compared with monitoring of end-tidal agent in patients at high risk for awareness; results corroborated in subsequent study; BIS probably not necessary for anesthetics with volatile agents; BIS adds no benefit if volatile agent delivering >0.5 minimum alveolar concentration (MAC); BIS needed when no volatile agent >0.5 MAC being delivered

Guidelines from speaker’s institution (University of North Carolina): reemphasize doubling of risk for awareness with neuromuscular blockers; use neuromuscular blockers for clear indications; do not use neuromuscular blockers to stop patient movement without deepening anesthetic; enable low end-tidal agent alarms; enabling end-tidal alarms may present unexpected challenges; desflurane only vaporizer with alarm for low volume; use BIS monitor whenever combined MAC of volatile anesthetic <0.5; consider risk factors, particularly prior intraoperative awareness

Follow-up for cases of awareness: interview patient in PACU immediately after surgery, at 7 days, and possibly after 14 days; apologize if appropriate; laws in some states (including North Carolina) prohibit use of apology to establish guilt in court of law; provide explanation to patient; refer patient for psychological support; alert and educate team members

Management: consult with surgeon and team before speaking with patient’s family; present consistent narrative; provide patient with reliable method for contacting involved providers; encourage psychological follow-up

Apologies and validation: thoughtful full disclosure desirable; University of Washington maintains awareness registry for patients

Impact on provider: intraoperative awareness as well as other catastrophic events have significant effects

Readings

Avidan MS et al: Prevention of intraoperative awareness in a high-risk surgical population. N Engl J Med 2011 Aug 18;365(7):591-600; Avidan MS et al: Prevention of intraoperative awareness with explicit recall: making sense of the evidence. Anesthesiology 2013 Feb;118(2):449-56; Bruchas RR et al: Anesthesia awareness: narrative review of psychological sequelae, treatment, and incidence. J Clin Psychol Med Settings 2011 Sep;18(3):257-67; Gazoni FM et al: The impact of perioperative catastrophes on anesthesiologists: results of a national survey. Anesth Analg 2012 Mar;114(3):596-603; Kent CD et al: Psychological impact of unexpected explicit recall of events occurring during surgery performed under sedation, regional anaesthesia, and general anaesthesia: data from the Anesthesia Awareness Registry. Br J Anaesth 2013 Mar;110(3):381-7; Mashour GA et al: A novel classification instrument for intraoperative awareness events. Anesth Analg 2010 Mar 1;110(3):813-5; Mashour GA et al: Intraoperative awareness: from neurobiology to clinical practice. Anesthesiology 2011 May;114(5):1218-33; Pandit JJ et al: A national survey of anaesthetists (NAP5 Baseline) to estimate an annual incidence of accidental awareness during general anaesthesia in the UK. Anaesthesia 2013 Apr;68(4):343-53; Sandin RH et al: Awareness during anaesthesia: a prospective case study. Lancet 2000 Feb 26;355(9205):707-11; Sebel PS et al: The incidence of awareness during anesthesia: a multicenter United States study. Anesth Analg 2004 Sep;99(3):833-9, table of contents; University of Washington: Anesthesia awareness registry. https://depts.washington.edu/asaccp/projects/anesthesia-awareness-registry. Accessed September 5, 2016.

Disclosures

For this program, members of the faculty and planning committee reported nothing to disclose.

Acknowledgements

Dr. Bullard was recorded at the 29th Annual Carolina Refresher Course 2016: Update in Anesthesiology, Pain, and Critical Care Medicine, held June 22-25, 2016, on Kiawah Island, SC, and presented by the University of North Carolina at Chapel Hill School of Medicine and the Mountain Area Health Education Center. For information about upcoming CME activities from the University of North Carolina at Chapel Hill School of Medicine, please visit med.unc.edu. For information about upcoming CME activities from the Mountain Area Health Education Center, please visit mahec.net. The Audio Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.

CME/CE INFO

Accreditation:

The Audio- Digest Foundation is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.

The Audio- Digest Foundation designates this enduring material for a maximum of 0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

Audio Digest Foundation is accredited as a provider of continuing nursing education by the American Nurses Credentialing Center's (ANCC's) Commission on Accreditation. Audio Digest Foundation designates this activity for 0 CE contact hours.

Lecture ID:

AN584302

Expiration:

This CME course qualifies for AMA PRA Category 1 Credits™ for 3 years from the date of publication.

Instructions:

To earn CME/CE credit for this course, you must complete all the following components in the order recommended: (1) Review introductory course content, including Educational Objectives and Faculty/Planner Disclosures; (2) Listen to the audio program and review accompanying learning materials; (3) Complete posttest (only after completing Step 2) and earn a passing score of at least 80%. Taking the course Pretest and completing the Evaluation Survey are strongly recommended (but not mandatory) components of completing this CME/CE course.

Estimated time to complete this CME/CE course:

Approximately 2x the length of the recorded lecture to account for time spent studying accompanying learning materials and completing tests.