PTSD incidence was 15.8% for patients who did experience awareness and 42.9% for those patients who did.  (Image source: Thinkstock)
PTSD incidence was 15.8% for patients who did experience awareness and 42.9% for those patients who did. (Image source: Thinkstock)

More than 10% of veterans who served in U.S. military operations after 9/11 suffer from PTSD. Patients who suffer awareness after anesthesia also suffer from PTSD. Up to 1.0 % of all general anesthetics are complicated by unintended intraoperative awareness with explicit recall. Dr. Elizabeth Whitlock (UCSF), Dr. Michael Avidan (Washington University), Dr. George A. Mashour (University of Michigan) and colleagues from the University of Manitoba, Winnipeg, Manitoba, Canada, sought to use screening instruments to identify which factors, including awareness, are independently associated with PTSD symptoms following surgery. Their findings are published in this month’s issue of Anesthesia & Analgesia in the article titled “Psychological Sequelae of Surgery in a Prospective Cohort of Patients from Three Intraoperative Awareness Prevention Trials. “

Patients for this study were drawn from three other trials: the B-Unaware trial, the BIS or Anesthetic Gas to Reduce Explicit Recall trial (BAG-RECALL), and the Michigan Awareness Control Study (MACS). Patients were enrolled in these trials between 2005 and 2010: B-Unaware took place between September 2006 and October 2006, BAG-RECALL took place between May 2008 and May 2010, and MACS took place between May 2008 and May 2010. Patients in all three trials underwent structured interviews to determine awareness.

Forty-nine patients who had definite or possible intraoperative awareness and 254 matched patients who denied awareness were included for study. Patient demographics in both groups were similar. The incidence of a symptom complex potentially consistent with the diagnosis of PTSD was 14.3% for patients who experienced definite or possible awareness (5 of 35 patients), and 7.6% for patients who did not experience awareness (14 of 184 patients). Impressively, the incidence of PTSD symptoms in those with awareness is as high as reported in recent combat veterans. Independent risk factors for PTSD symptoms included dissociation related to surgery, perceiving that one’s life was threatened during surgery, history of PTSD before surgery, low current social support, a history of mental health treatment, and actual awareness.

What’s fascinating is that even for those who did not experience recall, the incidence of a PTSD symptom complex was 7.6% following surgery. Certainly this study may have had patients more likely to be diagnosed with PTSD given that the patients came from other studies examining recall. The next question is whether early identification of PTSD after surgery might prompt treatment.