Nightmare Awareness: Don’t Wake Up!

4. February 2011

Intraoperative awareness is considered a horror scenario by both, physician and patient. The university hospital Vienna now proves: This phenomenon happens more frequently than physicians think.

The topics ranged somewhere between “Jeopardy” and “Wikileaks” during this surgery, even the winter weather was briefly discussed. And everything else, the surgeons spoke about, the 18-year old patient with an Achilles’ tendon rupture heard despite the anesthesia – but she didn’t have a chance to make herself be heard. This scenario is not a product of someone’s wild fantasy but is every day’s routine in anesthesiology. Up to 80 patients every year end up in this worst case situation: They catch everything going on around the OR table because narcotics transport pain and any motor movement into the Nirvana – everything but the consciousness of the patient. If you believe what was written in the professional magazine “Wiener Klinisches Magazin” (volume 13/ issue 5/ 2010, p. 26 ff.) in Vienna, about two per mille of all anesthesias go wrong just this way.

The problem nobody wanted

Because for a long time, the topic ‘awareness’ was considered irrelevant in the OR daily routine. Single cases becoming public were no reason to generalize the unwelcome phenomenon or make it a subject of discussion. On the contrary: A US study published in 2007 made in eight centers in North Carolina even seemed to give the ‘all-clear’ signal. The authors stated, that over a period of three years observing 87,361 patients they found only six cases of awareness. Statistically we are talking about 14,560 anesthesias with exactly one incident of undesired awareness – so what?

Most likely this illusive quiet in the OR is coming to an end now. “If you think, awareness experiences are rare, you are wrong”, thus a congress report published by the “Wiener Klinisches Magazin” (Vienna clinical magazine) at the Jahrestagung der Österreichischen Gesellschaft für Anästhesiologie, Reanimation und Intensivmedizin (annual meeting of the Austrian association of anesthesiology, reanimation and intensive medicine). A crystal clear statement of the congress participants: Type of surgery as well as certain patient factors lead to the unwelcome awareness. Medical professionals made out a complete armada of risk factors. Accordingly cardiosurgical operations are high up on the list, also surgeries after accidents and Cesarian surgeries are considered “operation-relating” risks. The correct anamnesis can supply additional clues for a potential awareness. For example patients with alcohol- and drug problems and limited hemodynamics are considered part of the risk group, also severely sick people have to expect a possible intraoperative awareness.

Tips against the unwelcome awareness

However, the phenomenon awareness is not as mysterious as many physicians think – and could be fought in the run-up of surgery. At first all anesthesiologists should identify the risk patients. “Also people never aware of their environment on the OR table before, can be part of the risk group if they are not prepared for the surgery by a dose of benzodiazepine”, as the author of the report, Anita Kreilhuber, writes. But if you give nitrous oxide to your patients you have to expect that they might wake up during surgery – without anyone noticing it. Anyhow, monitoring seems to be the key to success against any form of awareness. Significant indications for awareness are mainly provided by the bispectral index (BSI), the patient state index (PSI) and the so-called SNAP index, just like entropy and a functioning ‘depth of anesthesia’ monitor. Despite all data flowing, many anesthesiologists don’t know: The frequently used BSI often is at 60 and thus within the ‘grey area’ of intraoperative awareness. According to Kreilhuber many patients are fully aware during surgery with a BSI level at 60, thus a level closer to 40 would be desirable.

If all precautions fail and awareness occurs, anesthesiologists warn their colleague about a fatal mistake: The physician should at no time ask his already all churned up patient: “Did you have any psychological problems already before the surgery?”

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