Scientific American

re: Lifting the fog around anesthesia, June 2007, Scientific American

Dr. Orser has done an admirable job of sharing her (myopic) perspective about anesthesia, heavily biased by her corporately sponsored research. Reading her exhaustive discourse on the subject of GABA receptors, the reader might assume that GABA receptors were the only significant ones. Nothing could be farther from the truth. Another type of receptor, the N-methyl,d-aspartate (NMDA), can also play a significant role in the form of anesthesia known as 'dissociative anesthesia.' The term 'dissociative' is a code word for any technique that uses ketamine, an NMDA blocking agent. Unfortunately for patients, ketamine is a generic drug without significant financial rewards that might be associated with the successful marketing of Merck's Gaboxadol, Dr. Orser's research drug.

Approved for use in the US in 1970, ketamine is a phenyclidine class agent derived from the parent compound, phencylidine phosphate (PCP). In 1958, Parke-Davis attempted to market PCP in the US under the trade name Sernyl but it was quickly withdrawn because of troublesome, unpredictable side effects of dysphorias and hallucinations. Ketamine, too, shared these unacceptable side effects until a Las Vegas plastic surgeon, Charles A. Vinnik, published the 'secret' to avoiding them with hypnotic doses of diazepam (Valium) in 1981. Unfortunately, the anesthesia community does not routinely include the plastic surgery literature on its reading list. I first came in contact with Dr. Vinnik in December 1991 and later in early March 1992. My subsequent clinical work involved deleting his diazepam and replacing it with propofol.

Despite considerable resistance, I have succeeded in publishing the 'secret' to avoiding the unacceptable side effects of ketamine in the anesthesia literature. Since December 1997, I have routinely used the bispectral index (BIS) monitor on every one of my patient's to provide a reproducible numerical level of hypnosis (i.e. BIS < 75), below which ketamine can be administered without the historically reported side effects. The more intriguing effect of this process is the reproducible phenomenon of preemptive analgesia via blockade of NMDA receptors. A recent anesthesia publication declared there was no such phenomenon but arrived at this fallacious conclusion based solely on Level I studies in the peer reviewed literature and without examining the outcomes from dissociative anesthesia, in general, and BIS monitored propofol ketamine anesthesia, in particular.

In 2004, I published 'Minimally invasive anesthesia for minimally invasive surgery' in a trade (not a peer reviewed) journal. This article suggests that maximizing patient safety will result by minimally trespassing on patients with our anesthetics. Minimal trespass can only happen by measuring the effect of our agents on the target organ, the brain, with BIS. This article has been cited on the web site of the prestigious Karolinska Institute of Sweden. Apparently, the Swedes understand that not all clinical truths are contained in Level I studies in the peer reviewed literature.

It is an unconscionable omission on Dr. Orser's part not to mention the published benefits of BIS monitoring on reducing the phenomenon of intra-operative awareness by 80%. Maintaining BIS above 45 and below 60 (on a scale of 0-100) for general anesthesia could also go a long way to reducing the cognitive problems after general anesthesia; however, Dr. Orser appears not to be willing to share this possibility with readers of Scientific American. Also speciously reported was the confusion of a non-trauma heart patient's awareness with that experienced by trauma patients. This slight of hand subterfuge will do nothing to assure patients that BIS monitoring is known (by those who choose to inform themselves) to reduce the problem by 80%. Lastly, the page containing risk management tools includes vital signs monitors (i.e. heart rate and blood pressure) which have conclusively been demonstrated to be wildly inconsistent markers of depth of anesthesia. It is fascinating to me that all of my patients immediately grasp the value of medicating my target organ (i.e. the brain) while many of my professional colleagues, like Dr. Orser, have difficulty with this notion.

Disclaimer: Dr. Friedberg is not employed by Aspect Medical Systems, makers of the BIS monitor. He is not a stockholder or a paid consultant. The opinions expressed herein are his professional opinion based on 10 years experience with BIS monitoring.

Yours for better (and reproducible) outcomes,

Barry L. Friedberg, MD
Cosmetic Surgery Anesthesia
Corona del Mar, Calif.
drfriedberg@doctorfriedberg.com

Dr. Friedberg (drfriedberg@doctorfriedberg.com) is the author of the upcoming textbook Anesthesia in Cosmetic Surgery, Minimally Invasive Anesthesia for Minimally Invasive Surgery.