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Thursday, March 15, 2012

Bis- Is it Reliable?, what do the Anesthesiologists & Surgeons must know about Bis?.

New England Journal of Medicine is one of the Most respected and trustable medical journals out there, personally I place NEJM on top of some of even the well known American medical journals without a slightest doubts. 
And, this time it is the NEJM that has published some important results on BIS monitor usage by anesthesiologists inside the Operating Rooms.. The question many of the medical professionals must raise about this little tool is, is it a valuable technique to be used about patient's awareness or sleep/awake status during surgical procedures??. Now we know for sure from this study that the actual "validity" of BIS is seriously flawed and questionable?, further lead to a massive Re-call of FDA approved Bis monitors by the manufacturer Covidien, "Covidien PLC (COV) unveiled an expanded recall of its BIS Bilateral sensors" (Wall Street Journal)

Here is the RESULT of a study published in NEJM:

A total of 7 of 2861 patients (0.24%) in the BIS group, as compared with 2 of 2852 (0.07%) in the ETAC group, who were interviewed postoperatively had definite intraoperative awareness (a difference of 0.17 percentage points; 95% confidence interval [CI], −0.03 to 0.38; P=0.98). Thus, the superiority of the BIS protocol was not demonstrated. A total of 19 cases of definite or possible intraoperative awareness (0.66%) occurred in the BIS group, as compared with 8 (0.28%) in the ETAC group (a difference of 0.38 percentage points; 95% CI, 0.03 to 0.74; P=0.99), with the superiority of the BIS protocol again not demonstrated. There was no difference between the groups with respect to the amount of anesthesia administered or the
rate of major postoperative adverse outcomes.

This topic of whether or not BIS monitor can help the anesthesiologist regarding the level of anesthesiology administered to patient is enough, or deep enough for a surgical incision to be performed by surgeon without perturbing patient memory was under debate among professionals for quite sometime, but this research group headed by Michael S Avidan, the principle investigator along with a big team at Washington University School of Medicine clarified to a some extent and proves the major consensus in the field that bis is unreliable?, the patients may be sleep but not to an extent intended or needed by anesthesiologist, so the patient might still be able to recall some of the ongoing conversations or sounds in the OR, huh?.

It is not just about remembering what is going on in the OR while sleeping on the surgical bed, but beyond that the Pain the patient will be enduring and remembering the pain due to surgical procedure is simply unacceptable and need to be addressed by medical and health care communities immediately. As far as feeling or remembering the pain of a surgical knife cutting though lasts for few seconds to minutes, it still unacceptable medical practice for the patient to go through or endure such pain, we are not in a war zone or some third world where there is no proper medical facility or no other alternative but take a knife and cut in a emergency scenario?.  However, what we are discussing here is about a totally equipped, highly advanced, ethically and medically justified planned surgical set up, and there is no execuse.

Here is the Link to the Full Study:
Study Evaluating Whether the Bispectral Index Prevents Patients at Higher Risk From Being Awake During Surgery and Anesthesia (BAG-RECALL)

First Received on May 16, 2008.   Last Updated on January 3, 2011   History of Changes
Sponsor:Washington University School of Medicine
Collaborators:Foundation for Anesthesia Education and Research
American Society of Anesthesiologists
University of Chicago
University of Manitoba
University of Michigan
Information provided by:Washington University School of Medicine
ClinicalTrials.gov Identifier:NCT00682825