Letters to the Editor

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March 1, 2013 Volume 77, Number 3
Letters to the Editor

The Enemy Helped U.S. Troops
Dr. Bacon’s article in the November 2012 NEWSLETTER, titled “The 1 Per Cent,” was very interesting and enjoyable, especially in its praise of our Veterans Day military personnel who fought the great wars for a democratic country. Veterans Day, for the young readers, is a new name for the original Armistice Day, celebrating the end of World War I between Germany, France, England and the United States. This war ended in 1918. In many ways, the outcome and conditions of the treaty were the foundations that led to World War II, because the conditions over time severely restricted the German people and government. Politics in Germany changed, letting radical politicians take charge, instituting Socialism, Nazism and contributing to World War II.

Dr. Bacon’s praise of our troops was perfect, especially referring to our anesthesiologists’ attempts to save the critical service members. Some of these physicians were “90 day wonders” during the war. Because physicians take an oath to help all mankind, they also treated “prisoners of war” (the enemy).

What Dr. Bacon left out of the article was that the enemy, in a roundabout way, also aided our wounded battlefield soldiers, not with physicians but with drugs. Battlefield corpsmen (medics) had a drug researched and manufactured in Germany about 1932-37. This drug, “sulfa,” was used by corpsmen on both sides of the conflict in World War II. The drug was first produced by Bayer AG (a component of the large German chemical manufacturer IG Farben). It was a powder that the medics sprinkled on soldiers’ wounds before placing bandages; the drug was a new antibiotic in those days and later came out in tablet form for the general population. The sulfa drug came out just before the advent of penicillin. The drawback on sulfa was that it was broken down and excreted by the kidneys. It had a tendency to crystallize out and damage the kidneys, so plenty of fluids needed to be taken to prevent damage. There were quite a few sulfa products on the market, with names such as Sulfamerizine, Sulfaguanidine, Sulfapyridine and Sulfathiazole. Older physicians would probably still remember them, younger ones likely don’t.

Armistice Day, now Veterans Day, is a memorial to our armed forces who fought for our country and who deserve our undying appreciation. Hats off also to our anesthesiologists, surgeons and corpsmen/medics who treated the wounded. And hats off to, at that time, a new antibiotic (sulfa) that was discovered by those who would soon become our enemy.

Maurice Lippmann, M.D.
Rancho Palos Verdes, California
Clinton Kakazu, M.D.
Palos Verdes Estates, California

Taking AIMS at Vigilance in November Case Report
The AIRS Case Report in the November 2012 ASA NEWSLETTER deserves comment. The Davis article discussed therein has nothing to do with vigilance. It is about memory tasks. Memory tasks fatigue the mind and should worsen vigilance. Vigilance is a response time measured from the onset of a signal (not an event) and ending with the beginning of any response. Normal blood pressures are events. A systolic of 65 is a signal. The Davis article contains not one of the four characteristics of the vigilance paradigm.1

Vigilance is a system, not a human measure. AIMS may increase boredom for the human, but system vigilance is usually enhanced by correctly designed and used automation. Once a vigilance issue is identified, the reason for the decrement must be analyzed. Were the personnel making the AIRS comments well trained and experienced? Were they judging AIMS or their learning curve? AIMS has a vigilance problem during training, but the literature and experience suggest vigilance is improved with experience. The position of the AIMS in the cockpit and entry technology are some of many factors that affect vigilance. Is the record-keeping time for the AIMS system being discussed < 6min/hr? If not, time-consuming secondary tasks (charting) do detract from the vigilance of the primary task (anesthesia).

For decades, AIMS has been known to be more accurate and credible than hand records. How does writing down uneventful (often bogus) numbers make one more vigilant? If the AIMS system is correctly configured so that automatically recorded valid numbers cannot be erased, the anesthesia provider will not want the record to show a BP of 65 q5m x3 with no response. Vigilance is enhanced.

Prior to the installation of AIMS, hand records show a hypoxia rate close to zero. Yet for one new AIMS department, it was 7 percent! Airway training for a few individuals refocused on emergence dropped the rate to < 0.2 percent. Lying on the AIMS record is easier to discover because the entry time and other data are recorded in the background.

AIMS should improve vigilance directly. But it also should improve vigilance when used as a research tool. With the use of entry times, one can search large databases for signals and then determine the response time. What is the time from the BP of 65 until a rise in FiO2, or Desflurane drop, or dose of neo, etc.? How is this decrement affected by time of day, length of case, breaks, personnel experience or multiple other factors? This would avoid the use of artificial secondary tasks to study vigilance.

To derive these benefits, the database must be as clean as possible. ASA should state that one cannot change automatic AIMS data. Several other problems, such as MACRO design, must be corrected. Data entry should take less than five seconds and be entered within two minutes of the event. These issues are vital for the enhancement of vigilance and quality by AIMS.

David W. Edsall, M.D.
Ellsworth, Maine

1. Edsall DW. “Vigilance” discussed by ASA panel. Anesth Patient Safety Found Newsletter. 1993;8(1):1,4-5. http://www.apsf.org/newsletters/html/1993/spring/#art2. Accessed January 24, 2013.
2. Edsall DW. Computerized patient anesthesia records: less time and better quality than manually produced anesthesia records. J Clin Anesth. 1993;5(4):275-283.
3. Weinger MB, Smith NT. Vigilance, alarms, and integrated monitoring systems. In: Ehrenwerth J, Eisenkraft JB. Anesthesia equipment: principles and applications. St. Louis: Mosby; 1993:350-384. http://www.mc.vanderbilt.edu/criss/publications/Vigilance%20&%20Alarms.pdf. Accessed January 24, 2013.

Response to Dr. Edsall
The AIRS Steering Committee thanks Dr. Edsall for his close reading of our presentation and his further observations on the important topic of human:machine interfaces. As Dr. Edsall implies, the engineering of an AIMS is at least as important as the raw numbers being gathered. Whether an AIMS improves outcomes will depend on its underlying design, on its physical location in the O.R. and on how it is used to document care. Considerations include the data configuration, the user training provided, the default alarm settings, the intuitiveness of the display, the ease with which data are automatically captured or entered by hand, and the tolerance for error and artifact. The human side of the interface may vary in training, alertness and attention; these characteristics in turn being affected by such things as the intensity of the case, the circadian phase of the anesthesiologist and even the physician’s preoperative caffeine level! Vigilance is our goal, but is not a simple concept to define or study.

Our NEWSLETTER items necessarily focus on a few key points, and our intention with this case was to suggest that accurate documentation with an AIMS may have unintended consequences in the clinical arena. We appreciate Dr. Edsall’s plunge into the young science of human factors and his suggestion that we have much to learn about the best way to use technology to facilitate good patient care.

Richard P. Dutton, M.D., Executive Director
Anesthesia Quality Institute