Wednesday, December 8, 2010

Old School Anesthesia Assessment

Once in a while, when I have a few precious minutes to spare from my work and family, I'll get around to reading piles of old material sitting on my desk. Sometimes I'll even discover something interesting and useful in all those unread pages. The other day I finally perused a recent issue of the ASA Newsletter. In a column by Dr. Douglas Bacon, editor of the newsletter, he discusses how anesthesiologists assess the risk for a patient about to undergo surgery.

In the era of modern medicine, we anesthesiologists have a wide assortment of choices to help determine if a patient will survive an operation. Who amongst us hasn't requested that a patient first get a stress echocardiogram or a pulmonary function test to see if we can administer an anesthetic safely? But what if these state of the art examinations were not available to us? How can we assess the health of our patients with something more objective than asking them if they can walk up two flights of stairs without getting shortness of breath? What if they live in a one floor house? How many steps are on their stairs? How tall are the stairs? What is the pitch? Not very objective is it?

Dr. Bacon describes two tests that used to be conducted by anesthesiologists in the early years of the last century. The first one he describes as :

pulse pressure/diastolic pressure

If the answer falls within a ratio of 0.25-0.75 the patient is considered healthy enough for surgery.

Another test he relates is called the energy index:

(pulse rate * (systolic pressure + diastolic pressure)) / 1000

If the number is less than 13 the cardiovascular system is considered weak. If it is greater than 20, it is considered to be carrying an excessive load.

I've never tried these algorithms before when interviewing a patient in preop. I'm going to give a few tries to see how astute the old timers were without resorting to 21st century medical technology. If it works, it certainly would be more expeditious and cheaper than delaying a case to order a stress thallium scan.


  1. There's a reason the stress test is the gold standard for evaluating cardiac function.