Free
Correspondence  |   December 1997
An Algorithm for Quantifying Blood Pressure Lability 
Author Notes
  • Associate Professor of Anesthesiology, Department of Anesthesiology, Box 1010, Mount Sinai Medical Center, One Gustave L. Levy Place, New York, New York 10029–6574, dreich@smtplink.mssm.edu (Reich).
  • Assistant Professor of Anesthesiology, Department of Anesthesiology, Sinai Medical Center, New York, New York 10029 (Krol).
Article Information
Correspondence
Correspondence   |   December 1997
An Algorithm for Quantifying Blood Pressure Lability 
Anesthesiology 12 1997, Vol.87, 1594. doi:
Anesthesiology 12 1997, Vol.87, 1594. doi:
In Reply:-We are gratified by Dr. Cohn's interest in our recently published algorithm for the quantitative measurement of hemodynamic lability. The point that we were attempting to convey in the article is that we developed and validated an algorithm that could serve as a component of an expert system or “smart alarm.” In the paper, we made the circumspect statement that “the potential utility of the lability index algorithm in an expert system ('smart alarm') is an important issue and one that cannot yet be answered.”
The definition that Dr. Cohn applies to expert systems is somewhat complex, vague, and does not represent the sole definition of this term. Another authority defines an expert system as “a computer program designed to model the problem-solving ability of a human expert.”[1 ] Our long-term goal is to incorporate rules, such as the algorithm for quantitating lability, into a rule-based expert system. The algorithm reported in our publication is simply one component of an expert system that is in evolution.
We disagree with Dr. Cohn on certain minor points. In computer science as in medicine, some things are taken as empiric knowledge. For example, it seems fairly obvious to most anesthesiologists that assessing hemodynamic lability is a task that would not be performed well by an amateur. And even the experts have significant performance problems in this area because of imperfect vigilance. Dr. Cohn also implied that a simple system cannot be an expert system. On the contrary, we believe that complexity should be judged not by the internal structure of a system, but rather by the function(s) it performs.
In conclusion, this semantic discussion regarding the definition of an expert system should not obscure the fact that we share a common interest with Dr. Cohn-developing expert systems that will be useful to physicians caring for patients in the operating room and intensive care settings.
David L. Reich, M.D.
Associate Professor of Anesthesiology; Department of Anesthesiology, Box 1010; Mount Sinai Medical Center; One Gustave L. Levy Place; New York, New York 10029–6574
dreich@smtplink.mssm.edu
Marina Krol, Ph.D.
Assistant Professor of Anesthesiology; Department of Anesthesiology; Sinai Medical Center; New York, New York 10029
(Accepted for publication August 13, 1997.)
This “Letter-to-the-editor” and response were submitted electronically on July 25, 1997. The entire review process, as well as accompanying communication, was handled electronically. The letter was accepted for publication August 13, 1997.
Reference 
Reference 
Durkin J: Expert Systems. Design and Development. Englewood Cliffs, NJ, Prentice-Hall, 1994.