Physical Descriptors Aid Accuracy Of ASA Physical Status Designations

How good are anesthesiologists at choosing the correct American Society of Anesthesiologists physical status classification for their patients? Pretty good, according to the results of a recent analysis from the University of Iowa—at least when the ASA’s physical descriptors are used when making the decision.

“As we all know, there’s quite a bit of variability within ASA physical status classification,” said Anil Marian, MD, clinical associate professor of anesthesiology at the Iowa City institution. “What’s ASA I for me might be ASA II for someone else. So in 2015, the ASA came up with additional descriptors for physical status, to help create some consistency when clinicians assign ASA physical status.

“So we had the idea of actually incorporating these descriptors into our EMR [electronic medical record] at the point of data entry, which went live on Sept. 14, 2015. Our goal was to look at the impact of this display on the distribution of ASA physica l status in our surgical population.”

To help shed some light on this question, the researchers analyzed data for two six-month periods: one before the addition of ASA physical status examples to the EMR and one after. Data were limited to elective cases performed at the institution’s main operating suite. In total, 17,634 records were analyzed: 8,666 before and 8,968 after the change. The investigators examined both patient and surgical variables to ensure there was no change in patient mix during the two periods.

Changes in Class

Reporting at the ASA 2016 annual meeting (abstract A2111), Dr. Marian noted that there was a small decrease in ASA class I (12.1% to 10.2%), but ASA classes II (43.6% to 44.2%), III (37.4% to 37.8%) and IV (6.6% to 7.2%) all rose slightly. No changes in patient or surgical characteristics were noted between the time periods.

“Then, to make the study a bit more scientific, we looked at patients who had a surgical encounter both before and after we made the change,” Dr. Marian said. “A lot of patients had multiple surgical encounters. We just looked at the ones who had operations just prior to and just after the change.”

Analyses of these 392 individuals yielded slightly different results. ASA class I status fell from 9.7% to 8.4%, as did ASA class IV status (8.7% to 4.3%). Meanwhile, ASA class II and III status climbed (ASA II, 41.6% to 41.8%; ASA III, 40.1% to 45.4%). “So it seemed like the [class]Is and IVs came more toward a central distribution,” he explained.

“Perhaps the patients that we thought were healthy were not that healthy after all,” he said. “On the other hand, people that we thought were very unhealthy were perhaps better off than we initially thought.”

Leslie Jameson, MD, associate professor of anesthesiology at the University of Colorado School of Medicine, in Aurora, questioned whether this observation had more to do with the surgery than the addition of the examples. “I imagine that if the patients are undergoing surgery, it may have an effect on their physical status,” Dr. Jameson said. “Do you think that may have had something to do with the changes you observed?”

“That could well be,” Dr. Marian replied. “This is just the overall distribution of what we found.”

“My experience is that when it comes to ASA physical status, most anesthesiologists tend to assign whatever they want to assign,” said session co-moderator Uday Jain, MD, a staff anesthesiologist at the Alameda Health System, in Oakland, Calif. “They don’t necessarily look at the table.”

“Hopefully this will change that,” Dr. Marian replied. “The screen where we assign physical status actually had the definitions right there. We don’t know how many actually looked at it, but it was right there and could possibly influence their assignment of the ASA physical status.”

Whether this ultimately improves patient care is a much larger question. “It’s hard to say,” Dr. Marian said. “But maybe it would. Maybe the more accurate assignment of ASA physical status will help anesthesiologists to focus better on the kind of care and level of care needed for patients in the operating rooms.”