Anesthesia Workload and Surgery Risks: A Pivotal Linkage
Summary: For certain surgeries, staffing one anesthesiologist for three or four overlapping cases can increase complications in patients post surgery.
Most major surgeries would not be possible without the skilled services of an anesthesia provider to render the patient unconscious and pain free. It is the anesthesia provider who ultimately ensures that the patient's vital functions—including blood pressure, breathing, heart rate and rhythm—remain stable throughout the procedure. As the demand for such surgical care grows, many clinicians, including anesthesia care teams, are being asked to take care of a greater volume of patients, all while maintaining patient safety.
An anesthesia clinician—whether that be a certified registered nurse anesthetist (CRNA), anesthesiologist assistant, anesthesiology resident or anesthesiologist—is continuously present in the operating room and delivering important care during every surgery requiring anesthesia. However, it is not uncommon to have one anesthesiologist direct the anesthesia care delivered by other anesthesia clinicians for multiple surgical cases at a time. For example, an anesthesiologist may "medically direct" up to four concurrent cases. From a Medicare perspective, medical direction occurs when the anesthesiologist provides a specific set of seven supervision requirements, as outlined in the Medicare Claims Processing Manual (MCPM), Ch 12, Sec 50. Another example of an anesthesiologist being involved in multiple concurrent cases is when he or she is working with anesthesia residents, although the anesthesiologist should only be involved in a maximum of two cases in the teaching context.
How Busy Is Too Busy?
With all this directing and supervising taking place, some have naturally wondered if there is a correlation between the number of cases an anesthesiologist is simultaneously managing and patient outcomes. To help answer this question, a team at the University of Michigan submitted a recent study appearing in JAMA Surgery. Entitled, "Association of Anesthesiologist Staffing Ratio with Surgical Patient Morbidity and Mortality," the study examined the following question: to what extent does the number of overlapping procedures managed by an anesthesiologist increase the risk of death or complications after surgery? Using data from the Multicenter Perioperative Outcomes Group (MPOG) electronic health record registry, the team investigated surgical procedures that involved an anesthesiologist directing a CRNA or an anesthesia resident, which represent two of the most common models used to deliver anesthesia in the United States.
Focusing their analysis on cases with CRNA involvement and minimal anesthesiology resident involvement, the authors looked at data from more than 570,000 surgical cases at 23 hospitals in the United States between 2010 and 2017. They identified patients with similar demographics and health statuses who underwent surgical cases of various types, including general, gynecologic, neurologic, otolaryngologic, orthopedic, urologic and vascular procedures. For each patient, they calculated the average number of concurrent surgeries that were managed by that patient's anesthesiologist during the patient's procedure. They then compared instances where the anesthesiologist was directing one, between one to two, two to three, or three to four cases at a time.
Tale of the Tape
Overall, the team's findings showed that 5.19 percent of the cases reviewed resulted in some form of post-surgical complication. This included 30-day mortality or one of six major surgical morbidities: cardiac, respiratory, gastrointestinal, urinary, bleeding and infectious complications. Obviously, a certain percentage of cases will have complications, regardless of what's taking place with the anesthesia service. But what the Michigan team wanted to determine was whether there was a connection between the numbers of cases simultaneously managed and patient outcomes. To that end, they were able to unearth some interesting results.
The key finding of the study was that cases that included a busier anesthesiologist did, in fact, have poorer outcomes. That is, in contrast to cases where an anesthesiologist directed only one or two overlapping surgeries, those where the anesthesiologist was involved in two to three or three to four overlapping surgeries were tied to an observed increase in the rate of morbidity and mortality. To be more specific, instances where the anesthesiologist was directing three to four surgeries at a time had a complication rate of 5.75 percent, which represented a 14 percent increase compared to the complication rate of 5.06 percent for one to two overlapping surgeries.
Sachin Kheterpal, M.D. M.B.A., associate dean for Research Information Technology and professor of Anesthesiology at Michigan Medicine, weighed in on the implication of the study's findings:
Anesthesiologists have been saying for a long time that covering four operating rooms is possible but should be reserved for situations where we think it's safe. In fact, U-M Health rarely uses this model. We now have evidence to support the idea that in some situations, increasing overlapping responsibilities may have some potential downsides that balance the advantages of potential cost savings and access to care.
The team conceded that the study has several limitations, including the fact that the data analysis was limited to specific types of surgeries and thus may not reflect outcomes for all surgeries. Michael Burns, M.D., Ph.D., with the Department of Anesthesiology, noted, "While these results are important, they are limited to the data that was available in the study: anesthesia care team models with a single anesthesiologist directing up to 4 overlapping surgeries."
The Way Forward
According to Dr. Kheterpal, millions of patients receive care from an anesthesiologist who is directing more than two overlapping anesthetics. "Addressing any differences in care underlying the observed differences in outcome could reduce adverse events for hundreds of thousands of patients," he noted. And while Kheterpal acknowledges that more research is needed to replicate and further explore the differences found in this study, he does have advice for families who may be concerned about the increased risk:
If you are having high risk surgery or you are a medically complex patient, it may be prudent to ask your anesthesia care team about their typical anesthesia care processes.
That should tell our readers that they may want to consider being proactive in this regard. That is, if you come across a patient who is scheduled for a high-risk surgery and/or is already compromised with certain co-morbidities or physiological deficits, you may want to ensure to the extent practicable that your case load around that scheduled surgery is lighter and more manageable.
We want to thank Kelly Malcom of the Michigan Health Lab Blog for her significant contribution to the content of this alert. If you wish to contact us, please go to info@anesthesiallc.com.