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NSQIP: Using Caterpillar Graphs to Reduce Morbidity

Clifford Ko
Clifford Ko

Clifford Ko, director of the National Surgical Quality Improvement Program (NSQIP) of the American College of Surgeons presented a highly informative discussion of "surgical quality from bench to bedside". Citing the American College of Surgeons mission statement "to improve the care of surgical patients in an optimal and ethical environment", he addressed the basic question: How do we know that we are doing it right?

Many Canadian surgeons do not realize that the American College of Surgeons is a North American organization that clearly identifies itself as "founded by the surgeons of the United States and Canada". The College has had many Canadian presidents including William Gallie.

NSQIP started at the Veterans' Administration Hospitals in the United States in response to an inquiry from the US Congress into what seemed to be an unacceptably high mortality in V.A. Hospital surgery. This initial study was carried out in over 200 V.A. Hospitals. The often quoted explanation "Our patients are sicker", based on presumed tobacco, alcohol and age factors was examined using risk - adjusted data. The Hawthorne effect was immediate - observed behavior is improved behavior. The NSQIP program reduced the mortality by 27%, the morbidity by 45%, the length of stay from 9 to 4 days, and increased patient satisfaction. In 2004, the American College of surgeons initiated its NSQIP program. Its critical features are risk adjusted outcomes; clinical chart - based data (rather than administrative data), trained abstractors who are certified and examined yearly; audited data, multi-specialty expertise; and closing the loop with improvement tools.

The program records 135 data points per case and reports the observed-to-expected (O/E) ratios of all events--such as mortality and a range of complications- -on caterpillar graphs. Individual hospitals are notified of their standing within the group, but the identity of all the other hospitals is withheld.

The analysis is refined so that hospitals are ranked on the basis of the complexity of the procedures that they perform. For example, hospitals that perform esophagectomies and complex vascular procedures are not compared directly with hospitals performing only hernia

repairs, appendectomies and cholecystectomies. In general, clinical data are far more sensitive than administrative data. Administrative data missed 90% of complications because the charts were not examined. 45% of complications occur after discharge, so in - hospital complication rates are deceptive. Dr. Ko gave the example of colon resections where the average length of stay is 6 days and the average time of presentation of deep surgical site infections is at 9 days. The caterpillar graph has proved to be very motivating, as surgeons and hospitals strive to improve their O/E ratio. The NSQIP program also provides a dashboard of complications, and run charts that help identify changes in incidence of complications overtime. The NSQIP feedback loop provides guidance on the best practices for quality improvement, for example 1. the requirement that antibiotics be given within one hour of the incision, are stopped 24 hours later, and are not appropriate for the irrigation solutions; 2. maintaining a normal body temperature during surgery and the postoperative period; 3. use of clippers rather than razors for shaving the surgical site etc. The cost of a complication on average is $10,000 in hospital fees. 250 complications per year cost a hospital $2.5 million.

Caterpillar Graph


In the bench analysis of the NISQUIP data, the group found that measuring 5 variables is as helpful and far more economical than measuring 20 or 30 or 50. In addition, some complications can be grouped into clusters. For example, cardiac, neurologic, and other complications.

UHN is starting a NSQIP program in General Surgery under Tim Jackson. Michael Fehlings asked about the business plan for NSQIP. It clearly costs money, but saves money as well. In general, the answer is that accounting is not standardized enough to show where the savings have been realized. The public is able to find individual hospitals on the caterpillar graph, only 500 of the 5000 hospitals in the United States are in the NSQIP program. There are available NSQIP targets for nine subspecialties.

David Urbach with notes from Clifford Ko

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