2020 General Surgery Presentations

Matthew A Von Zimmerman, BS1, Timothy P Plackett, DO, MPH2; 1Lake Erie College of Osteopathic Medicine, 2759th Foward Surgical Team (Airborne)

Introduction: The surgical care provided in the military healthcare system has been characterized as low volume, high risk.  As a result, benchmarked outcomes have come under increasing scrutiny as a way of assuring our low volumes do not impact the quality of care.  Risk adjusted complications provide a common method for benchmarking, however it relies on both accurate risk assessments and tracking of complications.  Few studies have examined the accuracy of risk assessment within the military healthcare system.

Methods: A single institution retrospective review was performed using a previously identified data set of all patients ≥ 18 years old that underwent an appendectomy for acute appendicitis during 2012-2017. Medical records were abstracted for patient demographics, admission vitals and labs, past medical and social history, and ASA class.  The ACS NSQIP risk calculator was used to calculate the anticipated risk of post-operative surgical site infection for each patient.  The ASA class (as recorded in the preoperative anesthesia note) was examined more closely and compared against the admission vitals, labs, past medical history, and social history.  When appropriate the ASA class was adjusted to reflect the findings of these results and the ACS NSQIP risk calculator was used to calculate a revised risk of post-operative surgical site infection for each patient.

Results: 786 patients were included in the study.  The mean age was 32 ± 11 year and the majority (60.7%) were male.  710 patients had a non-perforated appendicitis (AAST grade I/II) and almost all (98.3%) underwent a laparoscopic appendectomy.  The mean risk of post-operative surgical site infection was 1.42% ± 0.69 without adjustment for inaccuracies in the ASA class.

A total of 98 patients (12.5%) had an inaccurate ASA class.  The under-classified risk was due to body mass index (64%), tobacco use (30%), sepsis (4%), and diabetes (2%) being inadequately accounted for in the preoperative anesthesia note’s assessment of the ASA class.  After adjusting for the error in ASA class, the overall mean risk of post-operative surgical site infection was 1.48% ± 0.71%.  This was a statistically significant increase in risk of complications (p <0.001).

Conclusions: Inaccurate documentation results in a significant underestimation of the anticipated risk of surgical site infections following appendectomy.  This causes a worsening of the observed:expected rate of surgical site infections.  While this does not necessarily affect outcomes, it decreases the appearance of the quality of care provided.