Risk Factors for Surgical Site Infection and Postoperative Intraabdominal Abscess after Appendectomy: An ACS-NSQIP Study

From the 2018 HVPAA National Conference

Joshua Tseng (Cedars-Sinai Medical Center), Tara Cohen (Cedars-Sinai Medical Center), Edward Phillips (Cedars-Sinai Medical Center), Rodrigo Alban (Cedars-Sinai Medical Center)

Background

Surgical site infections (SSI) and postoperative intraabdominal abscesses (IA) are common postoperative complications for appendicitis. Although laparoscopic appendectomies have been associated with reductions in postoperative pain, in-hospital length of stay, and SSI rates, other studies associate laparoscopic appendectomies with higher rates of postoperative IA.

Objectives

To evaluate risk factors for surgical site infections and postoperative intraabdominal abscesses after appendectomy using a large national database.

Methods

The 2016 ACS-NSQIP Procedure-Targeted Appendectomy database was used to identify cases with appendectomies for appendicitis confirmed on pathology. Cases were divided into the following cohorts: those with incisional SSI, postoperative IA, any SSI, and no postoperative infections. Comparisons between cohorts were made using the student’s t-test and Pearson’s chi-squared test as appropriate. Binary logistic regression analysis was used to identify independent predictors of incisional SSI and postoperative IA.

Results

A total of 11,314 patients underwent appendectomies for appendicitis, with an overall SSI rate of 4.5%. Patients with any SSI were more likely to be older (44.6 vs 39.5 years old, p<.001), male (59.3% vs 52.1%, p=.002), BMI>35 (20.8% vs 13.9%, p<.001), diabetic (9.3% vs 4.8%, p<.001), have preoperative sepsis (56.3% vs 43.7%, p<.001), open surgery (8.9% vs 3.0%, p<.001), laparoscopic conversion to open (9.3% vs 2.1%, p<.001), and longer operative times (68.0 vs 52.5 minutes, p<.001).  They were less likely to have uncomplicated appendicitis (34.2% vs 77.6%, p<.001), or have the surgical specimen placed in a bag prior to removal (85.4% vs 91.0%, p<.001).  On regression analysis, appendicitis complicated by abscess or perforation was an independent risk factor for both incisional SSI and IA.  Open surgery, conversion to open surgery, and BMI>35 had higher odds of incisional SSI.  Preoperative sepsis, diabetes, and longer operative times had higher odds of IA, while placing the specimen in bag had lower odds of IA.

Conclusion

Incisional SSI and postoperative IA are common complications after appendectomy. Independent predictors of postoperative infections include complicated appendicitis, open surgery, conversion to open surgery, BMI>35, diabetes, preoperative sepsis, and longer operative times.  Placing the surgical specimen in a bag prior to removal has lower odds of intraabdominal abscesses.

Implications for the Patient

In appendectomies, the practice of placing surgical specimens in sterile bags prior to removal is associated with lower odds of intraabdominal abscesses.

Click here to register for the 2022 Architecture of High Value Health Care National Conference!

What are academic medical centers across the country doing to improve healthcare value?

Value improvement guides: Published reviews in JAMA Internal Medicine coauthored by experienced faculty from multiple leading medical centers, with safety outcomes data and an implementation blue print.

Review article detailing 25 labs to refine for high value quality improvement | July 2020

MAVEN campaign: Free 4 year high value care curriculum online.

Join the Alliance! Membership is free with institutional approval and commitment to improving value in your medical center.

Learn more about HVPAA on Health Affairs Blog