EP784 - Is There Such A Thing As Primary Ileus?

Purpose/Background: To investigate the characteristics and causes of postoperative ileus in our colorectal patient population and examine the rate of primary versus secondary ileus.

Methods/Interventions: We performed a retrospective analysis of a prospectively maintained database of all patients undergoing colorectal surgery at a single academic medical center who received a nasogastric tube (NGT), May 2022 to August 2024.

Results/Outcomes: Hospitalization records for 208 patients were analyzed; patients who underwent urgent and/or emergent operation (18.3%), preoperative or perioperative NG tube placement (13.9%, 16.8%) and surgery for obstruction (16.8%) were excluded. For the remaining 120 patients undergoing elective colorectal surgery, mean age was 57 (19-92 years) and 40% were female. All 120 patients underwent the enhanced recovery protocol (ERAS) and 5.8% of these patients received alvimopam perioperatively. Type of surgeries performed included small bowel resection (0.8%), ostomy reversal (20.8%), ostomy creation (0.8%), right colectomy/ileocolic resection (14.1%), left colectomy/sigmoidectomy (11.6%), transverse colectomy (0.8%), low anterior resection (16.7%), abdominal perineal resection (13.3%), total abdominal colectomy/total proctocolectomy (14.9%), proctectomy with ileal pouch (3.3%), and lysis of adhesions (0.8%). End and diverting ostomies were created in 25% and 22.5% of patients, respectively. Indications for surgery included cancer (55%), IBD (16.6%), diverticular disease (10%), and 18.4% had surgery for another indication. 54.2% of patients had an open approach, and 45.8% had minimally invasive surgery. NGTs were placed on average POD day 3.3 (range 1-10) and mean duration of placement was 3.19 days. 52.5% of these patients had a postoperative complication which included: SSI (1.9%), anastomotic leak (3.3%), pneumonia/respiratory failure (9.2%), UTI (0.8%), intraabdominal fluid collection (13.3%), perforation/peritonitis (4.2%), DVT/PE (0.8%), bleeding (8.3%), urinary retention (5.0%), C. diff (0.8%), cardiac complications (6.7%), and AKI (7.5%). 53.3% had a CT scan performed, 22.5% of patients had more than one complication, and 18 patients (15%) required reoperation during the initial admission. The 52.5% of patients with at least one postoperative complication were considered to have a secondary ileus. Patients with secondary ileus were more likely to be female (p=0.021), have the NG replaced a second time during the initial admission (p=0.048), had more estimated blood loss during surgery (p < 0.001), and had longer LOS (p < 0.001). Unsurprisingly, those with secondary ileus were also more likely to have CT scan performed and undergo reoperation during the initial admission (p < 0.001). Interestingly, age, minimally invasive approach, readmissions overall, for ileus or SBO, and NG placement at readmission were not associated with secondary ileus.

Conclusion/Discussion: For patients undergoing elective colorectal surgery who had NGT placed, over 50% were considered to have a secondary ileus. These patients had more operative blood loss, more likely to have a second NGT placed, and longer LOS. Since CT scans were performed in only half of patients, it is possible that the rate of secondary ileus is underestimated and implicates that ileus may be associated with postoperative complications rather than occur as a primary phenomenon.