Intraoperative adverse events (iAEs) are frequent in visceral surgery, but severity and related postoperative outcome are poorly investigated. A novel classification of intraoperative adverse events, ClassIntra, includes surgical and anesthesiologic intraoperative adverse events using 5 severity grades and showed a high criterion and construct validity across all surgical disciplines. ClassIntra was studied for reproducibility in a prespecified group of patients undergoing visceral surgery.
iAEs were recorded in all patients enrolled in the ClassIntra validation study (NCT03009929). Postoperative complications were assessed daily according to the Clavien-Dindo classification. Results of the visceral group were compared with those of the non-visceral group and the full cohort. The risk-adjusted association between most severe intra and postoperative complications was investigated in a multivariable proportional odds model. Second, risk-adjusted association between ClassIntra grade and Comprehensive Complication Index, and postoperative length of stay was investigated.
In total, 1,270 out of 2,520 patients (50%) underwent visceral surgery. Compared with the nonvisceral group and full cohort, more intraoperative (337/1270 [27%] vs 273/1250 [22%] vs 610/2520 [24%] patients) and postoperative complications (457/1270 [36%] vs 381/1250 [30%] vs 838/2520 [33%] patients) occurred. The risk for a more severe postoperative complication increased with each ClassIntra grade (odds ratio [95% confidence interval] I vs 0 1.10 [0.73 to 1.66], II vs 0 1.69 [1.10 to 2.60], III vs 0 2.31 [1.21 to 4.41], IV vs 0 2.35 [0.69 to 8.06]). Accordingly, CCI and postoperative length of stay increased with each ClassIntra grade in the visceral group, comparable with the nonvisceral and full cohort.
Consistent results for the association of intraoperative adverse events and patient outcomes render ClassIntra a valuable instrument in visceral surgery.

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