Early postoperative severity of illness predicts outcomes after the stage I Norwood procedure

Abstract

Background: We hypothesize that a measure of the immediate postoperative severity of illness after the stage I Norwood operation reflects technical performance or the adequacy of anatomic repair and can serve as a predictor of hospital mortality, reinterventions, and clinical outcomes.

Methods: One hundred thirty-five patients undergoing stage I were retrospectively studied (2004 to 2007). The severity of illness on postoperative day 1 (POD1) was measured using the Pediatric Risk of Mortality III (PRISM) scoring system. Technical performance scores (optimal, adequate, inadequate) were calculated before hospital discharge. Hospital mortality, postoperative reinterventions, and complications were recorded. Postoperative reintervention was defined as need for cardiac catheterization laboratory or operating room based procedure that included balloon dilation or repair of arch obstruction, shunt revision, reoperations for bleeding, and extracorporeal membrane oxygenation support.

Results: Hospital mortality was 14.1% (n=19). The rate of complications and reinterventions was, respectively, 28.1% (n=38) and 26.7% (n=36). The POD1 PRISM score was associated with technical performance (p=0.003). Higher POD1 PRISM scores were associated with mortality (p<0.001), complications (p<0.001), and reinterventions (p=0.001). The POD1 PRISM score had high discrimination for mortality, complications, reinterventions, and inadequate technical performance (areas under the receiver operating characteristic curve were 0.835, 0.776, 0.773, and 0.710, respectively; p≤0.001 for all).

Conclusions: The severity of illness as measured by PRISM score on POD1 after the stage I Norwood operation has strong association and discrimination with hospital mortality, postoperative reinterventions, inadequate technical performance, and major postoperative complications. It may be used as an early surrogate of technical performance to initiate a search for and correction of technical deficiencies.